ORCID Profile
0000-0002-3870-4658
Current Organisation
Griffith University
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Publisher: Springer Science and Business Media LLC
Date: 11-2008
Publisher: Elsevier
Date: 2002
Publisher: American Roentgen Ray Society
Date: 07-2009
DOI: 10.2214/AJR.08.1670
Publisher: Radiological Society of North America (RSNA)
Date: 11-2015
Publisher: Springer Science and Business Media LLC
Date: 02-2004
DOI: 10.1007/BF02523998
Publisher: Wiley
Date: 22-12-2014
DOI: 10.1002/NBM.3239
Abstract: A growing body of literature has indicated that fucose-α(1-2)-galactose sugars are implicated in the molecular mechanisms that underlie neuronal development, learning and memory in the human brain. An understanding of the in vivo roles played by these terminal fucose residues has been h ered by the lack of technology to non-invasively monitor their levels in the human brain. We have implemented in vivo two-dimensional MRS technology to examine the human brain in a 3-T clinical MR scanner, and report that six fucose-α(1-2)-galactose residues and free α-fucose are available for inspection. Fucose-α(1-3)-galactose residues cannot yet be assigned using this technology as they resonate under the water resonance. This new application offers an unprecedented insight into the molecular mechanisms by which fucosylated sugars contribute to neuronal processes and how they alter during development, ageing and disease.
Publisher: Elsevier BV
Date: 06-2005
DOI: 10.1016/J.DIAGMICROBIO.2005.02.004
Abstract: Viable cryptococci load in biopsy material from an animal model of cerebral cryptococcoma were correlated with 1H NMR spectra and metabolite profiles. A statistical classification strategy was applied to distinguish among high-resolution 1H NMR spectra acquired from cryptococcomas, glioblastomas, and normal brain tissue. The overall classification accuracy was 100% when a genetic-algorithm-based optimal region selection preceded the development of linear discriminant analysis-based classifiers. The method remained robust despite differences in the microbial load of the cryptococcoma group when harvested at different time points. These results indicate the feasibility of the method for diagnosis without isolation of the pathogenic microorganism and its potential for in vivo diagnosis based on computerized analysis of magnetic resonance spectra.
Publisher: Radiological Society of North America (RSNA)
Date: 07-2008
Publisher: Springer Science and Business Media LLC
Date: 15-03-2015
Publisher: Radiological Society of North America (RSNA)
Date: 07-2003
Publisher: Radiological Society of North America (RSNA)
Date: 09-1993
DOI: 10.1148/RADIOLOGY.188.3.8351349
Abstract: The concept that high-resolution (8.5-T) hydrogen-1 magnetic resonance (MR) spectroscopy can be used as an adjunct to conventional histologic diagnosis of cervical neoplasia was investigated. Cervical biopsy specimens (n = 159) were examined with H-1 MR spectroscopy and the results compared with results of histopathologic analysis. A high-resolution lipid MR spectrum was observed in 39 of 40 invasive carcinomas, whereas the 119 preinvasive s les showed little or no lipid spectrum but were characterized by a strong unresolved resonance between 3.8 and 4.2 ppm. Peak ratios of the methylene/methyl and the unresolved/methylene resonances allowed accurate distinction between invasive and preinvasive epithelial malignancy (P < .0001). Since MR spectroscopic examination does not destroy the specimen, the specimens remained intact for further testing and histopathologic analysis. The authors conclude that H-1 MR spectroscopy can independently allow distinction between invasive and preinvasive lesions of the cervix and has the potential to assist in clinical management of cervical cancer.
Publisher: Radiological Society of North America (RSNA)
Date: 06-2015
Abstract: To use localized correlated spectroscopy (COSY) to assess for an altered biochemical state or states in breast tissue of women with BRCA gene mutations that potentially constitute preinvasive conditions. Institutional review board approval was obtained. Participants provided written informed consent. In vivo localized COSY images were recorded at 3 T in the breast tissue of women carrying BRCA1 (n = 9) or BRCA2 (n = 14) gene mutations and were compared with images in healthy control subjects with no family history of breast cancer (n = 10). All participants underwent contrast material-enhanced MR imaging and ultrasonography (US). Statistical significance was calculated with the Mann-Whitney two-sided nonparametric test. No abnormality was recorded with MR imaging or US. Metabolite levels in the BRCA1 cohort were reduced by 79% (P = .014) when compared with triglycerides level, and there was a 19% increase in lipid unsaturation and triglyceride levels (P = .027 and P = .086, respectively) when compared with cellular cholesterol level. Cholesterol level was reduced by 47% (P = .027) when compared with diallylic lipid level. Metabolite levels in the BRCA2 cohort showed increased unsaturation of 21% (P = .030) relative to triglycerides level. Comparison of the BRCA1 and BRCA2 cohorts showed a 47% (P = .002) increase in cholesterol level in the BRCA2 cohort when compared with diallylic lipid level and a 52% (P = .003) increase when compared with triglycerides level. Levels of diallylic lipid, unsaturated lipid, triglycerides, and terminal methyl on the acyl chain are reduced by 46% (P = .002), 57% (P = .003), 66% (P = .003), and 29% (P = .010), respectively, when compared with cholesterol level. Localized COSY recorded significant changes in women with BRCA1 and BRCA2 gene mutations when compared with control subjects. If these changes are ultimately proven to be a premalignant stage, this method may prove useful in screening.
