Volume flow assessment through simultaneous B-mode and Multigate Doppler

The typical approach for volumetric blood flow assessment consists of a velocity measurement performed in a single sample volume placed in the vessel centre, combined to an estimate of the average diameter. This simple approach produces large inaccuracies since it does not account for the complex flow configurations produced by complicated artery geometries and/or pulsatile conditions. Moreover, diameter changes, which in important regions like the common carotid artery can be larger than 10%, are totally neglected. In this work we propose an alternative volume flow method which overcomes some of the aforementioned limitations through the simultaneous measurement of the wall positions and of the velocity distribution in the artery. The wall positions are tracked by a detector based on the First Order Absolute Moment working on B-mode data, while the velocity profile is obtained by a Multigate Spectral Doppler analysis applied to PW-mode data. The method was implemented on the ULA-OP research system and validated on a flow phantom with more than 1700 experiments performed in rigid and flexible pipes. We found a systematic underestimation of 3.7% with 5.0% standard deviation. The mean coefficient of variation (CV) was 1.7%.