| Proton magnetic resonance spectroscopy is an in-vivo diagnostic advice that provides a non-invasive manner, determines the concentrations of a few detectable metabolites in brain. It's believed that multivoxel proton MR spectroscopy is a unique approach to provide great information concerning tissue characterization such as metabolites and biochemistry. We evaluated the clinical application of proton MR spectroscopy by comparison of the concentrations of metabolites and histologic pathology in brain tumors.Part I: Distribution of Metabolites in Different NormalBrain RegionsPurpose: To establish the average metabolic concentrations in differentnormal brain regions.Methods: One hundred patients with brain lesions underwent multi-voxel proton MR spectroscopy with PRESS sequence. The peak area of NAA, Cho and Cr in frontal lobe, temporal lobe, parietal lobe, basal ganglion and cerebellum was measured. The ratio of NAA/Cr, Cho/Cr and NAA/Chowas calculated.Results: The ratios of NAA/Cr, Cho/Cr and NAA/Cho in cerebellum were lower than frontal, parietal and occipital lobe. No significant difference was found in various sets of cerebrum. Cho/Cr was not statistical difference between cerebrum and cerebellum.Conclusion: Multi-voxel MR spectroscopy can estimate NAA, Cho and Cr. The metabolic concentrations varied in different normal brain regions. The determination of normal NAA/Cr, Cho/Cr and NAA/Cho provided a standard for detecting metabolic abnormality in brain tumors.Part II: Accuracy of Multi-Voxel Proton MR Spectroscopy in Distinguishing Neoplastic from Nonneoplastic BrainLesionsPurpose: To find out the ratios of NAA/Cr, Cho/Cr and NAA/Cho in order to calculate the accuracy of multivoxel, image guided proton MR spectroscopy in distinguishing normal from abnormal brain tissue and neoplastic from nonneoplastic brain lesions.Methods: 1H MR spectroscopy was performed with PRESS sequence. The ratios of NAA/Cr, Cho/Cr and NAA/Cho in normal, tumors and nonneoplasms were obtained from 74 cases of brain neoplasms and 5 cases of nonneoplasms. The sensitivity, specificity, positive and negativepredictive values and accuracy were calculated according to the receiver operator characteristic (ROC) curve.Results: The diagnostic accuracy of Cho/Cr was 0.91 and the specific value was 0.96 in distinguishing normal from abnormality while the area under ROC curve of NAA/Cr, Cho/Cr andNAA/Cho was 0.696 (p<0.001), 0.916 (p<0.001), 0.920 (p<0.001), respectively. Cho/Cr ratio played a role in distinguishing neoplasm from nonneoplastic brain lesions but NAA/Cr and NAA/Cho ratio was useless for differential diagnosis while the area under ROC curve of NAA/Cr, Cho/Cr and NAA/Cho was 0.653 (p=0.217), 0.750 (p=0.035), 0.707 (p=0.094), respectively. The diagnostic accuracy of multivoxel proton MR spectroscopy was 0.97 in distinguishing normal from abnormality and 0.91 in discrimination of neoplasms from nonneoplasms.Conclusion: Image guided multivoxel proton spectra from patients with suspected neoplasia can be distinguished from spectra from normal brain tissue and neoplastic spectra can be distinguished from nonneoplastic spectra with a high degree of diagnostic accuracy.Part III: Characteristics of Multivoxel Proton MRSpectroscopy in Brain Tumors:Comparison of Histological PathologyPurpose: To investigate multivoxel proton MR spectroscopy findings ofbrain tumors and clinical value in differential diagnosis. Methods: Sixty patients with brain tumors underwent multivoxel proton MR spectroscopic examination with PRESS sequence. Distribution of the 60 final diagnoses of neoplasms was follow: meningioma (n=22), glioma (n=21), lymphoma (n=3), metastasis (n=5), acoustic neuroma, pituitary tumor, PNET (n=2, respectively), vascularblastoma, arachnoid cyst, neurofibromatosis (n=l,respectively). The concentrations of NAA, Cho, Cr, Lac-Lip was obtained in the tumors and the contralateral normal brain region. The ratios of NAA/Cr, Cho/Cr, NAA/Cho, tumor NAA/normal NAA, tumor Cho/normal Cho, tumor Cr...
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