Publisher: Elsevier BV
Date: 05-2010
Publisher: Wiley
Date: 30-08-2023
Abstract: Invasive species threaten native biota, putting fragile ecosystems at risk and having a large‐scale impact on primary industries. Growing trade networks and the popularity of personal travel make incursions a more frequent risk, one only compounded by global climate change. With increasing publication of whole‐genome sequences lies an opportunity for cross‐species assessment of invasive potential. However, the degree to which published sequences are accompanied by satisfactory spatiotemporal data is unclear. We assessed the metadata associated with 199 whole‐genome assemblies of 89 invasive terrestrial invertebrate species and found that only 38% of these were derived from field‐collected s les. Seventy‐six assemblies (38%) reported an ‘undescribed’ s le origin and, while further examination of associated literature closed this gap to 23.6%, an absence of spatial data remained for 47 of the total assemblies. Of the 76 assemblies that were ultimately determined to be field‐collected, associated metadata relevant for invasion studies was predominantly lacking: only 35% (27 assemblies) provided granular location data, and 33% ( n = 25) lacked sufficient collection date information. Our results support recent calls for standardized metadata in genome sequencing data submissions, highlighting the impact of missing metadata on current research in invasion biology (and likely other fields). Notably, large‐scale consortia tended to provide the most complete metadata submissions in our analysis—such cross‐institutional collaborations can foster a culture of increased adherence to improved metadata submission standards and a standard of metadata stewardship that enables reuse of genomes in invasion science.
Publisher: Elsevier BV
Date: 03-1996
Abstract: Magnetic-resonance chemical-shift microimaging, with a spatial resolution of 40 x 40 microns, is a modality which can detect alterations to cellular chemistry and hence markers of pathological processes in human tissue ex vivo. This technique was used as a chemical microscope to assess follicular thyroid neoplasms, lesions which are unsatisfactorily investigated using standard histopathological techniques or water-based magnetic-resonance imaging. The chemical-shift images at the methyl frequency (0.9 ppm) identify chemical heterogeneity in follicular tumors which are histologically homogeneous. The observed changes to cellular chemistry, detectable in foci of approximately 100 cells or less, support the existence of a preinvasive state hitherto unidentified by current pathological techniques.
Publisher: Elsevier BV
Date: 03-2005
DOI: 10.1016/J.EJRAD.2004.03.016
Abstract: In vivo magnetic resonance (MR) spectroscopy at 1.5T was performed on a large polypoid cutaneous melanoma, and two enlarged lymph nodes containing metastatic melanoma, from three patients. Spectra were acquired in vivo from voxels wholly within the primary tumour or secondary lymph node and were thus uncontaminated by signals from adjacent tissue. Tissue biopsies taken after resection of primary tumours and secondary lymph nodes were examined by 8.5T magnetic resonance spectroscopy (MRS) and the results compared with the in vivo spectra, and with spectra from normal skin and a benign skin lesion. There was good agreement between the dominant features of 1.5T spectra acquired in vivo and 8.5T spectra acquired from resected tissue. However, less intense resonances observed at 8.5T in malignant biopsy tissue were not consistently observed at 1.5T in vivo. In vivo spectra from primary and metastatic melanoma showed high levels of choline metabolites. An intense lactate resonance was also present in the in vivo spectrum of primary melanoma. All 8.5T spectra of biopsies from primary and secondary melanoma showed high levels of choline metabolites and lactate, and additional resonances consistent with elevated levels of taurine, alanine, lysine, and glutamate/glutamine relative to normal and benign tissue. Elevated levels of choline, lactate, taurine, and amino acids appear to be clinically useful markers for identifying the pathology of primary and metastatic melanoma.
