Acquired demyelinating syndromes (ADS) represent acute neurologic illnesses characterized by deficits persisting for at least 24 hours and involving the optic nerve, brain, or spinal cord, associated with regional areas of increased T2 signal on conventional MRI. In contrast to the 75% of adult patients presenting with clinically isolated syndrome (CIS) who are eventually diagnosed with clinically defined multiple sclerosis (MS), the majority of children presenting with ADS have a monophasic illness with a good overall prognosis: more than 90% of children achieve a full neurologic recovery. Over the last decade, neuroimaging studies have focused on differentiating between MS and its mimics, and correlating radiologic measures with clinical outcome and neuropsychological testing in pediatric MS.