ORCID Profile
0000-0002-0805-2775
Current Organisations
Translational Research Institute
,
University of Queensland
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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)
Biostatistics | Biological Psychology (Neuropsychology, Psychopharmacology, | Psychology | Learning, Memory, Cognition And Language | Sensory Processes, Perception And Performance | Medical Physiology | Statistics | Biomedical Engineering | Biomedical Engineering Not Elsewhere Classified | Systems Physiology | Biomedical Engineering not elsewhere classified | Medical Biotechnology Diagnostics (incl. Biosensors) | Medical Physics | Image Processing
ANZSRC Socio-Economic Objective (SEO)
Behavioural and cognitive sciences | Respiratory System and Diseases (incl. Asthma) | Diagnostic Methods | Expanding Knowledge in the Biological Sciences | Medical instrumentation | Expanding Knowledge in the Mathematical Sciences | Scientific instrumentation |
Related Links
Publications
Radiological studies of fetal alcohol spectrum disorders in humans and animal models: An updated comprehensive review
Publisher: Elsevier BV
Date: 11-2017
DOI: 10.1016/J.MRI.2017.06.012
Abstract: Fetal Alcohol Spectrum Disorders encompass a wide range of birth defects in children born to mothers who consumed alcohol during pregnancy. Typical mental impairments in FASD include difficulties in life adaptation and learning and memory, deficits in attention, visuospatial skills, language and speech disabilities, mood disorders and motor disabilities. Multimodal imaging methods have enabled in vivo studies of the teratogenic effects of alcohol on the central nervous system, giving more insight into the FASD phenotype. This paper offers an up-to-date comprehensive review of radiological findings in the central nervous system in studies of prenatal alcohol exposure in both humans and translational animal models, including Magnetic Resonance Imaging, Computed Tomography, Positron Emission Tomography, Single Photon Emission Tomography and Ultrasonography.
Identification of Pre-Spike Network in Patients with Mesial Temporal Lobe Epilepsy
Publisher: Frontiers Media SA
Date: 28-10-2014
High‐field localized in vivo proton spectroscopy on micro volumes
Publisher: Wiley
Date: 03-1990
Abstract: A water-suppressed volume-selected in vivo 1H spectrum of 0.2 ml of a rat brain has been obtained at 200 MHz using the SPACE localization method. Good signal-to-noise and spectral resolution were obtained by averaging 256 acquisitions. The spectrum shows little T2 weighting effect.
WorkWays: Interacting with scientific workflows
Publisher: IEEE
Date: 11-2015
DOI: 10.1109/GCE.2014.6
Application of surface coil reception to record volume-selected high-resolution proton in vivo spectra using a combined DIGGER-SPACE pulse sequence
Publisher: Elsevier BV
Date: 06-1987
Differential changes in muscle composition exist in traumatic and nontraumatic neck pain
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 2014
A USPIO doped gel phantom for R2* relaxometry
Publisher: Springer Science and Business Media LLC
Date: 19-07-2017
DOI: 10.1007/S10334-016-0576-X
Abstract: This work describes a phantom containing regions of controlled R2* (1/T2*) values to provide a stable reference object for testing implementations of R2* relaxometry commonly used for liver and heart iron assessments. A carrageenan-strengthened gadolinium DTPA doped agarose gel was used to enclose nine gels additionally doped with ultra-small superparamagnetic iron oxide. R2* values were determined at 1.5 T using multi-echo GRE sequences and exponential regression of pixel values from a region of interest against echo time using non-linear regression algorithms. We measured R2*, R2 and R1 values and the inter-scan and inter-operator reproducibility. The phantom reliably demonstrated R2* values in seven steps between 22.4 s The phantom provides a durable test object with controlled R2* relaxation behaviour, useful for a range of R2* relaxometry reference work.
On the use of a slice‐selective 270° self‐refocusing Gaussian pulse for magnetic resonance imaging
Publisher: Wiley
Date: 06-1991
Measurement of the T2 relaxation time of ethanol and cerebral metabolites, in vivo
Publisher: Wiley
Date: 02-1992
Abstract: The SPACE volume selection technique was combined with a spin-echo sequence to measure the transverse relaxation time of the resonances of ethanol and cerebral metabolites in the dog brain, in vivo. The method was extended to measure brain metabolite T2 values in the rat using 1H NMR microspectroscopy. The T2 decays for the resonances of the metabolites N-acetylaspartate, creatine hosphocreatine, and choline hosphorylcholine were found to be biexponential with long T2 components of 490, 260, and 350 ms for the dog and 490, 220, and 355 ms for the rat brain, respectively. The existence of a second T2 component may originate from J-coupled nonresolved metabolite resonances. The relaxation decay for the ethanol triplet could be fitted to a single exponential giving a T2 relaxation time of 335 ms. However, given the large errors in the measurement of ethanol peak intensities at short echo times because of overlapping lipid signal and the effects of J-modulation, a biexponential decay with a long T2 component of 335 ms cannot be ruled out. Ambiguities regarding the reported partial detection of the 1H NMR signal of ethanol in the brain are discussed.
Magnetic resonance imaging and spectroscopy accurately estimate the severity of steatosis provided the stage of fibrosis is considered
Publisher: Elsevier BV
Date: 08-2009
DOI: 10.1016/J.JHEP.2009.04.012
Abstract: Currently the diagnosis and severity of hepatic steatosis can be established accurately only by liver biopsy. Previous small studies found that steatosis measured by magnetic resonance spectroscopy (MRS) and imaging (MRI) correlated with histological assessment of liver triglyceride content. However, the accuracy of MRS/MRI for grading the severity of steatosis has not been addressed. The aims of this study were (1) to determine whether MRS and MRI can discriminate grades of steatosis in a large cohort of consecutive patients with a wide spectrum of liver disease aetiology and severity (2) to evaluate the effect of hepatic fibrosis, inflammation and iron on quantitation of intrahepatocellular lipid (IHCL) by these techniques. Ninety-four sequential patients who underwent percutaneous liver biopsy or liver resection had MRS and MRI (Dixon in phase/out of phase (Dixon IP/OP) and with/without fat saturation (+/-FS) images) to determine IHCL. Histology was used as the reference standard. Close relationships were observed between the percentage of steatosis estimated by histology and MRS/MRI (r(s)=0.88 p or =0.87) as well as moderate/severe steatosis (AUROC > or =0.89). Hepatic inflammation and mild iron deposition (Perls' grade 1 and 2) did not interfere with estimation of steatosis by imaging. MRS and MRI had good accuracy for grading the severity of steatosis in subjects with liver disease, provided that stage of fibrosis was considered.
The unequivocal determination of lactic acid using a one‐ dimensional zero‐quantum coherence‐transfer technique
Publisher: Wiley
Date: 1989
Abstract: A method based on zero-quantum coherence transfer for spectral editing of metabolites in aqueous solution in a one-dimensional experiment is described. Water suppression factors of approximately 8000 were achieved by the use of pulsed B0 field gradients and excellent editing was obtained in a single acquisition. The methyl resonances of both lactate and acetaldehyde were readily observed in a mouse brain homogenate by generating zero-quantum coherence using Gaussian pulses for selective excitation of the respective CH resonances.
A comparison of some gradient-encoded volume-selection techniques for in vivo NMR spectroscopy
Publisher: Wiley
Date: 04-1987
Abstract: Four of the techniques proposed for in vivo volume-selected NMR spectroscopy have been compared using a simple phantom with a large background water signal which was outside the region of interest. The methods VSE, SPACE, SPARS, and DIGGER all use pulsed field gradients for spatial encoding and were tested with a symmetric and an asymmetric phantom. SPACE was used to obtain volume-selected 1H NMR spectra of a human leg, demonstrating excellent discrimination between bone marrow and muscle.
Metabolite editing via correlated z order with total inherent coherence. ECZOTIC
Publisher: Elsevier BV
Date: 06-1989
7-Tesla Functional Cardiovascular MR Using Vectorcardiographic Triggering – overcoming the magnetohydrodynamic effect
Publisher: Cold Spring Harbor Laboratory
Date: 14-05-2021
DOI: 10.1101/2021.05.10.21256949
Abstract: Ultra-high-field (B 0 ≥ 7 Tesla) cardiovascular magnetic resonance (CMR) offers increased resolution. However, ECG gating is impacted by the magneto-hydrodynamic (MHD) effect distorting the ECG trace. We explored the technical feasibility of a 7T MR scanner using ECG trigger learning algorithm to quantitatively assess cardiac volumes and vascular flow. 7T scans performed on 10 healthy volunteers on a whole-body research MRI (Siemens Healthcare, Erlangen, Germany) with 8 channel Tx/32 channel Rx cardiac coil (MRI Tools GmbH, Berlin, Germany). Vectorcardiogram ECG was performed using a learning phase outside of the magnetic field, with a trigger algorithm overcoming severe ECG signal distortions. Vectorcardiograms were quantitatively analyzed for false negative and false positive events. Cine CMR was performed after 3 rd -order B 0 shimming using a high-resolution breath-held ECG-retro-gated segmented spoiled gradient echo, and 2D phase contrast flow imaging. Artefacts were assessed using a semi-quantitative scale. 7T CMR scans were acquired in all patients (100%) using the VCG learning method. 3,142 R-waves were quantitatively analyzed, yielding sensitivity 97.6%, specificity 98.7%. Mean image quality score was 0.9, sufficient to quantitate both cardiac volumes, ejection fraction (EF), aortic and pulmonary blood flow. Mean LVEF was 56.4%, RVEF 51.4%. Reliable cardiac ECG triggering is feasible in healthy volunteers at 7T utilizing a state-of-the-art 3-lead trigger device despite signal distortion from the MHD effect. This provides sufficient image quality for quantitative analysis. Other ultra-high-field imaging applications such as human brain functional MRI with physiologic noise correction may benefit from this method of ECG triggering. Ultra-high field 7 Tesla cardiac MRI is challenging due to the impact of the magneto-hydrodynamic (MHD) effect causing severe distortions in the ECG trace. Using VCG with a learning phase outside the ultra-high field magnet, the R waves can be adequately detected to perform high quality Cardiac MRI scans, overcoming signal distortion from the MHD effect.
