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MR Spectroscopy (mr + spectroscopy)
Selected AbstractsMRI and 1H MRS of The Breast: Presence of a Choline Peak as Malignancy Marker is Related to k21 Value of the Tumor in Patients with Invasive Ductal CarcinomaTHE BREAST JOURNAL, Issue 6 2008Patricia R. Geraghty MD Abstract:, To assess which specific morphologic features, enhancement patterns, or pharmacokinetic parameters on breast Magnetic Resonance Imaging (MRI) could predict a false-negative outcome of Proton MR Spectroscopy (1H MRS) exam in patients with invasive breast cancer. Sixteen patients with invasive ductal carcinoma of the breast were prospectively included and underwent both, contrast-enhanced breast MRI and 1H MRS examination of the breast. The MR images were reviewed and the lesions morphologic features, enhancement patterns and pharmacokinetic parameters (k21-value) were scored according to the ACR BI-RADS-MRI lexicon criteria. For the in vivo MRS studies, each spectrum was evaluated for the presence of choline based on consensus reading. Breast MRI and 1H MRS data were compared to histopathologic findings. In vivo 1H MRS detected a choline peak in 14/16 (88%) cancers. A false-negative 1H MRS study occurred in 2/16 (14%) cancer patients. K21 values differed between both groups: the 14 choline positive cancers had k21 values ranging from 0.01 to 0.20/second (mean 0.083/second), whereas the two choline-negative cancers showed k21 values of 0.03 and 0.05/second, respectively (mean 0.040/second). Also enhancement kinetics did differ between both groups; typically both cancers that were choline-negative showed a late phase plateau (100%), whereas this was only shown in 5/14 (36%) of the choline positive cases. There was no difference between both groups with regard to morphologic features on MRI. This study showed that false-negative 1H MRS examinations do occur in breast cancer patients, and that the presence of a choline peak on 1H MRS as malignancy marker is related to the k21 value of the invasive tumor being imaged. [source] Dynamic study of cerebral bioenergetics and brain function using in vivo multinuclear MRS approachesCONCEPTS IN MAGNETIC RESONANCE, Issue 2 2005Wei Chen Abstract One of the greatest merits of nuclear magnetic resonance (NMR) methodology used in biomedical research and clinical settings is its capability of measuring various physiological parameters in vivo. Besides MR imaging (MRI), which has been routinely applied to obtain vital information in living organs at normal and diseased states, in vivo MR spectroscopy (MRS) provides an invaluable tool for determining metabolites, chemical reaction rates, bioenergetics, and their dynamic changes in the human and animals noninvasively. These MRS capabilities are further enhanced at high/ultrahigh magnetic fields because of significant gain in NMR detection sensitivity and improvement in the spectral resolution. Recent progress has shown that in vivo MRS holds great promise in many biomedical research areas,in particular, brain research. This article provides a broad review of (i) in vivo multinuclear MRS approaches, (ii) advanced MRS methodologies, and (iii) MRS applications for determining cerebral metabolism as well as bioenergetics at resting brain state and their dynamic changes in response to brain activation. © 2005 Wiley Periodicals, Inc. Concepts Magn Reson Part A 27A: 84-121, 2005 [source] Prospects for diffusion enhancement of signal and resolution in magnetic resonance microscopyCONCEPTS IN MAGNETIC RESONANCE, Issue 2 2003Charles H. Pennington Abstract The prospects for and practical requirements of the "diffusion enhancement of signal and resolution" (DESIRE) scheme proposed by Lauterbur as a method to enhance the sensitivity, spatial resolution, and contrast in magnetic resonance (MR) microscopy and localized MR spectroscopy is assessed. The method, which still has not been implemented, promises signal enhancements of 1,2 orders of magnitude in imaging or localized spectroscopy on the scale of ,10 microns and requires magnetic field gradient strengths (,10 T/m) that are not unreasonable. I emphasize the development of an understanding of the physical principles involved in this unfamiliar, "real-space" imaging method. © 2003 Wiley Periodicals, Inc. Concepts Magn Reson Part A 19A: 71,79, 2003. [source] In vivo proton spectroscopy without solvent suppressionCONCEPTS IN MAGNETIC RESONANCE, Issue 4 2001David B. Clayton Abstract In 1H MR spectroscopy of the human brain, it is common practice to suppress the solvent signal prior to acquisition. This reduces the large dynamic range which is otherwise required of the MR receiver and digitizer in order to detect the dilute metabolite resonances in the presence of the much larger water signal. However, complete solvent suppression is not always obtainable, particularly over large volumes and in superficial regions containing large susceptibility gradients. In this work, it demonstrated that modern commercial MR scanners possess the dynamic range necessary to adequately resolve the 1H metabolites in unsuppressed spectra. Moreover, a postacquisition method is presented which can completely remove the intact water signal and accurately quantitate the metabolite peaks. Preserving the water signal in in vivo spectroscopy has several useful benefits, such as providing a high signal-to-noise ratio internal concentration, frequency, and line shape reference. Comparison is made between suppressed and unsuppressed spectra from both a phantom and the human brain acquired at 4 T. © 2001 John Wiley & Sons, Inc. Concepts Magn Reson 13: 260,275, 2001 [source] Lifestyle intervention in individuals with normal versus impaired glucose toleranceEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 7 2007S. Schäfer Abstract Background, Lifestyle intervention is effective in the prevention of type 2 diabetes in individuals