Blood flow velocity in the pial arteries of cats, with particular reference to the vessel diameter.

The blood flow velocity and diameter of feline pial arteries, ranging in diameter from 20 to 200 microns, were measured simultaneously using a newly developed video camera method under steady-state conditions for all other parameters. There was a linear relationship between blood flow velocity and pial artery diameter (y = 0.340x + 0.309), the correlation coefficient being 0.785 (p less than 0.001). The average values for blood flow velocity in pial arteries less than 50 microns, greater than or equal to 50 but less than 100 microns, greater than or equal to 100 but less than 150 microns, and greater than or equal to 150 microns in diameter were 12.9 +/- 1.3, 24.6 +/- 3.4, 42.1 +/- 4.7, and 59.9 +/- 5.3 mm/s, respectively. Blood flow rate was calculated as a product of the cross-sectional area and the flow velocity. The blood flow rate increased exponentially as the pial artery diameter increased (y = 2.71 X 10(-4) x2.98). The average values for blood flow rate in pial arteries less than 50 microns, greater than or equal to 50 but less than 100 microns, greater than or equal to 100 but less than 150 microns and greater than or equal to 150 microns in diameter were 12.8 +/- 1.5, 122.1 +/- 24.8, 510.2 +/- 74.8, and 1524.2 +/- 174.4 10(-3) mm3/s, respectively. Hemorheological parameters such as the wall shear rate and Reynolds' number were also calculated. The data obtained provide a useful basis for further investigations in the field of cerebral circulation.