Morphometry of brain parenchymal vessels following subarachnoid hemorrhage

This study was performed to test the hypothesis that vascular spasm can occur in brain parenchymal vessels following subarachnoid hemorrhage (SAH). Five cc of autologous blood was injected into the cisterna magna of test cats and 5 cc of saline into control cats. After 2 hours, a cranial window was created and cortical tissue frozen in situ with liquid nitrogen. Statistical analysis of 124 test and 93 control arteries and arterioles showed a significantly greater mean wall to lumen ratio in the test vessels but with almost identical mean cross sectional areas for both groups of vessels. This finding provides evidence for at least vasoconstriction, if not frank spasm, in parenchymal vessels in conjunction with SAH.