A global view of standards for open image data formats and repositories
Publisher: Springer Science and Business Media LLC
Date: 04-05-2021
4D deformation modeling of cortical disease progression in Alzheimer's dementia
Publisher: Wiley
Date: 10-2001
DOI: 10.1002/MRM.1243
Abstract: This work describes the development of a model of cerebral atrophic changes associated with the progression of Alzheimer's disease (AD). Linear registration, region-of-interest analysis, and voxel-based morphometry methods have all been employed to elucidate the changes observed at discrete intervals during a disease process. In addition to describing the nature of the changes, modeling disease-related changes via deformations can also provide information on temporal characteristics. In order to continuously model changes associated with AD, deformation maps from 21 patients were averaged across a novel z-score disease progression dimension based on Mini Mental State Examination (MMSE) scores. The resulting deformation maps are presented via three metrics: local volume loss (atrophy), volume (CSF) increase, and translation (interpreted as representing collapse of cortical structures). Inspection of the maps revealed significant perturbations in the deformation fields corresponding to the entorhinal cortex (EC) and hippoc us, orbitofrontal and parietal cortex, and regions surrounding the sulci and ventricular spaces, with earlier changes predominantly lateralized to the left hemisphere. These changes are consistent with results from post-mortem studies of AD.
Intramuscular fat is present in cervical multifidus but not soleus in patients with chronic whiplash associated disorders
Publisher: Public Library of Science (PLoS)
Date: 24-05-2018
Cardiac Magnetic Resonance T1 Mapping in Cardiomyopathies.
Publisher: InTech
Date: 12-04-2017
DOI: 10.5772/65327
Interpretation of medical imaging data with a mobile application: A mobile digital imaging processing environment
Publisher: Frontiers Media SA
Date: 2013
Homonuclear coherence transfer experiments using shaped RF pulses having a tailored phase profile
Publisher: Elsevier BV
Date: 05-1989
THE EFFECT OF THE CALCIUM-ION ANTAGONIST 8-(N,N-DIETHYLAMINO)-OCTYL-3,4,5-TRIMETHOXYBENZOATE ON MALIGNANT HYPERPYREXIA-SUSCEPTIBLE PORCINE SKELETAL-MUSCLE
Publisher: Wiley
Date: 10-1983
DOI: 10.1111/J.1440-1681.1983.TB00227.X
Abstract: In malignant hyperpyrexia susceptible (MHS) porcine skeletal muscle, a low concentration (100 mumol/l) of the calcium ion antagonist 8-(N,N-diethylamino)-octyl-3,4,5-trimethoxybenzoate (TMB-8) inhibited KCl-induced contractures, but potentiated contractures induced by halothane, caffeine and succinylcholine. Higher concentrations of TMB-8 (333 mumol/l to 1 mmol/l) contracted MHS muscle, but had little effect on muscle tension in control preparations. Treatments which inhibit excitation-contraction coupling abolished TMB-8-induced hyper-reactivity in MHS muscle. TMB-8 (50 mumol/l and 1 mmol/l) did not alter 45Ca2+ levels in actively loaded microsomal preparations from MHS swine. These results suggest that in malignant hyperpyrexia the primary abnormality occurs proximal to the release of calcium from the sarcoplasmic reticulum, probably at the level of excitation-contraction coupling.
Post-traumatic stress disorder affects fucose-α(1–2)-glycans in the human brain
Publisher: Springer Science and Business Media LLC
Date: 18-01-2019
DOI: 10.1038/S41398-018-0365-6
Abstract: Post-traumatic stress disorder (PTSD) is triggered by experiencing terrifying event(s) for which there is currently no objective test for a definitive diagnosis. We report a pilot study where two-dimensional (2D) neuro magnetic resonance spectroscopy (MRS), collected at 3 T in a clinical scanner with a 64-channel head coil, identifies neuro deregulation in the PTSD cohort. The control subjects ( n = 10) were compared with PTSD participants with minimal co-morbidities ( n = 10). The 2D MRS identified statistically significant increases in the total spectral region containing both free substrate fucose and fucosylated glycans of 31% ( P = 0.0013), two of multiple fucosylated glycans (Fuc IV and VI) were elevated by 48% ( P = 0.002), and 41% ( P = 0.02), respectively, imidazole was increased by 12% ( P = 0.002), and lipid saturation was increased by 12.5% ( P = 0.009). This is the first evidence of fucosylated glycans, reported in animals to be involved in learning and memory, to be affected in humans with PTSD.
Isovalerylglycine and α-Ketobutyrate are novel biomarkers that discriminate clear cell renal cell carcinoma in biopsy specimens using two-dimensional magnetic resonance spectroscopy
Publisher: Elsevier BV
Date: 2023
A 1H MRS study of probable Alzheimer's disease and normal aging: Implications for longitudinal monitoring of dementia progression
Publisher: Elsevier BV
Date: 02-1999
DOI: 10.1016/S0730-725X(98)00168-4
Abstract: In order to evaluate the capability of 1H MRS to monitor longitudinal changes in subjects with probable Alzheimer's disease (AD), the temporal stability of the metabolite measures N-acetylaspartate and N-acetylaspartylglutamate (NA), total Creatine (Cr), myo-Inositol (mI), total Choline (Chol), NA/Cr, mI/Cr, Chol/Cr and NA/mI were investigated in a cohort of normal older adults. Only the metabolite measures NA, mI, Cr, NA/Cr, mI/Cr, and NA/mI were found to be stable after a mean interval of 260 days. Relative and absolute metabolite measures from a cohort of patients with probable AD were subsequently compared with data from a s le of normal older adult control subjects, and correlated with mental status and the degree of atrophy in the localized voxel. Concentrations of NA, NA/Cr, and NA/mI were significantly reduced in the AD group with concomitant significant increases in mI and mI/Cr. There were no differences between the two groups in measures of Cr, Chol, or Chol/Cr. Significant correlations between mental status as measured by the Mini-Mental State Examination and NA/mI, mI/Cr and NA were found. These metabolite measures were also significantly correlated with the extent of atrophy (as measured by CSF and GM composition) in the spectroscopy voxel.
Segmentation of the mouse hippocampal formation in magnetic resonance images
Publisher: Elsevier BV
Date: 10-2011
DOI: 10.1016/J.NEUROIMAGE.2011.06.025
Abstract: The hippoc al formation plays an important role in cognition, spatial navigation, learning, and memory. High resolution magnetic resonance (MR) imaging makes it possible to study in vivo changes in the hippoc us over time and is useful for comparing hippoc al volume and structure in wild type and mutant mice. Such comparisons demand a reliable way to segment the hippoc al formation. We have developed a method for the systematic segmentation of the hippoc al formation using the perfusion-fixed C57BL/6 mouse brain for application in longitudinal and comparative studies. Our aim was to develop a guide for segmenting over 40 structures in an adult mouse brain using 30 μm isotropic resolution images acquired with a 16.4 T MR imaging system and combined using super-resolution reconstruction.
The clinical presentation of chronic whiplash and the relationship to findings of MRI fatty infiltrates in the cervical extensor musculature: A preliminary investigation
Publisher: Springer Science and Business Media LLC
Date: 12-08-2009
Magnetic resonance imaging: The underlying principles
Publisher: Journal of Orthopaedic & Sports Physical Therapy (JOSPT)
Date: 11-2011
Abstract: The creation of a magnetic resonance image (MRI) and its inherent contrast are controlled by a variety of anatomical structure- and sequence-dependent parameters. While these may seem confusing to the uninitiated, they provide MRI with great flexibility and make it a powerful clinical tool. This article describes the principles of basic physics behind magnetic resonance spectroscopy (MRS) and imaging, including a basic description of the properties of magnetic resonance compatible nuclei, how a radiofrequency (RF) pulse produces a signal, and how this signal can be spatially encoded to produce an image. The relaxation properties of the MRI signal depend on biological tissue type and can provide information on tissue composition, environment, and pathological changes. The contrast properties within an image can be manipulated based on the relaxation properties of the anatomical s le and the nature of the imaging sequence. The benefits of T1- and T2-weighted images in musculoskeletal imaging and the common sequences used (including turbo spin echo [TSE], fat suppression sequences such as STIR, and rapid breath-hold sequences such as HASTE and FISP) are discussed. The principles behind contrast agents and diffusion-weighted imaging and how they can be applied in the body are considered.