Publisher: American Roentgen Ray Society
Date: 08-2009
DOI: 10.2214/AJR.09.3079
Publisher: Elsevier BV
Date: 09-2012
Publisher: Elsevier BV
Date: 09-2010
DOI: 10.1016/J.RCL.2010.07.017
Abstract: Contrast-enhanced magnetic resonance imaging (MRI), MR spectroscopy, and nuclear medicine sestamibi imaging using technetium-99m methoxyisobutyl isonitrile or positron emission tomography (PET) techniques provide information beyond that of structural imaging by displaying tumor neoangiogenesis, tumor metabolites, increased numbers of tumor cellular mitochondria, and hypermetabolic tumor cells. Much needs to be learned at the molecular level of normal cellular pathways either suppressed or enhanced by tumor-specific molecular changes. These discoveries will allow realization of true in idualized patient tumor detection, treatment, and surveillance.
Publisher: Elsevier BV
Date: 12-2007
DOI: 10.1086/522611
Publisher: Wiley
Date: 2009
DOI: 10.1002/NBM.1301
Abstract: Information for determining whether a primary breast lesion is invasive and its receptor status and grade can be obtained before surgery by performing proton MRS on a fine-needle aspiration biopsy (FNAB) specimen and analyzing the MRS information by a pattern recognition method. Two-dimensional MRS, on either specimens or cells, allows the unambiguous assignment of most resonances. When correlated with the spectral regions selected by the pattern recognition method, there are strong indications for the biochemical markers responsible for prognostic information of invasive capacity and metastatic spread. Spectral assignments and biological correlations can be made using cell models. In vivo MRS can distinguish invasive from benign lesions. This pathological distinction can be made from the presence of resonances at discrete frequencies. To achieve this level of spectral resolution and signal-to-noise ratio, there are stringent requirements when acquiring and processing the data. The challenge now is to implement two-dimensional MRS in vivo. Until this is realized, the combination of in vivo MR, for diagnosis and spatial location, and MRS, for image-guided biopsy to provide information on tumor spread, promises to provide a higher level of preoperative diagnosis than previously achieved.
Publisher: Radiological Society of North America (RSNA)
Date: 07-2005
DOI: 10.1148/RADIOL.2361040869
Abstract: To determine the feasibility of a statistical classification strategy (SCS) and the identity of metabolites of bacterial and host origins that potentially contributed to the most discriminatory regions of magnetic resonance (MR) spectra from Staphylococcus aureus abscesses of biopsy material from controls, gliomas, and staphylococcal abscesses. Human and animal study received ethics committee approval, and informed patient consent was obtained. A rat model of S aureus brain abscess was developed. Histologic and microbiologic examination was performed to assess abscess development 3-4, 6-8, and 10-15 days after initiation. Metabolite profiles in pus (n = 62) and controls (n = 37) were characterized with ex vivo MR spectroscopy and compared with data from rat gliomas (n = 27). SCS, optimal region selection, and development of pairwise classifiers allowed MR spectra of abscesses (n = 42, day 6-8) to be distinguished from those of glioblastoma multiforme and controls. MR spectroscopy profiles of pus from animal abscesses were compared with in vivo MR spectra from patients with staphylococcal brain abscesses (n = 7, aged 6-67 years) and ex vivo pus MR spectra from patients with S aureus abscesses. Histologically confirmed abscesses were present 6-8 days after stereotactic injection of S aureus in 42 of 47 rats (89%). MR spectra of abscesses and glioblastoma multiforme in the animal model were similar. Typical metabolites of abscesses due to anaerobe bacteria (acetate, succinate, amino acids) were not detectable in S aureus abscesses in rats or humans. MR spectroscopic findings from controls, abscesses, and gliomas were distinguished by means of SCS with an accuracy of 99%. Analysis of the most discriminatory regions with two-dimensional correlation spectra indicated that glutamine and/or glutamate and aspartate potentially contributed to successful classification. S aureus is detectable in abscesses with a non-culture-based method in an animal model.
Publisher: American Chemical Society (ACS)
Date: 08-2004
DOI: 10.1021/CR030410G
Publisher: Elsevier BV
Date: 2009
Publisher: Elsevier BV
Date: 02-2004
Publisher: Wiley
Date: 05-1988
Abstract: NMR spectroscopy is able to detect subtle changes to the surface chemistry of cells. We have previously shown that high-resolution 1H NMR methods can identify tumor cells with the capacity to metastasize, and we now report that the long T2 relaxation value (500-800 ms) observed in metastatic rat mammary adenocarcinoma cells is removed by treatment with fucosidase. Two-dimensional scalar-correlated NMR (COSY) spectra of fucosidase-treated cells show that a cross peak, consistent with scalar coupling between the methyl and methine groups on fucose and usually associated with malignancy and metastatic ability, is absent. Metastases were observed in only two out of ten rats injected subcutaneously with enzyme-treated cells compared to eight out of ten with untreated cells. NMR studies on isolated cellular lipids identified the long T2 relaxation value only in the ganglioside fraction. This fraction accounts for 51% of the total 14C-labelled fucose incorporated into the cells. We propose that fucogangliosides are an indicator of metastatic potential in rats. The observation that a cell surface metastasis marker has an NMR signal with a characteristically long relaxation value has important consequences for the future use of magnetic resonance imaging and spectroscopy in the cancer clinic.
