Experimental study on quantitative flow measurement by a Doppler flowmeter with a sound-spectrograph.

A bidirectional ultrasonic Doppler flowmeter equipped with a sound-spectrographic analyzer has enabled us to determine blood-flow direction and to obtain useful information from the flow pattern in assessing the cerebral blood flow transcutaneously or intraoperatively. Using a regulated flow system produced in a dog, we performed an experimental study in order to establish the optimal mode for its use and to study the reliability in the quantitative cerebral blood-flow measurements. Although we could not measure the absolute blood-flow volume directly with this apparatus, we were able to obtain useful, quantitative information on blood flow and flow pattern by placing the ultrasonic probe in an appropriate position with respect to a blood vessel.