On the calculation of magnetization slice profiles for NMR imaging and in vivo spectroscopy
Publisher: Wiley
Date: 11-1987
Abstract: When developing new techniques for NMR imaging and in vivo spectroscopy it is a major advantage to be able to calculate the magnetization slice profiles, at any point during a pulse sequence in the presence of a field gradient. While this has frequently been done by treating the problem as a number of discrete resonances, it is sometimes necessary to consider the continuous nature of the magnetization profiles. This paper describes a method used to simulate the free-induction decay at any point during the NMR experiment.
Improvements and extensions to the DIGGER technique for performing spatial selective excitation
Publisher: Elsevier BV
Date: 06-1987
The utilization of two frequency‐shifted sinc pulses for performing volume‐selected in vivo NMR spectroscopy
Publisher: Wiley
Date: 12-1986
Abstract: A new approach to volume-selected in vivo NMR spectroscopy uses two frequency-shifted sinc pulses, in conjunction with pulsed field gradients, to destroy the coherence of the unwanted signals. A hard pi/2 pulse can then be used to read the z magnetization in the region of interest. This method is independent of T2, provides complete volume selection in a single acquisition, and can be readily implemented on most high-field commercial imaging/spectroscopy systems.
Water‐suppressed volume‐selected 1H NMR spectroscopy in viva: Application to study tumor metabolism
Publisher: Wiley
Date: 11-1987
Abstract: Volume selection using SPACE has been combined with water suppression techniques to provide high-resolution 1H NMR spectra from aqueous solutions. The technique developed was used to obtain spectra from a tumor growing on the hind leg of a rat. Water suppression factors of between 1000 and 2000 were achieved simultaneously with excellent volume selection.
Visualization of mouse barrel cortex using ex-vivo track density imaging
Publisher: Elsevier BV
Date: 02-2014
DOI: 10.1016/J.NEUROIMAGE.2013.09.030
Abstract: We describe the visualization of the barrel cortex of the primary somatosensory area (S1) of ex vivo adult mouse brain with short-tracks track density imaging (stTDI). stTDI produced much higher definition of barrel structures than conventional fractional anisotropy (FA), directionally-encoded color FA maps, spin-echo T1- and T2-weighted imaging and gradient echo T1/T2*-weighted imaging. 3D high angular resolution diffusion imaging (HARDI) data were acquired at 48 micron isotropic resolution for a (3mm)(3) block of cortex containing the barrel field and reconstructed using stTDI at 10 micron isotropic resolution. HARDI data were also acquired at 100 micron isotropic resolution to image the whole brain and reconstructed using stTDI at 20 micron isotropic resolution. The 10 micron resolution stTDI maps showed exceptionally clear delineation of barrel structures. In idual barrels could also be distinguished in the 20 micron stTDI maps but the septa separating the in idual barrels appeared thicker compared to the 10 micron maps, indicating that the ability of stTDI to produce high quality structural delineation is dependent upon acquisition resolution. Close homology was observed between the barrel structure delineated using stTDI and reconstructed histological data from the same s les. stTDI also detects barrel deletions in the posterior medial barrel sub-field in mice with infraorbital nerve cuts. The results demonstrate that stTDI is a novel imaging technique that enables three-dimensional characterization of complex structures such as the barrels in S1 and provides an important complementary non-invasive imaging tool for studying synaptic connectivity, development and plasticity of the sensory system.
Hexarelin treatment preserves myocardial function and reduces cardiac fibrosis in a mouse model of acute myocardial infarction
Publisher: Wiley
Date: 05-2018
DOI: 10.14814/PHY2.13699
Altered functional connectivity in mesial temporal lobe epilepsy
Publisher: Elsevier BV
Date: 11-2017
DOI: 10.1016/J.EPLEPSYRES.2017.09.001
Abstract: Growing evidence of altered functional connectivity suggests that mesial temporal lobe epilepsy (mTLE) alters not only hippoc al networks, but also a number of resting state networks. These highly coherent, yet functionally distinct brain circuits interact dynamically with each other in order to mediate consciousness, memory, and attention. However, little is currently known about the modulation of these networks by epileptiform activity, such as interictal spikes and seizures. The objective of the study was to use simultaneous EEG-fMRI to investigate functional connectivity in three resting state networks: default mode network (DMN), salience network (SN), and dorsal attentional network (DAN) in patients with mTLE compared to a healthy cohort, and in relation to the onset of interictal spikes and the period immediately prior to the spikes. Compared to the healthy participants, mTLE patients showed significant alterations in functional connectivity of all three resting state networks, generally characterized by a lack of functional connectivity to prefrontal areas and increased connectivity to subcortical and posterior areas. Critically, prior to the onset of interictal spikes, compared to resting state, mTLE patients showed a lack of functional connectivity to the DMN and decreased synchronization within the SN and DAN, demonstrating alterations in functional coherence that may be responsible for the generation of epileptiform activity. Our findings demonstrate mTLE-related alterations of connectivity during the resting state as well as in relation to the onset of interictal spikes. These functional changes may underlie epilepsy-related cognitive abnormalities, because higher cognitive functions, such as memory or attention, rely heavily on the coordinated activity of all three resting state networks.
TissueStack: an Open Source HTML5 web based imaging viewer
Publisher: Frontiers Media SA
Date: 2013
CLODANOLENE SODIUM AND MALIGNANT HYPER-PYREXIA
Publisher: Elsevier BV
Date: 11-1982
Molecular dynamics and object kinetic Monte Carlo study of radiation-induced motion of voids and He bubbles in bcc iron
Publisher: American Physical Society (APS)
Date: 12-03-2013
In vivo high‐resolution volume‐selected proton spectroscopy and T1 measurements in the dog brain
Publisher: Wiley
Date: 02-1989
Abstract: Successful in vivo NMR spectroscopy requires a combination of techniques to address the problems of volume selection, water suppression, and resolution. All this needs to be done in the very heterogeneous environment found in living organisms. Previously published techniques are used to obtain 1H spectra from a dog brain, observing metabolites with concentrations below 1 mM. Measurements of spin-lattice relaxation times (T1) are also presented. The 1H relaxation times are long (T1 greater than 1.0 s) yielding information about the fluidity of the molecular environment. Comments are made concerning the achievable linewidth in vivo and the deficiencies that phase-encoding spectroscopic methods may have in obtaining high-resolution 1H spectra.
A wrapped edge transverse gradient coil design for increased gradient homogeneity
Publisher: Wiley
Date: 08-2009
DOI: 10.1002/CMR.B.20140
In vivo high angular resolution diffusion-weighted imaging of mouse brain at 16.4 Tesla
Publisher: Public Library of Science (PLoS)
Date: 25-06-2015
Repeated three-dimensional magnetic resonance imaging of atherosclerosis development in innominate arteries of low-density lipoprotein receptor-knockout mice
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 24-09-2002
DOI: 10.1161/01.CIR.0000030188.50326.8D
Abstract: Background— In vivo methods to evaluate the size and composition of atherosclerotic lesions in animal models of atherosclerosis would assist in the testing of antiatherosclerotic drugs. We have developed an MRI method of detecting atherosclerotic plaque in the major vessels at the base of the heart in low-density lipoprotein (LDL) receptor-knockout (LDLR −/− ) mice on a high-fat diet. Methods and Results— Three-dimensional fast spin-echo magnetic resonance images were acquired at 7 T by use of cardiac and respiratory triggering, with ≈140-μm isotropic resolution, over 30 minutes. Comparison of normal and fat-suppressed images from female LDLR −/− mice 1 week before and 8 and 12 weeks after the transfer to a high-fat diet allowed visualization and quantification of plaque development in the innominate artery in vivo. Plaque mean cross-sectional area was significantly greater at week 12 in the LDLR −/− mice (0.14±0.086 mm 2 [mean±SD]) than in wild-type control mice on a normal diet (0.017±0.031 mm 2 , P .01). In the LDLR −/− mice, but not control mice, increase in plaque burden at week 12 relative to week 1 was also highly significant ( P =0.001). Lumen cross section was not significantly different between time points or groups. MRI and histological assessments of plaque size were closely correlated ( R =0.8). The lumen of proximal coronary arteries could also be visualized. Conclusions— This is the first report of in vivo detection of aortic arch atherosclerosis in any animal model. The method could significantly assist rapid evaluation of experimental antiatherosclerotic therapies.
