Radiation necrosis - cystic change
MRI through the temporal lobes demonstrates bilateral cystic regions or variable signal intensity. On the right the lesion is similar to CSF on all sequences, whereas on the left the content is high T2, intermediate T1 and does not attenuate on FLAIR. Both sides demonstrate peripheral signal drop out suggesting hemosiderin deposition. There is little if any peripheral enhancement, and no restricted diffusion.
This patient has a past history of nasopharyngeal carcinoma treated with surgery and radiation. The findings are consistent with bilateral radiation necrosis with cystic change.