CASE REPORT Diffusion-Weighted MR Imaging Characteristics of an Acute Strokelike Form of Multiple Sclerosis

SUMMARY: The characteristics of multiple sclerosis (MS) lesions on diffusion-weighted sequences and apparent diffusion coefficient (ADC) mapping at the very early phase of symptoms have not been clearly described. We report the case of a young woman who presented with a sudden pseudostroke form of MS resulting in hemiplegia and sudden aphasia. MR imaging showed a lesion of the left internal capsule with reduced ADC, which suggests an ischemic stroke. This case shows that very acute MS lesions may have reduced ADC on MR imaging, reflecting cytotoxic and not vasogenic edema. Acute, pseudostroke manifestations of multiple sclerosis(MS) are rare: only a few cases of sudden aphasia, sudden deafness, or hemiplegia have been described.1-3 These mani-festations can be confused with the acute phase of stroke, and diffusion-weighted MR imaging (DWI) should facilitate the differential diagnosis. The current data in the literature con-cerning DWI of acute lesions of MS, however, are contradic-tory. Some authors consider that recent lesions present high-intensity signals on b-1000 sequences and an unreduced apparent diffusion coefficient (ADC) for less than 3months.4,