Ra-047. Baseline Spin-echo Echo-planar Perfusion ncbv Prior To Chemoradiation Is A Strong Independent Pre-therapy Predictor Of Progression-free And Overall Survival In Newly Diagnosed Glioblastoma

BACKGROUND: A growing literature demonstrates that gradient-echo echo-planar perfusion weighted imaging (GE-PWI) has independent prognostic value for patients with newly diagnosed glioblastoma. Spin-echo echo planar PWI (SE-PWI) is more selective than GE-PWI for blood volume in microvessels that are the size of glioma neocapillaries, but it has not been comprehensively studied in human clinical use. We assessed whether SE-PWI before and after initiating chemoradiation can stratify patients with respect to progression free survival (PFS) and overall survival (OS). METHODS: Sixty-eight glioblastoma patients with interpretable pre and post-treatment SE-PWI were identified. In each study, normalized cerebral blood volume (SE-nCBV) was calculated by hot-spot method from 3 regions of interest (ROI) selected within the areas of maximal cerebral blood volume (CBV) in enhancing and/or non-enhancing tumor and 1 ROI selected within the contralateral normal appearing white matter. SE-nCBV parameters predictive of PFS and OS were identified by univariate and multivariate Cox proportional hazards modeling. Receiver operator curve characteristic analysis was used to identify thresholds optimized for 15-month survival, and Kaplan-Meier estimates of PFS and OS were calculated. RESULTS: Multivariate analysis demonstrated that baseline tumor mean SE-nCBV was predictive of PFS (p = 0.038) and OS (p = 0.004). Baseline tumor mean SE-nCBV 2.0 (median PFS 25.3, median OS 56.0 weeks). Exploratory multi-group stratification demonstrated that very high tumor SE-nCBV > 4.0 was associated with worse patient OS than intermediate high SE-nCBV (>2.0,