In-vitro evaluation of a new ultrasonic volumetric flow measurement method with no angle correction

A new angle-independent Doppler flow measurement method has recently been developed. In order to assess the performance of this method an in-vitro study was performed using a laminar flow phantom. Given the practical limitations of ultrasound, such as limits in spatial resolution and variance of the velocity estimates, the accuracy of flow measurements was assessed using various sized vessels (6.5, 11 and 19 mm), different transmission frequencies (4 and 6 MHz) and high (≈60°) and medium (≈45°) mean angles of insonation. The results show little difference in the accuracy between the 4 and 6 MHz transducer frequencies for the low mean angle of insonation, but a large overestimation was encountered using the 4 MHz transducer frequency, high angle and the largest tube. There was a gradual deterioration in accuracy for smaller tube sizes