Publisher: Springer Science and Business Media LLC
Date: 19-09-2005
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 10-2008
Publisher: Springer Science and Business Media LLC
Date: 09-2009
Publisher: Springer Science and Business Media LLC
Date: 17-09-2008
DOI: 10.1007/S10334-008-0136-0
Abstract: Proton magnetic resonance spectroscopy (MRS) is used to compare the chemistry of the transition, central and peripheral zones of the prostate. The assignments are made using two-dimensional correlated spectroscopy and the results compared with histopathology. The chemistry associated with benign prostatic hyperplasia (BPH), prostate intraepithelial neoplasia (PIN) and malignant biopsy tissues are described. There are distinct MR spectral patterns for glandular and stromal BPH, PIN and adenocarcinoma. Importantly, there are also different spectral patterns from BPH in the transitional and central zones when compared to BPH in the peripheral zone. A pattern recognition method is used to analyze the MR spectra from the biopsy specimens. The resultant mathematical classifiers generated a high level of accuracy (sensitivity and specificity of 100 and 97%). It was found that for this accuracy to be achieved, the classifiers need to be developed by comparing the spectra with specialist serial sectioned histopathology. With serial sectioned pathology the pattern recognition method was capable of identifying less than 5% of adenocarcinoma in a given piece of tissue. Many of the chemicals identified in the biopsy specimens are available for inspection from the prostate, in vivo, at 3 T.
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.
Publisher: Elsevier BV
Date: 04-2010
Publisher: Radiological Society of North America (RSNA)
Date: 02-2010
DOI: 10.1148/RADIOL.2542090405
Abstract: To compare the capability of diffusion-weighted (DW) and contrast material-enhanced magnetic resonance (MR) imaging to provide diagnostic information on residual breast cancers following neoadjuvant chemotherapy and to assess apparent diffusion coefficients (ADCs) of the carcinoma prior to neoadjuvant chemotherapy to determine if the method could help predict response to chemotherapy. Institutional review board approval and informed consent were obtained. Three hundred ninety-eight patients underwent MR imaging of the breast, including DW MR (b values, 0 and 1500 sec/mm(2)) and contrast-enhanced MR imaging. Of these, the contralateral breast in 73 women was used as a control. Seventy-two patients with 73 lesions with malignant disease were treated by using neoadjuvant chemotherapy and were examined for residual disease following therapy. Three were excluded because of prolonged intervals between final MR imaging and surgery. Thus, 69 patients (70 lesions) with DW and contrast-enhanced MR imaging results were compared with postoperative histopathologic findings. The ADCs of the carcinoma prior to neoadjuvant chemotherapy were calculated for each patient, and those with complete response and residual disease were compared. The accuracy for depicting residual tumor was 96% for DW MR imaging, compared with an accuracy of 89% for contrast-enhanced MR imaging (P = .06). There was no significant difference in prechemotherapy ADCs between pathologic complete response cases and those with residual disease. DW MR imaging had at least as good of accuracy as did contrast-enhanced MR imaging for monitoring neoadjuvant chemotherapy. The ADCs prior to chemotherapy did not predict response to chemotherapy. The use of DW imaging to visualize residual breast cancer without the need for contrast medium could be advantageous in women with impaired renal function.
Publisher: Radiological Society of North America (RSNA)
Date: 07-2001
DOI: 10.1148/RADIOLOGY.220.1.R01JL25122
Abstract: To use magnetic resonance (MR) spectroscopy to characterize clinical isolates of Cryptococcus neoformans and a glioma cell line in culture and in experimental rats. One- and two-dimensional hydrogen 1 MR spectra were acquired from fungi cultured in vitro (16 isolates of C neoformans, three of Candida albicans, three of Aspergillus fumigatus, three of Saccharomyces cerevisiae) and a C6 glioma cell line. Cerebral biopsy specimens were obtained from healthy rats and animals with experimental infections or gliomas (19 healthy brains, 20 cryptococcomas, and 19 gliomas). Unequivocal signal assignment was performed for cell suspensions and tissue s les by using homo- and heteronuclear two-dimensional correlation spectra. MR spectra of C neoformans and cerebral cryptococcomas--but not of other fungi, healthy brains, or gliomas--were dominated by resonances from the cytosolic disaccharide alpha,alpha-trehalose. This spectral pattern was different from that of gliomas, which was dominated by lipids and an increased choline-creatine ratio, and that of healthy brain. A remarkably high concentration of alpha,alpha-trehalose in relation to other metabolites that are visible with MR spectroscopy is diagnostic of C neoformans. Cerebral cryptococcomas are an uncommon but serious manifestation of cryptococcosis in humans. Application of these results to the noninvasive diagnosis of cerebral cryptococcomas would help reduce the risk and expense of unnecessary surgery or biopsy and expedite patient treatment.
