APTmean

For the APT images, board-certified neuroradiologists (A.S. and T.D.) independently placed an ROI over a representative slice of the tumor (1 ROI per patient). In case of tumors with an enhancing portion, ROIs were drawn on the enhanced area (viable tumor core) on the contrast-enhanced T1-weighted images. When such enhancement was absent, ROIs were drawn by selecting abnormal signal areas on the FLAIR images. Foci of necrosis, hemorrhage, or calcification were manually avoided. All ROIs were applied to the resliced APT images, and mean values (APT_mean) were calculated.