Figure 3-11.

Two patients with temporal lobe epilepsy due to oligodendroglioma, one in the right temporal horn of the ventricle adjacent to the hippocampus (A–C) and the other (D–F) in the right inferior temporal gyrus. Oligodendrogliomas are nonspecifically hypointense on T1-weighted (D) and hyperintense on T2-weighted or fluid-attenuated inversion recovery (FLAIR) images (A, E). Occasionally, foci of increased signal on T1-weighted images (B) reflect intratumoral hemorrhage. Enhancement on CT or MRI is variable (C, F, arrows). On CT, calcifications are expected and may be shell-like, ringlike, or nodular.