Magnetic resonance imaging analysis of the upper cervical spine extensor musculature in an asymptomatic cohort: An index of fat within muscle
Publisher: Elsevier BV
Date: 03-2005
DOI: 10.1016/J.CRAD.2004.08.013
Abstract: To establish a simple method to quantify muscle/fat constituents in cervical muscles of asymptomatic women using magnetic resonance imaging (MRI), and to determine whether there is an age effect within a defined age range. MRI of the upper cervical spine was performed for 42 asymptomatic women aged 18-45 years. The muscle and fat signal intensities on axial spin echo T1-weighted images were quantitatively classified by taking a ratio of the pixel intensity profiles of muscle against those of intermuscular fat for the rectus capitis posterior major and minor and inferior obliquus capitis muscles bilaterally. Inter- and intra-examiner agreement was scrutinized. The average relative values of fat within the upper cervical musculature compared with intermuscular fat indicated that there were only slight variations in indices between the three sets of muscles. There was no significant correlation between age and fat indices. There were significant differences for the relative fat within the muscle compared with intermuscular fat and body mass index for the right rectus capitis posterior major and right and left inferior obliquus capitis muscles (p=0.032). Intraclass correlation coefficients for intraobserver agreement ranged from 0.94 to 0.98. Inter-rater agreement of the measurements ranged from 0.75 to 0.97. A quantitative measure of muscle/fat constituents has been developed, and results of this study indicate that relative fatty infiltration is not a feature of age in the upper cervical extensor muscles of women aged 18-45 years.
Two New Fucose-α (1–2)-Glycans Assigned In The Healthy Human Brain Taking The Number To Seven
Publisher: Springer Science and Business Media LLC
Date: 11-12-2019
DOI: 10.1038/S41598-019-54933-1
Abstract: Fucosylated glycans are involved in the molecular mechanisms that underpin neuronal development, learning and memory. The capacity to study the fucose-α(1–2)-glycan residues noninvasively in the human brain, is integral to understanding their function and deregulation. Five fucose crosspeaks were assigned to fucosylated glycans using in vivo two-dimensional magnetic resonance Correlated SpectroscopY (2D L-COSY) of the brain. Recent improvements encompassed on the 3T Prisma (Siemens, Erlangen) with a 64-channel head and neck coil have allowed two new assignments. These are Fuc VI (F2:4.44, F1:1.37 ppm) and Fuc VII (F2: 4.29, F1:1.36 ppm). The Fuc VI crosspeak, close to the water resonance, is resolved due to decreased T1 noise. Fuc VII crosspeak, located between Fuc I and III, is available for inspection due to increased spectral resolution. Spectra recorded from 33 healthy men and women showed a maximum variation of up to 0.02 ppm in chemical shifts for all crosspeaks.
WorkWays: interacting with scientific workflows
Publisher: Wiley
Date: 21-05-2015
DOI: 10.1002/CPE.3525
Hippocampal volume and cell density changes in a mouse model of human genetic epilepsy
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 06-03-2013
Author Correction: Post-traumatic stress disorder affects fucose-α(1–2)-glycans in the human brain: preliminary findings of neuro deregulation using in vivo two-dimensional neuro MR spectroscopy
Publisher: Springer Science and Business Media LLC
Date: 05-02-2019
DOI: 10.1038/S41398-019-0400-2
Abstract: The original article contained errors in the Fig. 1 caption. The incorrect sentence, “The region highlighted by the white box is expanded in Fig. 3” was corrected to, “The region highlighted by the white box is expanded in Fig. 2.” This has been corrected in the HTML and PDF of the article.
Non-invasive monitoring of sucrose mobilization from culm storage parenchyma by magnetic resonance spectroscopy
Publisher: Informa UK Limited
Date: 23-03-2013
DOI: 10.1271/BBB.120682
Abstract: Because sucrose stored in mature stalks (in excess of 40% of stalk dry weight) can be wholly mobilized to supply carbon for the growth of heterotrophic tissues, we propose that sucrose mobilization requires a net sink-to-source transition that acts in toto within sett internode storage parenchyma. Based on our data we propose that mobilization of sucrose from culm storage parenchyma requires minimal investment of metabolic resources, and that the mechanism of sucrose mobilization is metabolically neutral. By magnetic resonance spectroscopy and phloem-specific tracer dyes, strong evidence was found that sucrose is mobilized from sett storage parenchyma via phloem to the growing shoot tissue. An analysis of the enzyme activities involved in sucrose metabolism and glycolysis suggested that sucrose synthase activity is downregulated due to the effects of sucrose mobilization. Overall, metabolism in storage parenchyma shifts from futile cycling to a more quiescent state during sucrose mobilization.
ARE QUENCHES DANGEROUS
Publisher: Wiley
Date: 02-1986
Abstract: There exists some uncertainty about the hazards which the quenching of a superconducting magnet would present to a subject undergoing an NMR examination. To investigate this problem, a 1.6-T whole-body magnet was quenched with an anesthetized pig lying in the bore. This paper reports our findings which, in the circumstances of this experiment, suggest that the risks are small.
MR image-based measurement of rates of change in volumes of brain structures. Part II: Application to a study of Alzheimer's disease and normal aging
Publisher: Elsevier BV
Date: 2002
DOI: 10.1016/S0730-725X(02)00472-1
Abstract: We present global and regional rates of brain atrophy measured on serially acquired T1-weighted brain MR images for a group of Alzheimer's disease (AD) patients and age-matched normal control (NC) subjects using the analysis procedure described in Part I. Three rates of brain atrophy: the rate of atrophy in the cerebrum, the rate of lateral ventricular enlargement and the rate of atrophy in the region of temporal lobes, were evaluated for 14 AD patients and 14 age-matched NC subjects. All three rates showed significant differences between the two groups. However, the greatest separation of the two groups was obtained when the regional rates were combined. This application has demonstrated that rates of brain atrophy, especially in specific regions of the brain, based on MR images can provide sensitive measures for evaluating the progression of AD. These measures will be useful for the evaluation of therapeutic effects of novel therapies for AD.
STUDY OF HUMAN LIVER-DISEASE WITH P-31 MAGNETIC-RESONANCE SPECTROSCOPY
Publisher: BMJ
Date: 04-1990
DOI: 10.1136/GUT.31.4.463
Abstract: Liver metabolism and energetics of 24 patients with liver disease were studied using phosphorus-31 magnetic resonance spectroscopy. Significant abnormalities were detected in the majority of these patients. A striking ersity in metabolic patterns was observed. Patients with acute viral hepatitis had low liver phosphodiesters and high phosphomonoesters, possibly phosphocholine and phosphoethanolamine. In alcoholic hepatitis phosphomonoesters were raised. Intracellular inorganic phosphate and inorganic phosphate/ATP ratios were decreased in primary biliary cirrhosis and in some patients with hepatitis. These spectroscopic results were evaluated in respect of the pattern of liver damage and cellular regeneration. Liver tumours had raised phosphomonoesters and also showed evidence for altered spin-lattice relaxation of the phosphorus nucleus in various metabolites. In iron overload the liver ATP resonances were broadened. The line broadening correlated with the degree of iron overload suggesting the potential use of P-31 magnetic resonance spectroscopy for measuring liver iron.
TissueStack: a new way to view your imaging data
Publisher: Frontiers Media SA
Date: 2013
MRI resolution enhancement: How useful are shifted images obtained by changing the demodulation frequency?
Publisher: Wiley
Date: 06-10-2011
DOI: 10.1002/MRM.22653
Abstract: Super-resolution reconstruction is a process by which a set of different low resolution images of the same object are used to create an enhanced, higher resolution image of that object. Recently there has been debate amongst researchers whether it is possible to obtain in-plane image enhancement using a set of low resolution magnetic resonance images, acquired by making small, independent changes to the demodulation frequency. We show that shifted low-resolution images contain different information that can be used to obtain denser s ling, leading to image enhancement. We conclude this from specific phantom experiments, applying signal processing s ling theory and taking into consideration the relative s ling of the point spread function with respect to the location of signal sources. Furthermore, the maximum achievable resolution for Fourier encoded MRI data at a boundary or object feature is governed by the effective width of the point spread function or the Fourier pixel size determined by the extent of k-space this is verified experimentally.
Magnetic resonance imaging and spectroscopy for monitoring liver steatosis
Publisher: Wiley
Date: 26-09-2008
DOI: 10.1002/JMRI.21542
Abstract: To compare noninvasive MRI and magnetic resonance spectroscopy (MRS) methods with liver biopsy to quantify liver fat content. Quantification of liver fat was compared by liver biopsy, proton MRS, and MRI using in-phase/out-of-phase (IP/OP) and plus/minus fat saturation (+/-FS) techniques. The reproducibility of each MR measure was also determined. An additional group of overweight patients with steatosis underwent hepatic MRI and MRS before and after a six-month weight-loss program. A close correlation was demonstrated between histological assessment of steatosis and measurement of intrahepatocellular lipid (IHCL) by MRS (r(s) = 0.928, P < 0.0001) and MRI (IP/OP r(s) = 0.942, P < 0.0001 FS r(s) = 0.935, P 5% weight loss had a decrease in IHCL of >or=50%. These findings suggest that standard MRI protocols provide a rapid, safe, and quantitative assessment of hepatic steatosis. This is important because MRS is not available on all clinical MRI systems. This will enable noninvasive monitoring of the effects of interventions such as weight loss or pharmacotherapy in patients with fatty liver diseases.
