BACKGROUND AND PURPOSE In focal ischemic cortex, cerebral blood flow autoregulation is impaired, and perfusion passively follows blood pressure variations. Although it is generally agreed that profound hypotension is harmful in acute stroke, the hemodynamic and metabolic impact of increased blood pressure on the ischemic core and penumbra are less well understood. We, therefore, tested whether ...

BACKGROUND Thiopental and propofol are highly lipid-soluble, and their entry into the brain often is assumed to be limited by cerebral blood flow rather than by a diffusion barrier. However, there is little direct experimental evidence for this assumption. METHODS The cerebral kinetics of thiopental and propofol were examined over a range of cerebral blood flows using five and six chronically...

BACKGROUND AND PURPOSE External counterpulsation (ECP) is a novel noninvasive method used to improve the perfusion of vital organs, which may benefit ischemic stroke patients. We hypothesized that ECP may augment cerebral blood flow of ischemic stroke patients via induced hypertension. METHODS We recruited ischemic stroke patients with cerebral intracranial large artery occlusive disease and ...

Background and Purpose: Despite the documented diagnostic value of local cerebral blood flow maps by xenon-enhanced computed tomography, reports of cerebral blood flow activation by inhaled 33% Xe raised concerns about the method's safety and accuracy. We evaluated the effect of 33% Xe inhalation on cerebral blood flow and cerebral metabolic rates for oxygen and glucose in four awake and six fe...

OBJECTIVE To review methods of quantifying human cerebral autoregulation in health and disease. DATA SOURCES Articles and published abstracts on methods to quantify cerebral autoregulation in health and disease. SUMMARY OF REVIEW Cerebral autoregulation is defined as the relationship between cerebral blood flow and cerebral perfusion pressure. Complex neurohumoral processes are involved in ...

The influence of the sympathetic nervous system on the cerebral circulatory response to graded reductions in mean arterial blood pressure was studied in anesthetized baboons. Cerebral blood flow was measured by the 133Xe clearance method, and arterial blood pressure was decreased by controlled hemorrhage. In normal baboons, the constancy of cerebral blood flow was maintained until mean arterial...

We implemented a technique for measuring regional cerebral blood volume using single-photon emission computed tomography and in vivo technetium-99m-labeled red blood cells and then evaluated it in nine normal human volunteers (controls) and seven patients with bilateral occlusion or severe stenosis of the internal carotid artery. We also measured regional cerebral blood flow using single-photon...

Cerebral blood flow and cerebral oxygen consumption are not altered in patients with uncomplicated hypertension (1). Scheinberg observed that in a mixed group of patients who had congestive heart failure, the cerebral blood flow was depressed (2). This suggests altered cerebral hemodynamics either as a primary abnormality or as a result of disturbances in the cerebral circulatory dynamics secon...