MRI in ADEM demonstrates regions of high T2 signal, with surrounding oedema. Punctuate, ring or arc enhancement is often demonstrated along the leading edge of inflammation. The center of the lesion, although high on T2 and low on T1 does not have increased restriction on DWI (D/D abscess), nor however does it demonstrate absent signal on DWI as one would expect from a cyst. This is due to increase in extra cellular water in the region of demyelination. However, absence of enhancement does not exclude the diagnosis.
Second opinion by -Teleradiology Providers