Prospective longitudinal analysis of physiologic MRI-based tumor habitat predicts short-term patient outcomes in IDH-wildtype glioblastoma

Background. This study validates MRI-based tumor habitats in predicting time-to-progression (TTP), overall survival (OS), and progression sites in isocitrate dehydrogenase (IDH)-wildtype glioblastoma patients. Methods. Seventy-nine patients were prospectively enrolled between January 2020 and June 2022. MRI, including diffusion-weighted and dynamic susceptibility contrast imaging, were obtained immediately postoperation and at three serial timepoints. Voxels from cerebral blood volume and apparent diffusion coefficient maps were grouped into three habitats (hypervascular cellular, hypovascular cellular, and nonviable tissue) using k-means clustering. Predefined cutoffs for increases in hypervascular and hypovascular cellular habitat were applied to calculate the habitat risk score. Associations between spatiotemporal habitats, habitat risk score,TTP, and OS were investigated using Cox proportional hazards modeling. Habitat risk score was compared to tumor volume using time-dependent receiver operating characteristics analysis. Progression sites were matched with spatial habitats. Results. Increases in hypervascular and hypovascular cellular habitats and habitat risk scores were associated with shorterTTP and OS (all P < .05). Hypovascular cellular habitat and habitat risk scores 1 and 2 independently predictedTTP (hazard ratio [HR], 4.14; P = .03, HR, 4.51; P = .001 and HR, 10.02; P < .001, respectively). Hypovascular cellular habitat and habitat risk score 2 independently predicted OS (HR, 4.01, P = .003; and HR, 3.27, P < .001, respectively). Habitat risk score outperformed tumor volume in predicting TTP (12-month AUC, 0.762 vs. 0.646, P = .048). Hypovascular cellular habitat predicted progression sites (mean Dice index: 0.31). Conclusions. Multiparametric physiologic MRI-based spatiotemporal tumor habitats and habitat risk scores are useful biomarkers for early tumor progression and outcomes in IDH-wildtype glioblastoma patients.