Localized two‐dimensional shift correlated spectroscopy in humans at 2 Tesla
Publisher: Wiley
Date: 08-1994
Abstract: A method for the acquisition of localized 2D shift-correlated spectra, based on the combination of the stimulated-echo volume-selection and gradient-enhanced COSY experiments, is described. The sequence can be modified to perform a number of localized experiments including HOHAHA and DQF-COSY. The method is demonstrated in vivo by presentation of localized COSY and HOHAHA spectra of human tibia marrow, and a localized COSY spectrum of human brain acquired at a field strength of 2 Tesla. Cross peaks corresponding to correlations between coupled groups along the acyl chains of triglycerides are observed in the spectra of marrow. The major cerebral metabolites are represented in the in vivo COSY brain spectrum, including N-acetylaspartate, glutamate/glutamine, total creatine, aspartate, and myo-inositol. Difficulties in the implementation of localized shift-correlation spectroscopy, including water suppression and T2 relaxation, are discussed.
DISCRETE ISOLATION FROM GRADIENT-GOVERNED ELIMINATION OF RESONANCES - DIGGER, A NEW TECHNIQUE FOR INVIVO VOLUME-SELECTED NMR-SPECTROSCOPY
Publisher: Elsevier BV
Date: 11-1986
Magnetization transfer imaging for polymer gel dosimetry
Publisher: IOP Publishing
Date: 21-05-2002
DOI: 10.1088/0031-9155/47/11/304
Abstract: Off-resonance RF pre-saturation was used to obtain contrast in MRI images of polymer gel dosimeters irradiated to doses up to 50 Gy. Two different polymer gel dosimeters composed of 2-hydroxyethyl-acrylate or methacrylic acid monomers mixed with N, N'-methylene-bisacrylamide (BIS), dispersed in an aqueous gelatin matrix were evaluated. Radiation-induced polymerization of the co-monomers generates a fast-relaxing insoluble polymer. Saturation of the polymer using off-resonance Gaussian RF pulses prior to a spin-echo readout with a short echo time leads to contrast that is dependent on the absorbed dose. This contrast is attributed to magnetization transfer (MT) between free water and the polymer, and direct saturation of water was found to be negligible under the prevailing experimental conditions. The usefulness of MT imaging was assessed by computing the dose resolution obtained with this technique. We found a low value of dose resolution over a wide range of doses could be obtained with a single experiment. This is an advantage over multiple spin echo (MSE) experiments using a single echo spacing where an optimal dose resolution is achieved over only very limited ranges of doses. The results suggest MT imaging protocols may be developed into a useful tool for polymer gel dosimetry.
Identifying disease progression in chronic kidney disease using proton magnetic resonance spectroscopy
Publisher: Elsevier BV
Date: 04-2023
Fatty infiltration in the cervical extensor muscles in persistent whiplash-associated disorders: A magnetic resonance imaging analysis
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 10-2006
Use of spherical harmonic deconvolution methods to compensate for nonlinear gradient effects on MRI images
Publisher: Wiley
Date: 28-06-2004
DOI: 10.1002/MRM.20122
Abstract: Spatial encoding in MR techniques is achieved by s ling the signal as a function of time in the presence of a magnetic field gradient. The gradients are assumed to generate a linear magnetic field gradient, and typical image reconstruction relies upon this approximation. However, high-speed gradients in the current generation of MRI scanners often sacrifice linearity for improvements in speed. Such nonlinearity results in distorted images. The problem is presented in terms of first principles, and a correction method based on a gradient field spherical harmonic expansion is proposed. In our case, the amount of distortion measured within a typical field of view (FOV) required for head imaging is sufficiently large that without the use of some distortion correction technique, the images would be of limited use for stereotaxy or longitudinal studies, where precise volumetric information is required.
The temporal development of fatty infiltrates in the neck muscles following whiplash injury: An association with pain and posttraumatic stress
Publisher: Public Library of Science (PLoS)
Date: 16-06-2011
Current developments in MRI for assessing rodent models of multiple sclerosis
Publisher: Future Medicine Ltd
Date: 07-2014
DOI: 10.2217/FNL.14.33
Abstract: ABSTRACT: MRI is a key radiological imaging technique that plays an important role in the diagnosis and characterization of heterogeneous multiple sclerosis (MS) lesions. Various MRI methodologies such as conventional T 1 /T 2 contrast, contrast agent enhancement, diffusion-weighted imaging, magnetization transfer imaging and susceptibility weighted imaging have been developed to determine the severity of MS pathology, including demyelination/remyelination and brain connectivity impairment from axonal loss. The broad spectrum of MS pathology manifests in erse patient MRI presentations and affects the accuracy of patient diagnosis. To study specific pathological aspects of the disease, rodent models such as experimental autoimmune encephalomyelitis, virus-induced and toxin-induced demyelination have been developed. This review aims to present key developments in MRI methodology for better characterization of rodent models of MS.
Detection of dimethyl sulfone in the human brain by in vivo proton magnetic resonance spectroscopy
Publisher: Elsevier BV
Date: 2000
DOI: 10.1016/S0730-725X(99)00110-1
Abstract: We wish to report the detection of dimethyl sulfone (methylsulfonylmethane, C2H6O2S) in the brain of a normal 62-year-old male using in vivo proton magnetic resonance spectroscopy. The presence of this exogenous metabolite resulted from ingestion of a dietary supplement containing dimethyl sulfone. The concentration of this compound in the brain was measured to be 2.4 mmol, with a washout "half life" of approximately 7.5 days. The in vivo T1 and T2 relaxation times of dimethyl sulfone were measured to be 2180 ms and 385 ms, respectively. The concentration of major brain metabolites, namely N-acetylaspartate, total Creatine and Choline, and myo-Inositol were within normal limits.
Fatty infiltrate in the cervical extensor muscles is not a feature of chronic, insidious-onset neck pain
Publisher: Elsevier BV
Date: 06-2008
DOI: 10.1016/J.CRAD.2007.11.011
Abstract: To investigate the presence of fatty infiltrate in the cervical extensor musculature in patients with insidious-onset neck pain to better understand the possible pathophysiology underlying such changes in chronic whiplash-associated disorders (WAD). A s le of convenience of 23 women with persistent insidious-onset neck pain (mean age 29.2+/-6.9 years) was recruited for the study. Magnetic resonance imaging (MRI) was used to quantify fatty infiltration in the cervical extensor musculature. Quantitative Sensory Testing (QST pressure and thermal pain thresholds) was performed as sensory features are present in chronic whiplash. Self-reported pain and disability, as well as psychological distress, were measured using the Neck Disability Index (NDI) and the General Health Questionnaire-28 (GHQ-28), respectively. Measures were compared with those of a previous dataset of chronic whiplash patients (n=79, mean age 29.7+/-7.8 years). Using a classification tree, insidious-onset neck pain was clearly identified from whiplash (p<0.001), based on the presence of MRI fatty infiltrate in the cervical extensor musculature (0/102 in iduals) and altered temperature thresholds (cold 3/102 in iduals). Fatty infiltrates in the cervical extensor musculature and widespread hyperalgesia were not features of the insidious-onset neck pain group in this study whereas these features have been identified in patients with chronic WAD. This novel finding may enable a better understanding of the underlying pathophysiological processes in patients with chronic whiplash.
Gradient-induced water-suppression techniques for high-resolution NMR spectroscopy
Publisher: Elsevier BV
Date: 02-1989
Magnetic resonance spectroscopy: is it ripe for clinical practice?
Publisher: Elsevier BV
Date: 04-2010
Two-dimensional correlated spectroscopy records reduced neurotransmission in blast-exposed artillery soldiers after live fire training
Publisher: Wiley
Date: 18-04-2023
DOI: 10.1002/NBM.4934
Abstract: There is a requirement for an objective method to determine a safe level of low‐level military occupational blast, having recognised it can lead to neurological damage. The purpose of the current study was to evaluate the effect of artillery firing training on the neurochemistry of frontline soldiers using two‐dimensional (2D) COrrelated SpectroscopY (2D COSY) in a 3‐T clinical MR scanner. Ten men considered to be of sound health were evaluated before and after a week‐long live firing exercise in two ways. Prior to the live fire exercise, all participants were screened by a clinical psychologist using a combination of clinical interviews and psychometric tests, and were then scanned with 3‐T MRI. The protocols included T1‐ and T2‐weighted images for diagnostic reporting and anatomical localisation and 2D COSY to record any neurochemical effects from the firing. No changes to the structural MRI were recorded. Nine substantive and statistically significant changes in the neurochemistry were recorded as a consequence of firing training. Glutamine and glutamate, glutathione, and two of the seven fucose‐α (1–2)‐glycans were significantly increased. N‐acetyl aspartate, myo ‐inositol + creatine, and glycerol were also increased. Significant decreases were recorded for the glutathione cysteine moiety and tentatively assigned glycan with a 1–6 linkage (F2: 4.00, F1: 1.31 ppm). These molecules are part of three neurochemical pathways at the terminus of the neurons providing evidence of early markers of disruption to neurotransmission. Using this technology, the extent of deregulation can now be monitored for each frontline defender on a personalised basis. The capacity to monitor early a disruption in neurotransmitters, using the 2D COSY protocol, can observe the effect of firing and may be used to prevent or limit these events.
