ORCID Profile
0000-0002-2605-4766
Current Organisations
RMIT University
,
CSIRO
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Counselling, Welfare and Community Services | Community Planning | Pattern Recognition and Data Mining | Social Policy | Policy and Administration | Image Processing | Artificial Intelligence and Image Processing
ANZSRC Socio-Economic Objective (SEO)
Clinical Health (Organs, Diseases and Abnormal Conditions) not elsewhere classified | Expanding Knowledge in the Information and Computing Sciences | Social Class and Inequalities | Public Services Policy Advice and Analysis | Communication not elsewhere classified |
Related Links
Publications
Efficient Multi-scale Patch-Based Segmentation
Publisher: Springer International Publishing
Date: 2015
CapAIBL: Automated Reporting of Cortical PET Quantification Without Need of MRI on Brain Surface Using a Patch-Based Method
Publisher: Springer International Publishing
Date: 2016
Topology-corrected segmentation and local intensity estimates for improved partial volume classification of brain cortex in MRI
Publisher: Elsevier BV
Date: 05-2010
DOI: 10.1016/J.JNEUMETH.2010.02.020
Abstract: In magnetic resonance imaging (MRI), accuracy and precision with which brain structures may be quantified are frequently affected by the partial volume (PV) effect. PV is due to the limited spatial resolution of MRI compared to the size of anatomical structures. Accurate classification of mixed voxels and correct estimation of the proportion of each pure tissue (fractional content) may help to increase the precision of cortical thickness estimation in regions where this measure is particularly difficult, such as deep sulci. The contribution of this work is twofold: on the one hand, we propose a new method to label voxels and compute tissue fractional content, integrating a mechanism for detecting sulci with topology preserving operators. On the other hand, we improve the computation of the fractional content of mixed voxels using local estimation of pure tissue intensity means. Accuracy and precision were assessed using simulated and real MR data and comparison with other existing approaches demonstrated the benefits of our method. Significant improvements in gray matter (GM) classification and cortical thickness estimation were brought by the topology correction. The fractional content root mean squared error diminished by 6.3% (p<0.01) on simulated data. The reproducibility error decreased by 8.8% (p<0.001) and the Jaccard similarity measure increased by 3.5% on real data. Furthermore, compared with manually guided expert segmentations, the similarity measure was improved by 12.0% (p<0.001). Thickness estimation with the proposed method showed a higher reproducibility compared with the measure performed after partial volume classification using other methods.
Exploring peri-urbanisation and agricultural systems in the melbourne region
Publisher: Wiley
Date: 14-02-2013
3D shape context surface registration for cortical mapping
Publisher: IEEE
Date: 2010
Sensitivity of composite scores to amyloid burden in preclinical Alzheimer's disease: Introducing the Z-scores of Attention, Verbal fluency, and Episodic memory for Nondemented older adults composite score.
Publisher: Wiley
Date: 12-12-2015
Evaluation of novel data-driven metrics of amyloid β deposition for longitudinal PET studies
Publisher: Elsevier BV
Date: 10-2023
Comparison of texture features for segmentation of patterned wafers
Publisher: SPIE
Date: 27-02-2004
DOI: 10.1117/12.516500
MR-less surface-based amyloid estimation by subject-specific atlas selection and Bayesian fusion
Publisher: Springer Berlin Heidelberg
Date: 2012
A Normalisation Framework For Quantitative Brain Imaging; Application to Quantitative Susceptibility Mapping
Publisher: IEEE
Date: 04-2017
Gabor filtering for feature extraction on complex images: application to defect detection on semiconductors
Publisher: Informa UK Limited
Date: 12-2006
LOCATE: A mammalian protein subcellular localization database
Publisher: Oxford University Press (OUP)
Date: 23-12-2008
DOI: 10.1093/NAR/GKM950
Validating ASHS-T1 automated entorhinal and transentorhinal cortical segmentation in Alzheimer's disease
Publisher: Elsevier BV
Date: 10-2023
A Framework to Objectively Identify Reference Region for Normalizing Quantitative Imaging
Publisher: Springer International Publishing
Date: 2018
MEDITERRANEAN DIET ADHERENCE IS ASSOCIATED WITH ATTENUATED CORTICAL THINNING IN AN AUSTRALIAN STUDY OF AGEING
Publisher: Wiley
Date: 07-2017
The Routledge Companion to Rural Planning
Publisher: Routledge
Date: 15-01-2019
Performance on the Cogstate Brief Battery Is Related to Amyloid Levels and Hippocampal Volume in Very Mild Dementia
Publisher: Springer Science and Business Media LLC
Date: 09-2016
DOI: 10.1007/S12031-016-0822-8
Abstract: In a group of older adults with very mild dementia, we aimed to characterize the nature and magnitude of cognitive decline as measured by the Cogstate Brief Battery, in relation to Aβ levels and hippoc al volume. Participants were characterized according to their status on the Clinical Dementia Rating (CDR) scale. A total of 308 in iduals who were CDR 0 and had low cerebral Aβ levels (Aβ-), 32 in iduals who were Aβ- and CDR 0.5, and 43 in iduals who were Aβ+ and CDR 0.5 were included in this study. Participants completed the CogState brief battery at baseline, and at 18-, 36-, 54- and 72-month follow-up. Linear mixed model analyses indicated that relative to the Aβ- CDR 0 group, the Aβ+ CDR 0.5 group showed increased rates of memory decline and hippoc al volume loss. However, compared to the Aβ- CDR 0 group, the Aβ- CDR 0.5 group showed no changes in cognitive function or hippoc al volume over 72 months. The results of this study confirm that in in iduals with very mild dementia, who also have biomarker confirmation of Aβ+, changes in cognitive function manifest primarily as deterioration in memory processing, and this is associated with hippoc al volume loss. Conversely, the absence of any cognitive decline or loss in hippoc al volume in in iduals with very mild dementia but who are Aβ- suggests that some other non-AD disease process may underlie any static impairment in cognitive function.
O3‐13‐01: RETINAL AMYLOID FLUORESCENCE IMAGING PREDICTS CEREBRAL AMYLOID BURDEN AND ALZHEIMER'S DISEASE
Publisher: Wiley
Date: 07-2014
A surface based approach for cortical thickness comparison between PiB+ and PiB-healthy control subjects
Publisher: SPIE
Date: 23-02-2012
DOI: 10.1117/12.911752
MILXView: A Medical Imaging, Analysis and Visualization Platform
Publisher: Springer Berlin Heidelberg
Date: 2010
Consistent estimation of shape parameters in statistical shape model by symmetric EM algorithm
Publisher: SPIE
Date: 23-02-2012
DOI: 10.1117/12.911746
A Delphi study to identify intervention priorities to prevent the occurrence and reduce the impact of adverse childhood experiences
Publisher: SAGE Publications
Date: 07-07-2022
DOI: 10.1177/00048674211025717
Abstract: There is a lack of a systematic, coordinated approach to reducing the occurrence and impact of adverse childhood experiences. Hence, identifying feasible intervention priorities in this field will help inform policy and reformation of ongoing service delivery. The objective of this study was to identify expert consensus-driven priority interventions for reducing the occurrence and impact of adverse childhood experiences in children under 8 years of age in the Australian context. A three-round online Delphi survey was conducted to establish consensus on 34 interventions for adverse childhood experiences identified through a literature search. Six were general categories of interventions, 6 were broad intervention programmes and 22 were specific interventions. Participants were 17 health practitioners, 15 researchers, 9 policy experts, 7 educators and 3 consumer advocates with expertise in adverse childhood experiences or child mental health. Consensus was defined as an intervention being rated as ‘very high priority’ or ‘high priority’ according to its importance and feasibility by ⩾75% of all experts. Seven of the 34 interventions were endorsed as priority interventions for adverse childhood experiences. These included four general categories of intervention: community-wide interventions, parenting programmes, home-visiting programmes and psychological interventions. Two broad intervention programmes were also endorsed: school-based anti-bullying interventions and psychological therapies for children exposed to trauma. Positive Parenting Program was the only specific intervention that achieved consensus. This is the first study to identify stakeholder perspectives on intervention priorities to prevent the occurrence and impact of adverse childhood experiences. Prioritisation of effective, feasible and implementable intervention programmes is an important step towards better integration and coordination of ongoing service delivery to effectively prevent and respond to adverse childhood experiences.
Aβ-related memory decline in APOE ϵ4 noncarriers: Implications for Alzheimer disease
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 30-03-2016
Relationships between performance on the cogstate brief battery, neurodegeneration, and aβ accumulation in cognitively normal older adults and adults with MCI
Publisher: Oxford University Press (OUP)
Date: 02-12-2015
Abstract: We investigated the extent to which decline in memory and working memory in beta-amyloid (Aβ) positive non-demented in iduals was related to hippoc al atrophy and Aβ accumulation over 36 months. Cognitively normal older adults (CN) (n = 178) and adults with mild cognitive impairment (MCI) (n = 49) underwent positron emission tomography neuroimaging, magnetic resonance imaging, and cognitive assessments at baseline, 18- and 36-months. Relative to Aβ- CNs, Aβ+ CNs and Aβ+ MCIs showed greater rates of cognitive decline, Aβ accumulation, and hippoc al atrophy. Analysis of interrelationships between these Alzheimer's disease markers in Aβ+ CNs and MCIs indicated that rate of Aβ accumulation was associated with rate of hippoc al atrophy (β = -0.05, p = .037), which was in turn associated independently with rate of decline in memory (β = -0.03, p = .032). This suggests that Aβ accumulation precedes any neurodegeneration or clinical symptoms, and that the relationship between Aβ and cognitive decline is mediated by hippoc al atrophy.
Blood-Borne Amyloid-β Dimer Correlates with Clinical Markers of Alzheimer's Disease
Publisher: Society for Neuroscience
Date: 05-05-2010
DOI: 10.1523/JNEUROSCI.5180-09.2010
Abstract: Alzheimer's disease (AD) is the most common age-related dementia. Unfortunately due to a lack of validated biomarkers definitive diagnosis relies on the histological demonstration of amyloid-β (Aβ) plaques and tau neurofibrillary tangles. Aβ processing is implicated in AD progression and many therapeutic strategies target various aspects of this biology. While Aβ deposition is the most prominent feature of AD, oligomeric forms of Aβ have been implicated as the toxic species inducing the neuronal dysfunction. Currently there are no methods allowing routine monitoring of levels of such species in living populations. We have used surface enhanced laser desorption ionization time of flight (SELDI-TOF) mass spectrometry incorporating antibody capture to investigate whether the cellular membrane-containing fraction of blood provides a new source of biomarkers. There are significant differences in the mass spectra profiles of AD compared with HC subjects, with significantly higher levels of Aβ monomer and dimer in the blood of AD subjects. Furthermore, levels of these species correlated with clinical markers of AD including brain Aβ burden, cognitive impairment and brain atrophy. These results indicate that fundamental biochemical events relevant to AD can be monitored in blood, and that the species detected may be useful clinical biomarkers for AD.
Longitudinal assessment of Aβ and cognition in aging and Alzheimer disease
Publisher: Wiley
Date: 2011
DOI: 10.1002/ANA.22248
Contribution of FDOPA PET to radiotherapy planning for advanced glioma
Publisher: IOP Publishing
Date: 24-03-2014
Association of β-amyloid level, clinical progression and longitudinal cognitive change in normal older individuals
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 12-11-2020
DOI: 10.1212/WNL.0000000000011222
Abstract: To determine the effect of Aβ level on progression risk to MCI or dementia and longitudinal cognitive change in cognitively normal (CN) older in iduals. All CN from the Australian Imaging Biomarkers and Lifestyle study (AIBL) with Aβ PET and ≥3 years follow-up were included (n=534 age 72±6 yrs 27% Aβ positive follow-up 5.3±1.7 yrs). Aβ level was ided using the standardised 0-100 Centiloid scale: CL negative, 15-25 CL uncertain, 26-50 CL moderate, 51-100 CL high, CL very high, noting CL approximates a positive scan. Cox proportional hazards analysis and linear mixed effect models were used to assess risk of progression and cognitive decline. Aβ levels in 63% were negative, 10% uncertain, 10% moderate, 14% high and 3% very high. Fifty-seven (11%) progressed to MCI or dementia. Compared to negative Aβ, the hazard ratio for progression for moderate Aβ was 3.2 (95% CI 1.3-7.6 p .05), for high was 7.0 (95% CI 3.7-13.3 p .001) and for very high was 11.4 (95% CI 5.1-25.8 p .001). Decline in cognitive composite score was minimal in the moderate group (-0.02 SD/year, p=0.05) while the high and very high declined substantially (high -0.08 SD/year, p .001 very high -0.35 SD/year p .001). The risk of MCI or dementia over 5 years in older CN is related to Aβ level on PET, 5% if negative vs 25% if positive but ranging from 12% if 26-50 CL to 28% if 51-100 CL and 50% if CL. This information may be useful for dementia risk counselling and aid design of preclinical AD trials.
Compound heterozygous mutations with novel missense ABCA12 mutation in harlequin ichthyosis
Publisher: BMJ
Date: 03-01-2018
EVALUATION OF TAU TRACERS IN NORMAL AGEING AND ALZHEIMER'S DISEASE
Publisher: Wiley
Date: 04-2017
DOI: 10.1111/IMJ.13422
A blood-based predictor for neocortical Aβ burden in Alzheimer's disease: results from the AIBL study
Publisher: Springer Science and Business Media LLC
Date: 30-04-2013
DOI: 10.1038/MP.2013.40
Abstract: Dementia is a global epidemic with Alzheimer's disease (AD) being the leading cause. Early identification of patients at risk of developing AD is now becoming an international priority. Neocortical Aβ (extracellular β-amyloid) burden (NAB), as assessed by positron emission tomography (PET), represents one such marker for early identification. These scans are expensive and are not widely available, thus, there is a need for cheaper and more widely accessible alternatives. Addressing this need, a blood biomarker-based signature having efficacy for the prediction of NAB and which can be easily adapted for population screening is described. Blood data (176 analytes measured in plasma) and Pittsburgh Compound B (PiB)-PET measurements from 273 participants from the Australian Imaging, Biomarkers and Lifestyle (AIBL) study were utilised. Univariate analysis was conducted to assess the difference of plasma measures between high and low NAB groups, and cross-validated machine-learning models were generated for predicting NAB. These models were applied to 817 non-imaged AIBL subjects and 82 subjects from the Alzheimer's Disease Neuroimaging Initiative (ADNI) for validation. Five analytes showed significant difference between subjects with high compared to low NAB. A machine-learning model (based on nine markers) achieved sensitivity and specificity of 80 and 82%, respectively, for predicting NAB. Validation using the ADNI cohort yielded similar results (sensitivity 79% and specificity 76%). These results show that a panel of blood-based biomarkers is able to accurately predict NAB, supporting the hypothesis for a relationship between a blood-based signature and Aβ accumulation, therefore, providing a platform for developing a population-based screen.
Smells like politics: planning and the inconvenient politics of intensive peri‐urban agriculture
Publisher: Wiley
Date: 26-12-2018
P2–247: Modulation of beta‐amyloid‐related cognitive decline by brain‐derived neurotrophic factor Val66Met polymorphism in preclinical Alzheimer's disease
Publisher: Wiley
Date: 07-2013
Cerebrospinal Fluid Neurofilament Light Predicts Risk of Dementia Onset in Cognitively Healthy Individuals and Rate of Cognitive Decline in Mild Cognitive Impairment: A Prospective Longitudinal Study.
Publisher: MDPI AG
Date: 30-04-2022
DOI: 10.3390/BIOMEDICINES10051045
Abstract: Background: Biomarkers that are indicative of early biochemical aberrations are needed to predict the risk of dementia onset and progression in Alzheimer’s disease (AD). We assessed the utility of cerebrospinal fluid (CSF) neurofilament light (NfL) chain for screening preclinical AD, predicting dementia onset among cognitively healthy (CH) in iduals, and the rate of cognitive decline amongst in iduals with mild cognitive impairment (MCI). Methods: Neurofilament light levels were measured in CSF s les of participants (CH, n = 154 and MCI, n = 32) from the Australian Imaging, Biomarkers and Lifestyle study of ageing (AIBL). Cases of preclinical AD were identified using biomarker-guided classification (CH, amyloid-β [Aβ]+, phosphorylated-tau [P-tau]+ and total-tau [T-tau]± A+T+/N±). The prediction of dementia onset (questionable dementia) among CH participants was assessed as the risk of conversion from Clinical Dementia Rating [CDR = 0] to CDR ≥ 0.5 over 6 years. Mixed linear models were used to assess the utility of baseline CSF NfL levels for predicting the rate of cognitive decline among participants with MCI over 4.5 years. Results: Neurofilament light levels were significantly higher in preclinical AD participants (CH, A+T+/N±) as compared to A-T-N- (p 0.001). Baseline levels of CSF NfL were higher in CH participants who converted to CDR ≥ 0.5 over 6 years (p = 0.045) and the risk of conversion to CDR ≥ 0.5 was predicted (hazard ratio [HR] 1.60, CI 1.03–2.48, p = 0.038). CH participants with CSF NfL cut-off were at a higher risk of developing dementia (HR 4.77, CI 1.31–17.29, p = 0.018). Participants with MCI and with higher baseline levels of CSF NfL ( median) had a higher rate of decline in cognition over 4.5 years. Conclusion: An assessment of CSF NfL levels can help to predict dementia onset among CH vulnerable in iduals and cognitive decline among those with MCI.
Relationship between atrophy and β-amyloid deposition in Alzheimer disease
Publisher: Wiley
Date: 03-2010
DOI: 10.1002/ANA.21955
Abstract: Elucidating the role of aggregated beta-amyloid in relation to gray matter atrophy is crucial to the understanding of the pathological mechanisms of Alzheimer disease and for the development of therapeutic trials. The present study aims to assess this relationship. Brain magnetic resonance imaging and [(11)C]Pittsburgh compound B (PiB)-positron emission tomography scans were obtained from 94 healthy elderly subjects (49 with subjective cognitive impairment), 34 patients with mild cognitive impairment, and 35 patients with Alzheimer disease. The correlations between global and regional neocortical PiB retention and atrophy were analyzed in each clinical group. Global and regional atrophy were strongly related to beta-amyloid load in participants with subjective cognitive impairment but not in patients with mild cognitive impairment or Alzheimer disease. Global neocortical beta-amyloid deposition correlated to atrophy in a large brain network including the hippoc us, medial frontal and parietal areas, and lateral temporoparietal cortex, whereas regional beta-amyloid load was related to local atrophy in the areas of highest beta-amyloid load only, that is, medial orbitofrontal and anterior and posterior cingulate recuneus areas. There is a strong relationship between beta-amyloid deposition and atrophy very early in the disease process. As the disease progresses to mild cognitive impairment and Alzheimer disease clinical stages, pathological events other than, and probably downstream from, aggregated beta-amyloid deposition might be responsible for the ongoing atrophic process. These findings suggest that antiamyloid therapy should be administered very early in the disease evolution to minimize synaptic and neuronal loss.
