ADEM: Diffusion MRI findings

Acute disseminated encephalomyelitis (ADEM) usually reveals patchy demyelinated lesions with high signal on T2-weighted sequences. Diffusion MRI in a 10-year-old patient with ADEM demonstrated two distinct lesion patterns occurring simultaneously in the cerebral white matter. These were a restricted diffusion pattern (high-signal on b = 1000 mm2/s images with low apparent diffusion coefficient (ADC) values, and a demyelinating pattern (negative b = 1000 mm2/s images with high ADC values). The patient responded well to intravenous methylprednisolone therapy. Further studies are required for detailed evaluation of such patterns in ADEM, and their clinical relevance, and for discrimination from other inflammatory encephalopathies. © 2002 Elsevier Science Ireland Ltd. All rights reserved