Publisher: The Endocrine Society
Date: 04-1995
DOI: 10.1210/JCEM.80.4.7714105
Abstract: Most thyroidectomies are currently performed for diagnostic purposes. It has been established that proton magnetic resonance spectroscopy (MRS) on excised thyroid tissue can distinguish normal thyroid from invasive carcinomas (P < 0.0001). The purpose of this study was to assess whether the same discrimination could be obtained preoperatively from fine needle biopsy (FNB). This has clinical importance because cytological examination of fine needle aspirates cannot distinguish between benign and malignant follicular thyroid lesions. Here we demonstrate a sensitivity of 95% for proton MRS to correctly identify clinically or histologically proven carcinoma. MRS measurements were made on FNB specimens (containing as few as 10(6) cells) from solitary thyroid nodules. MR assessment of FNB was inconsistent with that of the corresponding tissue in only 6.5% of cases. The discrimination between cancer and normal tissue was based on altered cellular chemistry measured as a one-dimensional spectral ratio of resonances from the amino acid lysine and lipid. Benign follicular lesions were separated into two groups: 67% with a spectral ratio similar to malignant thyroid tumors, and 33% with a spectral ratio comparable to that in normal thyroid tissue. Thus, in contrast with histopathology, MRS offers a method for assessment of FNB of follicular lesions with the potential to identify a biologically benign group, which could avoid thyroid surgery for purely diagnostic purposes.
Publisher: Radiological Society of North America (RSNA)
Date: 09-1997
DOI: 10.1148/RADIOLOGY.204.3.9280241
Abstract: To determine whether invasive breast cancer can be distinguished from benign lesions with proton magnetic resonance (MR) spectroscopy ex vivo on the basis of altered cellular chemistry. Two hundred eighteen fine-needle biopsy specimens were obtained in 191 patients undergoing surgery and were analyzed with proton MR spectroscopy. MR spectroscopic and histopathologic findings were compared. Invasive carcinoma produced increased signal at 3.25 ppm, attributable to choline-containing metabolites. Discrimination between invasive carcinoma (n = 82), benign lesions (n = 106), or carcinoma in situ (n = 17) was based on the resonance intensity at 3.25 ppm standardized to the resonance at 3.05 ppm (P < .001). The ratio of peak height intensities of resonances at 3.25 to those at 3.05 ppm was less than 1.7 in 102 of the 106 normal or benign lesions. All carcinoma in situ specimens with comedonecrosis or a microinvasive component (n = 6) were categorized at MR spectroscopy with invasive carcinoma, while others with in situ disease alone were categorized with benign lesions (n = 11). The sensitivity and specificity of MR spectroscopy in fine-needle biopsy specimens in distinguishing benign lesions from invasive cancer were 95% and 96%, respectively. Proton MR spectroscopy of fine-needle biopsy specimens provides objective diagnostic information that complements findings of conventional preoperative investigations of breast lesions.
Publisher: Elsevier BV
Date: 09-2012
Publisher: Wiley
Date: 1982
Abstract: The specificities of two anti-neuraminidase monoclonal antibodies have been compared by their ability to fix complement. They were found to differ to some extent in their reactivity with a range of N2 influenza virus. Thus, as in the case of anti-hemagglutinin antibodies, anti-neuraminidase monoclonal antibodies are able to detect subtle structural changes in the vital antigen. Although both monoclonal antibodies fixed complement with intact virus, neither one fixed complement when complexed with isolated neuraminidase "heads".
Publisher: Elsevier BV
Date: 07-1992
Publisher: Radiological Society of North America (RSNA)
Date: 10-2007
Abstract: In vivo proton magnetic resonance (MR) spectroscopy (hydrogen 1 spectroscopy) provides useful information about the pathology of breast lesions by the measurement of diagnostic chemicals visible on the MR timescale. Spectroscopic measurements may be obtained following contrast-enhanced MR imaging by applying a point-resolved spatially localized spectroscopy sequence. The observation of resonances at discrete spectral frequencies allows an accurate diagnosis. In spectra obtained in vivo in malignant breast cancers, an observed resonance at 3.23 ppm is consistent with phosphocholine. In spectra from benign breast lesions and some normal breast tissue in lactating mothers and in some nonlactating healthy women, a recorded resonance at 3.28 ppm is thought to originate from glycerophosphocholine, taurine, or myoinositol. The success of in vivo spectroscopy depends on the appropriate pre-acquisition setup, acquisition protocol, and postprocessing techniques for achieving high spectral resolution and a signal-to-noise ratio sufficient to separate the resonances of the important biomarkers. When implemented correctly, the method is diagnostically accurate and robust.
