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Proton Magnetic Resonance Spectroscopic Imaging (proton + magnetic_resonance_spectroscopic_imaging)
Selected AbstractsProton magnetic resonance spectroscopic imaging to differentiate between nonneoplastic lesions and brain tumors in children,JOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 2 2006Roula Hourani MD Abstract Purpose To investigate whether in vivo proton magnetic resonance spectroscopic imaging (MRSI) can differentiate between 1) tumors and nonneoplastic brain lesions, and 2) high- and low-grade tumors in children. Materials and Methods Thirty-two children (20 males and 12 females, mean age = 10 ± 5 years) with primary brain lesions were evaluated retrospectively. Nineteen patients had a neuropathologically confirmed brain tumor, and 13 patients had a benign lesion. Multislice proton MRSI was performed at TE = 280 msec. Ratios of N-acetyl aspartate/choline (NAA/Cho), NAA/creatine (Cr), and Cho/Cr were evaluated in the lesion and the contralateral hemisphere. Normalized lesion peak areas (Chonorm, Crnorm, and NAAnorm) expressed relative to the contralateral hemisphere were also calculated. Discriminant function analysis was used for statistical evaluation. Results Considering all possible combinations of metabolite ratios, the best discriminant function to differentiate between nonneoplastic lesions and brain tumors was found to include only the ratio of Cho/Cr (Wilks' lambda, P = 0.012; 78.1% of original grouped cases correctly classified). The best discriminant function to differentiate between high- and low-grade tumors included the ratios of NAA/Cr and Chonorm (Wilks' lambda, P = 0.001; 89.5% of original grouped cases correctly classified). Cr levels in low-grade tumors were slightly lower than or comparable to control regions and ranged from 53% to 165% of the control values in high-grade tumors. Conclusion Proton MRSI may have a promising role in differentiating pediatric brain lesions, and an important diagnostic value, particularly for inoperable or inaccessible lesions. J. Magn. Reson. Imaging 2006. Published 2005 Wiley-Liss, Inc. [source] 1H spectroscopic imaging of human brain at 3 Tesla: Comparison of fast three-dimensional magnetic resonance spectroscopic imaging techniquesJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 3 2009Matthew L. Zierhut PhD Abstract Purpose To investigate the signal-to-noise-ratio (SNR) and data quality of time-reduced three-dimensional (3D) proton magnetic resonance spectroscopic imaging (1H MRSI) techniques in the human brain at 3 Tesla. Materials and Methods Techniques that were investigated included ellipsoidal k -space sampling, parallel imaging, and echo-planar spectroscopic imaging (EPSI). The SNR values for N-acetyl aspartate, choline, creatine, and lactate or lipid peaks were compared after correcting for effective spatial resolution and acquisition time in a phantom and in the brains of human volunteers. Other factors considered were linewidths, metabolite ratios, partial volume effects, and subcutaneous lipid contamination. Results In volunteers, the median normalized SNR for parallel imaging data decreased by 34,42%, but could be significantly improved using regularization. The normalized signal to noise loss in flyback EPSI data was 11,18%. The effective spatial resolutions of the traditional, ellipsoidal, sensitivity encoding (SENSE) sampling scheme, and EPSI data were 1.02, 2.43, 1.03, and 1.01 cm3, respectively. As expected, lipid contamination was variable between subjects but was highest for the SENSE data. Patient data obtained using the flyback EPSI method were of excellent quality. Conclusion Data from all 1H 3D-MRSI techniques were qualitatively acceptable, based upon SNR, linewidths, and metabolite ratios. The larger field of view obtained with the EPSI methods showed negligible lipid aliasing with acceptable SNR values in less than 9.5 min without compromising the point-spread function. J. Magn. Reson. Imaging 2009;30:473,480. © 2009 Wiley-Liss, Inc. [source] Proton magnetic resonance spectroscopic