with impaired glucose tolerance (IGT). It is currently unknown whether it has beneficial effects on metabolism to a similar extent, in individuals with normal glucose tolerance (NGT) compared to individuals with IGT. Materials and methods, Data from 181 subjects (133 with NGT and at risk for type 2 diabetes and 48 with IGT) who participated in the Tuebingen Lifestyle Intervention Program with increase in physical activity and decrease in caloric intake were included into this study. Body fat distribution was quantified by whole-body magnetic resonance (MR) tomography and liver fat and intramyocellular fat by 1H-MR spectroscopy. Insulin sensitivity was estimated from an oral glucose tolerance test (OGTT). Results, After 9 ± 2 months of follow-up, the diagnosis of IGT was reversed in 24 out of 48 individuals. Only 14 out of 133 participants with NGT developed IGT. Body weight decreased in both groups by 3% (both P < 0·0001). Two-hour glucose concentrations during an OGTT decreased in individuals with IGT (,14%, P < 0·0001) but not with NGT (+2%, P = 0·66). Insulin sensitivity increased both in individuals with IGT (+9%, P = 0·04) and NGT (+17%, P < 0·0001). Visceral fat (,8%, P = 0·006), liver fat (,28%, P < 0·0001) and intramyocellular fat (,15%, P = 0·006) decreased in participants with IGT. In participants with NGT these changes were significant for visceral fat (,16%, P < 0·0001) and liver fat (,35%, P < 0·0001). Conclusions, Moderate weight loss under a lifestyle intervention with reduction in total, visceral and ectopic fat and increase in insulin sensitivity improves glucose tolerance in individuals with IGT but not with NGT. In individuals with NGT, the beneficial effects of a lifestyle intervention on fat distribution and insulin sensitivity possibly prevent future deterioration in glucose tolerance. [source] MRI white matter hyperintensities, 1H-MR spectroscopy and cognitive function in geriatric depression: a comparison of early- and late-onset casesINTERNATIONAL JOURNAL OF GERIATRIC PSYCHIATRY, Issue 12 2001Tetsuhito Murata Abstract Background and Objectives Geriatric depression is often thought to differ from that at other times of adulthood. Recently, several studies have shown that the incidence of white matter hyperintense lessions identified by brain MRI is higher in patients with geriatric depression than in healthy elderly subjects, but a consensus has not yet been reached on the relationship between the severity of white matter lesions and either cognitive impairment or depressive symptoms. Method Forty-seven patients aged 50 to 75 years with major depression were divided into two groups based on age at onset of depression: early-onset (<,50 years) group (20 patients; mean age, 62.7,±,6.7) and late-onset (,50 years) group (27 patients; mean age, 65.6,±,5.4). The severity of hyperintense white matter lesions on MRI was classified by region, then a proton magnetic resonance spectroscopy (1H-MRS) focusing on the white matter of the frontal lobes, multidimensional neuropsychological tests and evaluation of depressive symptoms were conducted. Results The severity of the deep white matter lesions, the deterioration of cognitive function related to subcortical/frontal brain system and clinician-rated depressive symptoms were all more pronounced in the late-onset group compared with those in the early-onset group. It was further observed that the more severe the deep white matter lesions, the lower the levels of N-acetylaspartate/creatine. With the age of onset as the covariate, the patients with moderate deep white matter lesions had more pronounced cognitive impairment and clinician-rated depressive symptoms than those with none and/or mild lesions. Conclusion These results suggest that subcortical/frontal type cognitive impairment and the persistence of depressive symptoms in geriatric depression is related to moderate deep white matter lesions more often complicated in the late-onset group. The 1H-MRS findings were suggested to be a useful indicator of neuronal/axonal loss in the white matter of the frontal lobes which precedes cognitive impairment. Copyright © 2001 John Wiley & Sons, Ltd. [source] Nonalcoholic fatty liver disease: Quantitative assessment of liver fat content by computed tomography, magnetic resonance imaging and proton magnetic resonance spectroscopyJOURNAL OF DIGESTIVE DISEASES, Issue 4 2009Liang ZHONG OBJECTIVE: The purpose of this study was to evaluate the clinical application of imaging technology in the quantitative assessment of fatty liver with magnetic resonance imaging (MRI) and proton MR spectroscopy. METHODS: Overall 36 patients with diffuse fatty liver who had undertaken the computed tomography (CT) scan, MRI and proton MR spectroscopy (1H MRS) were analyzed. Their body mass index (BMI) was measured and their liver to spleen CT ratio (L/S) calculated on the plain CT scan. MR T1-weighted imaging (T1WI) was obtained with in-phase (IP) and out-of-phase (OP) images. T2-weighted imaging (T2WI) was acquired with or without the fat-suppression technique. The liver fat content (LFC) was quantified as the percentage of relative signal intensity loss on T1WI or T2WI images. The intrahepatic content of lipid (IHCL) was expressed as the percentage of peak value ratio of lipid to water by 1H MRS. RESULTS: The results of BMI measurement, CT L/S ratio, LFC calculated from MR T1WI and T2WI images, as well as IHCL measured by 1H MRS were 27.26 ± 3.01 kg/m2, 0.88 ± 0.26, 13.80 ± 9.92%, 40.67 ± 16.04% and 30.98 ± 20.43%, respectively. The LFC calculated from MR T1WI, T2WI images and IHCL measured by 1H MRS correlated significantly with the CT L/S ratio (r=,0.830, P= 0.000; r=,0.736, P= 0.000; r=,0.461, P= 0.005, respectively). BMI correlated significantly only with the liver fat contents measured by T1WI IP/OP and 1H MRS (r=,0.347, P= 0.038; r=,0.374, P= 0.025, respectively). CONCLUSION: CT, MR imaging and 1H MRS