Figure 6b. Ganglioglioma in a 19-year-old man with a 12-year history of medically refractory seizures. (a) Axial T2-weighted MR image shows an ill-defined mass of the posterior left parietotemporal lobe (arrows) that distorts the margin of the lateral ventricle. The mass is heterogeneous, with areas of high signal intensity combined with regions that are equivalent in signal intensity to the gray matter. (b) Axial positron emission tomographic (PET) image shows mild hypometabolic activity (arrows) in the region of the mass.