imaging to differentiate between nonneoplastic lesions and brain tumors in children,JOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 2 2006Roula Hourani MD Abstract Purpose To investigate whether in vivo proton magnetic resonance spectroscopic imaging (MRSI) can differentiate between 1) tumors and nonneoplastic brain lesions, and 2) high- and low-grade tumors in children. Materials and Methods Thirty-two children (20 males and 12 females, mean age = 10 ± 5 years) with primary brain lesions were evaluated retrospectively. Nineteen patients had a neuropathologically confirmed brain tumor, and 13 patients had a benign lesion. Multislice proton MRSI was performed at TE = 280 msec. Ratios of N-acetyl aspartate/choline (NAA/Cho), NAA/creatine (Cr), and Cho/Cr were evaluated in the lesion and the contralateral hemisphere. Normalized lesion peak areas (Chonorm, Crnorm, and NAAnorm) expressed relative to the contralateral hemisphere were also calculated. Discriminant function analysis was used for statistical evaluation. Results Considering all possible combinations of metabolite ratios, the best discriminant function to differentiate between nonneoplastic lesions and brain tumors was found to include only the ratio of Cho/Cr (Wilks' lambda, P = 0.012; 78.1% of original grouped cases correctly classified). The best discriminant function to differentiate between high- and low-grade tumors included the ratios of NAA/Cr and Chonorm (Wilks' lambda, P = 0.001; 89.5% of original grouped cases correctly classified). Cr levels in low-grade tumors were slightly lower than or comparable to control regions and ranged from 53% to 165% of the control values in high-grade tumors. Conclusion Proton MRSI may have a promising role in differentiating pediatric brain lesions, and an important diagnostic value, particularly for inoperable or inaccessible lesions. J. Magn. Reson. Imaging 2006. Published 2005 Wiley-Liss, Inc. [source] Role of Proton Magnetic Resonance Spectroscopy in Differentiating Oligodendrogliomas from AstrocytomasJOURNAL OF NEUROIMAGING, Issue 1 2010Sanjeev Chawla PhD ABSTRACT BACKGROUND AND PURPOSE Preoperative differentiation of astrocytomas from oligodendrogliomas is clinically important, as oligodendrogliomas are more sensitive to chemotherapy. The purpose of this study was to assess the role of proton magnetic resonance spectroscopy in distinguishing astrocytomas from oligodendrogliomas. METHODS Forty-six patients [astrocytomas (n= 17) and oligodendrogliomas (n= 29)] underwent magnetic resonance imaging and multi voxel proton magnetic resonance spectroscopic imaging before treatment. Peak areas for N-acetylaspartate (NAA), creatine (Cr), choline (Cho), myo-inositol (mI), glutamate/glutamine (Glx), and lipids + lactate (Lip+Lac) were analyzed from voxels that exhibited hyperintensity on fluid-attenuated inversion recovery images and were normalized to Cr from each voxel. The average metabolite/Cr ratios from these voxels were then compared between astrocytomas and oligodendrogliomas. Receiver-operating curve analyses were used as measures of differentiation accuracy of metabolite ratios. A threshold value for a metabolite ratio was estimated by maximizing the sum of sensitivity and specificity. RESULTS A significant difference in mI/Cr was observed between astrocytomas and oligodendrogliomas (.50 ± .18 vs. 0.66 ± 0.20, P < .05). Using a threshold value of .56 for mI/Cr ratio, it was possible to differentiate oligodendrogliomas from astrocytomas with a sensitivity of 72.4% and specificity of 76.4%. CONCLUSION These results suggest that mI/Cr might aid in distinguishing oligodendrogliomas from astrocytomas. J Neuroimaging 2010;20:3-8. [source] Brain Metabolite Concentrations and Neurocognition During Short-term Recovery from Alcohol Dependence: Preliminary Evidence of the Effects of Concurrent Chronic Cigarette SmokingALCOHOLISM, Issue 3 2006Timothy C. Durazzo Background: Longitudinal studies of brain tissue metabolite recovery in short-term abstinent alcoholics have primarily investigated the frontal lobes and cerebellum with