Experimental Cerebral Infarction. II. Clinicopathological Model of Deep Cerebral Infarction

Injection of silicone rubber cylinders into the internal carotid system permits selective occlusion of the proximal middle cerebral artery segment in the dog. Occlusions of this segment obstruct the mouths of the lenticulostriate arteries and result in deep cerebral hemisphere infarctions. Surface vessels distal to the occluded segment remain patent and the cortex of the hemisphere is spared, due to efficient collateral circulation. Hemorrhage in cortical infarctions may occur distal to the point of vascular occlusion and, therefore, may be a function of patent meningocerebral anastomoses. Hemorrhage into a deep infarction, however, occurred only when there was clinical and pathological evidence of distal migration of the embolus after an initial proximal occlusion. Infarctions of deep hemisphere structures were otherwise bland or "ischemic," probably because of the paucity of anastomoses among the penetrating blood vessels of the brain.