The Diagnostic and Prognostic Value of Magnetic Resonance Imaging for Evaluating Atypical Inflammatory Demyelinating Lesions

Abstract

Objective: The diagnosis of patients with atypical demiyelinating lesions has always been challenging, sometimes leading to a biopsy. Recent literature has radiologically classified atypical inflammatory demyelinating lesions as ring-like, Balo-like, infiltrative, megacystic, and unclassified lesions. In this study, we aimed to assess the demographics and clinical and radiologic findings in patients with atypical lesions. Materials and Methods: The records of 320 patients with demyelinating disorders were retrospectively assessed using iMed database. Patients with atypical lesions and whose magnetic resonance imaging evaluations were included. Clinical and radiologic findings were evaluated and lesions were classified according to the recommended criteria. Results: Twenty-seven patients (16 females) were included and the mean age was 34.26 +/- 6.12 (range: 26-49) years. Fourteeen patients had ring-like, three had Balo-like, three had megacystic, five had infiltrative, and two patients had unclassified lesions. Diffusion restriction was observed in contrast-enhancing sites in ring-like lesions, heterogeneously in infiltrative lesions and also peripherally in Balo-like lesions. Two patients with infiltrative lesions had additional lesions on follow-up and had to undergo biopsy. Two patients died despite aggressive treatment. Two patients with Balo-like lesions were evaluated as having acute disseminated encephalomyelitis and did not have further relapses. Seventeen patients from the study group converted to multiple sclerosis (MS) on follow-up. Conclusion: Differential diagnosis of atypical inflammatory demyelinating lesions is not always easy, the prognosis is not different from MS lesions. Mostly, ringlike lesions seem to convert to MS with recurrent relapses

however, infiltrative lesions seem to have poorer outcomes, especially if patients have additional relapses.