Computed tomography and stroke edema: case report with an analysis of water in acute infarction.

An index case and 13 other cases of acute ischemic cerebral infarction have been examined following the occurrence of death 1-6 days postictus. Histologic studies and water content assay involved both the infarct and peri-infarct tissue. The primary site of fluid accumulation was the infarcted white matter; however, after 3 days, edema in the adjacent white matter may be significant. The reduced attenuation of CT scans is caused only by edema since necrosis of the white matter is not present. Reactive vascular changes that occur in the cortex appear to be the basis of early contrast enhancement. Three different mechanisms of edema formation have been proposed to be involved in the mass effect.