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RESEARCH PRODUCT

A Scanning Technique to Measure Regional Cerebral Blood Flow and Oxyhemoglobin Level

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OBJECTIVE: The application of a laser scanning technique to measure regional cerebral blood flow (CBF) and tissue hemoglobin oxygenation (HbO 2 ) using the rat closed cranial window preparation is described. METHODS: Twenty-nine male Wistar rats were used to consecutively measure local CBF by laser Doppler flowmetry and tissue HbO 2 by a microspectrophotometric method at multiple corresponding cortical locations. The scanning technique used a computer-controlled micromanipulator. Data from three experimental models are presented: the whisker stimulation model, the ischemia-reperfusion model, and the sinus-vein thrombosis model. Sequential changes in local CBF and HbO 2 data before, during, and after stimulation, ischemia, and sinus thrombosis were examined. Data from predefined locations within the same region were correlated with the topographical location and then arranged in a three-dimensional image. RESULTS: In the whisker stimulation model, we found a disproportionate increase in CBF (32 6 12%) as compared with that of HbO 2 (9 6 4%) during stimulation. In the ischemia-reperfusion model, the three-dimensional image showed heterogeneous low CBF (depending on the area) and homogeneous HbO 2 at a reduced level during ischemia and postischemic hyperperfusion. However, the range of oxygenation was normal after reperfusion. In the sinus-vein thrombosis model, drainage of the unsaturated blood via the collateral pathways was noted. CONCLUSION: The laser scanning technique is useful for visualizing sequential changes in hemodynamic-metabolic interactions of cortical brain tissue. This technique can reveal phenomena not detected by traditional monitoring procedures. (Neurosurgery 48:1335‐1343, 2001)