3.3 MRI findings
Brain lesions were observed in all 10 patients by MRI scan. In a total
of 24 episodes of the 10 patients, lesions involved the cortical region
(33.3%, 8/24), deep nuclei (basal ganglia and thalamus) (25.0%, 6/24),
hippocampus (20.8%, 5/24), juxta white matters (corpus callosum,
cingulate gyrus) (12.5%, 3/24), brainstem (midbrain, pons, and medulla)
(37.5%, 9/24), and cerebellum (4.2%, 1/24) (lesion distributions
summarized in Figure 1C). All 10 patients exhibited hyperintense signals
on T2-sequences (Figure 3), and 6 patients showed lesional or meningeal
enhancements. In patient-6 who presented as seizures and acute confusion
and infected with herpes simplex virus 1 (HSV-1) prior to NMDAR
encephalitis, extensive cortical regions and hippocampi involvements
were found. After treatment with intravenous acyclovir and
methylprednisolone, the brain lesions were clearly adsorbed. However,
extensive meningeal enhancement was observed after the contrast agent
was administered (Figure 4 D-F).
Abnormal signals in the optic nerve presented in four patients with or
without nerve sheath enhancement. Transverse myelitis occurred in only
two patients, with one case longitudinally involving both the cervical
and thoracic spinal cords (Figure 4 A-C) and one case shortly involving
the superior cervical cord.