Generative atlases and atlas selection for C11-PIB PET-PET registration of elderly, mild cognitive impaired and Alzheimer disease patients
Publisher: IEEE
Date: 05-2008
Comparison of 18F-florbetaben quantification results using MR-based and MR-Less CapAIBL: Validation against histopathology
Publisher: Wiley
Date: 07-2017
Effectiveness of interventions for people bereaved through suicide: a systematic review of controlled studies of grief, psychosocial and suicide-related outcomes
Publisher: Springer Science and Business Media LLC
Date: 30-01-2019
Implementing the Centiloid transformation for 18F-Florbetaben and 18F-NAV4694 using CapAIBL
Publisher: Wiley
Date: 07-2017
Accumulation of amyloid-β alters white matter integrity in cognitively unimpaired middle-aged females
Publisher: Wiley
Date: 12-2022
DOI: 10.1002/ALZ.053113
Abstract: The APOE‐ ε 4 allele is the strongest known genetic risk factor for Alzheimer’s disease (AD) and is associated with higher amyloid‐β (Aβ) deposition. White matter (WM) microstructural damages are known to occur early at the preclinical stage of AD. Although stable associations between APOE‐ ε 4 status and WM alternations have been reported in patients with AD and mild cognitive impairment, few studies have described WM differences in cognitively unimpaired (CU) subjects at risk of AD. We aim to investigate associations of APOE‐ ε 4 status and Aβ load with WM microstructural changes in mid‐age CU in iduals. 151 CU participants from the Prospective Imaging Study of Ageing (PISA) were included (aged 44‐66, 78% female, 77 APOE‐ ε 4 carriers ( ε 4+) and 74 non‐carriers ( ε 4‐)) and underwent Aβ PET and 3T MRI scans including multi‐shell diffusion‐weighted images. Aβ load was quantified in Centiloid (CL) on PET and Aβ+ was defined as CL ≥ 20. Tract based spatial statistics (TBSS) analysis was performed on fractional anisotropy (FA), mean diffusivity (MD), radial diffusivity (RD) and axial diffusivity (AxD) to assess WM alternations associated with APOE‐ ε 4 status and/or Aβ load. All analyses were corrected for age and for multiple comparisons. A significant effect of gender, but not APOE‐ ε 4 or Aβ status was observed on WM integrity in the full cohort. When considering females only, APOE‐ ε 4 carriers showed regional increased MD in several right WM tracts. However, these differences were no longer significant when correcting for Aβ status. In contrast, significant WM alternations associated with Aβ+ status were found when correcting for APOE‐ ε 4 status. In this female‐only subset, widespread WM microstructural damages were observed in Aβ+ ε 4+ subjects (N=10) compared to Aβ‐ ε 4+ (N=51) and Aβ‐ ε 4‐ (N=54) subjects. No significant differences were observed between Aβ‐ ε 4+ and Aβ‐ ε 4‐ subjects. Similar differences were also observed in the global diffusion metrics of WM tracts. These findings suggest that WM alternations associated with Aβ accumulation appear in mid‐life CU female subjects. Future studies in larger cohorts enriched for gender, APOE and Aβ status are required to clarify the relative contributions of APOE‐ ε 4 and Aβ status on WM microstructural damage.
<title>Defect detection and classification on metallic parts</title>
Publisher: SPIE
Date: 14-03-2002
DOI: 10.1117/12.460196
Amorphous Regions-of-Interest Projection Method for Simplified Longitudinal Comparison of Dynamic Regions in Cancer Imaging
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 02-2014
Segmentation of the bones in MRIs of the knee using phase, magnitude, and shape information
Publisher: Elsevier BV
Date: 10-2007
DOI: 10.1016/J.ACRA.2007.06.021
Abstract: The segmentation of textured anatomy from magnetic resonance images (MRI) is a difficult problem. We present an approach that uses features extracted from the magnitude and phase of the MRI signal to segment the bones in the knee. Moreover, we show that by incorporating shape information, more accurate and anatomically valid segmentations are obtained. Eighteen volunteers were scanned in a whole-body 3T clinical scanner using a transmit-receive quadrature extremity coil. A gradient-echo sequence was used to acquire three-dimensional (3D) volumes of raw complex image data consisting of phase and magnitude information. These images were manually segmented and features were extracted using a bank of Gabor filters. The extracted features were then used to train a support vector machine (SVM) classifier. Each image was then automatically segmented using both the SVM classifier and a 3D active shape model (ASM) driven by the classifier. The use of phase and magnitude information from both echoes obtained the most accurate classifier results with an average dice similarity coefficient of 0.907. The use of 3D ASMs further improved the robustness, accuracy and anatomic validity of the segmentations with an overall DSC of 0.922 and an average point to surface error along the bone-cartilage interface of 0.73 mm. Our results demonstrate that the incorporation of phase and multiple echoes improve the results obtained by the classifier. Moreover, we show that 3D ASMs provide a robust and accurate way of using the classifier to obtain anatomically valid segmentation results.
Plasma pTau181/Aβ42 identifies cognitive change earlier than CSF pTau181/Ab42
Publisher: Wiley
Date: 12-2022
DOI: 10.1002/ALZ.064341
Abstract: Plasma biomarkers now show an accuracy in detecting Amyloid Beta (Aβ) similar to AD biomarkers derived from cerebral spinal fluid (CSF). However, the ability of plasma AD biomarkers, alone or in combination, to predict cognitive decline has not yet been compared to that of CSF AD biomarkers. Plasma biomarker data from 233 participants’ first visit in the Australian Imaging, Biomarkers and Lifestyle study (AIBL) was submitted to linear mixed effects models (LME) to quantify the relationship with change in cognition (measured using the AIBL PACC) and in clinical disease stage (CDR SoB) in both PET Aβ‐ (Centiloid value CL) and Aβ+ (Centiloid value ≥20CL) participant subgroups. Separate models were used to assess CSF (Elecsys) and plasma (ADx NeuroSciences) data for Aβ42, pTau181 and the pTau181/Aβ42 ratio. Biomarker values were classified into low vs high levels based on ROC‐derived thresholds optimizing separation of PET Aβ status (low vs high at 20 CL). Changes in cognitive and clinical symptoms were then compared between the low/high plasma biomarker groups. In Aβ‐ participants, no significant interactions between binary biomarker classification and time were observed for AIBL PACC or CDR SoB, for either CSF or plasma biomarkers. In the Aβ+ participants, interactions between the binary plasma biomarker classification and change in cognition were greater in magnitude that those detected for CSF biomarker classification. For plasma, abnormally high values of both pTau181 and the pTau181/Aβ42 ratio predicted a significant increase over time in CDR SoB (Figure 1H & 1L) and a significant decrease over time in the AIBL PACC score (Figure 1F & 1J), compared the group with low values on the same biomarkers. In cognitively unimpaired Aβ‐ participants, the AIBL PACC score declined in those with abnormally high values of the pTau181 and the pTau181/Aβ42 ratio (Figure 1F & 1J). Assays to measure pTau181 and Aβ42 in the plasma possess an accuracy equivalent to those derived from CSF. In particular, abnormally high levels of plasma pTau181 or the ratio of pTau181 to Aβ42 ratio provide a strong prediction of early cognitive changes, even in those with normal PET Aβ status.
Residual reserve index modifies the effect of amyloid pathology on fluorodeoxyglucose metabolism: Implications for efficiency and capacity in cognitive reserve
Publisher: Frontiers Media SA
Date: 12-08-2022
DOI: 10.3389/FNAGI.2022.943823
Abstract: The residual approach to measuring cognitive reserve (using the residual reserve index) aims to capture cognitive resilience conferred by cognitive reserve, but may be confounded by factors representing brain resilience. We sought to distinguish between brain and cognitive resilience by comparing interactions between the residual reserve index and amyloid, tau, and neurodegeneration [“AT(N)”] biomarkers when predicting executive function. We hypothesized that the residual reserve index would moderate at least one path from an AT(N) biomarker to executive function (consistent with cognitive resilience), as opposed to moderating a path between two AT(N) biomarkers (suggestive of brain resilience). Participants ( N = 332) were from the Alzheimer’s Disease Neuroimaging Initiative. The residual reserve index represented the difference between observed and predicted memory performance (a positive residual reserve index suggests higher cognitive reserve). AT(N) biomarkers were: CSF β-amyloid 1–42 /β-amyloid 1–40 (A), plasma phosphorylated tau-181 (T), and FDG metabolism in AD-specific regions ([N]). AT(N) biomarkers (measured at consecutive time points) were entered in a sequential mediation model testing the indirect effects from baseline amyloid to executive function intercept (third annual follow-up) and slope (baseline to seventh follow-up), via tau and/or FDG metabolism. The baseline residual reserve index was entered as a moderator of paths between AT(N) biomarkers (e.g., amyloid-tau), and paths between AT(N) biomarkers and executive function. The residual reserve index interacted with amyloid pathology when predicting FDG metabolism: the indirect effect of amyloid → FDG metabolism → executive function intercept and slope varied as a function of the residual reserve index. With lower amyloid pathology, executive function performance was comparable at different levels of the residual reserve index, but a higher residual reserve index was associated with lower FDG metabolism. With higher amyloid pathology, a higher residual reserve index predicted better executive function via higher FDG metabolism. The effect of the residual reserve index on executive function performance via FDG metabolism was consistent with cognitive resilience. This suggests the residual reserve index captures variation in cognitive reserve specifically, neural efficiency, and neural capacity to upregulate metabolism to enhance cognitive resilience in the face of greater amyloid pathology. Implications for future research include the potential bidirectionality between neural efficiency and amyloid accumulation.
3D Statistical Shape Models to Embed Spatial Relationship Information
Publisher: Springer Berlin Heidelberg
Date: 2005
DOI: 10.1007/11569541_7
Allowing Users to Benefit from Tree Shading: Using a Smartphone App to Allow Adaptive Route Planning during Extreme Heat
Publisher: MDPI AG
Date: 17-09-2020
DOI: 10.3390/F11090998
Abstract: This paper presents the outcomes from a joint research project that aims to develop a smartphone application/online platform to model the most thermally comfortable active transport route to a planned destination using heat information and tree shading (Shadeway). Here, we provide a summary of our systematic review of academic literature and applications from the Google Play and Apple App Store, to identify current knowledge about personal adaptation strategies when navigating travel in cities during high temperatures. The review identifies that there is a lack of attention regarding the use of smartphone applications to address urban thermal comfort for active transport by government and private industry. We then present the initial results of original research from three community focus groups and an online survey that elicited participants’ opinions about Shadeways in the City of Greater Bendigo (CoGB), Australia. The results clearly show the need for better management of Shadeways in CoGB. For ex le, 52.3% of the routes traveled by participants suffer from either no or poor levels of shading, and 53 of the shaded areas were located along routes that also experience heavy traffic, which can have an adverse effect on perceptions and actual safety. It is expected that this study will contribute to improve understanding of the methods used to identify adaptation strategies to increasingly extreme temperatures.
CenTauR: Towards a Universal Scale and Masks for Standardizing Tau Imaging Studies
Publisher: Wiley
Date: 07-2023
DOI: 10.1002/DAD2.12454
Abstract: Recently, an increasing number of tau tracers have become available. There is a need to standardize quantitative tau measures across tracers, supporting a universal scale. We developed several cortical tau masks and applied them to generate a tau imaging universal scale. One thousand forty‐five participants underwent tau scans with either 18 F‐flortaucipir, 18 F‐MK6240, 18 F‐PI2620, 18 F‐PM‐PBB3, 18 F‐GTP1, or 18 F‐RO948. The universal mask was generated from cognitively unimpaired amyloid beta (Aβ)− subjects and Alzheimer's disease (AD) patients with Aβ+. Four additional regional cortical masks were defined within the constraints of the universal mask. A universal scale, the CenTauR z , was constructed. None of the regions known to display off‐target signal were included in the masks. The CenTauR z allows robust discrimination between low and high levels of tau deposits. We constructed several tau‐specific cortical masks for the AD continuum and a universal standard scale designed to capture the location and degree of abnormality that can be applied across tracers and across centers. The masks are freely available at entaur‐project .
Quantitative susceptibility mapping of the hippocampus predicts hippocampal atrophy in Abeta+ elderly controls and Alzheimer’s disease patients
Publisher: Wiley
Date: 07-2017
Neuropsychology and neuroimaging profiles of amyloid‐positive versus amyloid‐negative amnestic mild cognitive impairment patients
Publisher: Wiley
Date: 2018
A Universal neocortical mask for Centiloid quantification
Publisher: Wiley
Date: 07-2023
DOI: 10.1002/DAD2.12457
Abstract: The Centiloid (CL) project was developed to harmonize the quantification of amyloid beta (Aβ) positron emission tomography (PET) scans to a unified scale. The CL neocortical mask was defined using 11 C Pittsburgh compound B (PiB), overlooking potential differences in regional distribution among Aβ tracers. We created a universal mask using an independent dataset of five Aβ tracers, and investigated its impact on inter‐tracer agreement, tracer variability, and group separation. Using data from the Alzheimer's Dementia Onset and Progression in International Cohorts (ADOPIC) study (Australian Imaging Biomarkers and Lifestyle + Alzheimer's Disease Neuroimaging Initiative + Open Access Series of Imaging Studies), age‐matched pairs of mild Alzheimer's disease (AD) and healthy controls (HC) were selected: 18 F‐florbetapir ( N = 147 pairs), 18 F‐florbetaben ( N = 22), 18 F‐flutemetamol ( N = 10), 18 F‐NAV ( N = 42), 11 C‐PiB ( N = 63). The images were spatially and standardized uptake value ratio normalized. For each tracer, the mean AD–HC difference image was thresholded to maximize the overlap with the standard neocortical mask. The universal mask was defined as the intersection of all five masks. It was evaluated on the Global Alzheimer's Association Interactive Network (GAAIN) head‐to‐head datasets in terms of inter‐tracer agreement and variance in the young controls (YC) and on the ADOPIC dataset comparing separation between HC/AD and HC/mild cognitive impairment (MCI). In the GAAIN dataset, the universal mask led to a small reduction in the variance of the YC, and a small increase in the inter‐tracer agreement. In the ADOPIC dataset, it led to a better separation between HC/AD and HC/MCI at baseline. The universal CL mask led to an increase in inter‐tracer agreement and group separation. Those increases were, however, very small, and do not provide sufficient benefits to support departing from the existing standard CL mask, which is suitable for the quantification of all Aβ tracers. This study built an amyloid universal mask using a matched cohort for the five most commonly used amyloid positron emission tomography tracers. There was a high overlap between each tracer‐specific mask. Differences in quantification and group separation between the standard and universal mask were small. The existing standard Centiloid mask is suitable for the quantification of all amyloid beta tracers.
Selective age-association of hippocampus subfields in cognitively healthy elderly
Publisher: Wiley
Date: 07-2017
Spatial and socioeconomic inequities in liveability in Australia'S 21 largest cities: Does city size matter?
Publisher: Elsevier BV
Date: 11-2022
DOI: 10.1016/J.HEALTHPLACE.2022.102899
Abstract: Spatial and area-level socioeconomic variation in urban liveability (access to social infrastructure, public transport, open space, healthy food choices, local employment, street connectivity, dwelling density, and housing affordability) was examined and mapped across 39,967 residential statistical areas in Australia's metropolitan (n = 7) and largest regional cities (n = 14). Urban liveability varied spatially, with inner-city areas more liveable than outer suburbs. Disadvantaged areas in larger metropolitan cities were less liveable than advantaged areas, but this pattern was reversed in smaller cities. Local data could inform policies to redress inequities, including those designed to avoid disadvantage being suburbanised as cities grow and gentrify.
Going deeper with brain morphometry using neural networks
Publisher: IEEE
Date: 13-04-2021
Decreases in cerebral blood flow are associated with Abeta status in preclinical Alzheimer’s disease
Publisher: Wiley
Date: 07-2015
BDNF Val66Met, Aβ amyloid, and cognitive decline in preclinical Alzheimer's disease
Publisher: Elsevier BV
Date: 11-2013
DOI: 10.1016/J.NEUROBIOLAGING.2013.05.006
Abstract: Brain-derived neurotrophic factor (BDNF) Val66Met polymorphism has previously been implicated in Alzheimer's disease (AD)-related cognitive impairment. We aimed to determine the relationship between BDNF Val66Met and beta-amyloid (Aβ) on cognitive decline, hippoc al atrophy, and Aβ accumulation over 36 months in 165 healthy adults enrolled in the Australian Imaging, Biomarkers and Lifestyle study. In healthy adults with high Aβ, Met carriers showed significant and moderate-to-large declines in episodic memory, executive function, and language, and greater hippoc al atrophy over 36 months, compared with Val/Val homozygotes. BDNF Val66Met was not found to be related to rates of change in cognition or hippoc al volume in healthy adults with low Aβ. BDNF Val66Met did not relate to the amount of Aβ or to the rate of Aβ accumulation in either group. High Aβ levels coupled with Met carriage may be useful prognostic markers of accelerated cognitive decline and hippoc al degeneration in in iduals in the preclinical stage of AD.
Sci-Sat AM(1): Planning - 05: Feasibility of Atlas-Based Organ Segmentation and Electron Density Mapping for MRI-Based Prostate Radiation Therapy Planning
Publisher: Wiley
Date: 07-2010
DOI: 10.1118/1.3476205
The prevalence and characteristics of commuting between small towns and regional centres in regional Victoria
Publisher: Informa UK Limited
Date: 10-2013
Automatic Delineation of Sulci and Improved Partial Volume Classification for Accurate 3D Voxel-Based Cortical Thickness Estimation from MR
Publisher: No publisher found
Date: 2008
DOI: 10.1007/978-3-540-85988-8_31
Abstract: Accurate cortical thickness estimation in-vivo is important for the study of many neurodegenerative diseases. When using magnetic resonance images (MRI), accuracy may be h ered by artifacts such as partial volume (PV) as the cortex spans only a few voxels. In zones of opposed sulcal banks (tight sulci) the measurement can be even more difficult. The aim of this work is to propose a voxel-based cortical thickness estimation method from MR by integrating a mechanism for correcting sulci delineation after an improved partial volume classification. First, an efficient and accurate framework was developed to enhance partial volume classification with structural information. Then, the correction of sulci delineation is performed after a homotopic thinning of a cost function image. Integrated to our voxel-based cortical thickness estimation pipeline, the overall method showed a better estimate of thickness and a high reproducibility on real data (R2 > 0.9). A quantitative analysis on clinical data from an Alzheimer's disease study showed significant differences between normal controls and Alzheimer's disease patients.
3D cGAN based cross-modality MR image synthesis for brain tumor segmentation
Publisher: IEEE
Date: 04-2018
Decreased platelet APP isoform ratios in autosomal dominant Alzheimer's disease: Baseline data from a DIAN cohort subset
Publisher: Bentham Science Publishers Ltd.
