Which imaging pattern is typical of Acute Disseminated Encephalomyelitis (ADEM) as compared with pediatric multiple sclerosis?

• A. MS presents with acute encephalopathy and diffuse edema-like lesions
• B. ADEM typically presents acutely with encephalopathy and multifocal edema-like lesions, often monophasic
• C. ADEM shows discrete, well-demarcated lesions with dissemination in time and space
• D. MS is always monophasic

Answer: (B)

The key idea is that ADEM in children usually presents with an acute onset of brain dysfunction (encephalopathy) and widespread, edema-like white-matter–signal changes on MRI that are multifocal and often look confluent. This pattern fits an acute inflammatory demyelinating process that is typically monophasic, meaning one episode with no ongoing/new demyelinating events after the initial event.

So, describing ADEM as occurring acutely with encephalopathy and multifocal edema-like lesions, often in a monophasic course, matches what clinicians expect for imaging and clinical behavior in this condition. In contrast, pediatric MS tends to show discrete, well-defined lesions and requires evidence of dissemination in time and space, and MS is not limited to a single attack.