CLINICAL AND MAGNETIC-RESONANCE-IMAGING STUDY OF EXTRAPYRAMIDAL SYMPTOMS IN MULTIPLE SYSTEM ATROPHY

Slit-hyperintensity in the outer margin of the putamen on T2 weighted MRI was found in 17 out of 28 patients with clinically diagnosed multi ple system atrophy. Thirteen of these 17 patients showed extrapyramida l signs. Five patients had only unilateral slit-hyperintensity; four o f them had contralateral rigidity; and one had bradykinesia. Despite m ild rigidity, one case showed no slit-hyperintensity. One of the 14 ca ses with parkinsonism showed no hyperintensity, and four of the 14 cas es without parkinsonism showed hyperintensity. On the other hand, slit -hyperintensity was not seen in any of 25 patients with clinically dia gnosed Parkinson's disease. Putaminal slit-hyperintensity is a useful MRI feature in the differential diagnosis between Parkinson's disease and multiple system atrophy predominantly affecting the extrapyramidal system.