Laser induced breakdown spectroscopy (LIBS) for whole rock geochemistry
Publisher: Elsevier BV
Date: 03-2023
Validating molecular dynamics with direct imaging of radiation damage debris
Publisher: American Physical Society (APS)
Date: 29-03-2012
SUXAMETHONIUM CHLORIDE AND MALIGNANT HYPERPYREXIA
Publisher: Elsevier BV
Date: 04-1986
DOI: 10.1093/BJA/58.4.447
Abstract: Pure suxamethonium chloride does not produce in vitro contracture of skeletal muscle from swine which are susceptible to malignant hyperpyrexia (MH), but does induce MH in vivo. It is suggested that suxamethonium chloride induces MH because the fasciculations which it causes lead to an increase in the myoplasmic calcium concentration.
A segmentation guide and probabilistic atlas of the C57BL/6J mouse brain from magnetic resonance imaging
Publisher: Frontiers Media SA
Date: 2014
Super-resolution track-density imaging studies of mouse brain: Comparison to histology
Publisher: Elsevier BV
Date: 2012
DOI: 10.1016/J.NEUROIMAGE.2011.07.014
Abstract: The recently proposed track-density imaging (TDI) technique was introduced as a means to achieve super-resolution using diffusion MRI. This technique is able to increase the spatial resolution of the reconstructed images beyond the acquired MRI resolution by incorporating information from whole-brain fibre-tracking results. It not only achieves super-resolution, but also provides very high anatomical contrast with a new MRI contrast mechanism. However, the anatomical information-content of this novel contrast mechanism has not yet been assessed. In this work, we perform such a study using diffusion MRI of ex vivo mouse brains acquired at 16.4 T, to compare the results of the super-resolution TDI technique with histological staining (myelin and Nissl stains) in the same brains. Furthermore, a modified version of the directionally-encoded colour TDI map using short-tracks is introduced, which reduces the TDI intensity dynamic range, and therefore enhances the directionality colour-contrast. Good agreement was observed between structures visualised in the super-resolution TDI maps and in the histological sections, supporting the anatomical information-content of the images generated using the TDI technique. The results therefore show that the TDI methodology does provide meaningful and rich anatomical contrast, in addition to achieving super-resolution. Furthermore, this study is the first to show the application of TDI to mouse brain imaging: the high-resolution, high-quality images demonstrate the useful complementary information that can be achieved using super-resolution TDI.
Feasibility of functional magnetic resonance lung imaging in Australia with long distance transport of hyperpolarized helium from Germany
Publisher: Wiley
Date: 12-03-2008
DOI: 10.1111/J.1440-1843.2008.01262.X
Abstract: MRI of the lung using hyperpolarized helium as an inhaled contrast agent has important research applications and clinical potential. Owing to the limited availability of hyperpolarized helium, this type of imaging has not been performed in the human lung outside of North America or Europe. The objective of this study was to test the feasibility of imaging human lungs in Australia using hyperpolarized helium gas imported from Germany. A Bruker 2-Tesla whole-body magnetic resonance scanner located in Brisbane, Australia was adapted with a helium-3 radiofrequency transceiver coil. Helium-3 was hyperpolarized to 72% in Mainz, Germany and airfreighted to Brisbane. The time taken for the journey was 32 h and scanning was performed 36-40 h after departure from Mainz, with an estimated polarization level of 44%. Procedures were developed to transfer 300 mL of the hyperpolarized helium to Tedlar bags filled with 700 mL of nitrogen. Healthy volunteers inhaled the 1 L helium/nitrogen mixture from FRC, and imaging was performed with a 10 s breathhold. Imaging showed very detailed and even ventilation of all regions of the lung with a good signal-to-noise ratio. No adverse effects of inhaling the gas mixture were noted. This report of MRI of the human lung using hyperpolarized helium demonstrates the feasibility of long distance gas transport from Germany to Australia. This will help to facilitate research and clinical application of this innovative functional lung imaging technique.
MRI study of the cross-sectional area for the cervical extensor musculature in patients with persistent whiplash associated disorders (WAD)
Publisher: Elsevier BV
Date: 06-2008
DOI: 10.1016/J.MATH.2007.01.012
Abstract: Cervical muscle function is disturbed in patients with persistent pain related to a whiplash associated disorder (WAD) but little is known about neck extensor muscle morphometry in this group. This study used magnetic resonance imaging to measure relative cross-sectional area (rCSA) of the rectus capitis posterior minor and major, multifidus, semispinalis cervicis and capitis, splenius capitis and upper trapezius muscles bilaterally at each cervical segment. In total, 113 female subjects (79 WAD, 34 healthy control 18-45 years, 3 months-3 years post-injury) were recruited for the study. Significant main effects for differences in muscle and segmental level were found between the two groups (P < 0.0001) as well as a significant group * muscle * level interaction (P < 0.0001). The cervical multifidus muscle in the WAD group had significantly larger rCSA at all spinal levels and in contrast, there were variable differences in rCSA measures across levels in the intermediate and superficial extensor muscles when compared to the healthy controls (P < 0.0001). There were occasional weak, although statistically significant relationships between age, body mass index (BMI), duration of symptoms and the size of some muscles in both healthy control and WAD subjects (P < 0.01). It is possible that the consistent pattern of larger rCSA in multifidus at all levels and the variable pattern of rCSA values in the intermediate and superficial muscles in patients with WAD may reflect morphometric change due to fatty infiltrate in the WAD muscles. Future clinical studies are required to investigate the relationships between muscular morphometry, symptoms and function in patients with persistent WAD.
A SIMPLE MODIFICATION FOR THE ELIMINATION OF PHASE DISTORTIONS, A CHARACTERISTIC OF BINOMIAL SOLVENT SUPPRESSION PULSE SEQUENCES
Publisher: Elsevier BV
Date: 08-1987
WATER SIGNAL ELIMINATION INVIVO, USING SUPPRESSION BY MISTIMED ECHO AND REPETITIVE GRADIENT EPISODES
Publisher: Elsevier BV
Date: 10-1986
Combined approach for non-invasive measurement of liver pathology by MR
Publisher: Elsevier BV
Date: 12-2009
A method to collect representative samples from water-driven percussion drilling techniques: examples from RoXplorer® coiled tubing drill rig
Publisher: Informa UK Limited
Date: 27-03-2022
T1 Mapping for Myocardial Fibrosis by Cardiac Magnetic Resonance Relaxometry—A Comprehensive Technical Review
Publisher: Frontiers Media SA
Date: 16-03-2017
Nodal inhomogeneity mapping by localized excitation—the “NIMBLE” shimming technique for high‐resolution in Vivo NMR spectroscopy
Publisher: Wiley
Date: 07-1988
Abstract: A method (NIMBLE) for obtaining optimum B0 field homogeneity at voxels located away from the magnet isocenter for use in volume-selected NMR spectroscopy is described. Voxels may be shimmed using only first-order X, Y, and Z shims to produce three-dimensional shim current maps, thus avoiding shim coupling problems. NIMBLE shimming prior to volume selection ensures optimum spectral resolution and improves the efficiency and accuracy of the volume-selection experiment. The benefits of the technique are illustrated by a high-resolution volume-selected spectrum of human tibia marrow.
The design of planar gradient coils. Part II: A weighted superposition method
Publisher: Wiley
Date: 2005
DOI: 10.1002/CMR.B.20050
The use of unwrapped phase in MR image segmentation: A preliminary study
Publisher: Springer Berlin Heidelberg
Date: 2005
DOI: 10.1007/11566489_100
Fak depletion in both hematopoietic and nonhematopoietic niche cells leads to hematopoietic stem cell expansion
Publisher: Elsevier BV
Date: 04-2012
Ventilation distribution in rats: Part 2 – A comparison of electrical impedance tomography and hyperpolarised helium magnetic resonance imaging
Publisher: Springer Science and Business Media LLC
Date: 2012
A reproducible method for automated extraction of brain volumes from 3D human head MR images
Publisher: Wiley
Date: 03-1998
Abstract: An automated method for extracting brain volumes from three commonly acquired three-dimensional (3D) MR images (proton density, T1 weighted, and T2-weighted) of the human head is described. The procedure is ided into four levels: preprocessing, segmentation, scalp removal, and postprocessing. A user-provided reference point is the sole operator-dependent input required. The method's parameters were first optimized and then fixed and applied to 30 repeat data sets from 15 normal older adult subjects to investigate its reproducibility. Percent differences between total brain volumes (TBVs) for the subjects' repeated data sets ranged from .5% to 2.2%. We conclude that the method is both robust and reproducible and has the potential for wide application.
