Transcutaneous quantitation of arterial flow with ultrasound

Arterial blood flow was measured in dogs simultaneously with electromagnetic flow probes and with ultrasonic "flow probes." The ultrasonic probes were used to determine transcutaneously the mean velocity of arterial flow and the cross-sectional area of the blood vessel. A 10 MHz probe was used for blood vessels 1 cm deep or less, while a 5 MHz probe was used for vessels between 1.0 and 2.5 cm deep. The correlation coefficient between the flow calculated with the ultrasound method and the flow measured with the electromagnetic flow probes was 0.966, p less than 0.01. Blood flow was also measured intraoperatively in five patients. There was a correlation coefficient of 0.999, p less than 0.01, between the flow obtained with the ultrasound method and that determined simultaneously by the electromagnetic flow probes. The coefficient of determination for the regression of electromagnetic-determined flow on ultrasound-determined flow was 0.99. Thus, accurate transcutaneous determination of blood flow is possible with slightly modified ultrasound equipment.