were effective methods for the quantitative assessment of LFC. The MR imaging, especially 1H MRS, would be used more frequently in the clinical evaluation of fatty liver and 1H MRS could more accurately reflect the severity of fatty liver. [source] Imaging biomarkers in multiple sclerosisJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 4 2010M. Filippi MD Abstract Recent years have witnessed impressive advances in the use of magnetic resonance imaging (MRI) for the assessment of patients with multiple sclerosis (MS). Complementary to the clinical evaluation, conventional MRI provides crucial pieces of information for the diagnosis of MS. However, the correlation between the burden of lesions observed on conventional MRI scans and the clinical manifestations of the disease remains weak. The discrepancy between clinical and conventional MRI findings in MS is explained, at least partially, by the limited ability of conventional MRI to characterize and quantify the heterogeneous features of MS pathology. Other quantitative MR-based techniques, however, have the potential to overcome such a limitation of conventional MRI. Indeed, magnetization transfer MRI, diffusion tensor MRI, proton MR spectroscopy, and functional MRI are contributing to elucidate the mechanisms that underlie injury, repair, and functional adaptation in patients with MS. Such techniques are likely to benefit from the use of high-field MR systems and thus allow in the near future providing additional insight into all these aspects of the disease. This review summarizes how MRI is dramatically changing our understanding of the factors associated with the accumulation of irreversible disability in MS and highlights the reasons why they should be used more extensively in studies of disease evolution and clinical trials. J. Magn. Reson. Imaging 2010;31:770,788. ©2010 Wiley-Liss, Inc. [source] Quantitative multivoxel proton spectroscopy of the brain in developmental delayJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 4 2009Krijn T. Verbruggen MD Abstract Purpose To assess whether proton MR spectroscopy of the brain in children with developmental delay reveals a consistent pattern of abnormalities. Materials and Methods Eighty-eight patients (median age, 4.6 years; interquartile range, 3.1,8.1 years) with unexplained developmental delay, were compared with 48 normally developing age-matched controls. Patients and controls were assigned to five age-groups. Multivoxel MR spectroscopy was performed on a volume of interest superior to the lateral ventricles. The relative levels of choline, creatine, N-acetyl aspartate, and glutamate/glutamine in 24 voxels containing white matter and 12 voxels containing gray matter were quantified in an operator-independent manner and expressed in proportion to the total metabolite peak area in the volume of interest. Results White matter choline in DD showed less decrease with age. Mean choline levels, compared with mean control levels, increased from 99 to 111% with increasing age. This was statistically significant in the highest age groups (P = 0.015 [7 < yr , 12.8] and P = 0.039 [12.8 < yr]). Other metabolites did not show clear alterations. Conclusion Proton MR spectroscopy in a group of patients with unexplained DD shows small differences in the metabolite pattern, compared with normally developing controls, that is, higher choline in the white matter. The pathophysiological origin and significance may relate to myelination and maturation of the white matter. J. Magn. Reson. Imaging 2009;30:716,721. © 2009 Wiley-Liss, Inc. [source] Impact of cerebrospinal fluid contamination on brain metabolites evaluation with 1H-MR spectroscopy: A single voxel study of the cerebellar vermis in patients with degenerative ataxiasJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 1 2009Laura Guerrini MD PhD Abstract Purpose To investigate the impact of cerebrospinal fluid (CSF) contamination on metabolite evaluation in the superior cerebellar vermis with single-voxel 1H-MRS in normal subjects and patients with degenerative ataxias. Materials and Methods Twenty-nine healthy volunteers and 38 patients with degenerative ataxias and cerebellar atrophy were examined on a 1.5 Tesla scanner. Proton spectra of a volume of interest placed in the superior vermis were acquired using a four TE PRESS technique. We calculated N-acetyl aspartate (NAA)/creatine (Cr), choline (Cho)/Cr, and NAA/Cho ratios, T2 relaxation times and concentrations of the same metabolites using the external phantom method. Finally, concentrations were corrected taking into account the proportion of nervous tissue and CSF, that was determined as Volume Fraction (VF). Results In healthy subjects, a significant difference was observed between metabolite concentrations with and without correction for VF. As compared to controls, patients with ataxias showed significantly reduced NAA/Cr and NAA concentrations, while only corrected Cr concentration was significantly increased. The latter showed an inverse correlation with VF. Conclusion CSF contamination has a not negligible effect on the estimation of brain metabolites. The increase of Cr concentration in patients with cerebellar atrophy presumably reflects the substitutive gliosis which takes place along with loss of neurons. J. Magn. Reson. Imaging 2009;30:11,17. © 2009 Wiley-Liss, Inc. [source] Quantification of hepatic steatosis with MRI: The effects of accurate fat spectral modelingJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 6 2009Scott B. Reeder MD Abstract Purpose To develop a chemical-shift,based imaging method for fat quantification that accounts for the complex spectrum of fat, and to compare this method with MR spectroscopy (MRS). Quantitative noninvasive biomarkers of hepatic steatosis are urgently needed for the diagnosis and management of nonalcoholic fatty liver disease (NAFLD). Materials and Methods Hepatic