New, angle-independent, low-cost Doppler system to measure blood flow

Background: A new Doppler flowmeter using a special transducer forming two ultrasound beams to insonate vessels was developed. This low-cost flowmeter allows the flow to be measured independently of the angle of insonation. Methods: Sixty-five flow determinations were made in the carotid arteries of five pigs. The flowmeter measured the flow in an artery bled into a calibrated vessel. Results were compared with the true volume of the blood captured. Results: On average, 13 measurements per animal were made at different flow rates (80 to 600 mL/min). The flowmeter measured flow-volume rates in mL/min were found to be within ± 15% of the cylinder captured volume. Conclusions: The accuracy of the angle-independent flowmeter is comparable with that of flowmeters currently used clinically. The small size and portability, low operator dependency, and low cost suggest potential for continuous acute and chronic-flow monitoring and a potential for an implantable flow-monitoring device