Publisher: Elsevier BV
Date: 12-2018
DOI: 10.1016/J.PSCYCHRESNS.2018.07.001
Abstract: Posttraumatic stress disorder (PTSD) is a trauma and stressor-related disorder that results in complex somatic, cognitive, affective and behavioural effects, after exposure to traumatic event(s). Conventional imaging (T1 and T2 weighted magnetic resonance imaging) has little to offer in the way of diagnosis of mental health conditions such as PTSD and there is currently no objective diagnostic test available. Magnetic resonance spectroscopy (MRS) allows for non-invasive measurement of metabolites and neurochemicals in the brain using a conventional MRI scanner and offers the potential to predict, diagnose and monitor PTSD. This systematic review summarises the results of 24 MRS studies, performed between 1998 and 2017, to measure neurochemical differences, occurring as a consequence of PTSD. The most consistent finding in subjects with PTSD is lower N-acetylaspartate levels in the hippoc us and anterior cingulate cortex, with and without atrophic change. More recent studies, using more advanced techniques and modern hardware, have shown evidence of glutamatergic dysfunction and differences in gamma-aminobutyric acid levels in the brain of patients with PTSD. Conflicting results have been reported in choline-containing metabolites and there is emerging evidence of glutathione being affected. Myo-inositol and creatine are unchanged in the majority of studies.
Publisher: Elsevier BV
Date: 08-1986
Publisher: Radiological Society of North America (RSNA)
Date: 05-2011
Publisher: Springer Science and Business Media LLC
Date: 03-09-2005
DOI: 10.1007/S00330-004-2475-1
Abstract: The purpose was to determine if in vivo proton magnetic resonance spectroscopy ((1)H MRS) at 1.5 T can accurately provide the correct pathology of breast disease. Forty-three asymptomatic volunteers including three lactating mothers were examined and compared with 21 breast cancer patients. Examinations were undertaken at 1.5 T using a purpose-built transmit-receive single breast coil. Single voxel spectroscopy was undertaken using echo times of 135 and 350 ms. The broad composite resonance at 3.2 ppm, which includes contributions from choline, phosphocholine (PC), glycerophosphocholine (GPC), myo-inositol and taurine, was found not to be a unique marker for malignancy providing a diagnostic sensitivity and specificity of 80.0 and 86.0%, respectively. This was due to three of the asymptomatic volunteers and all of the lactating mothers also generating the broad composite resonance at 3.2 ppm. Optimised post-acquisitional processing of the spectra resolved a resonance at 3.22 ppm, consistent with PC, in patients with cancer. In contrast the spectra recorded for three false-positive volunteers, and the three lactating mothers had a resonance centred at 3.28 ppm (possibly taurine, myo-inositol or GPC). This improved the specificity of the test to 100%. Careful referencing of the spectra and post-acquisitional processing intended to optimise spectral resolution of in vivo MR proton spectra from human breast tissue resolves the composite choline resonance. This allows the distinction of patients with malignant disease from volunteers with a sensitivity of 80% and specificity of 100%. Therefore, resolution of the composite choline resonance into its constituent components improves the specificity of the in vivo (1)H MRS method, but does not overcome the problem of 20% false-negatives.
Publisher: Wiley
Date: 08-08-2006
DOI: 10.1002/JMRI.20668
Abstract: In the last 25 years, MR spectroscopy (MRS) has moved from being a basic research tool into routine clinical use. The spectroscopy method reports on those chemicals that are mobile on the MR time scale. Many of these chemicals reflect specific pathological processes but are complicated by the fact that many chemicals change at one time. There are currently two clinical applications for spectroscopy. The first is in the pathology laboratory, where it can be an adjunct to, and in some cases replacement, for difficult pathologies like Barrett's esophagus and follicular adenoma of the thyroid. The spectroscopy method on a breast biopsy can also report on prognostic indicators, including the potential for spread, from information present in the primary tumor alone. The second application for spectroscopy is in vivo to provide a preoperative diagnosis and this is now achievable for several organs including the prostate. The development of spectroscopy for clinical purposes has relied heavily on the serially-sectioned histopathology to confirm the high accuracy of the method. The combination of in vivo MRI, in vivo MRS, and ex vivo MRS on biopsy s les offers a modality of very high accuracy for preoperative diagnosis and provision of prognostic information for human cancers.