Magnetic resonance microscopy of the equine hoof wall: A study of resolution and potential
Publisher: Wiley
Date: 05-01-2006
DOI: 10.2746/042516406778400565
Abstract: Obtaining magnetic resonance images of the inner hoof wall tissue at the microscopic level would enable early accurate diagnosis of laminitis and therefore more effective therapy. To optimise magnetic resonance imaging (MRI) parameters in order to obtain the highest possible resolution of the structures beneath the equine hoof wall. Magnetic resonance microscopy (MRM) was performed in front feet from 6 cadaver horses using T2-weighted fast spin echo (FSE-T2), and T1-weighted gradient echo (GRE-T1) sequences. In T2 weighted FSE images most of the stratum medium showed no signal, however the coronary, terminal and sole papillae were visible. The stratum lamellatum was clearly visible and primary epidermal lamellae could be differentiated from dermal lamellae. Most structures beneath the hoof wall were differentiated. Conventional scanners for diagnostic MRI in horses are low or high field. However this study used ultra-high field scanners currently not available for clinical use. Signal-to-noise ratio (S/N) increases as a function of field strength. An increase of spatial resolution of the image results in a decreased S/N. S/N can also be improved with better coils and the resolution of high field MRI scanners will increase as technology develops and surface array coils become more readily available. Although MR images with microscopic resolution were obtained ex vivo, this study demonstrates the potential for detection of lamellar pathology as it occurs. Early recognition of the development of laminitis to instigate effective therapy at an earlier stage and may improve the outcome for laminitic horses. Clinical MR is now readily available at 3 T, while 4 T, 7 T and 9 T systems are being used for human whole body applications.
MALIGNANT HYPERPYREXIA AND SUDDEN INFANT DEATH
Publisher: Elsevier BV
Date: 11-1982
Platelet GPIbα is a mediator and potential interventional target for NASH and subsequent liver cancer
Publisher: Springer Science and Business Media LLC
Date: 04-2019
DOI: 10.1038/S41591-019-0379-5
Abstract: Non-alcoholic fatty liver disease ranges from steatosis to non-alcoholic steatohepatitis (NASH), potentially progressing to cirrhosis and hepatocellular carcinoma (HCC). Here, we show that platelet number, platelet activation and platelet aggregation are increased in NASH but not in steatosis or insulin resistance. Antiplatelet therapy (APT aspirin/clopidogrel, ticagrelor) but not nonsteroidal anti-inflammatory drug (NSAID) treatment with sulindac prevented NASH and subsequent HCC development. Intravital microscopy showed that liver colonization by platelets depended primarily on Kupffer cells at early and late stages of NASH, involving hyaluronan-CD44 binding. APT reduced intrahepatic platelet accumulation and the frequency of platelet-immune cell interaction, thereby limiting hepatic immune cell trafficking. Consequently, intrahepatic cytokine and chemokine release, macrovesicular steatosis and liver damage were attenuated. Platelet cargo, platelet adhesion and platelet activation but not platelet aggregation were identified as pivotal for NASH and subsequent hepatocarcinogenesis. In particular, platelet-derived GPIbα proved critical for development of NASH and subsequent HCC, independent of its reported cognate ligands vWF, P-selectin or Mac-1, offering a potential target against NASH.
Erratum: The visibility of the 1H NMR signal of ethanol in the dog brain (volume 19, number 2 (1991), pages 340-348)
Publisher: Wiley
Date: 10-1991
MRI demodulation frequency changes provide different information
Publisher: Wiley
Date: 23-08-2011
DOI: 10.1002/MRM.23099
The design of planar gradient coils. Part I: A winding path correction method
Publisher: Wiley
Date: 2005
DOI: 10.1002/CMR.B.20049
A MITOCHONDRIAL ENCEPHALOMYOPATHY - A COMBINED P-31 MAGNETIC-RESONANCE AND BIOCHEMICAL INVESTIGATION
Publisher: Elsevier BV
Date: 11-1985
DOI: 10.1016/0022-510X(85)90040-1
Abstract: A 15-year-old girl presented with recurrent encephalopathic episodes, epilepsy, myopathy and chronic lactic acidosis. A muscle biopsy revealed the presence of ragged red fibres and mitochondria with paracrystalline inclusions. Biochemical studies on freshly isolated skeletal muscle mitochondria demonstrated a deficiency of NADH-CoQ reductase activity. Investigation of her gastrocnemius muscle at rest by phosphorus nuclear magnetic resonance displayed a reduced phosphocreatine concentration with elevated levels of inorganic phosphate and ADP. Abnormalities were also apparent in her brain spectrum. It is therefore possible that the mitochondrial defect present in skeletal muscle is also being expressed in the brain.
P-31 NUCLEAR MAGNETIC-RESONANCE STUDIES OF MUSCLE METABOLISM IN MALIGNANT HYPERPYREXIA
Publisher: Elsevier BV
Date: 06-1984
Abstract: We use a "chain of risks" model to identify risk factors for prolonged heavy drinking in a nationally representative US s le followed from adolescence to middle age, focusing on educational mediators and differential consequences of early exposure to family poverty and area-level disadvantage. Using data from the 1979 National Longitudinal Survey of Youth (civilian respondents ages 14-19 at baseline, N = 5781), longitudinal path models assessed racial/ethnic and gender differences in indirect effects of early disadvantage (duration of exposure to family poverty and area-level disadvantage during adolescence) on midlife heavy drinking. Educational mediators were high school academic performance (taking remedial coursework), high school completion, and attaining a college education. Subgroups were based on race/ethnicity (50.7% White, 30.5% Black, 18.8% Hispanic respondents) and gender (49.6% males). There was a significant indirect path from family poverty during adolescence to poor high school academic performance, lower educational attainment, and more heavy drinking in midlife. For Black respondents, there was an additional direct effect of early area-level disadvantage on greater midlife heavy drinking that was not seen for other groups. The effect of family poverty on reduced high school graduation was stronger for males than females. Enduring impacts of family poverty duration during adolescence on educational attainment have consequences for health risk behaviors in midlife. Due to differential exposure to early adversity, intersectoral interventions are needed to reduce disparities in alcohol outcomes and to promote health equity among high-risk populations.
A wave equation technique for designing compact gradient coils
Publisher: Wiley
Date: 2006
DOI: 10.1002/CMR.B.20061
Processing of urinary pheromones in antechinus Stuartii (marsupialia: Dasyuridae): Functional magnetic resonance imaging of the brain
Publisher: Oxford University Press (OUP)
Date: 02-2002
Quantification of β-Amyloidosis and rCBF with Dedicated PET, 7 T MR Imaging, and High-Resolution Microscopic MR Imaging at 16.4 T in APP23 Mice
Publisher: Society of Nuclear Medicine
Date: 06-08-2015
DOI: 10.2967/JNUMED.115.159350
Abstract: We present a combined PET/7 T MR imaging and 16.4 T microscopic MR imaging dual-modality imaging approach enabling quantification of the amyloid load at high sensitivity and high resolution, and of regional cerebral blood flow (rCBF) in the brain of transgenic APP23 mice. Moreover, we demonstrate a novel, voxel-based correlative data analysis method for in-depth evaluation of amyloid PET and rCBF data. We injected 11C-Pittsburgh compound B (PIB) intravenously in transgenic and control APP23 mice and performed dynamic PET measurements. rCBF data were recorded with a flow-sensitive alternating inversion recovery approach at 7 T. Subsequently, the animals were sacrificed and their brains harvested for ex vivo microscopic MR imaging at 16.4 T with a T2*-weighted gradient-echo sequence at 30-μm spatial resolution. Additionally, correlative amyloid histology was performed. The 11C-PIB PET data were quantified to nondisplaceable binding potentials (BPND) using the Logan graphical analysis flow-sensitive alternating inversion recovery data were quantified with a simplified version of the Bloch equation. Amyloid load assessed by both 11C-PIB PET and amyloid histology was highest in the frontal cortex of transgenic mice (11C-PIB BPND: 0.93±0.08 amyloid histology: 15.1%±1.5%), followed by the temporoparietal cortex (11C-PIB BPND: 0.75±0.08 amyloid histology: 13.9%±0.7%) and the hippoc us (11C-PIB BPND: 0.71±0.09 amyloid histology: 9.2%±0.9%), and was lowest in the thalamus (11C-PIB BPND: 0.40±0.07 amyloid histology: 6.6%±0.6%). However, 11C-PIB BPND and amyloid histology linearly correlated (R2=0.82, P<0.05) and were significantly higher in transgenic animals (P<0.01). Similarly, microscopic MR imaging allowed quantifying the amyloid load, in addition to the detection of substructures within single amyloid plaques correlating with amyloid deposition density and the measurement of hippoc al atrophy. Finally, we found an inverse relationship between 11C-PIB BPND and rCBF MR imaging in the voxel-based analysis that was absent in control mice (slopetg: -0.11±0.03 slopeco: 0.004±0.005 P=0.014). Our dual-modality imaging approach using 11C-PIB PET/7 T MR imaging and 16.4 T microscopic MR imaging allowed amyloid-load quantification with high sensitivity and high resolution, the identification of substructures within single amyloid plaques, and the quantification of rCBF.
