Fig. 1.

MRI findings. Case 1: A fluid attenuated inversion recovery (FLAIR) image (A) displays an extensive bilateral white matter lesions (WMLs). The WMLs partially show high signals in diffusion-weighted image (DWI) (B), although they are unremarkable in apparent diffusion coefficient (ADC) maps (C). A part of the WMLs is enhanced with gadolinium contrast (an arrow, D). FLAIR images show lesions (arrows) in the splenium (E) and left corticospinal tract (F). Case 2: FLAIR image of a tumefactive extensive WML in the left hemisphere (G). The lesion has cores (which show high signals in DWI [H]) with surrounding vasogenic edema (which shows high intensity in ADC maps [I]). One of the cores is enhanced with gadolinium contrast (an arrow, J). Longitudinally extensive transverse myelitis was evident at the recurrence (K).