PO33CORRELATION BETWEEN EXTEND OF RESECTION IN DIFFUSION TENSOR MR AND GLIOBLASTOMA PATIENT OUTCOME

Abstract

INTRODUCTION: Extent of resection (EOR) based on the T1 contrast MRI had been shown as an important prognostic factor in glioblastoma patients. However, tumor can extend beyond these areas. These invasive regions can be detected using diffusion tensor imaging (DTI) due to subtle white mater change. This study is to analyze the influence of extending resection into the DTI-determined invasive region with patient outcome. METHOD: Immediate (within 72 hours) post-operative MRI were reviewed from 14 patients who had undergone 5-ALA guided resection of a glioblastoma. Post-operative images were further co-registered with pre-operative images for calculating volumetric change. DTI was split into isotropic (p) and anisotropic (q) components. Extent of resection was assessed in p map, q map, T2 Flair and T1 contrast enhanced MR images by using 3D volumetric calculator. RESULTS: The EOR of the p map showed significant correlation to both event free survival and progression free survival (PFS) (r2 = 0.3991, 0.4415; p value = 0.015, 0.0257). Further multiple regression study with age and EOR based on T1 contrast MR revealed a higher correlation between PFS and EOR (r2 = 0.632, p value =0.01). There was no correlation with overall survival or with the EOR of q map and FLAIR to any clinical outcomes. CONCLUSION: DTI can detect tumor outside T1 contrast enhanced image and extending resections beyond this region appears to be associated with a prolonged progression free survival.