Fig. 1

Brain magnetic resonance images and single photon emission computed tomography (SPECT). a-c Two months after fever onset, fluid-attenuated inversion recovery (FLAIR) images show diffuse high signal intensity in the splenium of the corpus callosum and right-hemisphere dominant subcortical white matters. However, this finding is (a) neither exhibited in the temporal lobes nor exhibited in the brainstem (c). No contrast enhanced lesions are observed in gadolinium-enhanced T1-weighted images (b). d SPECT study shows hyperperfusion in the basal ganglia, thalamus and brainstem. (E-H) Axial FLAIR images. Approximately five months after the onset of fever, hyperintensity lesions extended to the frontotemporal lobes, bilaterally (e, f). Twelve months after the onset of fever, FLAIR images show diffuse progression of infiltrative lesions in the whole brain including the brainstem with systemic brain atrophy (g, h)