Date: 24-02-2015
DOI: 10.2174/1567205012666150204125732
Abstract: This study examines platelet amyloid precursor protein (APP) isoform ratios of 120KDa to 110KDa (APPr) between mutation carriers (MC) carrying a mutation for autosomal dominant Alzheimer's disease (ADAD) and non-carriers (NC). Two previous studies reported no significant difference in APPr between ADAD MC and NC, which may have been due to the small s le size in both studies. The current study examines APPr in MC versus NC in a larger s le. In addition, it investigated whether APPr correlate with neuroimaging data, neuropsychological data and cerebrospinal fluid biomarkers in a cohort subset derived from the Dominantly Inherited Alzheimer Network (DIAN) study. APPr were quantified by western blotting. Fifteen MC (symptomatic and asymptomatic) were compared against twelve NC using univariate general linear model. All participants underwent neuroimaging and neuropsychological testing which were correlated with APPr using Pearson's correlation coefficient (r). APPr were lower in MC compared to NC (p=0.003) while Mini-Mental State Examination (MMSE) scores were not significantly different (p>0.1). Furthermore, APPr inversely correlated with amyloid imaging in the Caudate Nucleus (r=-0.505 p<0.05) and Precuneus (r=-0.510 p<0.05). APPr are lower in ADAD MC compared to NC, and inversely correlated with brain amyloid load prior to significant differences in cognitive health. However, the use of APPr as a biomarker needs to be explored further.
Texture-Based Segmentation of the Knee Bones in MRI Using Phase Information
Publisher: IEEE
Date: 2006
Atlas selection strategy using least angle regression in multi-atlas segmentation propagation
Publisher: IEEE
Date: 03-2011
Mesial temporal tau in amyloid-β-negative cognitively normal older persons
Publisher: Springer Science and Business Media LLC
Date: 08-04-2022
DOI: 10.1186/S13195-022-00993-X
Abstract: Tau deposition in the mesial temporal lobe (MTL) in the absence of amyloid-β (Aβ−) occurs with aging. The tau PET tracer 18 F-MK6240 has low non-specific background binding so is well suited to exploration of early-stage tau deposition. The aim of this study was to investigate the associations between MTL tau, age, hippoc al volume (HV), cognition, and neocortical tau in Aβ− cognitively unimpaired (CU) in iduals. One hundred and ninety-nine Aβ− participants (Centiloid 25) who were CU underwent 18 F-MK6240 PET at age 75 ± 5.2 years. Tau standardized uptake value ratio (SUVR) was estimated in mesial temporal (Me), temporoparietal (Te), and rest of the neocortex (R) regions and four Me sub-regions. Tau SUVR were analyzed as continuous variables and compared between high and low MTL SUVR groups. In this cohort with a stable clinical classification of CU for a mean of 5.3 years prior to and at the time of tau PET, MTL tau was visually observed in 9% of the participants and was limited to Braak stages I–II. MTL tau was correlated with age ( r = 0.24, p 0.001). Age contributed to the variance in cognitive scores but MTL tau did not. MTL tau was not greater with subjective memory complaint, nor was there a correlation between MTL tau and Aβ Centiloid value, but high tau was associated with smaller HV. Participants with MTL tau had higher tau SUVR in the neocortex but this was driven by the cerebellar reference region and was not present when using white matter normalization. In an Aβ− CU cohort, tau tracer binding in the mesial temporal lobe was age-related and associated with smaller hippoc i, but not with subjective or objective cognitive impairment.
<title>Gabor filters and SVM classifier for pattern wafer segmentation</title>
Publisher: SPIE
Date: 11-2004
DOI: 10.1117/12.581242
Influence of BDNF Val66Met on the relationship between physical activity and brain volume
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 03-09-2014
MilxXplore: a web-based system to explore large imaging datasets
Publisher: Oxford University Press (OUP)
Date: 11-2013
Automated voxel-based 3D cortical thickness measurement in a combined Lagrangian-Eulerian PDE approach using partial volume maps
Publisher: Elsevier BV
Date: 10-2009
Plasma p217+tau versus NAV4694 amyloid and MK6240 tau PET across the Alzheimer's continuum
Publisher: Wiley
Date: 2022
DOI: 10.1002/DAD2.12307
Abstract: We evaluated a new Simoa plasma assay for phosphorylated tau (P‐tau) at aa217 enhanced by additional p‐tau sites (p217+tau). Plasma p217+tau levels were compared to 18 F‐NAV4694 amyloid beta (Aβ) positron emission tomography (PET) and 18 F‐MK6240 tau PET in 174 cognitively impaired (CI) and 223 cognitively unimpaired (CU) participants. Compared to Aβ− CU, the plasma levels of p217+tau increased 2‐fold in Aβ+ CU and 3.5‐fold in Aβ+ CI. In Aβ− the p217+tau levels did not differ significantly between CU and CI. P217+tau correlated with Aβ centiloids P = .67 (CI, P = .64 CU, P = .45) and tau SUVR MT P = .63 (CI, P = .69 CU, P = .34). Area under curve (AUC) for Alzheimer's disease (AD) dementia versus Aβ− CU was 0.94, for AD dementia versus other dementia was 0.93, for Aβ+ versus Aβ− PET was 0.89, and for tau+ versus tau− PET was 0.89. Plasma p217+tau levels elevate early in the AD continuum and correlate well with Aβ and tau PET.
NMF-based Centiloid Normalisation
Publisher: CSIRO
Date: 2020
SA-LuT-Nets: Learning Sample-Adaptive Intensity Lookup Tables for Brain Tumor Segmentation
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 05-2021
Correlation of MRI-Derived Apparent Diffusion Coefficients in Newly Diagnosed Gliomas with [F-18]-Fluoro-L-Dopa PET: What Are We Really Measuring with Minimum ADC?
Publisher: American Society of Neuroradiology (ASNR)
Date: 18-10-2013
DOI: 10.3174/AJNR.A3315
18F-AV1451 Tau Quantification without MRI
Publisher: Wiley
Date: 07-2017
Comparing the longitudinal progression of CSF biomarkers with PET Amyloid biomarkers for Alzheimer’s disease
Publisher: Wiley
Date: 12-2022
DOI: 10.1002/ALZ.068082
Abstract: Cerebrospinal fluid (CSF) soluble biomarkers are useful at detecting pre‐clinical levels of Alzheimer’s disease (AD) biomarkers of b‐amyloid (Ab) and tau. Disease progression times for participants in longitudinal studies can be estimated for different biomarkers. Utilizing a new technique, this work compared the disease progression times between CSF and PET biomarkers. Four hundred and ten participants from the Alzheimer’s Dementia Onset and Progression in International Cohorts (ADOPIC) including participants form ACS/OASIS, ADNI and AIBL with three or more data points of longitudinal CSF Ab42 and pTau181 (pTau) and Ab PET were selected. PET results were expressed in Centiloid (CL), (299 cognitively unimpaired, 107 mild cognitively impaired, 4 AD dementia aged 69±9 216 females (N AIBL =30, N ADNI =252, N OASIS =128). Disease trajectory curves for in idual biomarkers and the pTau/Ab42 ratio were created by: 1) Fitting a function to the rates of change of the variable of interest versus its mean value), 2) integrating the fit to obtain longitudinal trajectory curves as a function of disease progression time for each of the variables. The participants’ disease progression time along each curve were estimated. Threshold values for Ab PET and pTau/Ab42 ratios were calculated using a gaussian mixture model. Estimates of age of onset were calculated using the progression times. The participants’ disease progression times for each of the different variables were compared using rank correlations. Rank correlations for the progression times were: r(Ab42, Ab PET) = 0.75, r(pTau, Ab PET)=0.62, and r(pTau/Ab42, Ab PET)=0.83. The estimated ages at which participants’ reach Ab PET and the pTau/Ab42 ratio thresholds are compared in Fig 1, the average age at which were estimated to reach the threshold values were 55 yr for pTau/Ab42 (threshold of 0.021) and 61 yr for Ab PET (threshold of 22 CL). The high correlation between pTau/Ab42 and Ab PET, indicates that pTau/Ab42 captures the progression of AD pathology better than the in idual CSF biomarkers. On average participants’ reach abnormal levels of pTau/Ab42 earlier than Ab PET. Further work is required to understand in idual variations in progression times.
MR Image Segmentation Using Phase Information and a Novel Multiscale Scheme
Publisher: Springer Berlin Heidelberg
Date: 2006
DOI: 10.1007/11866763_113
Abstract: This paper considers the problem of automatic classification of textured tissues in 3D MRI. More specifically, it aims at validating the use of features extracted from the phase of the MR signal to improve texture discrimination in bone segmentation. This extra information provides better segmentation, compared to using magnitude only features. We also present a novel multiscale scheme to improve the speed of pixel based classification algorithm, such as support vector machines. This algorithm dramatically increases the speed of the segmentation process by an order of magnitude through a reduction of the number of pixels that needs to be classified in the image.
An improved 3D shape context based non-rigid registration method and its application to small animal skeletons registration
Publisher: Elsevier BV
Date: 06-2010
DOI: 10.1016/J.COMPMEDIMAG.2009.12.003
Abstract: 3D shape context is a method to define matching points between similar shapes. It can be used as a pre-processing step in a non-rigid registration. The main limitation of the method is point mismatching, which includes long geodesic distance mismatch causing wrong topological structure, and neighbors crossing mismatch between two adjacent points. In this paper, we propose a topological structure verification method to correct the long geodesic distance mismatch and a correspondence field smoothing method to correct the neighbors crossing mismatch. A robust 3D shape context model is generated and further combined with thin-plate spline model for non-rigid registration. The method was tested on phantoms and applied to rat hind limb and mouse hind limb skeletons registration from micro-CT images. Errors between the registered surfaces were reduced by using the proposed method. The robustness of the method is demonstrated.
Tiny houses and planning regulation for housing alternatives: the context of regional Victoria
Publisher: Informa UK Limited
Date: 02-10-2018
Partial volume correction using either PMOD® or CapAIBL® does little to improve 18F-AV1451 PET quantification
Publisher: Wiley
Date: 07-2018
Detecting global and local hippocampal shape changes in Alzheimer's disease using statistical shape models
Publisher: Elsevier BV
Date: 02-2012
DOI: 10.1016/J.NEUROIMAGE.2011.10.014
Abstract: The hippoc us is affected at an early stage in the development of Alzheimer's disease (AD). With the use of structural magnetic resonance (MR) imaging, we can investigate the effect of AD on the morphology of the hippoc us. The hippoc al shape variations among a population can be usually described using statistical shape models (SSMs). Conventional SSMs model the modes of variations among the population via principal component analysis (PCA). Although these modes are representative of variations within the training data, they are not necessarily discriminative on labeled data or relevant to the differences between the subpopulations. We use the shape descriptors from SSM as features to classify AD from normal control (NC) cases. In this study, a Hotelling's T2 test is performed to select a subset of landmarks which are used in PCA. The resulting variation modes are used as predictors of AD from NC. The discrimination ability of these predictors is evaluated in terms of their classification performances with bagged support vector machines (SVMs). Restricting the model to landmarks with better separation between AD and NC increases the discrimination power of SSM. The predictors extracted on the subregions also showed stronger correlation with the memory-related measurements such as Logical Memory, Auditory Verbal Learning Test (AVLT) and the memory subscores of Alzheimer Disease Assessment Scale (ADAS).
A non-rigid registration method for mouse whole body skeleton registration
Publisher: SPIE
Date: 04-03-2010
DOI: 10.1117/12.844067
BDNF Val66Met in preclinical Alzheimer's disease is associated with short-term changes in episodic memory and hippocampal volume but not serum mBDNF
Publisher: Cambridge University Press (CUP)
Date: 19-07-2017
DOI: 10.1017/S1041610217001284
Abstract: The brain-derived neurotrophic factor ( BDNF ) Val66Met polymorphism Met allele exacerbates amyloid (Aβ) related decline in episodic memory (EM) and hippoc al volume (HV) over 36–54 months in preclinical Alzheimer's disease (AD). However, the extent to which Aβ+ and BDNF Val66Met is related to circulating markers of BDNF (e.g. serum) is unknown. We aimed to determine the effect of Aβ and the BDNF Val66Met polymorphism on levels of serum mBDNF, EM, and HV at baseline and over 18-months. Non-demented older adults ( n = 446) underwent Aβ neuroimaging and BDNF Val66Met genotyping. EM and HV were assessed at baseline and 18 months later. Fasted blood s les were obtained from each participant at baseline and at 18-month follow-up. Aβ PET neuroimaging was used to classify participants as Aβ– or Aβ+. At baseline, Aβ+ adults showed worse EM impairment and lower serum mBDNF levels relative to Aβ- adults. BDNF Val66Met polymorphism did not affect serum mBDNF, EM, or HV at baseline. When considered over 18-months, compared to Aβ– Val homozygotes, Aβ+ Val homozygotes showed significant decline in EM and HV but not serum mBDNF. Similarly, compared to Aβ+ Val homozygotes, Aβ+ Met carriers showed significant decline in EM and HV over 18-months but showed no change in serum mBDNF. While allelic variation in BDNF Val66Met may influence Aβ+ related neurodegeneration and memory loss over the short term, this is not related to serum mBDNF. Longer follow-up intervals may be required to further determine any relationships between serum mBDNF, EM, and HV in preclinical AD.
Joint Factor and Kinetic Analysis of Dynamic FDOPA PET Scans of Brain Cancer Patients
Publisher: Springer Berlin Heidelberg
Date: 2010
DOI: 10.1007/978-3-642-15745-5_23
Abstract: Kinetic analysis is an essential tool of Positron Emission Tomography image analysis. However it requires a pure tissue time activity curve (TAC) in order to calculate the system parameters. Pure tissue TACs are particularly difficult to obtain in the brain as the low resolution of PET means almost all voxels are a mixture of tissues. Factor analysis explicitly accounts for mixing but is an underdetermined problem that can give arbitrary results. A joint factor and kinetic analysis is proposed whereby factor analysis explicitly accounts for mixing of tissues. Hence, more meaningful parameters are obtained by the kinetic models, which also ensure a less ambiguous solution to the factor analysis. The method was tested using a cylindrical phantom and the 18F-DOPA data of a brain cancer patient.
Predicting Poststroke Depression from Brain Connectivity
Publisher: Springer International Publishing
Date: 2014
Statistical machine learning to identify traumatic brain injury (TBI) from structural disconnections of white matter networks
Publisher: Elsevier BV
Date: 04-2016
DOI: 10.1016/J.NEUROIMAGE.2016.01.056
Abstract: Identifying diffuse axonal injury (DAI) in patients with traumatic brain injury (TBI) presenting with normal appearing radiological MRI presents a significant challenge. Neuroimaging methods such as diffusion MRI and probabilistic tractography, which probe the connectivity of neural networks, show significant promise. We present a machine learning approach to classify TBI participants primarily with mild traumatic brain injury (mTBI) based on altered structural connectivity patterns derived through the network based statistical analysis of structural connectomes generated from TBI and age-matched control groups. In this approach, higher order diffusion models were used to map white matter connections between 116 cortical and subcortical regions. Tracts between these regions were generated using probabilistic tracking and mean fractional anisotropy (FA) measures along these connections were encoded in the connectivity matrices. Network-based statistical analysis of the connectivity matrices was performed to identify the network differences between a representative subset of the two groups. The affected network connections provided the feature vectors for principal component analysis and subsequent classification by random forest. The validity of the approach was tested using data acquired from a total of 179 TBI patients and 146 controls participants. The analysis revealed altered connectivity within a number of intra- and inter-hemispheric white matter pathways associated with DAI, in consensus with existing literature. A mean classification accuracy of 68.16%±1.81% and mean sensitivity of 80.0%±2.36% were achieved in correctly classifying the TBI patients evaluated on the subset of the participants that was not used for the statistical analysis, in a 10-fold cross-validation framework. These results highlight the potential for statistical machine learning approaches applied to structural connectomes to identify patients with diffusive axonal injury.
Validation of quantitative assessment of florbetaben PET scans as an adjunct to the visual assessment across 15 software methods
Publisher: Springer Science and Business Media LLC
Date: 10-06-2023
DOI: 10.1007/S00259-023-06279-0
Abstract: Amyloid positron emission tomography (PET) with [ 18 F]florbetaben (FBB) is an established tool for detecting Aβ deposition in the brain in vivo based on visual assessment of PET scans. Quantitative measures are commonly used in the research context and allow continuous measurement of amyloid burden. The aim of this study was to demonstrate the robustness of FBB PET quantification. This is a retrospective analysis of FBB PET images from 589 subjects. PET scans were quantified with 15 analytical methods using nine software packages (MIMneuro, Hermes BRASS, Neurocloud, Neurology Toolkit, statistical parametric mapping (SPM8), PMOD Neuro, CapAIBL, non-negative matrix factorization (NMF), Amyloid IQ ) that used several metrics to estimate Aβ load (SUVR, centiloid, amyloid load, and amyloid index). Six analytical methods reported centiloid (MIMneuro, standard centiloid, Neurology Toolkit, SPM8 (PET only), CapAIBL, NMF). All results were quality controlled. The mean sensitivity, specificity, and accuracy were 96.1 ± 1.6%, 96.9 ± 1.0%, and 96.4 ± 1.1%, respectively, for all quantitative methods tested when compared to histopathology, where available. The mean percentage of agreement between binary quantitative assessment across all 15 methods and visual majority assessment was 92.4 ± 1.5%. Assessments of reliability, correlation analyses, and comparisons across software packages showed excellent performance and consistent results between analytical methods. This study demonstrated that quantitative methods using both CE marked software and other widely available processing tools provided comparable results to visual assessments of FBB PET scans. Software quantification methods, such as centiloid analysis, can complement visual assessment of FBB PET images and could be used in the future for identification of early amyloid deposition, monitoring disease progression and treatment effectiveness.
Bayesian modeling of multiple structural connectivity networks during the progression of Alzheimer's disease
Publisher: Wiley
Date: 19-02-2020
DOI: 10.1111/BIOM.13235
Nonrigid correction of interleaving artefacts in pelvic MRI
Publisher: SPIE
Date: 26-02-2009
DOI: 10.1117/12.812460
Non-rigid registration of small animal skeletons from micro-CT using 3D shape context
Publisher: SPIE
Date: 26-02-2009
DOI: 10.1117/12.812461
Improved cortical thickness measurement from MR images using partial volume estimation
Publisher: IEEE
Date: 05-2008
Content-based segmentation of patterned wafer for automatic threshold determination
Publisher: SPIE
Date: 19-05-2003
DOI: 10.1117/12.479689
Making regions: localisation and the new periphery in emerging regional governance
Publisher: Informa UK Limited
Date: 18-03-2020
Rates of regional tau accumulation in ageing and across the Alzheimer's disease continuum: an AIBL 18F-MK6240 PET study
Publisher: Elsevier BV
Date: 02-2023
Early prediction of treatment response in advanced gliomas with 18F-DOPA positron-emission tomography
Publisher: MDPI AG
Date: 02-2014
DOI: 10.3747/CO.21.1772
Abstract: Imaging markers that enable prediction of survival are of interest for aiding clinical decision-making for patients with advanced glioma. [...]
