Continuous measurement of cerebral blood flow in anesthetized @entity468 and XXXX .

@entity101 @entity2944 @entity235 @entity468 @entity13147
We have developed a method for virtually continuous measurement of changes in cerebral blood flow (CBF) in @entity468 and @entity235 . CBF was computed by multiplying cross-sectional area (CSA) and mean blood velocity in a pial artery. CSA was determined by measuring pial artery diameter with an electronic micrometer every 2-4 s through a cranial window. Velocity was measured continuously with a pulsed Doppler crystal positioned under a pial artery. CBF was determined in 12 anesthetized @entity468 during 1) control, 2) @entity13147 , 3) @entity2944 , and 4) @entity2944 plus @entity101 . Microspheres were injected under steady-state conditions to compare the two methods. During control, the diameter of the cerebral arteries observed was 388 +/- 28 (SE) micrometers, and CBF measured with microspheres was 40 +/- 4 ml.min-1.100 g-1. CBF decreased 18 +/- 2% during @entity13147 and increased 152 +/- 36% during @entity2944 . During steady-state conditions, the correlation coefficient between changes in CBF (CSA X velocity and microspheres) was 0.94, and the slope of the regression line was 1.02. In similar studies on seven anesthetized @entity235 , the correlation coefficient between CSA X velocity and microspheres was 0.98, and the slope of the regression line was 0.94. We conclude that the product of CSA and blood velocity of a pial artery provides accurate on-line measurement of changes in CBF.