Publisher: American Society for Microbiology
Date: 08-2001
DOI: 10.1128/JCM.39.8.2916-2923.2001
Abstract: A new fingerprinting technique with the potential for rapid identification of bacteria was developed by combining proton magnetic resonance spectroscopy ( 1 H MRS) with multivariate statistical analysis. This resulted in an objective identification strategy for common clinical isolates belonging to the bacterial species Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, Streptococcus pneumoniae, Streptococcus pyogenes, Streptococcus agalactiae , and the Streptococcus milleri group. Duplicate cultures of 104 different isolates were examined one or more times using 1 H MRS. A total of 312 cultures were examined. An optimized classifier was developed using a bootstrapping process and a seven-group linear discriminant analysis to provide objective classification of the spectra. Identification of isolates was based on consistent high-probability classification of spectra from duplicate cultures and achieved 92% agreement with conventional methods of identification. Fewer than 1% of isolates were identified incorrectly. Identification of the remaining 7% of isolates was defined as indeterminate.
Publisher: Wiley
Date: 2003
DOI: 10.1002/NBM.815
Abstract: The leakage of metabolites from frozen and thawed tissue biopsies was measured semi-quantitatively by high-field (8.5 T) proton MRS. Human prostate and rat brain tissue specimens, frozen within 1 min of collection, lost significant and variable amounts of diagnostic metabolites immediately upon thawing. For prostate tissue 30-50% of initial total choline compounds, total creatines and citrate were detected in the collection buffer immediately after thawing. The widely used protocol for MR assessment of tissue biopsies, which involves washing of thawed tissue s les in fresh buffer, results in loss of large and unpredictable amounts of possibly diagnostic metabolites prior to MRS. This reduces the reproducibility of MR analysis of tissue biopsies and compromises the reliable identification of MR spectral patterns diagnostic of tissue pathology. The problem can be avoided by minimizing the volume of storage buffer, omitting tissue washing and performing MRS measurements on the tissue immersed in the original storage buffer.
Publisher: American Chemical Society (ACS)
Date: 13-04-2010
DOI: 10.1021/CR900250Y
Publisher: Elsevier BV
Date: 11-2010
DOI: 10.1016/J.NEUROIMAGE.2010.06.051
Abstract: Spinal cord injury (SCI) can be accompanied by chronic pain, the mechanisms for which are poorly understood. Here we report that magnetic resonance spectroscopy measurements from the brain, collected at 3T, and processed using wavelet-based feature extraction and classification algorithms, can identify biochemical changes that distinguish control subjects from subjects with SCI as well as sub iding the SCI group into those with and without chronic pain. The results from control subjects (n=10) were compared to those with SCI (n=10). The SCI cohort was made up of subjects with chronic neuropathic pain (n=5) and those without chronic pain (n=5). The wavelet-based decomposition of frequency domain MRS signals employs statistical significance testing to identify features best suited to discriminate different classes. Moreover, the features benefit from careful attention to the post-processing of the spectroscopy data prior to the comparison of the three cohorts. The spectroscopy data, from the thalamus, best distinguished control subjects without SCI from those with SCI with a sensitivity and specificity of 0.9 (Percentage of Correct Classification). The spectroscopy data obtained from the prefrontal cortex and anterior cingulate cortex both distinguished between SCI subjects with chronic neuropathic pain and those without pain with a sensitivity and specificity of 1.0. In this study, where two underlying mechanisms co-exist (i.e. SCI and pain), the thalamic changes appear to be linked more strongly to SCI, while the anterior cingulate cortex and prefrontal cortex changes appear to be specifically linked to the presence of pain.
Publisher: IEEE
Date: 08-2011
Publisher: Wiley
Date: 10-2010
DOI: 10.1002/MRM.22535
Publisher: Wiley
Date: 24-05-2021
Abstract: Some Serratia entomophila isolates have been successfully exploited in biopesticides due to their ability to cause amber disease in larvae of the Aotearoa (New Zealand) endemic pasture pest, Costelytra giveni . Anti‐feeding prophage and ABC toxin complex virulence determinants are encoded by a 153‐kb single‐copy conjugative plasmid (pADAP a mber d isease‐ a ssociated p lasmid). Despite growing understanding of the S . entomophila pADAP model plasmid, little is known about the wider plasmid family. Here, we sequence and analyse mega‐plasmids from 50 Serratia isolates that induce variable disease phenotypes in the C . giveni insect host. Mega‐plasmids are highly conserved within S . entomophila , but show considerable ergence in Serratia proteamaculans with other variants in S . liquefaciens and S . marcescens , likely reflecting niche adaption. In this study to reconstruct ancestral relationships for a complex mega‐plasmid system, strong co‐evolution between Serratia species and their plasmids were found. We identify 12 distinct mega‐plasmid genotypes, all sharing a conserved gene backbone, but encoding highly variable accessory regions including virulence factors, secondary metabolite biosynthesis, Nitrogen fixation genes and toxin‐antitoxin systems. We show that the variable pathogenicity of Serratia isolates is largely caused by presence/absence of virulence clusters on the mega‐plasmids, but notably, is augmented by external chromosomally encoded factors.
