New Technology Of MR Imaging In The Evaluation Of Glioma Recurrence

Part I: Conventioanl MR Imaging Clues to Diagnosis of Glioma RecurrencePurpose: To explore the value of the conventioanl MR imaging manifestations in the diagnosis of glioma recurrence through comparision of glioma recurrence with radiation necrosis. Materials and methods: Thirty-seven patients confirmed to tumor recurrence on the basis of surgical pathology (8 cases ) or the following criteria (29 cases ) and eight patients diagnosised of radiation necrosis (among of them four nasopharyngesal carcinoma patients diagnosised of radiation necrosis by histopathology ) were enrolled in this study. All the patients were examined by a GE Singa Horizontal 1.5T super conduct MR unit. The difference of recurrent time of different grades of glioma and different kinds of operation were analyzed. The relationship of recurrent types and operative kinds was studied. The manifestations of glioma recurrence and radiation necrosis were compared. Results: 1.The prognosis of low grade glioma is superior to high grade. 2. The malignance of glimoa would increase, with tumor recurrence. 3. Different kinds of operation had different recurrent time. The recurrent time would be longer with the tumor totally resection. 4. No significant relationship of tumor recurrent types and operative kinds was revealed. Penetration with the ventricle after operation often contributed to tumor spreading through subependymal and cerebrospinal fluid. 5. Corpus callosum involvement, in conjunction with multiple enhancing lesions with or without crossing of the midline and subependymal spread, favors glioma recurrence. Conclusion: Conventional MR imaging findings are useful in diagnosis of the morphology of the lesion, and can assist with the further examination.Part II: Manifestations of MR Imaging Specrum in glioma recurrence and radiation necrosisPurpose: To reveal the biological feature of glioma recurrence in MR spectrum and to explore the utility of MRSI in the differential diagnoses between tumor recurrence and radiation necrosis. Materials and methods: Two-dimentioal mutlti-voxel MR spectroscopy was performed in twenty-nine patients confirmed to tumor recurrence on the basis of surgical pathology (4 cases ) or the following criteria (25 cases ) and five patients diagnosised of radiation necrosis (among of them two nasopharyngesal carcinoma patients diagnosised of radiation necrosis by histopathology ). Functool software package was used for post-processing of spectrum. Relative quantifications of NAA,Cho,Cr,Lac/Lip were analyzed and compared with which of the normal white matter and radiation necrosis. Results: 1. NAA,Cr and NAA/Cr were significantly lower in recrrent tumor than in the normal white matter, while Cho/Cr,Cho/NAA and most of Cho were significantly higher. 2. No significant difference metabolic ratios were revealed in low grade and high grade glioma. 3. NAA,Cr were also significantly lower in radiation necrosis than in the normal white, most of Cho was lower. 4. Cho was useful in the differentiation between tumor recurrence and radiation necrosis, while NAA,Cr,Lac/Lip were not. Conclusion: 2-D MRS is helpful in the differential diagnoses between tumor recurrence and radiation necrosis.Part III: Dynamic Susceptilility Contrast MR Perfusion Imaging in the diagnosis of Glioma RecurrencePurpose: To investigate the value of DSC MR perfusion imaging in the diagnosis of tumor recurrence by analysis of the relative quantifications of cerebral blood volum and vascular permeability, and the correlation between cerebral blood volum and Cho. Materials and methods: DSC MR perfusion and 2-D mutlti-voxel MR spectroscopy were performed in twenty patients confirmed to tumor recurrence on the basis of surgical pathology (4 cases ) or the following criteria (16 cases ). Functool software package was used for post-processing of perfusion and spectrum. 15 cases showed high perfusion on pseudocolor images of CBV. The difference of vascular permeability between high and low perfusion spots, and the correlation of rCBV and permeability on high perfusion spots were analyzed. The correlation of the normalized rCBV and Cho of tumor was also discussed. Results: 1. High perfusion on pseudocolor images of CBV could reflect most tumor recurrence directly. 2. Significant difference in vascular permeability between high and low perfusion spots was realved. 3. No correlation of rCBV and permeability on high perfusion spots was found. 4. Significant correlation of the normalized rCBV and Cho of tumor was realved. Conclusion: DSC MR perfusion can be the first choice of examination in the diagnosis of glioma recurrence.