High-frequency Doppler Ultrasound Flowmeter

This paper discusses a new Doppler device for measuring blood flow in small vessels. The ultrasound frequency applied is 20MHz. Two different ultra:;ound probes were designed with transducer diameters of 0.9mm and 1.6mm. The transducers were located at the point of a catheter. As measured at 1.5mm depth, the lateral resolutions were 1mm and 1.7mm, respectively. The flowmeter is very sensitive. Compared with standard flowmeters (from 2 to 8MHz), signals from subcutaneous vessels are greater by 10-20dB.