1.Differential Diagnosis Of Brain Space Occupying Lesions By Using 3D Proton MR Spectroscopy Imaging 2.MR Spectrosopic Imaging And Diffusion Tensor Imaging Study Corticospinal Tract Degeneration In Amyotrophic Lateral Sclerosis

Differential diagnosis of brain space occupying lesions by using 3D proton MRspectroscopy imagingPurpose: The more accurate method of clinical MR spectroscopy (MRSI) interpretation remains an open question. The contrast between normal and abnormal tissue is important in discrimination neoplastic and nonneoplastic brain lesions, 3D MRSI has benefit of high spatial resolution and can show us the metabolism feature of tumor that may help us make diagnosis. We compared sensitivity and specificity of 3D MRSI in discrimination. Materials and methods: 35 brain space occupying patient were carried 3D proton MRSI presurgical and stereotactic biopsy, the diagnosis were proven by pathology and serial MR and clinical examination. Results: Of 35 cases, 21 were neoplasm and 14 were nonneoplastic lesion, the specificity of 3D MRSI diagnosis is 31/35, of 16 brain glioma,14 were diagnosed correctly, the MRS of glioma is remarkable increased Cho and decreased NAA, the Cho/NAA>1,the lesion and neighboring brain tissue has no obvious border, the central necrosis show decreased metabolism and elevated Lac; Metastasis tumor show remarkable increased Cho and no NAA peak, Lac increasing can be observed; Lymphoma has characteristic of high Cho and Lipids, and normal peritumor MRS; Radiation necrosis has decreased all metabolism, Cho is relative high; Demyelinating lesion show decreased NAA and normal Cho, Lac increased slightly. Beside MRI characteristic, 4 brain abscess 3DMRS show obvious border between abscess and neighboring brain tissue, and Lac increased in the central of lesion; Conclusion: 3D MRSI has high spatial resolution, and high specificity for discrimination brain tumors.MR spectroscopic imaging and diffusion tensor imaging study corticospinal tract degeneration in amyotrophic lateral sclerosisPurpose: Motor neuron damage and cortical spinal tract (CST) degeneration are pathological features of amyotrophic lateral sclerosis (ALS). We combined whole-brain diffusion tensor imaging (DTI) and three-dimensional magnetic resonance spectroscopic imaging (MRSI) to study the CST at different locations. Materials and methods: 8 ALS patients were compared to 12 normal controls. Fractional anisotropy (FA) and mean diffusivity (MD), and the ratio of N-acetyl-asparte (NAA) to creatine (Cr) were measured at various locations in the CST, including the subcortical white matter (SWM), centrum semiovale (CS), periventricular white matter (PV), posterior limb of the internal capsule (PIC) and cerebral peduncle (CP). Results: Patients showed significantly lower FA than controls in the CST, including the SWM, CS, PV and PIC(p<0.05). Although there was a trend towards elevated MD in ALS patients, this did not reach statistical significance. NAA/Cr ratios were also decreased in ALS patients compared to normal controls(p<0.05), with significant differences in the SWM and PV but not in PIC. Conclusion: Combinedwhole-brain DTI and MRSI can detect axonal degeneration in ALS. Measurements of FA obtained in the SWM, CS, PV and PIC, and NAA/Cr ratios in the SWM and PV yield the most robust results.