Infarcts in the region of the middle cerebral artery. Study of 501 cases in 484 patients

: We report a study of 501 infarcts in the middle cerebral artery (MCA) territory, in 484 patients. All cases had an appropriate low-density area on computed tomography. The basal (perforators) territory was involved in half the cases and the motor pathways either in the pre-rolandic area or in the internal capsule in 90%. In all locations, except for watershed infarcts, the main cause was cardiac embolism. Atrial fibrillation accounted for 59%, the two other main causes were myocardial infarction and paradoxical embolism. Atherosclerosis accounted for less than one third of the cases. Among 102 internal carotid artery occlusions less than one half were due to atherosclerosis, cardiac embolism and dissecting aneurysms accounted for 22% each. None of 34 MCA occlusions were due to atherosclerotic thrombotic occlusion. Transient ischemic attacks were recorded in 22% of the cases. Stroke-in-progression with a mean duration of 6-8 hours in hospital, was noted in nearly half the cases. In a small group of MCA infarcts paralysis began and predominated on the lower limb, fifteen contralateral old MCA infarcts were silent. Ten of these were on the right side. The 15 patients with silent infarcts were all right-handed.