Solitary hemispheric demyelination in acute disseminated encephalomyelitis: clinicoradiological correlation.

We retrospectively studied 13 patients with solitary hemispheric demyelination in acute disseminated encephalo--myelitis (solitary-ADEM) to look for specific MRI features. Thirteen patients were subjected to routine MRI with varying initial clinical diagnosis, including demyelination, neoplasm, encephalitis and infarct. The provisional MRI diagnosis was based on lesion morphology, size, location, mass effect, effect on adjacent sulci, cisterns and gyral shape. On long repetition time (TR)/long echo time (TE) spin echo sequences, the lesions were heterogeneously hyperintense, and on short TR/short TE spin echo sequences, heterogeneously hypointense. Later, the provisional MRI diagnosis was corroborated with clinical parameters such as multimode-evoked potentials, electro--physiological studies and analysis of cerebrospinal fluid (CSF) in order to establish a definitive diagnosis. The diagnosis was established in all except one patient with tumour-like clinical and MRI features. The combination of MRI features and clinical parameters can establish a definitive diagnosis in the majority of cases, and this avoids a biopsy.