steatosis was measured with "fat-fraction" images in 31 patients using a multiecho chemical-shift,based water-fat separation method at 1.5T. Fat-fraction images were reconstructed using a conventional signal model that considers fat as a single peak at ,210 Hz relative to water ("single peak" reconstruction). Fat-fraction images were also reconstructed from the same source images using two methods that account for the complex spectrum of fat; precalibrated and self-calibrated "multipeak" reconstruction. Single-voxel MRS that was coregistered with imaging was performed for comparison. Results Imaging and MRS demonstrated excellent correlation with single peak reconstruction (r2 = 0.91), precalibrated multipeak reconstruction (r2 = 0.94), and self-calibrated multipeak reconstruction (r2 = 0.91). However, precalibrated multipeak reconstruction demonstrated the best agreement with MRS, with a slope statistically equivalent to 1 (0.96 ± 0.04; P = 0.4), compared to self-calibrated multipeak reconstruction (0.83 ± 0.05, P = 0.001) and single-peak reconstruction (0.67 ± 0.04, P < 0.001). Conclusion Accurate spectral modeling is necessary for accurate quantification of hepatic steatosis with MRI. J. Magn. Reson. Imaging 2009;29:1332,1339. © 2009 Wiley-Liss, Inc. [source] MRI of late microstructural and metabolic alterations in radiation-induced brain injuriesJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 5 2009Kevin C. Chan BEng Abstract Purpose To evaluate the late effects of radiation-induced damages in the rat brain by means of in vivo multiparametric MRI. Materials and Methods The right hemibrains of seven Sprague-Dawley rats were irradiated with a highly collimated 6 MV photon beam at a single dose of approximately 28 Gy. Diffusion tensor imaging (DTI), proton MR spectroscopy (1H-MRS), T2-weighted imaging, and T1-weighted imaging were performed to the same animals 12 months after radiation treatment. Results Compared with the contralateral side, a significantly higher percentage decrease in fractional anisotropy was observed in the ipsilateral fimbria of hippocampus (29%) than the external capsule (8%) in DTI, indicating the selective vulnerability of fimbria to radiation treatment. Furthermore, in 1H-MRS, significantly higher choline, glutamate, lactate, and taurine peaks by 24%, 25%, 87%, and 58%, respectively, were observed relative to creatine in the ipsilateral brain. Postmortem histology confirmed these white matter degradations as well as glial fibrillary acidic protein and glutamine synthetase immunoreactivity increase in the ipsilateral brain. Conclusion The microstructural and metabolic changes in late radiation-induced brain injuries were documented in vivo. These multiparametric MRI measurements may help understand the white matter changes and neurotoxicity upon radiation treatment in a single setting. J. Magn. Reson. Imaging 2009;29:1013,1020. © 2009 Wiley-Liss, Inc. [source] Detection of choline signal in human breast lesions with chemical-shift imagingJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 5 2008Hyeon-Man Baek PhD Abstract Purpose To investigate the application of MR spectroscopy using chemical-shift imaging (CSI) for characterizing human breast lesions at 1.5T, and to evaluate the diagnostic performance using ROC (receiver operating characteristics) analysis. Materials and Methods Thirty-six patients (35,73 years old, mean 52), with 27 malignant and 9 benign lesions, underwent anatomical imaging, dynamic contrast-enhanced MR imaging, and CSI. The ROC analysis was performed and the cutoff point yielding the highest accuracy was found to be a choline (Cho) signal-to-noise ratio (SNR) >3.2. Results The mean Cho SNR was 2.8 ± 0.8 (range, 1.8,4.3) for the benign group and 5.9 ± 3.4 (2.1,17.5) for the malignant group (P = 0.01). Based on the criterion of Cho SNR >3.2 as malignant, CSI correctly diagnosed 22 of 27 malignant lesions and 7 of 9 benign lesions, resulting in a sensitivity of 81%, specificity of 78%, and overall accuracy of 81%. If the criterion was set higher at Cho SNR >4.0 the specificity improved to 89% but sensitivity was lowered to 67%. Conclusion The ROC analysis presented in this work could be used to set an objective diagnostic criterion depending on preferred emphasis on sensitivity or specificity. J. Magn. Reson. Imaging 2008;27:1114,1121. © 2008 Wiley-Liss, Inc. [source] Selective maximization of 31P MR spectroscopic signals of in vivo human brain metabolites at 3TJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 3 2007Rose-Ann M. Blenman PhD Abstract Purpose To develop a short TR, short TE, large flip angle (LFA), in vivo 31P MR spectroscopy (MRS) technique at 3T that selectively maximizes the signal-to-noise ratio (SNR) of long T1 human brain metabolites implicated in bipolar disorder. Materials and Methods Two pulse sequences were evaluated for efficiency. Slice profiles acquired with the scaled, sinc-shaped, radiofrequency (RF) LFA pulses were compared to those acquired with Shinnar-Le Roux (SLR) RF LFA pulses. The SLR-based LFA pulse sequence was used to maximize the inorganic phosphate signal in a phantom, after which volunteer metabolite signals were selectively maximized and compared to their correlates acquired with conventional spin-echo methods. Results The comparison of slice profiles acquired with sinc-shaped RF LFA pulses vs. SLR RF LFA pulses showed that SLR-based pulse sequences, with their improved excitation and slice profiles, yield significantly better results. In vivo LFA spin-echo MRS implemented with SLR pulses selectively increased the 31P MRS signal, by as much as 93%, of human brain metabolites that have T1 times longer than the TR of the acquisition. Conclusion The data show that the LFA technique can be employed in vivo to maximize the signal of long T131P brain metabolites at a given TE and TR. LFAs ranging between 120° and 150° are shown to maximize the 