Publisher: Institute of Electrical and Electronics Engineers (IEEE)
Date: 2014
Publisher: SAGE Publications
Date: 2016
DOI: 10.4137/MRI.S32903
Abstract: Partial volume effects have the potential to cause inaccuracies when quantifying metabolites using proton magnetic resonance spectroscopy (MRS). In order to correct for cerebrospinal fluid content, a spectroscopic voxel needs to be segmented according to different tissue contents. This article aims to detail how automated partial volume segmentation can be undertaken and provides a software framework for researchers to develop their own tools. While many studies have detailed the impact of partial volume correction on proton magnetic resonance spectroscopy quantification, there is a paucity of literature explaining how voxel segmentation can be achieved using freely available neuroimaging packages.
Publisher: Oxford University Press (OUP)
Date: 09-2001
DOI: 10.1046/J.0007-1323.2001.01864.X
Abstract: The aim was to develop robust classifiers to analyse magnetic resonance spectroscopy (MRS) data of fine-needle aspirates taken from breast tumours. The resulting data could provide computerized, classification-based diagnosis and prognostic indicators. Fine-needle aspirate biopsies obtained at the time of surgery for both benign and malignant breast diseases were analysed by one-dimensional proton MRS at 8·5 Tesla. Diagnostic correlation was performed between the spectra and standard pathology reports, including the presence of vascular invasion by the primary cancer and involvement of the excised axillary lymph nodes. Malignant tissue was distinguished from benign lesions with an overall accuracy of 93 per cent. From the same spectra, lymph node involvement was predicted with an overall accuracy of 95 per cent, and tumour vascular invasion with an overall accuracy of 94 per cent. The pathology, nodal involvement and tumour vascular invasion were predicted by computerized statistical classification of the proton MRS spectrum from a fine-needle aspirate biopsy taken from the primary breast lesion.
Publisher: Wiley
Date: 28-03-2019
DOI: 10.1002/MRM.27742
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 04-2006
DOI: 10.1213/01.ANE.0000198333.22687.A6
Abstract: Magnetic resonance (MR) spectroscopy is a noninvasive technique that can be used to detect and measure the concentration of metabolites and neurotransmitters in the brain and other organs. We used in vivo (1)H MR spectroscopy in subjects with low back pain compared with control subjects to detect alterations in biochemistry in three brain regions associated with pain processing. A pattern recognition approach was used to determine whether it was possible to discriminate accurately subjects with low back pain from control subjects based on MR spectroscopy. MR spectra were obtained from the prefrontal cortex, anterior cingulate cortex, and thalamus of 32 subjects with low back pain and 33 control subjects without pain. Spectra were analyzed and compared between groups using a pattern recognition method (Statistical Classification Strategy). Using this approach, it was possible to discriminate between subjects with low back pain and control subjects with accuracies of 100%, 99%, and 97% using spectra obtained from the anterior cingulate cortex, thalamus, and prefrontal cortex, respectively. These results demonstrate that MR spectroscopy, in combination with an appropriate pattern recognition approach, is able to detect brain biochemical changes associated with chronic pain with a high degree of accuracy.
Publisher: Elsevier BV
Date: 10-1991
Publisher: Wiley
Date: 17-05-2011
DOI: 10.1002/JMRI.22555
Abstract: To describe an enhanced version of a localized correlation spectroscopy (L-COSY) by introducing adiabatic radiofrequency (RF) pulses for localization in two dimensions. Adiabatic pulses will improve slice selection profile and reduce chemical shift artifacts. Optimized Mao and adiabatic hyperbolic secant pulses are tested in vivo. Region of interest is localized by a 90° nonselective adiabatic RF pulse followed by two pairs of adiabatic RF pulses and a terminal 90° RF sinc pulse. Slice profiles for both refocusing pulses and chemical shift artifacts are measured in a water-oil phantom for L-COSY and AL-COSY. In vivo results of both COSY sequences are shown from muscle and brain on a 3 Tesla (T) scanner. Chemical shift artifacts were reduced with AL-COSY compared with L-COSY. Slice profiles of adiabatic pulses were found to be sharper and more symmetrical than those of traditional Mao pulses. One-dimensional (1D) phantom studies showed longer T2 values using AL-COSY sequence. Comparison of 2D spectra obtained revealed spectroscopic peak volume improvements in AL-COSY and less residual water. In vivo 1D comparison showed more inphase and sharper peaks in AL-COSY spectrum. The AL-COSY sequence is an improved sequence due to sharper slice selection profiles, reduction of chemical shift artifacts, peak volume improvements in 2D techniques, and less J-modulation.
No related grants have been discovered for Carolyn Mountford.