Glioblastoma is a particularly malevolent disease, with median expected survival around 14 months. Standard protocols for treatment assessment and recurrence rely on morphological approximations of tumor burden. Recently included by the RANO criteria, T2/FLAIR is now standard in imaging protocols, highlighting edema, presumed to be associated with tumor cell infiltration and critical for accurate description of tumor burden and radiation treatment planning. Advanced methods for early detection of change are underutilized. Application of the Parametric Response Map technique provides greater sensitivity to FLAIR signal changes indicative of tumor progression prior to those detectable by morphological analysis alone.