Diffuse and ill-defined areas of high T2/FLAIR signal involving the white matter along the left frontotemporal and insular lobes, splenium of the corpus callosum, basal ganglia on the left, and extending inferiorly through the thalamus to the left cerebellar peduncle and mesencephalon. Foci of restricted diffusion are present in those areas and enhancement is irregular and scattered throughout the lesion.