The open ring or white-matter-crescent pattern of enhancement differentiates demyelinating brain disease with tumor-like presentation from infection and neoplasm

Occasionally, demyelinating disease of the brain presents with ring- enhancing lesions, many times the diagnosis is not clear and demyelination has been mistaken for neoplasm or infection. We reviewed the literature to test the specificity for demyelinating disease of an open-ring or crescent pattern of contrast enhancement present only in the white matter. The open- ring sign was more common in demyelinating lesions than in infections or tumors and is helpful for differential diagnosis. The open-ring sign was more frequent in demyelinating lesions than in infections or tumors. The open- ring sign is often present in large, contrast-enhancing, demyelinating lesions of the brain and helps to differentiate them from tumors and, particularly, from infections.