LOCAL CEREBRAL BLOOD-FLOW MEASURED BY XENON-ENHANCED CT DURING CRYOGENIC BRAIN EDEMA AND INTRACRANIAL HYPERTENSION IN MONKEYS

We developed a closed-skull model of freeze injury-induced brain edema , a model classically thought to produce vasogenic edema, and observed the natural course of changes in edema and blood flow using xenon-enh anced computed tomography (CT) in five rhesus monkeys before and for u p to 6 h post insult. Intracranial pressure (ICP) gradually rose throu ghout the duration of the experiment. CT scans and CBF images permitte d direct observation of the evolution of the lesion and revealed early ischemia in the periphery of the injury zone that progressed over tim e in association with edema. Frequency histogram analysis of local CBF (lCBF) demonstrated subtle but potentially important changes in distr ibution of lCBF between and within hemispheres at various times post i nsult. Changes in lCBF distribution were phasic and dissociated from i ncreases in ICP in the latter stages of injury. The Xe/CT CBF method c an be used to evaluate the effects of injury and therapy on CBF in thi s and other models of acute brain injury.