| PrefacePresurgical determination of malignancy and prognosis of cerebral gliomas plays an important role in clinical work due to different methods of treatment. Routine MR imaging is difficult to provide functional information such as pathological grading, angiogenesis, and biochemical information though it may be useful for morphological diagnosis of gliomas. Diffusion weighted imaging (DWI) allows us to observe the microcosmic movement of the water molecules in the living tissues; dynamic contrast-enhanced perfusion imaging ( PWI) can evaluate the cerebral hemodynamic status noninvasively, which is developing with the presence of fast MR imaging technique. And proton MR spectroscopy (1 HMRS) can determine the biochemical and metabolic levels of both brain tissues and cerebral tumors noninvasively, may be helpful for observation of occurrence, development, as well as therapeutic reaction of brain tumors. All of these three methods, as complementary methods for routine MR examination, may give us more functional information in the diagnosis of gliomas, and provide the objective criterion for the early diagnosis and prognostic assessment.Our studies introduce leading theory of tumorigenesis into territory of imaging study, improve present methods of imaging study, break through traditional imaging study theory and engage in the study of microcirculation and cerebral metabolites noninvasively. For the first time, we combine MR functional techniques to study the biological characteristics of cerebral gliomas, correlated with histopathology in order to improve the early diagnostic rate of gliomas.PurposeDWI, PWI, and 1HMRS study of biological characteristics of animal modelof gliomas in rat brain was performed to evaluate these three methods in the determination of pathological grading, microcirculation, and metabolites of the tumor, and to establish internal connection between DWI/PWI and histology/ microvessel counting. Meanwhile, correlation between l HMRS manifestations of patients suffered from gliomas and pathological results were performed to evaluate l HMRS in the diagnosis, differential diagnosis, pathological grading, as well as prognostic assessment of cerebral gliomas.Materials and Methods41 female Wistar rats were used for this study. 36 rats Glial tumors were implanted into the left hemisphere by intracerebral injection of 1 x 10s C6 glioma cells in 5ul Ham' s F12 medium. As a control, five rats also received stereotac-tic injection of 5ul Ham' s F12 medium without tumor cells in the same location. Between 1 and 4 weeks after the C6 glioma cells were injected intracere-brally, eight to ten different rats were imaged at each weekly time point. The brain of each rat was imaged with precontrast T, weighted spin-echo imaging (T1WI), 12 weighted spin-echo imaging (T2WI), diffusion weighted imaging (DWI), perfusion weighted imaging (PWI), and postcontrast T,WI. Meanwhile, 'HMRS were performed in eight different rats at 2 weeks and 4 weeks after implantation respectively. Five rats were also done for comparison. MR examination was performed using GE Signa MR/iTM 1. 5T Hispeed Plus superconductive MR system. A cylindrical surface coil with 3 inch in diameter was positioned over the rat head. Images were acquired parallel to the anterior-posterior direction ( " horizontally" ). Transverse diameter values of tumors were measured on both T2WI and postcontrast TjWI. Apparent diffusion coefficient (ADC) maps and regional cerebral blood volume (rCBV) maps were formatted, and ADC values and maximal rCBV values in both tumoral regions and peritu-moral regions were calculated. Relative metabolite levels including N-acetylas-partate (NAA), choline ( CHO) , creatine compounds ( CR) , lipid ( Lip), lactate ( LAC) , glutamate and glutamine ( Glu-n) were measured, related to the peak area, and expressed with reference to CR. Immediately after MRI,each rat was killed and the brain was removed and post-fixed overnight. After the brains were fixed, they were paraffin-embedded, sectioned, and examined...
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