variable results. Preliminary proton magnetic resonance spectroscopic imaging (1H MRSI) suggested that chronic cigarette smoking exacerbates alcohol-induced brain injury in 1-week abstinent alcoholics. However, the potential effects of chronic cigarette smoking on the recovery of alcohol-induced brain injury have not been studied. Methods: Multislice short-echo time 1H MRSI was used to measure longitudinal changes in common brain metabolites in 25 recovering alcohol-dependent individuals (RA), retrospectively assigned to smoking (n=14) and nonsmoking (n=11) subgroups. Recovering alcohol-dependent individuals in longitudinal analyses were studied after approximately 7 and 34 days of abstinence from alcohol. In cross-sectional analyses, 36 RA (19 smokers, 17 nonsmokers) with approximately 34 days of sobriety were compared with 29 light drinkers (LD). Relationships between neurocognition and metabolite concentrations in abstinent RA were also examined. Results: Over 1 month of abstinence from alcohol, RA, as a group, showed significant increases of regional N -acetylaspartate (NAA; marker of neuronal viability) and choline-containing compounds (Cho; marker of cell membrane synthesis/turnover) primarily in frontal and parietal lobes. These increases appeared to be driven by nonsmoking RA. Cross-sectional results indicate that metabolite levels in RA at 35 days of sobriety are not significantly different from those in LD in most regions, except for lower NAA and Cho in parietal WM and subcortical structures. However, metabolite levels at that time appear to be strongly modulated by smoking status. The patterns of metabolite,neurocognition relationships were different for nonsmoking and smoking RA. Conclusions: Within the first weeks of sobriety, regional brain NAA and Cho levels increased, but metabolite levels did not normalize in all brain regions after 35 days of sobriety. Neurobiologic recovery in RA appeared to be adversely affected by chronic smoking. Greater consideration of the effects of continued cigarette smoking on the neurobiologic and neurocognitive recovery of alcohol-dependent individuals is warranted. [source] Choline, myo-inositol and mood in bipolar disorder: a proton magnetic resonance spectroscopic imaging study of the anterior cingulate cortexBIPOLAR DISORDERS, Issue 3p2 2000Constance M Moore Objectives: Alterations in choline and myo-inositol metabolism have been noted in bipolar disorder, and the therapeutic efficacy of lithium in mania may be related to these effects. We wished to determine the relationship between anterior cingulate cortex choline and myo-inositol levels, assessed using proton magnetic resonance spectroscopic imaging (MRSI), and mood state in subjects with bipolar disorder. Methods: Serial assessments of anterior cingulate cortex choline and myo-inositol metabolism were performed in nine subjects with bipolar disorder, taking either lithium or valproate, and 14 controls. Each bipolar subject was examined between one and four times (3.1±1.3). On the occasion of each examination, standardized ratings of both depression and mania were recorded. Results: In the left cingulate cortex, the bipolar subjects' depression ratings correlated positively with MRSI measures of Cho/Cr-PCr. In the right cingulate cortex, the Cho/Cr-PCr ratio was significantly higher in subjects with bipolar disorder compared with control subjects. In addition, bipolar subjects not taking antidepressants had a significantly higher right cingulate cortex Cho/Cr-PCr ratio compared with patients taking antidepressants or controls. No clinical or drug-related changes were observed for the Ino/Cr-PCr ratio. Conclusions: The results of this study suggest that bipolar disorder is associated with alterations in the metabolism of cytosolic, choline-containing compounds in the anterior cingulate cortex. As this resonance arises primarily from phosphocholine and glycerophosphocholine, both of which are metabolites of phosphatidylcholine, these results are consistent with impaired intraneuronal signaling mechanisms. [source] | ||||||||||