Pure motor hemiplegia: CT study of 30 cases.

Pure motor hemiplegia (PMH) is a well defined syndrome usually caused by ischemic lesions of lacunar type located either in the internal capsule or in the pons. Angiography and isotope scanning are usually normal. CT scan reveals small deep infarcts and appears to be the most reliable investigative method. The CT scan findings are described of thirty patients with PMH of rapid onset (less than 36 hours). In 29 of the 30 cases a lesion was found which could explain the PMH. Small hemorrhages (2 cm in diameter) in the posterior limb of the internal capsule were noted in two cases. Ischemic lesions were found in 27 patients, 22 patients had a single lesion (20 capsular and 2 pontine), while 5 patients had 2 lesions (2 bi-capsular, 3 capsular and pontine). Three varieties of ischemic capsular lesions were observed. We found in 15 cases a capsulo-putamine-caudate infarct (type I); in 8 cases a capsulo-pallidal infarct (type II); and in 2 cases an anterior capsulo-caudate infarct (type III). Type I corresponded to the area of the lateral lenticulostriate branches of the middle cerebral artery. Type II involved the territory of the perforating branches of the anterior choroidal artery. We suggest that type III involves the territory of the internal lenticulostriate branches of the anterior cerebral artery. Lacunes are generally linked to arterial systemic hypertension. However, only 16 of 30 patients in this series were chronically hypertensive.