“Cloud‐like enhancement” is a magnetic resonance imaging abnormality specific to neuromyelitis optica

Abstract

Neuromyelitis optica (NMO) is presumably mediated by an autoantibody against aquaporin‐4 densely expressed at the blood‐brain barrier. In 18 patients with NMO, brain magnetic resonance imaging (MRI) findings were systematically reviewed. Brain MRI abnormalities were found for 89% of the patients, and the most prominent feature was “cloud‐like enhancement,” multiple patchy enhancing lesions with blurred margin, found in 90% of the patients with positive contrast enhancement. In NMO, brain MRI abnormalities are frequent, and cloud‐like enhancement appears to be an MRI finding specific to NMO, possibly caused by primary involvement of the blood‐brain barrier by the autoantibodies. Ann Neurol 2009;66:425–428