Figure 2.

Posttreatment changes on DSC-MRI: A 68-year-old woman with left frontal GBM with two prior surgical resections and adjuvant radiation, temozolomide, and lomustine therapy undergoing routine surveillance imaging. (A) CE-MRI 2 years after initial diagnosis demonstrated increased nodular enhancement along the resection cavity concerning recurrent tumor. (B) The DSC FTB map derived from relative cerebral blood volume (rCBV) thresholds demonstrate a small area of high FTB centrally (arrowhead) suggesting tumor recurrence, but the majority of the surrounding tissue had low rCBV consistent with posttreatment effect. (C) Stereotactic biopsies were performed and cross-registered with areas of enhancement, but only corresponded with low rCBV regions. Pathology showed scant atypical cells in a background of extensive therapy-related changes, compatible with the rCBV map. No viable GBM was identified. Unfortunately, the central portion of the tumor was not sampled and cross-registration with the DSC images at the time of biopsy may have been helpful in fully characterizing the lesion pathologically.