31P signal of human brain metabolites at 3T. J. Magn. Reson. Imaging 2007. © 2007 Wiley-Liss, Inc. [source] Magnetic resonance imaging and proton MR spectroscopy of the brain in a patient with carbohydrate-deficient glycoprotein syndrome type IJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 6 2003Mayumi Takeuchi MD Abstract This is a report on a case of carbohydrate-deficient glycoprotein syndrome (CDGS) with neurological deficits. Magnetic resonance (MR) images showed remarkable atrophy of the cerebellum and brainstem, and hypointensity was seen in the pallidum on diffusion-weighted images (DWI), suggesting deposits of metal substances. In the cerebellum, proton MR spectroscopy (MRS) showed decreased concentrations of N-acetylaspartate and a complex of glutamine and glutamate (Glx) while the concentration of myo-inositol was increased, indicating neuronal impairment and gliosis. In the parietal lobe, there was an increased concentration of Glx, possibly reflecting dysfunction caused by liver injury. J. Magn. Reson. Imaging 2003;17:722,725. © 2003 Wiley-Liss, Inc. [source] MR and MRS Characteristics of Intraventricular MeningiomaJOURNAL OF NEUROIMAGING, Issue 3 2010Nada Vu ABSTRACT Meningiomas are frequent intracranial, non-glial tumors of adults. We present the unusual left lateral ventricular localization of meningioma in a 51-year-old man. The magnetic resonance (MR) images showed well demarcated, large mass of the atrium of the left lateral ventricle with transependymal extension into the left temporal lobe. MR spectroscopy revealed the presence of "choline only" spectrum, typical for extra axial neoplasms. The mass was completely resected. The diagnosis of transitional type intraventricular meningioma, with psammoma bodies, histologic grade I was made. Progesterone and estrogen receptors were negative. [source] MR Spectroscopy Findings in Lafora DiseaseJOURNAL OF NEUROIMAGING, Issue 4 2009Ebru Altindag MD ABSTRACT PURPOSE Our aim was to investigate the [1H] MR spectroscopy (MRS) findings of Lafora Disease (LD), which is a disabling form of progressive myoclonic epilepsy. METHODS Twelve patients diagnosed with LD and 12 control subjects underwent MRS studies with single-voxels of 8 cc obtained in the frontal lobe, pons, and cerebellum. The metabolites and NAA/Cr, NAA/Cho, Cho/Cr, mI/Cr ratios were calculated. Subgroup analysis was also done between 5 patients with EPM2B and 6 patients with EPM2A mutations. Two investigators scored neurological symptom severity. RESULTS We found a statistically significant difference of NAA/Cho ratio in LD patients compared with normal controls in cerebellum (P= 0.04). In addition, both myoclonus and ataxia scores showed significant correlation with NAA/Cho ratios in the pons (P= 0.03, P= 0.04) and in the cerebellum (P= 0.04, P= 0.01), respectively. CONCLUSION We conclude that the cerebellum is the mostly affected structure in LD and there are significant correlations of MRS findings with some clinical parameters. The differences in the group may be related to different genetic mutations besides disease duration and other clinical variables. MRS studies could provide insights about the severity of the involvement of LD. [source] Pathological Laughing As a Manifestation in a Clinically Isolated Brainstem Syndrome: A Case ReportJOURNAL OF NEUROIMAGING, Issue 3 2009Belgin Kocer MD ABSTRACT The prevalence of pathological laughing and crying in multiple sclerosis (MS) is 10%. It has been speculated that the anatomical lesion responsible for the pathological laughing is located in the pontine base, prefrontal cortex, and cerebellum. We report an 18-year-old male patient presenting with pathological laughing and hypomania. In his neurological examination, he had a euphoric effect with ataxic walking and dysarthria speech. He had a bilateral conjugated gaze limitation, with a prominent bilateral horizontal nystagmus on left gaze, dysmetria, dysdiadokokinesia, and remarkable dysfunction in a heel-to-shin test on the left. The IgG index in cerebrospinal fluid was normal with an oligoclonal band was present. In cranial MRI, there was a lesion on central pons which was hypointense in T1 images with contrast enhancement and hyperintense in T2 and flair images. Also another lesion in right brachium pontis which did not contrast enhancement but was hyperintense on T2 and flair images was present. There was an elevation of myoinositol/creatine ratio and choline and a reduction of NAA in proton MR spectroscopy. MR spectroscopic evaluation of the patient demonstrated the demyelination process. There has been no report of patients in whom pathological laughter was the presenting symptom of clinically isolated brainstem syndrome. [source] Magnetic Resonance Imaging Monitoring of Multiple Sclerosis Lesion EvolutionJOURNAL OF NEUROIMAGING, Issue 2005Matilde Inglese MD ABSTRACT The characteristic feature of multiple sclerosis (MS) pathology is the demyelinated plaque distributed throughout the central nervous system. Although MS is a primary demyelinating disease, acute axonal injury is common in actively demyelinating MS lesions and it is considered one of the major determinants of neurological deficit. Magnetic resonance imaging (MRI) has had a dramatic impact on MS in both the clinical practice and basic science settings. Techniques such as T2-weighted and gadolinium-enhanced T1-weighted MRI are very sensitive in detecting lesions and, thus, increase the level of certainty of MS diagnosis. Conventional MRI has also improved our understanding of the pathogenesis of the disease and has provided objective and reliable measures to monitor the effect of experimental treatments in clinical trials. However, conventional MR,I does not provide specific information on the heterogeneous pathologic substrate of MS lesions. Advanced MRI techniques, such as magnetization transfer imaging, diffusion tensor imaging, and proton MR