Which imaging feature is more characteristic of pediatric multiple sclerosis than acute disseminated encephalomyelitis?

• A. Lesions limited to the brainstem
• B. No lesions on MRI
• C. Discrete, well-demarcated lesions with possible dissemination in time and space
• D. Acute diffuse edema with encephalopathy

Answer: (C)

The key imaging difference is the appearance and distribution of lesions over time. Pediatric MS is characterized by discrete, well-demarcated plaques that can appear in multiple brain regions and show dissemination in time and space on MRI—meaning new lesions or enhancing lesions appear on follow-up imaging in different locations. This reflects the relapsing, multifocal nature of MS.

In contrast, ADEM typically presents with large, poorly defined, confluent white-matter lesions that are often bilateral and symmetric, with less tendency to produce multiple lesions in separate places or to demonstrate new lesions over time. ADEM is usually a monophasic, single-event process, not the chronic, relapsing pattern seen in MS.

So the imaging feature most characteristic of pediatric MS over ADEM is discrete, well-demarcated lesions with possible dissemination in time and space.