fig 5.

A and B, Anatomic distortion due to tumor mass effect, case 2 (Table 2): 33-year-old man with a biopsy-proved recurrent high-grade astrocytoma. A, which shows enhancing areas within the tumor, was acquired with the patient in a rigid stereotactic frame, which accounts for the distortion of the scalp. Tumor mass effect produced substantial distortion of normal cortical landmarks, and functional MR imaging was performed to determine the topographic relationship between the tumor and functional hand area in the right hemisphere (B). Functional MR imaging showed that the tumor had displaced the functional hand area posteriorly. While the functional hand area was involved with tumor edema, the majority of the tumor volume was anterior to the motor strip. The patient underwent a tumor debulking procedure with intraoperative cortical stimulation mapping