Automated segmentation and T2-mapping of the posterior cruciate ligament from MRI of the knee: Data from the osteoarthritis initiative
Publisher: IEEE
Date: 04-2016
PET-only 18F-AV1451 tau quantification
Publisher: IEEE
Date: 04-2017
Correcting for PET scanner changes in longitudinal studies
Publisher: Wiley
Date: 07-2019
Sample-Adaptive GANs: Linking Global and Local Mappings for Cross-Modality MR Image Synthesis
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 07-2020
An improved 3D shape context registration method for non-rigid surface registration
Publisher: SPIE
Date: 04-03-2010
DOI: 10.1117/12.844058
Simultaneous super‐resolution and contrast synthesis of routine clinical magnetic resonance images of the knee for improving automatic segmentation of joint cartilage: data from the Osteoarthritis Ini
Publisher: Wiley
Date: 15-08-2020
DOI: 10.1002/MP.14421
Comparison of 18F-florbetaben quantification results using the standard Centiloid, MR-based, and MR-less CapAIBL® approaches: Validation against histopathology.
Publisher: Wiley
Date: 14-05-2019
DOI: 10.1016/J.JALZ.2019.02.005
Abstract: Data from eighty-eight subjects (52 male subjects, aged 79.8 ± 10.6 years) who underwent antemortem Against combined Bielschowsky silver staining and immunohistochemistry histopathological scores, statistical parametric mapping had 96% sensitivity, 96% specificity, and 95% accuracy, whereas magnetic resonance-less CapAIBL standardized uptake value ratio Quantification of
Impact of APOE-ε4 carriage on the onset and rates of neocortical Aβ-amyloid deposition
Publisher: Elsevier BV
Date: 11-2020
Cross-Sectional and Longitudinal Comparison of Tau Imaging with 18F-MK6240 and 18F-Flortaucipir in Populations Matched for Age, MMSE and Brain Beta-Amyloid Burden
Publisher: SERDI
Date: 2023
Cognitive reserve predicts future executive function decline in older adults with Alzheimer's disease pathology but not age-associated pathology
Publisher: Elsevier BV
Date: 04-2020
DOI: 10.1016/J.NEUROBIOLAGING.2019.12.022
Abstract: Cognitive reserve has been described as offering protection against Alzheimer's disease (AD) and other neurodegenerative conditions, but also against age-associated brain changes. Using data from the Alzheimer's Disease Neuroimaging Initiative, we defined cognitive reserve using the residual reserve index: episodic memory performance residualized for 3T MRI-derived brain volumes and demographics. We examined whether cognitive reserve predicted executive function (EF) decline equally across 2 groups of older adults-AD biomarker-positive (n = 468) and -negative (n = 402)-defined by the tau-to-amyloid ratio in cerebrospinal fluid. A significant interaction between the residual reserve index and biomarker group revealed that the effect of cognitive reserve on EF decline was dependent on pathology status. In the biomarker-positive group, higher cognitive reserve predicted EF decline over five years. However, cognitive reserve did not predict EF decline in the biomarker-negative group. These results suggest a certain level of AD pathology may be needed before cognitive reserve exerts its protective effects on future cognition however, further research that tracks cognitive reserve longitudinally is needed.
Expectation maximisation classification and Laplacian based thickness measurement for cerebral cortex thickness estimation
Publisher: SPIE
Date: 08-03-2007
DOI: 10.1117/12.710510
Independent contribution of temporal β-amyloid deposition to memory decline in the pre-dementia phase of Alzheimer's disease
Publisher: Oxford University Press (OUP)
Date: 09-02-2011
DOI: 10.1093/BRAIN/AWQ383
Abstract: The relationship between β-amyloid deposition and memory deficits in early Alzheimer's disease is unresolved, as past studies show conflicting findings. The present study aims to determine the relative contribution of regional β-amyloid deposition, hippoc al atrophy and white matter integrity to episodic memory deficits in non-demented older in iduals harbouring one of the characteristic hallmarks of Alzheimer's disease, i.e. with β-amyloid pathology. Understanding these relationships is critical for effective therapeutic development. Brain magnetic resonance imaging and [(11)C]Pittsburgh Compound B-positron emission tomography scans were obtained in 136 non-demented in iduals aged over 60 years, including 93 healthy elderly and 43 patients with mild cognitive impairment. Voxel-based correlations were computed between a memory composite score and grey matter volume, white matter volume and β-amyloid deposition imaging datasets. Hierarchical linear regression analyses were then performed using values extracted in regions of most significant correlations to determine the relative contribution of each modality to memory deficits. All analyses were conducted pooling all groups together as well as within separate subgroups of cognitively normal elderly, patients with mild cognitive impairment and in iduals with high versus low neocortical β-amyloid. Brain areas of highest correlation with episodic memory deficits were the hippoc i for grey matter volume, the perforant path for white matter volume and the temporal neocortex for β-amyloid deposition. When considering these three variables together, only hippoc al volume and temporal β-amyloid deposition provided independent contributions to memory deficits. In contrast to global β-amyloid deposition, temporal β-amyloid deposition was still related to memory independently from hippoc al atrophy within subgroups of cognitively normal elderly, patients with mild cognitive impairment or cases with high neocortical β-amyloid. In the pre-dementia stage of Alzheimer's disease, subtle episodic memory impairment is related to β-amyloid deposition, especially in the temporal neocortex, and independently from hippoc al atrophy, suggesting that both factors should be independently targeted in therapeutic trials aimed at reducing cognitive decline.
Automated segmentation of the menisci from MR images
Publisher: IEEE
Date: 06-2009
The place of our children in community building: Turning theory into practice. Policy review report. (Vol. 1).
Publisher: La Trobe University
Date: 2012
Assessing reactive astrogliosis with 18F-SMBT-1 across the Alzheimer's disease spectrum.
Publisher: Society of Nuclear Medicine
Date: 27-01-2022
Atlas selection strategy in multi-atlas segmentation propagation with locally weighted voting using diversity-based MMR re-ranking
Publisher: SPIE
Date: 03-03-2011
DOI: 10.1117/12.877866
Detecting Hippocampal Shape Changes in Alzheimer's Disease using Statistical Shape Models
Publisher: SPIE
Date: 03-03-2011
DOI: 10.1117/12.877869
Tau, Aβ-Amyloid, Brain Structure and Cognitive Function Following Service-Related Traumatic Brain Injury in Australian Vietnam War Veterans
Publisher: Wiley
Date: 07-2018
Supervised method to build an atlas database for multi-atlas segmentation-propagation
Publisher: SPIE
Date: 04-03-2010
DOI: 10.1117/12.844048
Finding space for nature in cities: the considerable potential of redundant car parking
Publisher: Springer Science and Business Media LLC
Date: 29-11-2022
DOI: 10.1038/S42949-022-00073-X
Abstract: Nature-based solutions (NBS) are recognised as a means to address challenges such as heatwaves, flooding and bio ersity loss. Delivering these benefits at scale will require large areas of scarce urban land to be converted into green space. Here we show an approach by which cities can make substantial progress towards their sustainability targets using NBS, by converting redundant street parking into bio erse green space. We demonstrate that up to half of street parking in our case study municipality (The City of Melbourne) could be accommodated in garages within 200 m, freeing up large areas for greening. Our modelling projects significant benefits in terms of tree canopy over, stormwater and ecological connectivity. These would represent strong progress towards a number of the city’s ambitious NBS targets. As many cities allocate extensive areas to both street parking and off-street garages, this approach to freeing up space for nature in cities is widely applicable.
Implementing the centiloid transformation for 11C-PiB and β-amyloid 18F-PET tracers using CapAIBL.
Publisher: Elsevier BV
Date: 12-2018
DOI: 10.1016/J.NEUROIMAGE.2018.08.044
Abstract: The centiloid scale was recently proposed to provide a standard framework for the quantification of β-amyloid PET images, so that amyloid burden can be expressed on a standard scale. While the framework prescribes SPM8 as the standard analysis method for PET quantification, non-standard methods can be calibrated to produce centiloid values. We have previously developed a PET-only quantification: CapAIBL. In this study, we show how CapAIBL can be calibrated to the centiloid scale. Calibration images for Using the calibration images, there was a very strong agreement, and very little bias between the centiloid values computed using CapAIBL and those computed using the standard method with R The PET-only quantification method, CapAIBL, can produce reliable centiloid values. The bias observed in the AIBL dataset for 18F-NAV4694 and
Diversity in the Glucose Transporter-4 Gene (SLC2A4) in Humans Reflects the Action of Natural Selection along the Old-World Primates Evolution
Publisher: Public Library of Science (PLoS)
Date: 23-03-2010
Improved Centiloid robustness using non-negative matrix factorisation
Publisher: Wiley
Date: 12-2020
DOI: 10.1002/ALZ.040085
Fuzzy classification of brain MRI using a priori knowledge: weighted fuzzy C-means
Publisher: IEEE
Date: 2007
Relationship between amyloid and tau levels and its impact on tau spreading.
Publisher: Springer Science and Business Media LLC
Date: 26-01-2021
DOI: 10.1007/S00259-021-05191-9
Abstract: Previous studies have shown that Aβ-amyloid (Aβ) likely promotes tau to spread beyond the medial temporal lobe. However, the Aβ levels necessary for tau to spread in the neocortex is still unclear. Four hundred sixty-six participants underwent tau imaging with [18F]MK6420 and Aβ imaging with [ 18 F]NAV4694. Aβ scans were quantified on the Centiloid (CL) scale with a cut-off of 25 CL for abnormal levels of Aβ (A+). Tau scans were quantified in three regions of interest (ROI) (mesial temporal (Me) temporoparietal neocortex (Te) and rest of neocortex (R)) and four mesial temporal region (entorhinal cortex, amygdala, hippoc us, and parahippoc us). Regional tau thresholds were established as the 95%ile of the cognitively unimpaired A- subjects. The prevalence of abnormal tau levels (T+) along the Centiloid continuum was determined. The plots of prevalence of T+ show earlier and greater increase along the Centiloid continuum in the medial temporal area compared to neocortex. Prevalence of T+ was low but associated with Aβ level between 10 and 40 CL reaching 23% in Me, 15% in Te, and 11% in R. Between 40 and 70 CL, the prevalence of T+ subjects per CL increased fourfold faster and at 70 CL was 64% in Me, 51% in Te, and 37% in R. In cognitively unimpaired, there were no T+ in R below 50 CL. The highest prevalence of T+ were found in the entorhinal cortex, reaching 40% at 40 CL and 80% at 60 CL. Outside the entorhinal cortex, abnormal levels of cortical tau on PET are rarely found with Aβ below 40 CL. Above 40 CL prevalence of T+ accelerates in all areas. Moderate Aβ levels are required before abnormal neocortical tau becomes detectable.
Computational Analysis of PET by AIBL (CapAIBL): A cloud-based processing pipeline for the quantification of PET images
Publisher: SPIE
Date: 20-03-2015
DOI: 10.1117/12.2082492
Constrained reverse diffusion for thick slice interpolation of 3D volumetric MRI images
Publisher: Elsevier BV
Date: 03-2012
DOI: 10.1016/J.COMPMEDIMAG.2011.08.004
Abstract: Due to physical limitations inherent in magnetic resonance imaging scanners, three dimensional volumetric scans are often acquired with anisotropic voxel resolution. We investigate several interpolation approaches to reduce the anisotropy and present a novel approach - constrained reverse diffusion for thick slice interpolation. This technique was compared to common methods: linear and cubic B-Spline interpolation and a technique based on non-rigid registration of neighboring slices. The methods were evaluated on artificial MR phantoms and real MR scans of human brain. The constrained reverse diffusion approach delivered promising results and provides an alternative for thick slice interpolation, especially for higher anisotropy factors.
Efficient machine learning framework for computer-aided detection of cerebral microbleeds using the radon transform
Publisher: IEEE
Date: 04-2014
An accurate 3D shape context based non-rigid registration method for mouse whole-body skeleton registration
Publisher: SPIE
Date: 03-03-2011
DOI: 10.1117/12.877915
Disease progression modelling of Alzheimer’s disease using probabilistic principal components analysis
Publisher: Elsevier BV
Date: 09-2023
Interaction between 18F-THK5317, 18F-Flutemetamol SUVR and cortical thickness
Publisher: Wiley
Date: 07-2015
BDNF, Aβ and cortical atrophy in preclinical Alzheimer's disease
Publisher: Wiley
Date: 07-2015
Learning Sample-Adaptive Intensity Lookup Table for Brain Tumor Segmentation
Publisher: Springer International Publishing
Date: 2020
Content based segmentation of patterned wafers
Publisher: SPIE-Intl Soc Optical Eng
Date: 07-2004
DOI: 10.1117/1.1762518
Mouse whole-body organ mapping by non-rigid registration approach
Publisher: SPIE
Date: 03-03-2011
DOI: 10.1117/12.877921
Reduced cortical cholinergic innervation measured using [18F]-FEOBV PET imaging correlates with cognitive decline in mild cognitive impairment
Publisher: Elsevier BV
Date: 2022
Alzheimer's disease and the early signs of age-related macular degeneration
Publisher: Bentham Science Publishers Ltd.
Date: 19-10-2016
DOI: 10.2174/1567205013666160603003800
Abstract: This study investigated signs of age related macular degeneration (AMD) in Alzheimer's disease (AD). These age-related diseases primarily affect different parts of the central nervous system but are substantially similar in terms of abnormal extracellular deposits, metabolic and oxidative stress, neuroinflammation and microvascular abnormalities. While AMD is a retinal disease, AD is reported to affect not only the brain but also the retina, with Aβ deposits, neurodegeneration and vascular changes. Large population based studies have provided conflicting results regarding the comorbidity of AD and AMD. This study investigated signs of AMD in a small but well characterized cohort from the Australian Imaging Biomarkers and Lifestyle study of aging (AIBL). The cohort consisted of 22 AD patients (age 70.2 ± 9.0 yrs, 13 male, 9 female) and 101 cognitively normal (CN) participants (age 71.3 ± 6.0 yrs, 40 male, 61 female). In comparison with the CN group, the AD group had a greater proportion of participants with early AMD (p < 0.0001, odds ratio 18.67, 95% CI 4.42 - 78.80). A logistic model for early AMD found a significant association with AD diagnosis (p < 0.0001), after adjusting for confounders (age, smoking, hypertension, high and low density lipoproteins, cataract surgery and APOE ε4 carrier status). The results of this study are consistent with an increased risk of AMD in AD. While the pathophysiology of these diseases are unclear, understanding the shared features between them may provide further knowledge about their pathogenesis and could lead to accelerated development of therapies for both diseases.
Shape based segmentation of MRIs of the bones in the knee using phase and intensity information - art. no. 651212
Publisher: SPIE
Date: 08-03-2007
DOI: 10.1117/12.711234
IC‐P‐024: Localization of hippocampal atrophy in Alzheimer's disease
Publisher: Wiley
Date: 07-2011
ANZSNM Oral Presentations
Publisher: Wiley
Date: 24-08-2012
Anatomical hubs from spectral clustering of structural connectomes
Publisher: IEEE
Date: 04-2016
Classifier combination for wafer segmentation
Publisher: SPIE
Date: 24-02-2005
DOI: 10.1117/12.592109
KIBRA is associated with accelerated cognitive decline and hippocampal atrophy in APOE ϵ4-positive cognitively normal adults with high Aβ-amyloid burden
Publisher: Springer Science and Business Media LLC
Date: 02-2018
DOI: 10.1038/S41598-018-20513-Y
Abstract: A single nucleotide polymorphism, rs17070145, in the KIdney and BRAin expressed protein ( KIBRA ) gene has been associated with cognition and hippoc al volume in cognitively normal (CN) in iduals. However, the impact of rs17070145 on longitudinal cognitive decline and hippoc al atrophy in CN adults at greatest risk of developing Alzheimer’s disease is unknown. We investigated the impact rs17070145 has on the rate of cognitive decline and hippoc al atrophy over six years in 602 CN adults, with known brain Aβ-amyloid levels and whether there is an interactive effect with APOE genotype. We reveal that whilst limited independent effects of KIBRA genotype were observed, there was an interaction with APOE in CN adults who presented with high Aβ-amyloid levels across study duration. In comparison to APOE ε4-ve in iduals carrying the rs17070145-T allele, significantly faster rates of cognitive decline (global, p = 0 . 006 verbal episodic memory, p = 0 . 004 ), and hippoc al atrophy ( p = 0 . 04 ) were observed in in iduals who were APOE ε4 + ve and did not carry the rs17070145-T allele. The observation of APOE effects in only non-carriers of the rs17070145-T allele, in the presence of high Aβ-amyloid suggest that carriers of the rs17070145-T allele are conferred a level of resilience to the detrimental effects of high Aβ-amyloid and APOE ε4.
Quantifiable brain atrophy synthesis for benchmarking of cortical thickness estimation methods
Publisher: Elsevier BV
Date: 11-2022
DOI: 10.1016/J.MEDIA.2022.102576
Abstract: Cortical thickness (CTh) is routinely used to quantify grey matter atrophy as it is a significant biomarker in studying neurodegenerative and neurological conditions. Clinical studies commonly employ one of several available CTh estimation software tools to estimate CTh from brain MRI scans. In recent years, machine learning-based methods emerged as a faster alternative to the main-stream CTh estimation methods (e.g. FreeSurfer). Evaluation and comparison of CTh estimation methods often include various metrics and downstream tasks, but none fully covers the sensitivity to sub-voxel atrophy characteristic of neurodegeneration. In addition, current evaluation methods do not provide a framework for the intra-method region-wise evaluation of CTh estimation methods. Therefore, we propose a method for brain MRI synthesis capable of generating a range of sub-voxel atrophy levels (global and local) with quantifiable changes from the baseline scan. We further create a synthetic test set and evaluate four different CTh estimation methods: FreeSurfer (cross-sectional), FreeSurfer (longitudinal), DL+DiReCT and HerstonNet. DL+DiReCT showed superior sensitivity to sub-voxel atrophy over other methods in our testing framework. The obtained results indicate that our synthetic test set is suitable for benchmarking CTh estimation methods on both global and local scales as well as regional inter-and intra-method performance comparison.
Planning for rural land use and the stages of productivism in Australia’s emerging multi-functional rural regions
Publisher: Australasian Urban History Planning History Group
Date: 2018
Tau, β-Amyloid, and Glucose Metabolism Following Service-Related Traumatic Brain Injury in Vietnam War Veterans: The Australian Imaging Biomarkers and Lifestyle Study of Aging-Veterans Study (AIBL-VETS)
Publisher: Mary Ann Liebert Inc
Date: 06-2023
NMF-based Centiloid Normalisation
Publisher: CSIRO
Date: 2020
Gabor filters in industrial inspection: a review. Application to semiconductor industry
Publisher: SPIE
Date: 09-11-2005
DOI: 10.1117/12.637675
Advances in structural and molecular neuroimaging in Alzheimer's disease
Publisher: AMPCo
Date: 02-2011
DOI: 10.5694/J.1326-5377.2011.TB02938.X
Abstract: Longer life expectancies lead to increases in the prevalence of age-associated illnesses. The number of Australians with dementia is predicted to rise, from 234,000 in 2009 to over 1 million by 2050, as a result of the increased prevalence of Alzheimer's disease (AD), the leading cause of dementia in the elderly. Early diagnosis of AD will become more important as disease-modifying therapies emerge within the next decade. Advances in molecular neuroimaging with amyloid-β-specific radioligands for positron emission tomography, aided by magnetic resonance imaging techniques, allow detection of AD years before symptoms of dementia develop. Longitudinal prospective studies, such as the Australian Imaging Biomarkers and Lifestyle (AIBL) study of ageing, will determine the sensitivity and specificity of these analysis techniques for diagnosing AD and predicting cognitive decline.
