MET-04 EVALUATION OF PERITUMORAL BRAIN PARENCHYMA USING CONTRAST-ENHANCED FIESTA IMAGING FOR DIFFERENTIATING METASTATIC BRAIN TUMORS AND GLIOBLASTOMAS

Introduction: Metastatic brain tumors and glioblastomas commonly revealed heterogenous enhancement lesions with peritumoral brain edema on magnetic resonance imaging (MRI). In particular, distinguishing solitary metastatic brain tumors from glioblastomas is difficult on conventional MRI. Fast imaging employing steady-state acquisition (FIESTA) can emphasize the water content signal with a high spatial resolution. In this study, we evaluate a role of contrast-enhanced FIESTA(CE-FIESTA) by focusing on the peritumoral brain parenchyma between metastatic brain tumors and glioblastomas. Materials and Methods: We included patients who underwent initial surgery and were histologically diagnosed with metastatic brain tumor (43 cases) or glioblastoma (14 cases) between November 2008 and May 2016. We evaluated CE-FIESTA findings of peritumoral brain parenchyma. Next, we performed an observer performance study with neuroradiologists based on the findings of peritumoral brain parenchyma using conventional MRI and CE-FIESTA. Results: CE-FIESTA revealed hyperintense rim in peritumoral brain parenchyma. We classified hyperintense rim in three groups, as follow: type A, no hyperintense rim; type B, partial hyperintense rim; and type C, extended hyperintense rim. Regarding the diagnosis of metastatic brain tumors, the observer performance demonstrated high sensitivity (95.3%), specificity (85.7%) and accuracy (93.0%) of type C on CE-FIESTA, and thus, CE-FIESTA could distinguish metastatic brain tumors from glioblastomas with high accuracy. Conclusions: CE-FIESTA may provide useful information for distinguish metastatic brain tumors from glioblastomas, focusing on the differences in the peritumoral brain parenchyma.