Pitfalls Using Doppler Ultrasound to Transduce Blood Flow

General testing procedures which will ascertain whether a Doppler ultrasonic blood flowmeter is correctly designed and operating properly are presented. A commercial Doppler ultrasonic blood flowmeter using the procedure is evaluated. Two pitfalls were encountered which prevented its proper operation. High-frequency response was inadequate, which introduced a nonlinearity into the input-output calibration curve. Low-frequency gain was too high, resulting in wall-motion artifacts. These problem areas are described in detail, and a remedy for each is suggested.