Effect of BDNF Val66Met on memory decline and hippocampal atrophy in prodromal alzheimer's disease: A preliminary study
Publisher: Public Library of Science (PLoS)
Date: 27-01-2014
Increased Cerebral Blood Flow with Increased Amyloid burden in the preclinical phase of Alzheimer’s disease
Publisher: Wiley
Date: 30-05-2020
DOI: 10.1002/JMRI.26810
Abstract: Arterial spin labeling (ASL) is an emerging MRI technique for noninvasive measurement of cerebral blood flow (CBF) that has been used to show hemodynamic changes in the brains of people with Alzheimer's disease (AD). CBF changes have been measured using positron emission tomography (PET) across the AD spectrum, but ASL showed limited success in measuring CBF variations in the preclinical phase of AD, where amyloid β (Aβ) plaques accumulate in the decades prior to symptom onset. To investigate the relationship between CBF measured by multiphase‐pseudocontinuous‐ASL (MP‐PCASL) and Aβ burden as measured by 11 C‐PiB PET imaging in a study of cognitively normal (CN) subjects age over 65. Cross‐sectional. Forty‐six CN subjects including 33 with low levels of Aβ burden and 13 with high levels of Aβ. 3T/3D MP‐PCASL. The MP‐PCASL method was chosen because it has a high signal‐to‐noise ratio. Furthermore, the data were analyzed using an efficient processing pipeline consisting of motion correction, ASL motion correction imprecision removal, temporal and spatial filtering, and partial volume effect correction. General Linear Model. In CN subjects positive for Aβ burden ( n = 13), we observed a positive correlation between CBF and Aβ burden in the hippoc us, amygdala, caudate ( P 0.01), frontal, temporal, and insula ( P 0.05). To the best of our knowledge, this is the first study using MP‐PCASL in the study of AD, and the results suggest a potential compensatory hemodynamic mechanism that protects against pathology in the early stages of AD. Level of Evidence: 1 Technical Efficacy: Stage 3 J. Magn. Reson. Imaging 2020 :505–513.
Spline Based Inhomogeneity Correction for 11C-PIB PET Segmentation Using Expectation Maximization
Publisher: Springer Berlin Heidelberg
Date: 2007
DOI: 10.1007/978-3-540-75757-3_28
Abstract: With the advent of biomarkers such as 11C-PIB and the increase in use of PET, automated methods are required for processing and analyzing datasets from research studies and in clinical settings. A common preprocessing step is the calculation of standardized uptake value ratio (SUVR) for inter-subject normalization. This requires segmented grey matter (GM) for VOI refinement. However 11C-PIB uptake is proportional to amyloid build up leading to inhomogeneities in intensities, especially within GM. Inhomogeneities present a challenge for clustering and pattern classification based approaches to PET segmentation as proposed in current literature. In this paper we modify a MR image segmentation technique based on expectation maximization for 11C-PIB PET segmentation. A priori probability maps of the tissue types are used to initialize and enforce anatomical constraints. We developed a Bézier spline based inhomogeneity correction techniques that is embedded in the segmentation algorithm and minimizes inhomogeneity resulting in better segmentations of 11C-PIB PET images. We compare our inhomogeneity with a global polynomial correction technique and validate our approach using co-registered MRI segmentations.
Reduced cortical cholinergic innervation correlates with cognitive decline in mild cognitive impairment
Publisher: Wiley
Date: 06-2023
DOI: 10.1002/ALZ.063527
Abstract: Dysfunction of the cholinergic basal forebrain (BF) neurotransmitter system, including cholinergic axon denervation of the cortex, plays an important role in cognitive decline and dementia. The association of cortical cholinergic denervation with erse cognitive profiles in dementia, particularly at early stages, has not yet been fully explored. We assessed the relationship of cholinergic denervation in the cortex measured using 18 F‐fluoroethoxybenzovesamicol (FEOBV) with cognitive decline at an early stage of dementia. Participants (8 with mild cognitive impairment (MCI) and 10 cognitively unimpaired (CU) controls, aged 60‐86, 55.6% female, MMSE = 28.7±1.5) underwent neuropsychological assessment and FEOBV PET imaging. The neuropsychological battery of tests included measures of memory, executive function, attention and language. Domain‐specific composite scores were calculated by averaging z‐scores of the related tests or subtasks within a domain. FEOBV images were co‐registered to the concurrent structural MRI and normalised to the supratentorial white matter reference region resulting in a standardized uptake value ratio (SUVR). Voxel‐wise analysis was performed on normalised FEOBV images to investigate associations with clinical diagnosis and domain‐specific cognitive performance. Voxel‐based morphometry was also performed to rule out differences in brain morphology. All analyses were corrected for age, sex and total intracranial volume and adjusted for multiple comparisons. The MCI group showed significantly lower global FEOBV SUVR in the cortex although only a focal cluster of reductions near the right middle temporal gyrus was found in the voxel‐wise comparisons. When associations with cognitive performance profiles were assessed in the full cohort, regional positive correlations were found between FEOBV SUVR and cognitive scores across different domains (Figure 1), although these did not include memory. For executive functioning, widespread correlation patterns were observed across both cortical and subcortical regions. Moreover, overlapping profiles were identified for all three cognitive domains of executive function, attention and language, which covered the anterior cingulate gyrus, olfactory cortex, calcarine cortex, middle temporal gyrus and caudate nucleus. We have demonstrated that the topographic profile of FEOBV retention correlated with reduced cognitive performance in different domains, suggesting that reduced cortical cholinergic terminal integrity is an important pathological feature of cognitive decline.
Increasing Power to Predict Mild Cognitive Impairment Conversion to Alzheimer's Disease Using Hippocampal Atrophy Rate and Statistical Shape Models
Publisher: No publisher found
Date: 2010
DOI: 10.1007/978-3-642-15745-5_16
Abstract: Identifying mild cognitive impairment (MCI) subjects who will convert to clinical Alzheimer's disease (AD) is important for therapeutic decisions, patient counselling and clinical trials. Hippoc al volume and rate of atrophy predict clinical decline at the MCI stage and progression to AD. In this paper, we create p-maps from the differences in the shape of the hippoc us between 60 normal controls and 60 AD subjects using statistical shape models, and generate different regions of interest (ROI) by thresholding the p-maps at different significance levels. We demonstrate increased statistical power to classify 86 MCI converters and 128 MCI stable subjects using the hippoc al atrophy rates calculated by the boundary shift integral within these ROIs.
Intercultural communications in remote Aboriginal Australian communities: What works in dementia education and management?
Publisher: Informa UK Limited
Date: 2012
Analysis of 15 software pipelines for validation of [18F]florbetaben PET quantitation
Publisher: SERDI
Date: 2022
Cross-sectional and longitudinal analysis of the relationship between aβ deposition, cortical thickness, and memory in cognitively unimpaired individuals and in alzheimer disease
Publisher: American Medical Association (AMA)
Date: 07-2013
Adjudicating faith: 20 years of secular decision-making for religious spaces
Publisher: Australian Cities Research Network
Date: 2018
Limited cerebral microbleeds effect on regional magnetic susceptibility measured by MRI
Publisher: Wiley
Date: 12-2020
DOI: 10.1002/ALZ.044125
Evaluating early cholinergic degeneration in preclinical Alzheimer’s disease: Milestone 2 - MRI and PET imaging and analysis
Publisher: CSIRO
Date: 2018
Development, dilution, and functional change in the peri-urban landscape: What does it really mean for agriculture?
Publisher: Springer US
Date: 11-09-2013
Encounters with the unfamiliar: international planning education
Publisher: Informa UK Limited
Date: 19-06-2018
Iron and Amyloid depositions are positively related in non-demented individuals
Publisher: Wiley
Date: 07-2016
Towards a universal cortical tau sampling mask
Publisher: Wiley
Date: 12-2021
DOI: 10.1002/ALZ.055816
Abstract: The introduction of the AT(N) framework raised several issues in regards to the definition of T+. What brain regions should be s led? Based on one or on multiple tracers? In this work, we developed a “universal” cortical tau mask for the AD continuum derived from all the major tau ligands. This “universal” cortical mask will serve as the common tau area for all tracers over which several different regional s ling VOI or composites can be then applied. Guaranteeing s ling of the same common regions is the first step to develop a common scale for all tau tracers: the CenTauR. 464 participants underwent tau scans with either 18 F‐AV1451 (CN=54/AD=24), 18 F‐MK6240 (CN=157/AD=22), 18 F‐PI2620 (CN=10/AD=21), 18 F‐PM‐PBB3 (CN=30/AD=28), 18 F‐GTP1 (CN=15/AD=38) or 18 F‐RO948 (CN=35/AD=30). All CN were Aß‐ and all AD were Aß+. The tau scans were spatially normalized using CapAIBL and the cerebellar cortex was used as reference region. For each tracer, a difference image between the means of the Aß‐ CN and Aß+ AD patients was generated. Difference images were subsequently thresholded at 1/3 of the difference between Aß‐ CN and Aß+ AD in the inferior temporal lobe. A single tau specific mask was then constructed from the intersection of all the specific tau tracer masks. A MRI‐derived grey matter mask at PET resolution was applied to the composite mask only s ling grey matter regions. Finally, the mask was mirrored and fused to remove the hemispherical asymmetry of tau pathology. Agreement between masks was assessed by dice‐scores. Visually, all the tracer‐specific masks appeared very similar. None of the known off‐target binding regions were discernible in the resulting masks (Figure 1). There was good agreement between all masks, with dice‐scores of 0.60 and 0.66 for cortical regions. We constructed an “universal” tau mask for the AD continuum based on all the commonly used tau tracers aiming at standardizing tau s ling and quantification across tracers and across centres. The “universal” tau mask demarcates a tau specific space that can then be sub‐segmented into smaller regions to focus on specific areas or composite regions that might better capture early tau deposition and spreading.
A novel semiautomated method for background activity and biological tumour volume definition to improve standardisation of 18F-FET PET imaging in glioblastoma
Publisher: Springer Science and Business Media LLC
Date: 05-02-2022
DOI: 10.1186/S40658-022-00438-2
Abstract: Multicentre clinical trials evaluating the role of 18 F-Fluoroethyl- l -tyrosine ( 18 F-FET) PET as a diagnostic biomarker in glioma management have highlighted a need for standardised methods of data analysis. 18 F-FET uptake normalised against background in the contralateral brain is a standard imaging technique to delineate the biological tumour volume (BTV). Quantitative analysis of 18 F-FET PET images requires a consistent and robust background activity. Currently, defining background activity involves the manual selection of an arbitrary region of interest, a process that is subject to large variability. This study aims to eliminate methodological errors in background activity definition through the introduction of a semiautomated method for region of interest selection. A new method for background activity definition, involving the semiautomated generation of mirror-image (MI) reference regions, was compared with the current state-of-the-art method, involving manually drawing crescent-shape (gCS) reference regions. The MI and gCS methods were tested by measuring values of background activity and resulting BTV of 18 F-FET PET scans of ten patients with recurrent glioblastoma multiforme generated from inputs provided by seven readers. To assess intra-reader variability, each scan was evaluated six times by each reader. Intra- and inter-reader variability in background activity and BTV definition was assessed by means of coefficient of variation. Compared to the gCS method, the MI method showed significantly lower intra- and inter-reader variability both in background activity and in BTV definition. The proposed semiautomated MI method minimises intra- and inter-reader variability, providing a valuable approach for standardisation of 18 F-FET PET quantitative parameters. Trial registration ANZCTR, ACTRN12618001346268. Registered 9 August 2018, www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=374253
3d brain mri gan-based synthesis conditioned on partial volume maps
Publisher: Springer International Publishing
Date: 2020
Regional dynamics of amyloid-β deposition in healthy elderly, mild cognitive impairment and Alzheimer's disease: A voxelwise PiB-PET longitudinal study
Publisher: Oxford University Press (OUP)
Date: 23-05-2012
DOI: 10.1093/BRAIN/AWS125
Abstract: Amyloid-β deposition in Alzheimer's disease is thought to start while in iduals are still cognitively unimpaired and it is hypothesized that after an early phase of fast accumulation, a plateau is reached by the time of cognitive decline. However, few longitudinal Pittsburgh compound B-positron emission tomography studies have tested this hypothesis, and with conflicting results. The purpose of this work is to further our understanding of the dynamics of amyloid-β deposition in a large longitudinal cohort. A total of 32 patients with Alzheimer's disease, 49 subjects with mild cognitive impairment and 103 healthy controls underwent two Pittsburgh compound B-positron emission tomography scans 18 months apart. For each participant, a parametric map of Pittsburgh compound B-positron emission tomography rate of change was created [(follow-up scan - baseline scan)/follow-up duration] and entered in a voxelwise three-way analysis of covariance, with clinical status (healthy controls, mild cognitive impairment or Alzheimer's disease), disease progression (clinical conversion from healthy controls to mild cognitive impairment or Alzheimer's disease, or from mild cognitive impairment to Alzheimer's disease) and Pittsburgh compound B status (positive versus negative) as independent factors. Only a significant effect of the Pittsburgh compound B status was found: both Pittsburgh compound B-positive and -negative subjects showed a significant increase in amyloid-β deposition, with this increase being significantly higher in Pittsburgh compound B-positive in iduals. This finding suggests either that Pittsburgh compound B-negative in iduals have slower rates of amyloid-β accumulation than positive, or that the proportion of in iduals showing significant increase in amyloid-β deposition, termed 'Pittsburgh compound B accumulators', is higher within the Pittsburgh compound B-positive group than within the Pittsburgh compound B-negative group. The bimodal distribution of the in idual rates of neocortical amyloid-β accumulation observed support the existence of 'Pittsburgh compound B non-accumulators' and 'Pittsburgh compound B accumulators' and different clustering analyses led to a consistent threshold to separate these two subgroups (0.014-0.022 standardized uptake value ratio(pons)/year). The voxelwise three-way analysis of covariance was thus recomputed with the 'Pittsburgh compound B accumulators' only and the results were almost unchanged, with the Pittsburgh compound B-positive group showing higher accumulation than the Pittsburgh compound B-negative group. Finally, a significant negative correlation was found between Pittsburgh compound B rate of change and Pittsburgh compound B baseline burden, but only in the Pittsburgh compound B-positive group (r= -0.24 P=0.025). Higher rates of amyloid-β deposition are associated with higher amyloid-β burden suggesting that amyloid-β deposition does not reach a plateau when cognitive impairments manifest but is instead an ongoing process present even at the Alzheimer's disease stage. amyloid-β accumulation also seems to slow down at the latest stages of the process, i.e. in participants with the highest amyloid burden. Furthermore, this study identified the existence of Pittsburgh compound 'accumulators' and 'non-accumulators', notably within the Pittsburgh compound B-negative group, which may be a relevant concept for future studies.
Cerebral quantitative susceptibility mapping predicts amyloid-β-related cognitive decline
Publisher: Oxford University Press (OUP)
Date: 24-07-2017
DOI: 10.1093/BRAIN/AWX137
Abstract: See Derry and Kent (doi:10.1093/awx167) for a scientific commentary on this article.The large variance in cognitive deterioration in subjects who test positive for amyloid-β by positron emission tomography indicates that convergent pathologies, such as iron accumulation, might combine with amyloid-β to accelerate Alzheimer's disease progression. Here, we applied quantitative susceptibility mapping, a relatively new magnetic resonance imaging method sensitive to tissue iron, to assess the relationship between iron, amyloid-β load, and cognitive decline in 117 subjects who underwent baseline magnetic resonance imaging and amyloid-β positron emission tomography from the Australian Imaging, Biomarkers and Lifestyle study (AIBL). Cognitive function data were collected every 18 months for up to 6 years from 100 volunteers who were either cognitively normal (n = 64) or diagnosed with mild cognitive impairment (n = 17) or Alzheimer's disease (n = 19). Among participants with amyloid pathology (n = 45), higher hippoc al quantitative susceptibility mapping levels predicted accelerated deterioration in composite cognition tests for episodic memory [β(standard error) = -0.169 (0.034), P = 9.2 × 10-7], executive function [β(standard error) = -0.139 (0.048), P = 0.004), and attention [β(standard error) = -0.074 (0.029), P = 0.012]. Deteriorating performance in a composite of language tests was predicted by higher quantitative susceptibility mapping levels in temporal lobe [β(standard error) = -0.104 (0.05), P = 0.036] and frontal lobe [β(standard error) = -0.154 (0.055), P = 0.006]. These findings indicate that brain iron might combine with amyloid-β to accelerate clinical progression and that quantitative susceptibility mapping could be used in combination with amyloid-β positron emission tomography to stratify in iduals at risk of decline.
Larger temporal volume in elderly with high versus low beta-amyloid deposition
Publisher: Oxford University Press (OUP)
Date: 25-08-2010
DOI: 10.1093/BRAIN/AWQ187
Abstract: β-Amyloid deposition is one of the main hallmarks of Alzheimer's disease thought to eventually cause neuronal death. Post-mortem and neuroimaging studies have consistently reported cases with documented normal cognition despite high β-amyloid burden. It is of great interest to understand what differentiates these particular subjects from those without β-amyloid deposition or with both β-amyloid deposition and cognitive deficits, i.e. what allows these subjects to resist the damage of the pathological lesions. [¹¹C]Pittsburgh compound B positron emission tomography and magnetic resonance brain scans were obtained in 149 participants including healthy controls and patients with subjective cognitive impairment, mild cognitive impairment and Alzheimer's disease. Magnetic resonance data were compared between high versus low-[11C]Pittsburgh compound B cases, and between high-[¹¹C]Pittsburgh compound B cases with versus those without cognitive deficits. Larger temporal (including hippoc al) grey matter volume, associated with better episodic memory performance, was found in high- versus low-[¹¹C]Pittsburgh compound B healthy controls. The same finding was obtained using different [¹¹C]Pittsburgh compound B thresholds, correcting [¹¹C]Pittsburgh compound B data for partial averaging, using age, education, Mini-Mental State Examination, apolipoprotein E4 and sex-matched subs les, and using manual hippoc al delineation instead of voxel-based analysis. By contrast, in participants with subjective cognitive impairment, significant grey matter atrophy was found in high-[¹¹C]Pittsburgh compound B cases compared to low-[¹¹C]Pittsburgh compound B cases, as well as in high-[¹¹C]Pittsburgh compound B cases with subjective cognitive impairment, mild cognitive impairment and Alzheimer's disease compared to high-[¹¹C]Pittsburgh compound B healthy controls. Larger grey matter volume in high-[¹¹C]Pittsburgh compound B healthy controls may reflect either a tissue reactive response to β-amyloid or a combination of higher 'brain reserve' and under-representation of subjects with standard/low temporal volume in the high-[¹¹C]Pittsburgh compound B healthy controls. Our complementary analyses tend to support the latter hypotheses. Overall, our findings suggest that the deleterious effects of β-amyloid on cognition may be delayed in those subjects with larger brain (temporal) volume.