spectroscopy, offer the unprecedented ability to observe and quantify pathological changes in lesions and normal-appearing brain tissue over time. The present review will discuss the major contributions of conventional MRI and quantitative MRI techniques to understand how individual MS lesions evolve. [source] Magnetic Resonance Imaging Outcomes From a Comprehensive Magnetic Resonance Study of Children With Fetal Alcohol Spectrum DisordersALCOHOLISM, Issue 10 2009Susan J. Astley Background:, Magnetic resonance (MR) technology offers noninvasive methods for in vivo assessment of neuroabnormalities. Methods:, A comprehensive neuropsychological/psychiatric battery, coupled with MR imaging, (MRI), MR spectroscopy (MRS), and functional MRI (fMRI) assessments, were administered to children with fetal alcohol spectrum disorders (FASD) to determine if global and/or focal abnormalities could be identified, and distinguish diagnostic subclassifications across the spectrum. The 4 study groups included: (i) fetal alcohol syndrome (FAS)/partial FAS (PFAS); (ii) static encephalopathy/alcohol exposed (SE/AE); (iii) neurobehavioral disorder/alcohol exposed (ND/AE) as diagnosed with the FASD 4-Digit Code; and (iv) healthy peers with no prenatal alcohol exposure. Presented here are the MRI assessments that were used to compare the sizes of brain regions between the 4 groups. The neuropsychological/behavioral, MRS, and fMRI outcomes are reported separately. Results:, Progressing across the 4 study groups from Controls to ND/AE to SE/AE to FAS/PFAS, the mean absolute size of the total brain, frontal lobe, caudate, putamen, hippocampus, cerebellar vermis, and corpus callosum length decreased incrementally and significantly. The FAS/PFAS group (the only group with the 4-Digit FAS facial phenotype) had disproportionately smaller frontal lobes relative to all other groups. The FAS/PFAS and SE/AE groups [the 2 groups with the most severe central nervous system (CNS) dysfunction] had disproportionately smaller caudate regions relative to the ND/AE and Control groups. The prevalence of subjects in the FAS/PFAS, SE/AE, and ND/AE groups that had 1 or more brain regions, 2 or more SDs below the mean size observed in the Control group was 78, 58, and 43%, respectively. Significant correlations were observed between size of brain regions and level of prenatal alcohol exposure, magnitude of FAS facial phenotype, and level of CNS dysfunction. Conclusions:, Magnetic resonance imaging provided further validation that ND/AE, SE/AE, and FAS/PFAS as defined by the FASD 4-Digit Code are 3 clinically distinct and increasingly more affected diagnostic subclassifications under the umbrella of FASD. Neurostructural abnormalities are present across the spectrum. MRI could importantly augment diagnosis of conditions under the umbrella of FASD, once population-based norms for structural development of the human brain are established. [source] Acamprosate: Recent Findings and Future Research DirectionsALCOHOLISM, Issue 7 2008Karl Mann This article explores the mechanisms of action and the potential responder profile of acamprosate, a compound efficacious in relapse prevention of alcoholism. New evidence at the molecular and cellular level suggests that acamprosate attenuates hyper-glutamatergic states that occur during early abstinence and involves iono (NMDA)- and metabotrotropic (mGluR5) glutamate receptors along with augmented intracellular calcium release and electrophysiological changes. Thus mutant mice with enhanced glutamate levels exhibit higher alcohol consumption than wild type mice and respond better to acamprosate, demonstrating that acamprosate acts mainly on a hyper-glutamatergic system. This mode of action further suggests that acamprosate exhibits neuroprotective properties. In rats, cue-induced reinstatement behavior is significantly reduced by acamprosate treatment whereas cue-induced craving responses in alcohol-dependent patients seem not to be affected by this treatment. An ongoing study ("Project Predict") defines specific responder profiles for an individualized use of acamprosate and naltrexone. Neurophysiological as well as psychometric data are used to define 2 groups of patients: "reward cravers" and "relief cravers". While naltrexone should work better in the first group, acamprosate is hypothesized to be efficacious in the latter where withdrawal associated and/or cue induced hyper-glutamatergic states are thought to trigger relapse. Further research should target the definition of subgroups applying endophenotypic approaches, e.g. by detecting a hyperglutamatergic syndrome using MR spectroscopy. [source] Cerebral oedema in minimal hepatic encephalopathy due to extrahepatic portal venous obstructionLIVER INTERNATIONAL, Issue 8 2010Amit Goel Abstract Background: Minimal hepatic encephalopathy (MHE) has recently been reported in patients with extrahepatic portal venous obstruction (EHPVO). Aims: To evaluate brain changes by magnetic resonance studies in EHPVO patients. Methods: Blood ammonia level, critical flicker frequency (CFF), brain metabolites on 1H-magnetic resonance (MR) spectroscopy and brain water content on diffusion tensor imaging and magnetization transfer ratio (MTR) were studied in 31 EHPVO patients with and without MHE, as determined by neuropsychological tests. CFF and magnetic resonance imaging studies were also performed in 23 controls. Results: Fourteen patients (14/31, 45%) had MHE. Blood ammonia level was elevated in all, being significantly higher in the MHE than no MHE group. CFF was abnormal in 13% (4/31) with EHPVO and in 21% (3/14) with MHE. On 1H-MR spectroscopy, increased Glx/Cr, decreased mIns/Cr, and no change in Cho/Cr were noted in patients with MHE compared with controls. Significantly increased mean diffusivity (MD) and decreased (MTR) were observed in the MHE group, suggesting presence of interstitial cerebral oedema (ICE). MD