The Open Ring A New Imaging Sign in Demyelinating Disease

Abstract

Because demyelinating disease of the brain occasionally presents with large ring-enhancing lesions on computed tomography (CT) scans and magnetic resonance images (MRIs), the authors sought to determine whether the ring pattern differed from that found in other common brain lesions with ring enhancement. Published MRI and CT scans of patients with adrenoleukodystrophy (23), and multiple sclerosis or similar demyelinating disorders (21), as well as a variety of tumors (44) and infections (44) matched to the demyelinating lesions by year of publication, in which ring enhancement was evident, were photographed. Photographs without diagnostic identification were presented randomly to two independent observers. The observers rated the contrast enhancement pattern as (1) open ring, with enhancement in the border of the lesion abutting the white matter; (2) closed ring; or (3) uncertain. For all diagnostically certain cases (n = 112), inter-rater agreement was excellent (kappa = 0.75). As an average of the two reviewers, scans for 11 of 132 cases were read as uncertain; 89% of adrenoleukodystrophy cases, 41% of the multiple sclerosis cases, 3% of tumors, and 9% of infections were classified as having the open-ring pattern. Overall, 66% of demyelinating lesions had an open-ring pattern compared with 7% of the non-demyelinating lesions (chi2 = 41.2, p< 0.0001). An open-ring pattern of enhancement is more likely to be associated with demyelinating lesions than with nondemyelinating lesions.

Intracranial demyelinating pseudotumor: a case report and review of the literature

“…In most cases, CT imaging shows low or modest densities, while MRI shows abnormal long T1 and T2 signals. In the literature, the majority of demyelinating pseudotumor cases presented with non-closed ring enhancements (also called crescent sign) on CT and (or) MRI scans (11,12). However, intracranial tumors often lack this signal (13,18).…”

MRI in Multiple Sclerosis: What’s Inside the Toolbox?

“…4). Homogeneousenhancing lesions are the most commonly seen form in patients with MS. Open ring enhancement is fairly specific for MS. 38 Ring-enhancing lesions show higher levels of tissue destruction 39,40 than homogeneously-enhancing lesions and thus tend to resolve more slowly. Moreover, ring-enhancing lesions are at high risk for conversion to chronic T1-hypointense lesions 41 and predict global brain parenchymal loss.…”

Proton Magnetic Resonance Spectroscopy and Diffusion-Weighted Imaging of Tumefactive Demyelinating Plaque -Case Report-

“…6,7,14) Neuroimaging of 168 cases of TDP requiring biopsy suggested various enhancement patterns and a strong statistical association between lesion size and presence of mass effects and peripheral edema. 13) Therefore, no neuroradiological indications for TDP can be defined as specific findings.…”