Three dimensional (3D) ultrasound flow imaging promises to provide true 3D depiction of regurgitant jets which can then be used to calculate regurgitant volume (RV). Methods: Steady (30 cc/sec - 100 cc/sec) and pulsatile(15 - 40 cc/beat) flows through orifices (0.2 - 1.8 cm2) were imaged using a Toshiba ultrasound scanner interfaced to a Tomtec 3D reconstruction system. 3D flow images were analyzed off-line by first calibrating the color Doppler velocity map to the 3D grey levels. Flow rate was computed by integration of all velocities over the cross-sectional slices of the distal 3D jet which allowed for true mean flows to be obtained with no velocity profile assumptions. Results: 3D calculated flow rates for steady flow correlated well with actual flows with overestimation (y = 3.64x - 0.42; r = 0.985; SEE = 0.51 L/min). 3D flow images of pulsatile flow could be also be used to automatically calculate instantaneous flow rates(Figure) Conclusions: 3D flow imaging of regurgitant jets promises to increase the accuracy of jet volume calculations. Automation of such flow calculations provides an effective and easy method to take advantage of the large amount of information provided by 3D flow imaging.

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Figure 1