Blood flow measurements in studies of macro- and microcirculation.

Ultrasound blood flow transducers were tested by using pulsating flows in a dynamic test system with Pito tube. Simultaneous studies of rat ascending aorta with a Doppler strip detector (13 MHz) and ultrasound catheter (33 MHz) produced a 10% discrepancy of the results. Here we describe a computing unit to estimate the volume flow rate in biomicroscopic studies. The value of blood flow rate estimated with a 38.5-MHz Doppler probe and diameter of the microscopically examined vessel were inputted into a computer for real-time processing. Blood flow rate in microvessels of rat mesentery and cremaster muscle was 10-700 nl/sec.