Clinical and cognitive trajectories in cognitively healthy elderly individuals with suspected non-Alzheimer's disease pathophysiology (SNAP) or Alzheimer's disease pathology: a longitudinal study
Publisher: Elsevier BV
Date: 09-2016
Regional differences in the reduction in cerebral FDG uptake induced by the ketogenic diet.
Publisher: Springer Science and Business Media LLC
Date: 15-12-2022
DOI: 10.1186/S41824-022-00150-5
Abstract: The postulated benefits of the ketogenic diet in the management of multiple medical conditions have seen more patients who are in therapeutic ketosis attending 18 F-FDG PET scans. This study aimed to investigate the effect of ketosis on cerebral glucose metabolism in a clinical PET scanning environment using 18 F-FDG uptake as a surrogate marker. A retrospective audit was conducted of the brain 18 F-FDG uptake in 52 patients who underwent PET scans for possible cardiac sarcoidosis or suspected intracardiac infection, following a ketogenic diet and prolonged fasting. SUVbw for whole brain and separate brain regions was compared with serum glucose and serum ketone body (beta-hydroxybutyrate) levels. The expected negative association between serum glucose levels and whole brain 18 F-FDG uptake was confirmed. A reduction in SUVbw due to increasing serum ketones levels was also observed that was independent of and in addition to the effects of glucose. The magnitude of the reduction in SUVbw related to serum glucose level and serum ketone level was found to be greater in the precuneus than in the cerebellum or whole brain. In a real-world clinical PET setting, cerebral 18 F-FDG uptake appears to be affected by glycaemia and ketonaemia. This means when assessing the brain, both serum glucose and ketone levels need to be considered when SUVs are used to distinguish between pathologic and physiologic states. The magnitude of this effect appears to vary between different brain regions. This regional difference should be taken into consideration when selecting the appropriate brain region for SUV normalisation, particularly when undertaking database comparison in the assessment of dementia.
Diagnostic value of 8.5 T magnetic resonance spectroscopy of benign and malignant skin lesion biopsies
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 08-2010
DOI: 10.1097/CMR.0B013E32833BD0EC
Abstract: Proton magnetic resonance spectroscopy at 8.5 T ex vivo was used to investigate skin lesions for metabolic signatures to predict malignancy or indicate malignant potential. Magnetic resonance spectroscopy was performed on biopsy tissue obtained from 63 skin lesions and five melanoma metastases from 55 patients. S les were grouped and compared according to five clinically significant distinctions: melanoma (n=38) or nonmelanoma (n=30), primary melanoma (n=33) or secondary melanoma (involved nodes and distant metastases, n=5), primary melanoma (n=33) or nevi (n=8), malignant (n=46) or nonmalignant (n=22), and melanocytic (n=46) or nonmelanocytic (n=22). In all comparisons, the average magnetic resonance spectrum of each class lay within 1 standard deviation of the average spectrum of the other class. There was a higher average choline metabolite signal intensity in melanoma-containing biopsies compared with nonmelanoma biopsies. Discriminant analysis based on the intensity of the choline resonance alone achieved 69% accuracy in separation of melanoma and nonmelanoma tissue. Inclusion of other metabolite resonances in the analysis did not increase discrimination accuracy. Tissue heterogeneity in conventionally collected full thickness skin biopsies and possible biochemical variance within in idual tissue types limit classification accuracy using the methods and magnetic field strength that were earlier reported to provide accurate discrimination in other cancer types.
Place of children in community building: Putting theory into practice. Children's and young people's engagement report (Vol. 2)
Publisher: La Trobe University; Southern Cross University
Date: 2012
Introduction
Publisher: Cambridge University Press
Date: 17-03-2005
Effect of dietary potassium supplementation on the calcium absorption capacity in the rumen and abomasum and fractional excretion of urinary minerals in sheep
Publisher: CSIRO Publishing
Date: 2015
DOI: 10.1071/AN12366
Abstract: The aim of this study was to determine the effect of potassium (K) supplementation on the calcium (Ca) absorption capacity from the rumen and abomasum of sheep. The Ca absorption capacity from the rumen and abomasum of sheep was measured using stable strontium (Sr) as a Ca-analogue tracer method. The sheep, cannulated at either the rumen or abomasum, were randomly allocated to one of two groups (control or K-supplemented) and fed in in idual metabolism pens twice daily with a diet comprising oaten hay, lucerne chaff and barley fortified with or without potassium carbonate (K2CO3). The K content of the diet of the K-supplemented animals was 3.1% of dry matter compared with 1.4% for the control animals. The animals were fed their respective diets for a period of 2 weeks. The fractional absorption capacity (FC) of Ca was estimated before, during and after the treatment period. Supplementation with K decreased the FC of Ca in both the rumen and abomasum during treatment and increased the FC of Ca in the abomasum post-treatment. Supplementation with K also increased the fractional excretion of K in the urine, but decreased the fractional excretion of Ca and magnesium (Mg) (P 0.05), showing that K supplementation significantly affected Ca and Mg metabolism. Results suggest that renal conservation of Ca and Mg is an important mechanism controlling the Ca and Mg pool for vital functions of the body. In times of high demand for these minerals during lactation and pregnancy, high K in the diets may predispose sheep to hypomagnesaemia and hypocalcaemia, which in turn will have a negative impact on productivity and economic returns.
A human-centred assessment framework to prioritise heat mitigation efforts for active travel at city scale
Publisher: Elsevier BV
Date: 04-2021
Automatic Brain Tumour Segmentation In 18F-FDOPA PET using PET/MRI Fusion
Publisher: IEEE
Date: 12-2012
Local government co-ordination: metropolitan governance in twenty-first century Australia
Publisher: Australian Housing and Urban Research Institute (AHURI)
Date: 11-03-2021
Expectation-Maximization with Image-Weighted Markov Random Fields to Handle Severe Pathology
Publisher: IEEE
Date: 11-2015
Subjective memory decline predicts greater rates of clinical progression in preclinical Alzheimer's disease
Publisher: Wiley
Date: 04-02-2016
DOI: 10.1016/J.JALZ.2015.12.013
Abstract: The objective of this study was to determine the utility of subjective memory decline (SMD) to predict episodic memory change and rates of clinical progression in cognitively normal older adults with evidence of high β-amyloid burden (CN Aβ+). Fifty-eight CN Aβ+ participants from the Australian Imaging, Biomarkers, and Lifestyle study responded to an SMD questionnaire and underwent comprehensive neuropsychological assessments. Participant data for three follow-up assessments were analyzed. In CN Aβ+, subjects with high SMD did not exhibit significantly greater episodic memory decline than those with low SMD. High SMD was related to greater rates of progression to mild cognitive impairment or Alzheimer's disease (AD) dementia (hazard ratio = 5.1 95% confidence interval, 1.4-20.0, P = .02) compared with low SMD. High SMD was associated with greater depressive symptomatology and smaller left hippoc al volume. High SMD is a harbinger of greater rates of clinical progression in preclinical AD. Although SMD reflects broader diagnostic implications for CN Aβ+, more sensitive measures may be required to detect early subtle cognitive change.
Trans-ResNet: Integrating Transformers and CNNs for Alzheimer’s disease classification
Publisher: IEEE
Date: 28-03-2022
Using imputation to provide harmonized longitudinal measures of cognition across AIBL and ADNI.
Publisher: Springer Science and Business Media LLC
Date: 10-12-2021
DOI: 10.1038/S41598-021-02827-6
Abstract: To improve understanding of Alzheimer’s disease, large observational studies are needed to increase power for more nuanced analyses. Combining data across existing observational studies represents one solution. However, the disparity of such datasets makes this a non-trivial task. Here, a machine learning approach was applied to impute longitudinal neuropsychological test scores across two observational studies, namely the Australian Imaging, Biomarkers and Lifestyle Study (AIBL) and the Alzheimer's Disease Neuroimaging Initiative (ADNI) providing an overall harmonised dataset. MissForest, a machine learning algorithm, capitalises on the underlying structure and relationships of data to impute test scores not measured in one study aligning it to the other study. Results demonstrated that simulated missing values from one dataset could be accurately imputed, and that imputation of actual missing data in one dataset showed comparable discrimination (p 0.001) for clinical classification to measured data in the other dataset. Further, the increased power of the overall harmonised dataset was demonstrated by observing a significant association between CVLT-II test scores (imputed for ADNI) with PET Amyloid-β in MCI APOE -ε4 homozygotes in the imputed data (N = 65) but not for the original AIBL dataset (N = 11). These results suggest that MissForest can provide a practical solution for data harmonization using imputation across studies to improve power for more nuanced analyses.
Predicting Alzheimer disease with β-amyloid imaging: Results from the Australian imaging, biomarkers, and lifestyle study of ageing
Publisher: Wiley
Date: 12-2013
DOI: 10.1002/ANA.24040
Abstract: Biomarkers for Alzheimer disease (AD) can detect the disease pathology in asymptomatic subjects and in iduals with mild cognitive impairment (MCI), but their cognitive prognosis remains uncertain. We aimed to determine the prognostic value of β-amyloid imaging, alone and in combination with memory performance, hippoc al atrophy, and apolipoprotein E ε4 status in nondemented, older in iduals. A total of 183 healthy in iduals (age = 72.0 ± 7.26 years) and 87 participants with MCI (age = 73.7 ± 8.27) in the Australian Imaging, Biomarkers, and Lifestyle study of ageing were studied. Clinical reclassification was performed after 3 years, blind to biomarker findings. β-Amyloid imaging was considered positive if the (11) C-Pittsburgh compound B cortical to reference ratio was ≥1.5. Thirteen percent of healthy persons progressed (15 to MCI, 8 to dementia), and 59% of the MCI cohort progressed to probable AD. Multivariate analysis showed β-amyloid imaging as the single variable most strongly associated with progression. Of combinations, subtle memory impairment (Z score = -0.5 to -1.5) with a positive amyloid scan was most strongly associated with progression in healthy in iduals (odds ratio [OR] = 16, 95% confidence interval [CI] = 3.7-68 positive predictive value [PPV] = 50%, 95% CI = 19-81 negative predictive value [NPV] = 94%, 95% CI = 88-98). Almost all amnestic MCI subjects (Z score ≤ -1.5) with a positive amyloid scan developed AD (OR = ∞ PPV = 86%, 95% CI = 72-95 NPV = 100%, 95% CI = 80-100). Hippoc al atrophy and ε4 status did not add further predictive value. Subtle memory impairment with a positive β-amyloid scan identifies healthy in iduals at high risk for MCI or AD. Clearly amnestic patients with a positive amyloid scan have prodromal AD and a poor prognosis for dementia within 3 years.
Vulnerability to Bushfire Risk at Melbourne's Urban Fringe: The Failure of Regulatory Land Use Planning
Publisher: Wiley
Date: 05-10-2010
Australia in 2030: what is our path to health for all?
Publisher: AMPCo
Date: 05-2021
DOI: 10.5694/MJA2.51020
Abstract: CHAPTER 1: HOW AUSTRALIA IMPROVED HEALTH EQUITY THROUGH ACTION ON THE SOCIAL DETERMINANTS OF HEALTH: Do not think that the social determinants of health equity are old hat. In reality, Australia is very far away from addressing the societal level drivers of health inequity. There is little progressive policy that touches on the conditions of daily life that matter for health, and action to redress inequities in power, money and resources is almost non-existent. In this chapter we ask you to pause this reality and come on a fantastic journey where we envisage how COVID-19 was a great disruptor and accelerator of positive progressive action. We offer glimmers of what life could be like if there was committed and real policy action on the social determinants of health equity. It is vital that the health sector assists in convening the multisectoral stakeholders necessary to turn this fantasy into reality. CHAPTER 2: ABORIGINAL AND TORRES STRAIT ISLANDER CONNECTION TO CULTURE: BUILDING STRONGER INDIVIDUAL AND COLLECTIVE WELLBEING: Aboriginal and Torres Strait Islander peoples have long maintained that culture (ie, practising, maintaining and reclaiming it) is vital to good health and wellbeing. However, this knowledge and understanding has been dismissed or described as anecdotal or intangible by Western research methods and science. As a result, Aboriginal and Torres Strait Islander culture is a poorly acknowledged determinant of health and wellbeing, despite its significant role in shaping in iduals, communities and societies. By extension, the cultural determinants of health have been poorly defined until recently. However, an increasing amount of scientific evidence supports what Aboriginal and Torres Strait Islander people have always said - that strong culture plays a significant and positive role in improved health and wellbeing. Owing to known gaps in knowledge, we aim to define the cultural determinants of health and describe their relationship with the social determinants of health, to provide a full understanding of Aboriginal and Torres Strait Islander wellbeing. We provide ex les of evidence on cultural determinants of health and links to improved Aboriginal and Torres Strait Islander health and wellbeing. We also discuss future research directions that will enable a deeper understanding of the cultural determinants of health for Aboriginal and Torres Strait Islander people. CHAPTER 3: PHYSICAL DETERMINANTS OF HEALTH: HEALTHY, LIVEABLE AND SUSTAINABLE COMMUNITIES: Good city planning is essential for protecting and improving human and planetary health. Until recently, however, collaboration between city planners and the public health sector has languished. We review the evidence on the health benefits of good city planning and propose an agenda for public health advocacy relating to health-promoting city planning for all by 2030. Over the next 10 years, there is an urgent need for public health leaders to collaborate with city planners - to advocate for evidence-informed policy, and to evaluate the health effects of city planning efforts. Importantly, we need integrated planning across and between all levels of government and sectors, to create healthy, liveable and sustainable cities for all. CHAPTER 4: HEALTH PROMOTION IN THE ANTHROPOCENE: THE ECOLOGICAL DETERMINANTS OF HEALTH: Human health is inextricably linked to the health of the natural environment. In this chapter, we focus on ecological determinants of health, including the urgent and critical threats to the natural environment, and opportunities for health promotion arising from the human health co-benefits of actions to protect the health of the planet. We characterise ecological determinants in the Anthropocene and provide a sobering snapshot of planetary health science, particularly the momentous climate change health impacts in Australia. We highlight Australia's position as a major fossil fuel producer and exporter, and a country lacking cohesive and timely emissions reduction policy. We offer a roadmap for action, with four priority directions, and point to a scaffold of guiding approaches - planetary health, Indigenous people's knowledge systems, ecological economics, health co-benefits and climate-resilient development. Our situation requires a paradigm shift, and this demands a recalibration of health promotion education, research and practice in Australia over the coming decade. CHAPTER 5: DISRUPTING THE COMMERCIAL DETERMINANTS OF HEALTH: Our vision for 2030 is an Australian economy that promotes optimal human and planetary health for current and future generations. To achieve this, current patterns of corporate practice and consumption of harmful commodities and services need to change. In this chapter, we suggest ways forward for Australia, focusing on pragmatic actions that can be taken now to redress the power imbalances between corporations and Australian governments and citizens. We begin by exploring how the terms of health policy making must change to protect it from conflicted commercial interests. We also examine how marketing unhealthy products and services can be more effectively regulated, and how healthier business practices can be incentivised. Finally, we make recommendations on how various public health stakeholders can hold corporations to account, to ensure that people come before profits in a healthy and prosperous future Australia. CHAPTER 6: DIGITAL DETERMINANTS OF HEALTH: THE DIGITAL TRANSFORMATION: We live in an age of rapid and exponential technological change. Extraordinary digital advancements and the fusion of technologies, such as artificial intelligence, robotics, the Internet of Things and quantum computing constitute what is often referred to as the digital revolution or the Fourth Industrial Revolution (Industry 4.0). Reflections on the future of public health and health promotion require thorough consideration of the role of digital technologies and the systems they influence. Just how the digital revolution will unfold is unknown, but it is clear that advancements and integrations of technologies will fundamentally influence our health and wellbeing in the future. The public health response must be proactive, involving many stakeholders, and thoughtfully considered to ensure equitable and ethical applications and use. CHAPTER 7: GOVERNANCE FOR HEALTH AND EQUITY: A VISION FOR OUR FUTURE: Coronavirus disease 2019 has caused many people and communities to take stock on Australia's direction in relation to health, community, jobs, environmental sustainability, income and wealth. A desire for change is in the air. This chapter imagines how changes in the way we govern our lives and what we value as a society could solve many of the issues Australia is facing - most pressingly, the climate crisis and growing economic and health inequities. We present an imagined future for 2030 where governance structures are designed to ensure transparent and fair behaviour from those in power and to increase the involvement of citizens in these decisions, including a constitutional voice for Indigenous peoples. We imagine that these changes were made by measuring social progress in new ways, ensuring taxation for public good, enshrining human rights (including to health) in legislation, and protecting and encouraging an independent media. Measures to overcome the climate crisis were adopted and democratic processes introduced in the provision of housing, education and community development.
β-amyloid PET harmonisation across longitudinal studies: Application to AIBL, ADNI and OASIS3
Publisher: Elsevier BV
Date: 11-2022
Comparison of MR-less PiB SUVR quantification methods
Publisher: Elsevier BV
Date: 2015
DOI: 10.1016/J.NEUROBIOLAGING.2014.04.033
Abstract: (11)C-Pittsburgh compound B (PiB) is a positron emission tomography (PET) tracer designed to bind to amyloid-β (Aβ) plaques, one of the hallmarks of Alzheimer's disease (AD). The potential of PiB as an early marker of AD led to the increasing use of PiB in clinical research studies and development of several F-18-labeled Aβ radiotracers. Automatic quantification of PiB images requires an accurate parcellation of the brain's gray matter (GM). Typically, this relies on a coregistered magnetic resonance imaging (MRI) to extract the cerebellar GM, compute the standardized uptake value ratio (SUVR), and provide parcellation and segmentation for quantification of regional and global SUVR. However, not all subjects can undergo MRI, in which case, an MR-less method is desirable. In this study, we assess 3 PET-only quantification methods: a mean atlas, an adaptive atlas, and a multi-atlas approaches on a database of 237 subjects having been imaged with both PiB PET and MRI. The PET-only methods were compared against MR-based SUVR quantification and evaluated in terms of correlation, average error, and performance in classifying subjects with low and high Aβ deposition. The mean atlas method suffered from a significant bias between the estimated neocortical SUVR and the PiB status, resulting in an overall error of 5.6% (R(2) = 0.98), compared with the adaptive and multi-atlas approaches that had errors of 3.06% and 2.74%, respectively (R(2) = 0.98), and no significant bias. In classifying PiB-negative from PiB-positive subjects, the mean atlas had 10 misclassified subjects compared with 0 for the adaptive and 1 for the multi-atlas approach. Overall, the adaptive and the multi-atlas approaches performed similarly well against the MR-based quantification and would be a suitable replacements for PiB quantification when no MRI is available.
