Section Editor: Sandy Cheng-Yu Chen, M.D.
Taipei Medical University Hospital, Taipei, Taiwan
Figure Caption
Rasmussen encephalitis (RE), also known as chronic focal encephalitis, is a disease of unknown etiology resulting in chronic progressive brain inflammation. Viral origin and autoimmune mechanisms have been implicated as the possible etiologies. Progressive partial seizure and limb weakness are the typical clinical presentation, mostly in children. The classic MR imaging features include progressive atrophy of the cerebral cortices (white arrows in A) and basal ganglion (yellow arrows in A and B). In this case, atrophy of the left frontotemporal and parietal lobe regions and mesial temporal sclerosis, along with dilatation of the temporal horn of the left lateral ventricle (yellow arrow in C), are seen.