fig 2.

Case 20. The patient was suffering from an anaplastic astrocytoma invading the precentral gyrus. She presented with focal epileptic seizures of the face on the left side but did not have a motor deficit. Overlay of the activation map onto the functional echo-planar image (3500/84/1) shows activation nearly symmetrical in the upper two sections lining the Ω-shaped hand-motor area. There is less activation in the ipsilateral sensorimotor cortex on the lower two sections. The signal hyperintense parts of the sensorimotor cortex do not display BOLD contrast enhancement. Region of interest 1 is the cluster of activated voxels in the most medial part of the pre- and postcentral gyrus. Region of interest 2 is on the lateral continuation of the pre- and postcentral gyrus within an area of T2 signal hyperintensity of the cerebral cortex. The signal hyperintensity likely indicates gliomatous infiltration; in this case, histologic analysis of the resected specimen showed diffuse infiltration of the cortex. The interval of the signal intensity of region of interest 1 shows task-related signal changes (BOLD contrast enhancement) of approximately 6%, with hemodynamic delays of one to three images (gray bars indicate stimulation measurements). Region of interest 2 does not show BOLD contrast enhancement, although the analogous area in the left hemisphere is strongly activated.