correlated positively with blood ammonia level (r=0.65, P=0.003) and Glx (r=0.60, P=0.003). Discussion: MHE was detected in 45% of patients with EHPVO while CFF was abnormal in only 13%. ICE was present in 7/10 brain regions examined, particularly in those with MHE. Hyperammonaemia elevated cerebral Glx levels correlated well with ICE. Conclusions: MHE was common in EHPVO; CFF could identify it only in a minority. ICE was present in EHPVO, particularly in those with MHE. It correlated with blood ammonia and Glx/Cr levels. Hyperammonaemia seems to contribute to ICE in EHPVO. [source] Noninvasive detection of pulmonary tissue destruction in a mouse model of emphysema using hyperpolarized 129Xe MRS under spontaneous respirationMAGNETIC RESONANCE IN MEDICINE, Issue 4 2010Hirohiko Imai Abstract In the present study, a chemical shift saturation recovery method in hyperpolarized 129Xe MR spectroscopy measurements was applied to two groups of spontaneously breathing mice, an elastase-induced emphysema model and a control group. Parameters detected were those related to lung structures and functions, such as alveolar septal thickness, h, the ratio of the alveolar septal volume relative to gas space volume, Vs/Va, and the transit time of blood through the gas exchange region, ,. To investigate the potential of these parameters as biomarkers, an attempt was made to detect physiologic changes in the lungs of elastase-treated mice. Our results showed that Vs/Va was significantly reduced in elastase-treated mice, reflecting emphysema-like destruction of the alveolar wall. Compared with histologic results, this degree of reduction was shown to reflect the severity of wall destruction. On the other hand, significant changes in other parameters, h and ,, were not shown. This study is the first application of hyperpolarized 129Xe MR spectroscopy to a mouse model of emphysema and shows that the Vs/Va volume ratio is an effective biomarker for emphysema that could become useful in drug research and development through noninvasive detection of pathologic changes in small rodents. Magn Reson Med, 2010. © 2010 Wiley-Liss, Inc. [source] Metabolite proton T2 mapping in the healthy rhesus macaque brain at 3 TMAGNETIC RESONANCE IN MEDICINE, Issue 5 2009Songtao Liu Abstract The structure and metabolism of the rhesus macaque brain, an advanced model for neurologic diseases and their treatment response, is often studied noninvasively with MRI and 1H-MR spectroscopy. Due to the shorter transverse relaxation time (T2) at the higher magnetic fields these studies favor, the echo times used in 1H-MR spectroscopy subject the metabolites to unknown T2 weighting, decreasing the accuracy of quantification which is key for inter- and intra-animal comparisons. To establish the "baseline" (healthy animal) T2 values, we mapped them for the three main metabolites' T2s at 3 T in four healthy rhesus macaques and tested the hypotheses that their mean values are similar (i) among animals; and (ii) to analogs regions in the human brain. This was done with three-dimensional multivoxel 1H-MR spectroscopy at (0.6 × 0.6 × 0.5 cm)3 = 180 ,L spatial resolution over a 4.2 × 3.0 × 2.0 = 25 cm3 (,30%) of the macaque brain in a two-point protocol that optimizes T2 precision per unit time. The estimated T2s in several gray and white matter regions are all within 10% of those reported in the human brain (mean ± standard error of the mean): N -acetylaspartate = 316 ± 7, creatine = 177 ± 3, and choline = 264 ± 9 ms, with no statistically significant gray versus white matter differences. Magn Reson Med, 2009. © 2009 Wiley-Liss, Inc. [source] Inductively coupled helmholtz coil on a dedicated imaging platform for the in vivo1H-MRS measurement of intramyocellular lipids in the hind leg of ratsMAGNETIC RESONANCE IN MEDICINE, Issue 4 2009Michael Neumaier PhD Abstract Skeletal muscle triglycerides are markers for insulin resistance in type 2 diabetes. Recently, MR spectroscopy was adapted for in vivo measurement of triglycerides in animal models and for the characterization of new therapeutic approaches. Because of small MR spectroscopy voxel sizes used in skeletal muscles, surface coils are used for signal reception. Furthermore, to obtain well-resolved and undistorted lipid spectra, muscle fibers must be aligned parallel to the magnetic field. Consequently, to achieve a high signal-to-noise ratio and spectral quality, a coil setup must combine high sensitivity with a reliable and reproducible positioning of muscle and voxel. These demands are difficult to match using surface coils. Here, a coil platform is described, which uses inductively coupled Helmholtz coil setup combined with a leg retainer system for rats. The new system allows for measurement of intramyocellular lipids with high signal-to-noise ratio and for significantly improved animal handling, positioning, and throughput. Magn Reson Med, 2009. © 2009 Wiley-Liss, Inc. [source] Application of subsecond spiral chemical shift imaging to real-time multislice metabolic imaging of the rat in vivo after injection of hyperpolarized 13C1 -pyruvateMAGNETIC RESONANCE IN MEDICINE, Issue 3 2009Dirk Mayer Abstract Dynamic nuclear polarization can create hyperpolarized compounds with MR signal-to-noise ratio enhancements on the order of 10,000-fold. Both exogenous and normally occurring endogenous compounds can be polarized, and their initial concentration and downstream metabolic products can be assessed using MR spectroscopy. Given the transient nature of the hyperpolarized signal enhancement, fast imaging techniques are a critical requirement for real-time metabolic imaging. We report on the development of an ultrafast, multislice, spiral chemical shift imaging sequence, with subsecond acquisition time, achieved on a clinical MR scanner. The technique was used for dynamic metabolic imaging in rats, with measurement of time-resolved spatial distributions