Symmetrical chronic bilateral subdural hematoma.

Neurology India | June 2005 | Vol 53 | Issue 2 Ring-enhancing lesions pose a common diagnostic challenge. This sign is invaluable in differentiating demyelination from other similar lesions, which usually show complete ring enhancement. The ring is complete towards the white matter, indicating active demyelination. An open-ring pattern of enhancement is more likely to be associated with demyelinating lesions than nondemyelinating lesions. In one study, the likelihood ratio of demyelination versus neoplasm averaged 5.2, and vs infection, 17.2. Moreover, the specificity in diagnosis was approximately 90%.