Early gestational ethanol exposure in mice: Effects on brain structure, energy metabolism and adiposity in adult offspring
Publisher: Elsevier BV
Date: 03-2019
DOI: 10.1016/J.ALCOHOL.2018.04.008
Abstract: We examined whether an early-life event - ethanol exposure in the initial stages of pregnancy - affected offspring brain structure, energy metabolism, and body composition in later life. Consumption of 10% (v/v) ethanol by inbred C57BL/6J female mice from 0.5 to 8.5 days post coitum was used to model alcohol exposure during the first 3-4 weeks of gestation in humans, when pregnancy is not typically recognized. At adolescence (postnatal day [P] 28) and adulthood (P64), the brains of male offspring were scanned ex vivo using ultra-high field (16.4 T) magnetic resonance imaging and diffusion tensor imaging. Energy metabolism and body composition were measured in adulthood by indirect calorimetry and dual-energy X-ray absorptiometry (DXA), respectively. Ethanol exposure had no substantial impact on white matter organization in the anterior commissure, corpus callosum, hippoc al commissure, internal capsule, optic tract, or thalamus. Whole brain volume and the volumes of the neocortex, cerebellum, and caudate putamen were also unaffected. Subtle, but non-significant, effects were observed on the hippoc us and the hypothalamus in adult ethanol-exposed male offspring. Ethanol exposure was additionally associated with a trend toward decreased oxygen consumption, carbon dioxide production, and reduced daily energy expenditure, as well as significantly increased adiposity, albeit with normal body weight and food intake, in adult male offspring. In summary, ethanol exposure restricted to early gestation had subtle long-term effects on the structure of specific brain regions in male offspring. The sensitivity of the hippoc us to ethanol-induced damage is reminiscent of that reported by other studies - despite differences in the level, timing, and duration of exposure - and likely contributes to the cognitive impairment that characteristically results from prenatal ethanol exposure. The hypothalamus plays an important role in regulating metabolism and energy homeostasis. Our finding of altered daily energy expenditure and adiposity in adult ethanol-exposed males is consistent with the idea that central nervous system abnormalities also underpin some of the metabolic phenotypes associated with ethanol exposure in pregnancy.
An approach of deriving relative sensitivity profiles for image reconstruction in MRI
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 12-2008
The visibility of the 1H NMR signal of ethanol in the dog brain
Publisher: Wiley
Date: 06-1991
Abstract: In vivo, high-resolution, volume-selected 1H NMR spectroscopy was used to monitor the concentration of ethanol in the dog brain following intravenous injection of ethanol. Equilibration of ethanol in the body water should result in approximately equivalent concentrations of ethanol in the blood and brain. However, the mean equilibrium brain ethanol concentration determined using N-acetylaspartate as an internal standard was only 23 +/- 5% of the blood ethanol concentration. The disparity between blood and brain ethanol concentrations was attributed to underestimation of the ethanol concentration due to overlapping resonances with NAA and to T2 attenuation or possible nondetection of the 1H signal from ethanol bound at the surface of cell membranes and partitioned into the hydrophobic core of membrane lipids.
In vivo volume‐selective metabolite editing via correlated z‐order
Publisher: Wiley
Date: 12-1990
Abstract: Volume-selected 1H NMR spectroscopy was combined with spectral editing to selectively detect brain metabolites. The SPACE localization sequence was used to create a voxel of zeta-magnetization which could then be edited for any scalar coupled metabolite by the use of selective excitation in the ECZOTIC sequence to generate longitudinal spin order. The sequence returns an edited signal with no intrinsic loss of magnetization. The method was applied to observe approximately 10 mM ethanol and 17 mM lactate in the brain of a dog.
Utilising geochemical data for the identification and characterisation of mineral exploration sample media within cover sequence materials
Publisher: Informa UK Limited
Date: 20-11-2019
Segmentation of the C57BL/6J mouse cerebellum in magnetic resonance images
Publisher: Elsevier BV
Date: 09-2012
DOI: 10.1016/J.NEUROIMAGE.2012.05.061
Abstract: The C57BL mouse is the centerpiece of efforts to use gene-targeting technology to understand cerebellar pathology, thus creating a need for a detailed magnetic resonance imaging (MRI) atlas of the cerebellum of this strain. In this study we present a methodology for systematic delineation of the vermal and hemispheric lobules of the C57BL/6J mouse cerebellum in magnetic resonance images. We have successfully delineated 38 cerebellar and cerebellar-related structures. The higher signal-to-noise ratio achieved by group averaging facilitated the identification of anatomical structures. In addition, we have calculated average region volumes and created probabilistic maps for each structure. The segmentation method and the probabilistic maps we have created will provide a foundation for future studies of cerebellar disorders using transgenic mouse models.
Advances in and applications of imaging and radiomics in head and neck cancer survivorship
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 07-08-2023
DOI: 10.1097/MOO.0000000000000918
Abstract: Radiological imaging is an essential component of head/neck cancer (HNC) care. Advances in imaging modalities (including CT, PET, MRI and ultrasound) and analysis have enhanced our understanding of tumour characteristics and prognosis. However, the application of these methods to evaluate treatment-related toxicities and functional burden is still emerging. This review showcases recent literature applying advanced imaging and radiomics to the assessment and management of sequelae following chemoradiotherapy for HNC. Whilst primarily early-stage/exploratory studies, recent investigations have showcased the feasibility of using radiological imaging, particularly advanced/functional MRI (including diffusion-weighted and dynamic contrast-enhanced MRI), to quantify treatment-induced tissue change in the head/neck musculature, and the clinical manifestation of lymphoedema/fibrosis and dysphagia. Advanced feature analysis and radiomic studies have also begun to give specific focus to the prediction of functional endpoints, including dysphagia, trismus and fibrosis. There is demonstrated potential in the use of novel imaging techniques, to help better understand pathophysiology, and improve assessment and treatment of functional deficits following HNC treatment. As larger studies emerge, technologies continue to progress, and pathways to clinical translation are honed, the application of these methods offers an exciting opportunity to transform clinical practices and improve outcomes for HNC survivors.
Carotid ultrasound pulsatility indices and cardiovascular risk in A ustralian women
Publisher: Wiley
Date: 21-10-2014
Abstract: Ultrasound-acquired internal carotid arterial (ICA) pulsatility indices (PI) have been demonstrated to be useful measures of cerebrovascular disease. The purpose of this cross-sectional study was to investigate the association between carotid artery PI, cardiovascular risk and ischaemic heart disease in aging women. One hundred and fifty-eight female participants of the Longitudinal Assessment of Ageing in Women study, aged 48-85 years, were evaluated. The relationships between common carotid artery (CCA) and ICA Doppler PI to cardiovascular risk factors (age, body mass index, systolic and mean arterial blood pressure, smoking and diabetes), carotid-femoral (femPWV) and carotid-radial (radPWV) pulse wave velocities, and ischaemic heart disease (IHD) were assessed using Spearman's rank correlation (ρ), multiple regression and logistic regression. Dependent variables were Box-Cox transformed to meet linear regression assumptions. CCA and ICA PI were significantly correlated to femPWV (ρ = 0.414 and ρ = 0.544, respectively). Cardiovascular risk factors were significantly predictive of CCA PI (Adj R(2) = 0.176, P < 0.01) however, their relationship to ICA PI (Adj R(2) = 0.508, P < 0.01) was stronger. This result was comparable with the relationship between cardiovascular risk factors and femPWV (Adj R(2) = 0.561, P < 0.01). Age and systolic blood pressure were the dominant risk factors for IHD in this group. ICA PI is comparable with femPWV in its association with cardiovascular disease. PI does not improve the prediction of IHD over age and systolic blood pressure.
O179 Early Detection of Hypertensive Myocardial Fibrosis by Cardiac Magnetic Resonance Relaxometry
Publisher: Ubiquity Press, Ltd.
Date: 03-2014
Changes in the hippocampus induced by glucose in thiamin deficient rats detected by MRI
Publisher: Elsevier BV
Date: 04-1998
DOI: 10.1016/S0006-8993(98)00203-0
Abstract: Using T2-weighted Magnetic Resonance Imaging (MRI) in a pyrithiamin-treated, thiamin deficient (TD) rat model of Wernicke's encephalopathy (WE), we have observed hyperintensity in the thalamus, hypothalamus, collicular bodies and hippoc us which was enhanced 40 min after a glucose load. Hyperintensity was not evident in these structures in thiamin replete rats receiving glucose nor was it enhanced in TD rats administered 2-deoxyglucose. Residual hyperintensity was still evident in the hippoc us as long as 30 days after thiamin administration and was increased by repeat glucose challenge at that time. These data indicate that the hippoc us is as vulnerable as the thalamus to some persistent pathological change when glucose is metabolised in a state of thiamin deficiency.
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