of hyperpolarized 13C1 -pyruvate and metabolic products 13C1 -lactate and 13C1 -alanine, with a temporal resolution of as fast as 1 s. Metabolic imaging revealed different signal time courses in liver from kidney. These results demonstrate the feasibility of real-time, hyperpolarized metabolic imaging and highlight its potential in assessing organ-specific kinetic parameters. Magn Reson Med, 2009. © 2009 Wiley-Liss, Inc. [source] In vivo differentiation of N-acetyl aspartyl glutamate from N-acetyl aspartate at 3 TeslaMAGNETIC RESONANCE IN MEDICINE, Issue 6 2007Richard A.E. Edden Abstract A method is described that allows the in vivo differentiation of N-acetyl aspartate (NAA) from N-acetyl aspartyl glutamate (NAAG) by in vivo MR spectroscopy (MRS) at 3 Tesla (3T). The method, which is based on MEGA-point-resolved spectroscopy (PRESS) editing, selectively targets the aspartyl spin system of one species while deliberately removing the other species from the spectrum. This allows quantitative measurements of NAA and NAAG without the need for fitting of unresolved peaks. White matter concentrations of NAA (6.7 ± 0.3 mM) and NAAG (2.2 ± 0.3 mM) were measured in 10 healthy volunteers to demonstrate the method. Magn Reson Med 57:977,982, 2007. © 2007 Wiley-Liss, Inc. [source] Human brain-structure resolved T2 relaxation times of proton metabolites at 3 teslaMAGNETIC RESONANCE IN MEDICINE, Issue 6 2007Wafaa Zaaraoui Abstract The transverse relaxation times, T2, of N -acetylaspartate (NAA), total choline (Cho), and creatine (Cr) obtained at 3T in several human brain regions of eight healthy volunteers are reported. They were obtained simultaneously in 320 voxels with three-dimensional (3D) proton MR spectroscopy (1H-MRS) at 1 cm3 spatial resolution. A two-point protocol, optimized for the least error per given time by adjusting both the echo delay (TEi) and number of averages, Ni, at each point, was used. Eight healthy subjects (four males and four females, age = 26 ± 2 years) underwent the hour-long procedure of four 15-min, 3D acquisitions (TE1 = 35 ms, N1 = 1; and TE2 = 285 ms, N2 = 3). The results reveal that across all subjects the NAA and Cr T2s in gray matter (GM) structures (226 ± 17 and 137 ± 12 ms, respectively) were 13,17% shorter than the corresponding T2s in white matter (WM; 264 ± 10 and 155 ± 7 ms, respectively). The T2s of Cho did not differ between GM and WM (207 ± 17 and 202 ± 8, respectively). For the purpose of metabolic quantification, these values justify to within ±10% the previous use of one T2 per metabolite for 1) the entire brain and 2) all subjects. These T2 values (which to our knowledge were obtained for the first time at this field, spatial resolution, coverage, and precision) are essential for reliable absolute metabolic quantification. Magn Reson Med 57:983,989, 2007. © 2007 Wiley-Liss, Inc. [source] Age and gender dependence of human cardiac phosphorus metabolites determined by SLOOP 31P MR spectroscopyMAGNETIC RESONANCE IN MEDICINE, Issue 4 2006Herbert Köstler Abstract The aim of this study was to apply 31P magnetic resonance spectroscopy (MRS) using spatial localization with optimal point spread function (SLOOP) to investigate possible age and gender dependencies of the energy metabolite concentrations in the human heart. Thirty healthy volunteers (18 males and 12 females, 21,67 years old, mean = 40.7 years) were examined with the use of 31P-MRS on a 1.5 T scanner. Intra- and interobserver variability measures (determined in eight of the volunteers) were both 3.8% for phosphocreatine (PCr), and 4.7% and 8.3%, respectively, for adenosine triphosphate (ATP). High-energy phosphate (HEP) concentrations in mmol/kg wet weight were 9.7 ± 2.4 (age < 40 years, N = 16) and 7.7 ± 2.5 (age , 40 years, N = 14) for PCr, and 5.1 ± 1.0 (age < 40 years) and 4.1 ± 0.8 (age , 40 years) for ATP, respectively. Separated by gender, PCr concentrations of 9.2 ± 2.4 (men, N = 18) and 8.0 ± 2.8 (women, N = 12) and ATP concentrations of 4.9 ± 1.0 (men) and 4.2 ± 0.9 (women) were measured. A significant decrease of PCr and ATP was found for volunteers older than 40 years (P < 0.05), but the differences in metabolic concentrations between both sexes were not significant. In conclusion, age has a minor but still significant impact on cardiac energy metabolism, and no significant gender differences were detected. Magn Reson Med, 2006. © 2006 Wiley-Liss, Inc. [source] Optimized detection of lactate at high fields using inner volume saturationMAGNETIC RESONANCE IN MEDICINE, Issue 4 2006Richard A.E. Edden Abstract In localized proton MR spectroscopy (1H-MRS) in vivo, the detection of lactate (Lac) is affected by modulation of its resonances due to homonuclear scalar couplings (J). A simple and convenient way to distinguish Lac from lipids is to set the TE to 1/J so that the Lac signal is inverted while other resonances (such as lipid) remain in-phase. However, at high field strengths, such as 3 Tesla or above, the modulation of the Lac signal is complicated by chemical shift effects that cause modulation patterns to vary within different subregions of the localized volume. Under some conditions the Lac signal may even disappear completely. In this note we introduce the concept of inner volume saturation (IVS), which makes use of high bandwidth spatial pulses to remove the signal corresponding to the regions of the localized volume that contribute unwanted modulation patterns. The method is described theoretically and demonstrated experimentally at 3 Tesla in a phantom and a patient with acute stroke. The phantom measurements indicate that virtually 100% of the Lac signal can be recovered using this method. The method should be feasible at magnetic fields above 3 Tesla, and may also be applied to other coupled spin systems in which modulation effects are important. Magn Reson Med, 2006. © 2006 Wiley-Liss, Inc. [source] | |||||||||||||||||||||||||