Fig 4.

Cavernoma/telangiectasia. This 24-year-old student was being evaluated for partial complex seizures, and an MR image revealed a left temporal lobe lesion (not shown) that was thought to be a low-grade glioma, as well as an incidental lesion in the left pons. Contrast-enhanced coronal GRE T1-weighted image (A) depicts a small mildly enhancing lesion in the left pons (arrow). The lesion was not visible on T2-weighted images (not shown) but appears on axial SWI (B) as a markedly hypointense area. The ill-defined blush is commonly seen in low-flow vascular malformations, and the marked hypointensity of the lesion on the SWI sequence suggests that this represents an occult vascular malformation. Although there was no pathologic confirmation, given the location and size, it likely represents a cavernoma that had not bled.