A sustainability agenda in planning education
Publisher: Springer Netherlands
Date: 2012
Partial volume model for brain MRI scan using MP2RAGE
Publisher: Wiley
Date: 05-07-2017
DOI: 10.1002/HBM.23719
Motivations for retention and mobility: Pathways of skilled migrants in regional Victoria, Australia
Publisher: Informa UK Limited
Date: 04-2014
Two-year prognostic utility of plasma p217+tau across the Alzheimer’s continuum
Publisher: SERDI
Date: 2023
Predicting motor outcome in preterm infants from very early brain diffusion MRI using a deep learning convolutional neural network (CNN) model
Publisher: Elsevier BV
Date: 07-2020
Relationship between amyloid and tau levels and its impact on tau spreading
Publisher: Wiley
Date: 12-2021
DOI: 10.1002/ALZ.055714
Abstract: Previous studies have shown that Aß‐amyloid (Aß) likely promotes tau to spread beyond the medial temporal lobe. However, the Aß levels necessary for tau to spread in the neocortex is still unclear. 466 participants underwent tau imaging with [ 18 F]MK6420 and Aß imaging with [ 18 F]NAV4694 (Fig. 1). Aß scans were quantified on the Centiloid (CL) scale with a cut‐off of 25CL for abnormal levels of Aß (A+). Tau scans were quantified in three regions of interest (ROI) (mesial temporal (Me) temporoparietal neocortex (Te) and rest of neocortex (R)) and four mesial temporal region (entorhinal cortex, amygdala, hippoc us and parahippoc us) using the cerebellar cortex as reference region. Regional tau thresholds were established as the 95%ile of the cognitively unimpaired A‐ subjects. The prevalence of abnormal tau levels (T+) along the Centiloid continuum was determined. The plots of prevalence of T+ (Fig. 2) show earlier and greater increase along the Centiloid continuum in the medial temporal area compared to neocortex. Prevalence of T+ was low but associated with Aß level between 10‐40 CL reaching 23% in Me, 15% in Te and 11% in R. Between 40‐70 CL, the prevalence of T+ subjects per CL increased four‐fold faster and at 70 CL was 64% in Me, 51% in Te and 37% in R. In cognitively unimpaired (Fig. 3), there were no T+ in R below 50 CL. The highest prevalence of T+ was found in the entorhinal cortex, reaching 40% at 40 CL and 80% at 60 CL. Outside the entorhinal cortex, abnormal levels of cortical tau on PET are rarely found with Aß levels below 40 CL. Above 40 CL prevalence of T+ accelerates in all areas. Moderate Aß levels are required before neocortical tau becomes detectable.
Identification of Functional Connectivity Features in Depression Subtypes Using a Data-Driven Approach
Publisher: Springer International Publishing
Date: 2019
Real-time image segmentation for anomalies detection using SVM approximation
Publisher: SPIE
Date: 30-04-2003
DOI: 10.1117/12.515163
Assessing atrophy measurement techniques in dementia: Results from the MIRIAD atrophy challenge
Publisher: Elsevier BV
Date: 12-2015
A randomized, exploratory molecular imaging study targeting Aβ-amyloid with a novel 8-OH quinoline in Alzheimer’s disease (The PBT2-204 IMAGINE Study).
Publisher: Wiley
Date: 11-2017
Non-negative matrix factorisation improves Centiloid robustness in longitudinal studies.
Publisher: Elsevier BV
Date: 02-2020
Local government perspectives on rural retirement migration and social sustainability
Publisher: Informa UK Limited
Date: 19-06-2019
Amyloid β deposition, neurodegeneration, and cognitive decline in sporadic Alzheimer's disease: a prospective cohort study
Publisher: Elsevier BV
Date: 04-2013
Functional Change and the Peri-Urban Region: Food Systems and Agricultural Vulnerability
Publisher: Wiley
Date: 09-2013
MR image segmentation of the knee bone using phase information
Publisher: Elsevier BV
Date: 08-2007
DOI: 10.1016/J.MEDIA.2007.03.003
Abstract: Magnetic resonance (MR) imaging is a widely available and well accepted non invasive imaging technique. Development of automatic and semi-automatic techniques to analyse MR images has been the focus of much research and numerous publications. However, most of this research only uses the magnitude of the acquired complex MR signal, discarding the phase information. In MR, the phase relates to the magnetic properties of tissues, information which is not found in the magnitude signal. As a result, phase is a complement to the magnitude signal and can improve the segmentation and analysis of MR images. In this paper, we consider the automatic classification of textured tissues in 3D MRI. Specifically, we include features extracted from the phase of the MR signal to improve texture discrimination in the bone segmentation. Our approach does not require phase unwrapping, with the MR signal processed in its complex form. The extra information extracted from the phase provides better segmentation, compared to only using magnitude features. The segmentation approach is integrated within a novel multiscale scheme, designed to improve the speed of pixel based classification algorithms, such as support vector machines. An order of magnitude increase is obtained, by reducing the number of pixels that need to be classified.
Does mental health-related discrimination predict health service use 2 years later? Findings from an Australian national survey
Publisher: Springer Science and Business Media LLC
Date: 27-08-2020
DOI: 10.1007/S00127-019-01762-2
Abstract: Stigma and discrimination are central concerns for people with mental health problems. The aim of the study was to carry out a follow-up survey of a national survey of experiences of avoidance, discrimination and positive treatment in people with mental health problems to explore how those experiences relate to health service use. In 2017, telephone interviews were carried out with 655 Australians aged 18+, who had participated in a 2014 survey and reported a mental health problem or scored highly on a symptom screening questionnaire. Questions covered mental health, disclosure, health service utilisation, and experiences of avoidance, discrimination and positive treatment in a variety of different settings. Regression analyses were used to assess the extent to which count of settings of experiences of avoidance, discrimination or positive treatment at baseline (2014) or follow-up (2017) predicted health service use at follow-up. An increase in past experiences of discrimination was associated with a greater number of visits to hospital or specialist doctors and an increase in positive treatment was associated with a greater number of visits to a mental health professional. Increases in both positive and negative experiences were associated with greater healthcare costs, but the costs were greatest for discrimination at follow-up (concurrent discrimination), primarily due to the cost of nights in hospital. While both discrimination and positive treatment are associated with greater healthcare costs, concurrent experiences were shown to be more important correlates of health service use than past experiences. Moreover, those in supportive environments may be more willing to engage in earlier evidence-based treatment for mental health problems.
Features extraction on complex images
Publisher: IEEE
Date: 2004
Political pragmatism and the creative economy: Singapore as a City for the Arts
Publisher: Informa UK Limited
Date: 11-2010
Assessing local outcomes in heterogeneous gliomas
Publisher: IOP Publishing
Date: 24-03-2014
Automatic 11C PiB SUVR quantification
Publisher: Wiley
Date: 07-2013
Partial volume estimation of brain cortex from MRI using topology-corrected segmentation
Publisher: IEEE
Date: 06-2009
Partnerships of learning for planning education Who is learning what from whom? The beautiful messiness of learning partnerships/Experiential learning partnerships in Australian and New Zealand higher
Publisher: Informa UK Limited
Date: 03-07-2015
Retinal vascular biomarkers for early detection and monitoring of Alzheimer's disease
Publisher: Springer Science and Business Media LLC
Date: 26-02-2013
DOI: 10.1038/TP.2012.150
Computer-aided detection of cerebral microbleeds in susceptibility-weighted imaging
Publisher: Elsevier BV
Date: 12-2015
DOI: 10.1016/J.COMPMEDIMAG.2015.10.001
Abstract: Susceptibility-weighted imaging (SWI) is recognized as the preferred MRI technique for visualizing cerebral vasculature and related pathologies such as cerebral microbleeds (CMBs). Manual identification of CMBs is time-consuming, has limited reliability and reproducibility, and is prone to misinterpretation. In this paper, a novel computer-aided microbleed detection technique based on machine learning is presented: First, spherical-like objects (potential CMB candidates) with their corresponding bounding boxes were detected using a novel multi-scale Laplacian of Gaussian technique. A set of robust 3-dimensional Radon- and Hessian-based shape descriptors within each bounding box were then extracted to train a cascade of binary random forests (RF). The cascade consists of consecutive independent RF classifiers with low to high posterior probability constraints to handle imbalanced training sets (CMBs and non-CMBs), and to progressively improve detection rates. The proposed method was validated on 66 subjects whose CMBs were manually stratified into "possible" and "definite" by two medical experts. The proposed technique achieved a sensitivity of 87% and an average false detection rate of 27.1 CMBs per subject on the "possible and definite" set. A sensitivity of 93% and false detection rate of 10 CMBs per subject was also achieved on the "definite" set. The proposed automated approach outperforms state of the art methods, and promises to enhance manual expert screening. Benefits include improved reliability, minimization of intra-rater variability and a reduction in assessment time.
Computer-aided detection of cerebral microbleeds in susceptibility-weighted imaging
Publisher: No publisher found
Date: 2015
Tau and amyloid biomarkers modify the degree to which cognitive reserve and brain reserve predict cognitive decline
Publisher: Cambridge University Press (CUP)
Date: 30-08-2022
DOI: 10.1017/S1355617722000546
Abstract: Brain reserve, cognitive reserve, and education are thought to protect against late-life cognitive decline, but these variables have not been directly compared to one another in the same model, using future cognitive and functional decline as outcomes. We sought to determine whether the influence of these protective factors on executive function (EF) and daily function decline was dependent upon Alzheimer’s disease (AD) pathology severity, as measured by the total tau to beta-amyloid (T-τ/Aβ 1-42 ) ratio in cerebrospinal fluid (CSF). Participants were 1201 older adult volunteers in the Alzheimer’s Disease Neuroimaging Initiative (ADNI) study. Brain reserve was defined using a composite index of structural brain volumes (total brain matter, hippoc us, and white matter hyperintensity). Cognitive reserve was defined as the variance in episodic memory performance not explained by brain integrity and demographics. At higher levels of T-τ/Aβ 1-42 , brain and cognitive reserve predicted slower decline in EF. Only brain reserve attenuated decline at lower levels of T-τ/Aβ 1-42 . Education had no independent association with cognitive decline. These results point to a hierarchy of protection against aging- and disease-associated cognitive decline. When pathology is low, only structural brain integrity predicts rate of future EF decline. The ability of cognitive reserve to predict future EF decline becomes stronger as CSF biomarker evidence of AD increases. Although education is typically thought of as a proxy for cognitive reserve, it did not show any protective effects on cognition after accounting for brain integrity and the residual cognitive reserve index.
Core Alzheimer's disease cerebrospinal fluid biomarker assays are not affected by aspiration or gravity drip extraction methods.
Publisher: Springer Science and Business Media LLC
Date: 16-04-2021
DOI: 10.1186/S13195-021-00812-9
Abstract: CSF biomarkers are well-established for routine clinical use, yet a paucity of comparative assessment exists regarding CSF extraction methods during lumbar puncture. Here, we compare in detail biomarker profiles in CSF extracted using either gravity drip or aspiration. Biomarkers for β-amyloidopathy (Aβ1–42, Aβ1–40), tauopathy (total tau), or synapse pathology (BACE1, Neurogranin Trunc-p75, α-synuclein) were assessed between gravity or aspiration extraction methods in a sub-population of the Australian Imaging, Biomarkers and Lifestyle (AIBL) study (cognitively normal, N = 36 mild cognitive impairment, N = 8 Alzheimer’s disease, N = 6). High biomarker concordance between extraction methods was seen (concordance correlation 0.85). Passing Bablock regression defined low beta coefficients indicating high scalability. Levels of these commonly assessed CSF biomarkers are not influenced by extraction method. Results of this study should be incorporated into new consensus guidelines for CSF collection, storage, and analysis of biomarkers.
Automatic detection of small spherical lesions using multiscale approach in 3D medical images
Publisher: IEEE
Date: 09-2013
Ea-GANs: Edge-Aware Generative Adversarial Networks for Cross-Modality MR Image Synthesis
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 07-2019
Pupil response biomarkers for early detection and monitoring of Alzheimer's disease.
Publisher: Bentham Science Publishers Ltd.
Date: 21-10-2013
DOI: 10.2174/15672050113106660163
Abstract: A screening process that could provide early and accurate diagnosis or prognosis for Alzheimer's disease (AD) would enable earlier intervention, and enable current and future treatments to be more effective. Ocular pathology and changes to vision and ocular function are being investigated for early detection and monitoring of AD. To explore the relationship between pupil flash response (PFR) parameters, AD and brain amyloid plaque burden. Nineteen AD and seventy healthy control (HC) participants were recruited from the Australian Imaging, Biomarkers and Lifestyle (AIBL) Flagship Study of Ageing. The potential correlations between PFR parameters and 1) AD and 2) brain amyloid plaque burden in the HC group (as a pre-clinical feature of AD), were investigated in this study. Our results demonstrate statistically significant relationships between PFR parameters, neocortical plaque burden and AD. A logistical model combining PFR parameters provided AD-classification performance with sensitivity 84.1%, specificity 78.3% and area under the curve 89.6%. Furthermore, some of the AD specific PFR parameters were also associated with neocortical plaque burden in pre-clinical AD. These PFR changes show potential as an adjunct for noninvasive, cost-effective screening for pre-clinical AD.
Plasma p217+tau vs NAV4694 amyloid and MK6240 tau PET across the Alzheimer continuum
Publisher: Cold Spring Harbor Laboratory
Date: 19-02-2022
DOI: 10.1101/2022.02.16.22271024
Abstract: We evaluated a new Simoa plasma assay for phosphorylated tau at aa217 enhanced by additional ptau sites (p217+tau). Plasma p217+tau levels were compared to 18 F-NAV4694 amyloid-beta (Aβ) PET and 18 F-MK6240 tau PET in 174 cognitively impaired (CI) and 223 cognitively unimpaired (CU) participants. Compared to Aβ-CU, the plasma levels of p217+tau increased two-fold in Aβ+ CU and 3.5-fold in Aβ+ CI. In Aβ-the p217+tau levels did not significantly differ between CU, MCI or dementia. P217+tau correlated with Aβ centiloids ρ=0.67 (CI 0.64 CU 0.45) and tau SUVR MT ρ=0.63 (CI 0.69 CU 0.34). Area under curve (AUC) for AD vs Aβ-CU was 0.94, for AD vs other dementia was 0.93, for Aβ+ vs Aβ– PET was 0.89 and for tau+ vs tau-PET was 0.89. Plasma p217+tau levels elevate early in the AD continuum and correlate well with Aβ and tau PET. Systematic review: The authors reviewed the literature using PubMed, meeting abstracts and presentations. Plasma phospho-tau measures compare well to PET and post-mortem across the continuum of AD but accuracy varies across ptau target sites and assay methods. There are no reports comparing PET to plasma assays targeting multiple sites of tau phosphorylation as typically found in AD. The p217+tau assay targets p217 with binding enhanced by phosphorylation at additional sites such as aa212. Interpretation: Plasma p217+tau elevates early and correlates with both Aβ and tau as measured by PET indicating that tau phosphorylation is an early event in AD and occurs with Aβ deposition. Plasma p217+tau measurement should assist both selection for trials and diagnosis of AD. Future directions: Further validation studies, head-to-head comparison to other assays, assessing the influence of co-morbidities and the ability to measure change in brain Aβ and tau levels are required.
EFFICIENT USE OF CEREBRAL CORTICAL THICKNESS TO CORRECT BRAIN MR SEGMENTATION
Publisher: IEEE
Date: 2007
Lesion segmentation from multimodal MRI using random forest following ischemic stroke
Publisher: Elsevier BV
Date: 09-2014
DOI: 10.1016/J.NEUROIMAGE.2014.04.056
Abstract: Understanding structure-function relationships in the brain after stroke is reliant not only on the accurate anatomical delineation of the focal ischemic lesion, but also on previous infarcts, remote changes and the presence of white matter hyperintensities. The robust definition of primary stroke boundaries and secondary brain lesions will have significant impact on investigation of brain-behavior relationships and lesion volume correlations with clinical measures after stroke. Here we present an automated approach to identify chronic ischemic infarcts in addition to other white matter pathologies, that may be used to aid the development of post-stroke management strategies. Our approach uses Bayesian-Markov Random Field (MRF) classification to segment probable lesion volumes present on fluid attenuated inversion recovery (FLAIR) MRI. Thereafter, a random forest classification of the information from multimodal (T1-weighted, T2-weighted, FLAIR, and apparent diffusion coefficient (ADC)) MRI images and other context-aware features (within the probable lesion areas) was used to extract areas with high likelihood of being classified as lesions. The final segmentation of the lesion was obtained by thresholding the random forest probabilistic maps. The accuracy of the automated lesion delineation method was assessed in a total of 36 patients (24 male, 12 female, mean age: 64.57±14.23yrs) at 3months after stroke onset and compared with manually segmented lesion volumes by an expert. Accuracy assessment of the automated lesion identification method was performed using the commonly used evaluation metrics. The mean sensitivity of segmentation was measured to be 0.53±0.13 with a mean positive predictive value of 0.75±0.18. The mean lesion volume difference was observed to be 32.32%±21.643% with a high Pearson's correlation of r=0.76 (p<0.0001). The lesion overlap accuracy was measured in terms of Dice similarity coefficient with a mean of 0.60±0.12, while the contour accuracy was observed with a mean surface distance of 3.06mm±3.17mm. The results signify that our method was successful in identifying most of the lesion areas in FLAIR with a low false positive rate.
The use of unwrapped phase in MR image segmentation: A preliminary study
Publisher: Springer Berlin Heidelberg
Date: 2005
DOI: 10.1007/11566489_100
Aβ-amyloid and tau imaging in dementia
Publisher: Elsevier BV
Date: 2017
DOI: 10.1053/J.SEMNUCLMED.2016.09.006
Abstract: The introduction of in vivo imaging of Aβ-amyloid (Αβ) pathology more than a decade ago, transformed the assessment of Alzheimer disease (AD) allowing the evaluation of Aβ deposition over time by providing highly accurate, reliable, and reproducible quantitative statements of regional or global Aβ burden in the brain to the extent that Aβ imaging has already been approved for clinical use and is being used for both patient recruitment and outcome measure in current anti-Αβ therapeutic trials. Aβ imaging studies have deepened our insight into Aβ deposition, showing that Aβ accumulation is a slow and protracted process extending for more than two decades before the onset of the clinical phenotype. Although cross-sectional evaluation of Αβ burden does not strongly correlate with cognitive impairment in AD, Αβ burden does correlate with memory impairment and a higher risk for cognitive decline in the aging population and mild cognitive impairment subjects. These associations suggest that Αβ deposition is not a benign process. The recent addition of selective tau imaging will allow to elucidate if these effects are directly associated with Αβ deposition or if they are mediated, in toto or in parte, by tau as it spreads out of the mesial temporal lobe into neocortical association areas. The combination of Aβ and tau imaging studies would likely help elucidate the relationship or interplay between the two pathologic hallmarks of the disease. Longitudinal observations to assess their potential independent or synergistic, sequential or parallel effects on cognition, disease progression, and other disease-specific biomarkers of neurodegeneration would be required to further clarify the respective role of Αβ and tau deposition play in the course of AD.
