Head CT > Stroke > CT Pathophysiology

CT Pathophysiology

After a stroke, edema progresses, and brain density decreases proportionately. Severe ischemia results in a 3% increase in intraparenchymal water within 1 hour. This corresponds to 7-8 Hounsfield Unit decrease in brain density. There is also a 6% increase in water at 6 hours. The degree of edema is related to the severity of hypoperfusion and the adequacy of collateral vessels.

Sharply circumscribed hypodense edema (arrowheads)
in the right middle cerebral artery territory.

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