Cortical thickness measurement from magnetic resonance images using partial volume estimation
Publisher: SPIE
Date: 06-03-2008
DOI: 10.1117/12.770058
Tau Imaging with 18F-MK6240 across the Alzheimer’s Disease spectrum
Publisher: Cold Spring Harbor Laboratory
Date: 15-02-2022
DOI: 10.1101/2022.02.13.22270894
Abstract: Tau deposition plays a critical role over cognition and neurodegeneration in Alzheimer’s disease (AD). Recent generation tracers have high target to background ratios giving a wide dynamic range that may improve sensitivity for detection of low levels of tau (Pascoal, Shin et al. 2018). Building on previous evidence, this study aims to characterize the effects of tau deposition as assessed by 18 F-MK6240, in a large cohort of patients across the AD disease spectrum. A total of 464 participants, enrolled in the AIBL-ADNeT study, underwent 18 F-MK6240 tau PET, 18 F-NAV4964 Aβ PET, 3D structural MRI (hippoc al and whole-brain cortical volumes) and extensive neuropsychological evaluation. Participants included 266 cognitively unimpaired controls (CU), 112 patients with mild cognitive impairment (MCI), and 86 patients with probable AD dementia. Evaluation included the characterization of the pattern and degree of 18 F-MK6240 tracer retention in each clinical group as well as assessment of the relationship between 18 F-MK6240 and age, Aβ imaging, brain volumetrics and cognition in each of the clinical groups. Standard uptake value ratios (SUVR) were estimated in four predefined composite regions of interest (ROIs), reflecting the stereotypical progression of tau pathology in the brain: 1. Mesial-temporal (Me), 2. Temporoparietal (Te), 3. Remainder of neocortex (R), 4. A temporal meta-region termed metaT+. 18 F-MK6240 retention was higher in AD patients compared with all other diagnostic groups, with 18 F-MK6240 distinguishing patients with AD from CU in iduals, with the highest effect size obtained in the amygdala (Cohen’s d : 2.07), and Me (Cohen’s d : 1.99). When considering Aβ status, 18 F-MK6240 not only was able to distinguish between Aβ+ AD patients and Aβ- CU (Cohen’s d : 2.23), but also between Aβ+ and Aβ- CU (Cohen’s d : 1.32). In Aβ- CU, 18 F-MK6240 retention in Me showed a slow age-related increase, while 18 F-MK6240 retention was higher in younger elderly Aβ+ AD patients compared to their older counterparts. There was a sigmoidal relationship between subthreshold tau and Aβ, providing evidence for a very slow but steady increase in subthreshold tau prior to a fast increase in cortical Aβ. Moreover, a non-linear relationship between Aβ and tau suggest that detectable cortical Aβ precedes detectable cortical tau. While age was the main predictor of cognitive decline in CU, and Aβ and hippoc al volume in MCI, the main predictor of cognitive decline in the AD group was tau. High tau was associated with faster cognitive decline and clinical progression in the CU and MCI groups. This large study provides further evidence that 18 F-MK6240 discriminates CU from AD and, most importantly, Aβ+ from Aβ- CU in iduals with high effect sizes, suggesting that 18 F- MK6240 can detect lower tau levels than earlier tau tracers, crucial for early detection of tau deposition as well as tracking small tau changes over time. In conclusion, identification of regional cortical tau deposition has critical diagnostic and prognostic implications and should become a standard tool to identify in iduals at risk, as well as outcome measure, in both anti- Aβ and anti-tau trials.
Head-to-Head Centiloid comparison between Philips Gemini TF64 and Siemens Biograph Vision 600
Publisher: Wiley
Date: 06-2023
DOI: 10.1002/ALZ.066283
Abstract: The Centiloid (CL) scale calibrates the beta‐amyloid (Aβ) deposition from different PET tracers to a standardised 0‐100 CL unit scale. As imaging sites update their PET cameras, most are switching to digital detector systems with superior resolution and sensitivity that may affect quantitation. This has significant implications for dementia clinical trials. In this study, we examine the impact on CL quantification between Philips Gemini TF64 and Siemens Biograph Vision 600. Seven subjects (76.4±2.2 yo) were imaged with 18 F‐NAV4694 on both Gemini TF64 and Biograph Vision consecutively with an average scan interval of 25.1±11.2 weeks. The injected doses were 200MBq and 100MBq, respectively. On the Gemini TF64, the PET images were reconstructed by LOR‐RAMLA algorithm with smoothing parameter setup as ‘SHARP’. On Biograph Vision, the PET images were reconstructed by OSEM‐3D (8 iterations and 5 subsets, TOF enabled) with 3mm post Gaussian smoothing. A T1 MRI image was acquired for each subject. As per the standard Centiloid method the whole cerebellum was used as the reference in SUVR images, and all images were processed using CapAIBL to calculate the CL using both MR‐based and MR‐Less spatial normalisation. Figure 1 shows the CL images of a subject scanned on Gemini TF64 and Biograph Vision within sixteen weeks. The Biograph Vision images have higher contrast and higher spatial resolution despite using half of the dose. Figure 2 shows the linear regression plot of the scanner comparison. Biograph Vision CL are progressively higher than those obtained from the Gemini TF64 as the CL value rises (Table 1). There were no significant differences between the MR‐based and MR‐less results. Biograph Vision yields higher SUVR and therefore CL values compared to Gemini TF64 in a head‐to‐head comparison. These results show that the selection of PET camera has a significant impact on CL quantification, which needs to be considered when merging cohorts from different studies or changing cameras during longitudinal studies or trials. These initial results indicate that the CL difference could be corrected by a linear transform.
The Cognitive and Brain Volumetric Trajectories of Healthy Ederly Controls with either Alzheimer’s Pathology, Neurodegeneration (SNAP) or both
Publisher: Wiley
Date: 07-2015
Higher Coffee Consumption Is Associated With Slower Cognitive Decline and Less Cerebral Aβ-Amyloid Accumulation Over 126 Months: Data From the Australian Imaging, Biomarkers, and Lifestyle Study.
Publisher: Frontiers Media SA
Date: 19-11-2021
DOI: 10.3389/FNAGI.2021.744872
Abstract: Background: Worldwide, coffee is one of the most popular beverages consumed. Several studies have suggested a protective role of coffee, including reduced risk of Alzheimer’s disease (AD). However, there is limited longitudinal data from cohorts of older adults reporting associations of coffee intake with cognitive decline, in distinct domains, and investigating the neuropathological mechanisms underpinning any such associations. Methods: The aim of the current study was to investigate the relationship between self-reported habitual coffee intake, and cognitive decline assessed using a comprehensive neuropsychological battery in 227 cognitively normal older adults from the Australian Imaging, Biomarkers, and Lifestyle (AIBL) study, over 126 months. In a subset of in iduals, we also investigated the relationship between habitual coffee intake and cerebral Aβ-amyloid accumulation ( n = 60) and brain volumes ( n = 51) over 126 months. Results: Higher baseline coffee consumption was associated with slower cognitive decline in executive function, attention, and the AIBL Preclinical AD Cognitive Composite (PACC shown reliably to measure the first signs of cognitive decline in at-risk cognitively normal populations), and lower likelihood of transitioning to mild cognitive impairment or AD status, over 126 months. Higher baseline coffee consumption was also associated with slower Aβ-amyloid accumulation over 126 months, and lower risk of progressing to “moderate,” “high,” or “very high” Aβ-amyloid burden status over the same time-period. There were no associations between coffee intake and atrophy in total gray matter, white matter, or hippoc al volume. Discussion: Our results further support the hypothesis that coffee intake may be a protective factor against AD, with increased coffee consumption potentially reducing cognitive decline by slowing cerebral Aβ-amyloid accumulation, and thus attenuating the associated neurotoxicity from Aβ-amyloid-mediated oxidative stress and inflammatory processes. Further investigation is required to evaluate whether coffee intake could be incorporated as a modifiable lifestyle factor aimed at delaying AD onset.
Basal forebrain atrophy and tau pathology occur prior to hippocampal atrophy in prodromal AD
Publisher: Wiley
Date: 12-2020
DOI: 10.1002/ALZ.046111
Cerebrospinal fluid neurofilament light concentration predicts brain atrophy and cognition in Alzheimer's disease
Publisher: Wiley
Date: 2020
DOI: 10.1002/DAD2.12005
Surface-base Approach using a Multi-Scale EM-ICP Registration for Statistical Population Analysis
Publisher: IEEE
Date: 12-2011
Classifier vote and Gabor filter banks for wafer segmentation
Publisher: IEEE
Date: 2005
A Research Translation, Implementation and Impact Strategy for the Australian Healthy Environments and Lives (HEAL) Research Network
Publisher: MDPI AG
Date: 18-07-2023
Abstract: Healthy Environments And Lives (HEAL) is the Australian national research network established to support improvements to health, the Australian health system, and the environment in response to the unfolding climate crisis. The HEAL Network comprises researchers, community members and organisations, policymakers, practitioners, service providers, and other stakeholders from erse backgrounds and sectors. HEAL seeks to protect and improve public health, reduce health inequities and inequalities, and strengthen health system sustainability and resilience in the face of environmental and climate change, all with a commitment to building on the strengths, knowledge, wisdom, and experience of Aboriginal and Torres Strait Islander people, culture, and communities. Supporting applied research that can inform policy and practice, and effective research translation, implementation, and impact are important goals across the HEAL Network and essential to achieve its intended outcomes. To aid translation approaches, a research translation, implementation, and impact strategy for the HEAL Network was developed. The strategy has been created to inform and guide research translation across HEAL, emphasising communication, trust, partnerships, and co-design with communities and community organisations as well as the decision-makers responsible for public policies and programs. Development of the strategy was guided by research translation theory and practice and the Health in All Policies and Environment in All Policies frameworks. As described in this paper, the strategy is underpinned by a set of principles and outlines preliminary actions which will be further expanded over the course of the HEAL Network’s activities. Through these actions, the HEAL Network is well-positioned to ensure successful research translation and implementation across its program of work.
A snapshot of brain and cognition in healthy mid-life and older adults
Publisher: Cold Spring Harbor Laboratory
Date: 22-01-2022
DOI: 10.1101/2022.01.20.476706
Abstract: Deficits in memory are seen as a canonical sign of ageing and a prodrome to dementia in older adults. However, the nature of cognitive and brain changes across a wider aperture of adulthood is not well known. We quantify the relationship between cognitive function and brain morphology from mid-life to older adulthood, and the influence of age, sex, amyloid and genetic risk for dementia. We analyzed three observational cohorts (PISA, AIBL, ADNI) with cognitive, genetic and neuroimaging measures comprising a total of 1570 healthy mid-life and older adults (mean age 72, range 49-90 years, 1330 males) and 1365 age- and sex-matched adults with mild cognitive impairment or Alzheimer’s disease. Among healthy adults, we find robust modes of co-variation between regional sulcal width and multidomain cognitive function that change from mid-life to the older age range. The most prominent cortical changes in mid-life are predominantly associated with changes in executive functions, whereas they are most strongly associated with poorer memory function in older age. These cognitive changes are accompanied by an age-dependent pattern of sulcal widening. Amyloid exerts a weak, but significant, influence on cognition, but not on sulcal width. The APOE ɛ4 allele also exerts a weak influence on cognition, but only significantly in the (larger and older) AIBL cohort. These findings provide new insights into brain and cognition in mid-life and older adults, suggesting that cognitive screening in mid-life cohorts should encompass executive functions as well as memory.
Revisiting, Revising and Refining the Natural History of Aβ Deposition and Its Effects on Neurodegeneration and Cognitive Decline in Sporadic Alzheimer’s Disease
Publisher: Wiley
Date: 07-2016
Data augmentation using synthetic lesions improves machine learning detection of microbleeds from MRI
Publisher: Springer International Publishing
Date: 2018
Plasma p-tau181/Aβ1-42 ratio predicts Aβ-PET status and correlates with CSF-p-tau181/Aβ1-42 and future cognitive decline
Publisher: Wiley
Date: 2022
DOI: 10.1002/DAD2.12375
Abstract: In Alzheimer's disease (AD), plasma amyloid beta (Aβ) 1‐42 and phosphorylated tau (p‐tau) predict high amyloid status from Aβ positron emission tomography (PET) however, the extent to which combination of these plasma assays can predict remains unknown. Prototype Simoa assays were used to measure plasma s les from participants who were either cognitively normal (CN) or had mild cognitive impairment (MCI)/AD in the Australian Imaging, Biomarkers and Lifestyle (AIBL) study. The p‐tau181/Aβ 1‐42 ratio showed the best prediction of Aβ‐PET across all participants (area under the curve [AUC] = 0.905, 95% confidence interval [CI]: 0.86–0.95) and in CN (AUC = 0.873 0.80–0.94), and symptomatic (AUC = 0.908 0.82–1.00) adults. Plasma p‐tau181/Aβ 1‐42 ratio correlated with cerebrospinal fluid (CSF) p‐tau181 (Elecsys, Spearman's ρ = 0.74, P 0.0001) and predicted abnormal CSF Aβ (AUC = 0.816 0.74–0.89). The p‐tau181/Aβ 1‐42 ratio also predicted future rates of cognitive decline assessed by AIBL Preclinical Alzheimer Cognitive Composite or Clinical Dementia Rating Sum of Boxes ( P 0.0001). Plasma p‐tau181/Aβ 1‐42 ratio predicted both Aβ‐PET status and cognitive decline, demonstrating potential as both a diagnostic aid and as a screening and prognostic assay for preclinical AD trials.
Making the Blood Broil: Conflicts Over Imagined Rurality in Peri-Urban Australia
Publisher: Informa UK Limited
Date: 07-04-2017
Traits and Trammels of Tau Tracer Imaging
Publisher: Springer International Publishing
Date: 2023
Reproducibility of multiphase pseudo-continuous arterial spin labeling and the effect of post-processing analysis methods
Publisher: Elsevier BV
Date: 08-2015
DOI: 10.1016/J.NEUROIMAGE.2015.05.048
Abstract: Arterial spin labeling (ASL) is an emerging MRI technique for non-invasive measurement of cerebral blood flow (CBF). Compared to invasive perfusion imaging modalities, ASL suffers from low sensitivity due to poor signal-to-noise ratio (SNR), susceptibility to motion artifacts and low spatial resolution, all of which limit its reliability. In this work, the effects of various state of the art image processing techniques for addressing these ASL limitations are investigated. A processing pipeline consisting of motion correction, ASL motion correction imprecision removal, temporal and spatial filtering, partial volume effect correction, and CBF quantification was developed and assessed. To further improve the SNR for pseudo-continuous ASL (PCASL) by accounting for errors in tagging efficiency, the data from multiphase (MP) acquisitions were analyzed using a novel weighted-averaging scheme. The performances of each step in terms of SNR and reproducibility were evaluated using test-retest ASL data acquired from 12 young healthy subjects. The proposed processing pipeline was shown to improve the within-subject coefficient of variation and regional reproducibility by 17% and 16%, respectively, compared to CBF maps computed following motion correction but without the other processing steps. The CBF measurements of MP-PCASL compared to PCASL had on average 23% and 10% higher SNR and reproducibility, respectively.
Centiloid harmonisation strategies across longitudinal studies. Evaluation on AIBL, ADNI and OASIS3
Publisher: Wiley
Date: 12-2021
DOI: 10.1002/ALZ.053660
Abstract: The Centiloid (CL) was proposed to harmonise the quantification of Amyloid PET images across tracers, scanners, and processing pipelines. However, several groups have reported differences across tracers and scanners. In this study, we aim to evaluate the impact of different pre ost‐processing harmonisation steps on the consistency of longitudinal data across multiple large studies. All Amyloid PET data in AIBL (N=3830), ADNI (N=3453) and OASIS3 (N=1398) were quantified using the Centiloid SPM pipeline. SUVR were converted into Centiloids using each tracer’s respective transform. All images were smoothed to a uniform 8mm FWHM PSF. Both Raw and 8mm FWHM smoothed images were quantified. For Florbetapir, we evaluated using both the standard Whole Cerebellum (WC) and a Composite WM+WC reference region, which has been previously shown to improve longitudinal consistency. Additionally, our recently proposed Non‐negative Matrix Factorisation quantification (NMF: Neuroimage 2021) was applied to all spatially and SUVR normalised images. Longitudinal consistency was evaluated using: fitting error when fitting a regression line to each subject percentage of longitudinal changes exceeding 95 th percentile of changes seen with PiB when using a single scanner (6.56CL/y in the negative and 17.06CL/y in the positive) Spearman rank correlation ρ between the baseline Centiloid and the rate of change. Figure 1 illustrates the longitudinal consistency, while the fitting error and percentage of outliers are presented in Table 1. These results indicate that the 8mm FWHM smoothing reduced some of the variability, but its impact was limited. Using the Composite reference region on Florbetapir had a bigger impact in reducing the variability. The best results were however obtained when using the NMF method, compared to SPM. Figure 2 shows the baseline vs rate of CL changes. These plots also show a moderate influence of the FWHM smoothing, and a stronger influence of the Composite reference region. They also show that the NMF method produced the highest Spearman and peak CL/y regardless of the pre‐processing or normalisation method used. FWHM smoothing has moderate impact on longitudinal consistency or outliers. A Composite reference region including subcortical WM should be used for Florbetapir longitudinal Centiloids. NMF improves consistency over SPM.
Classification forests and Markov Random Fields to segment chronic ischemic infarcts from multimodal MRI
Publisher: Springer International Publishing
Date: 2013
Distance informed Track-Weighted Imaging (diTWI): A framework for sensitising streamline information to neuropathology
Publisher: Elsevier BV
Date: 02-2014
DOI: 10.1016/J.NEUROIMAGE.2013.07.077
Abstract: Track-Weighted Imaging (TWI), where voxel intensity is based on image metrics encoded along streamline trajectories, provides a mechanism to study white matter disease. However, with generalised streamline weighting, it is difficult to localise the precise anatomical source and spread of injury or neuropathology. This limitation can be overcome by modulating the voxel weight based on the distance of the voxel from a given anatomical location along the tract, which we term diTWI: distance informed Track-Weighted Imaging. The location of known neuropathology can be delineated on any given imaging modality (e.g. MRI or PET). To demonstrate the clinical utility of this approach, we measured tumour cell infiltration along WM fibre tracts in 13 patients with newly diagnosed glioblastoma and 1 patient with Anaplastic Astrocytoma. TWI and diTWI maps were generated using information obtained from dynamic contrast enhanced MRI (area under the curve, AUC) and diffusivity maps (ADC and FA) with tumour boundaries automatically extracted using a logistic regression classifier. The accuracy of the derived tumour volumes was compared to those generated using 3,4-dihydroxy-6-[(18)F]-fluoro-l-phenylalanine (FDOPA) PET imaging. The accuracy of the tumour volumes generated from the diTWI maps was superior to volumes derived from the TWI, geometric distance or baseline AUC, FA and ADC maps. The relative overlap and relative dissimilarity rates for the diTWI generated tumour volumes after classification were found to be 82.3±15.3% (range 69.1-91.9) and 16.9±8.8% (range 7.9-37.5), respectively. These findings show that diTWI maps provide a useful framework for localising neuropathological processes occurring along WM pathways.
Longitudinal trajectories of basal forebrain volume in normal ageing and Alzheimer’s disease
Publisher: Elsevier BV
Date: 12-2023
Related Organisations
Commonwealth Scientific And Industrial Research Organisation
Location: Australia
Related Funding Activities
Linkage Projects - Grant ID: LP200301335
Start Date: 03-2022
End Date: 02-2025
Amount: $484,777.00
Funder: Australian Research Council
View Funded ActivityDiscovery Projects - Grant ID: DP200103223
Start Date: 06-2020
End Date: 05-2024
Amount: $396,000.00
Funder: Australian Research Council
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