UTILITY OF 3-DIMENSIONAL ULTRASOUND DOPPLER FLOW RECONSTRUCTION OF THE PROXIMAL JET TO QUANTIFY EFFECTIVE ORIFICE AREA - IN-VITRO STEADY AND PULSATILE FLOW STUDIES

We examined the utility of three-dimensional (3D) reconstruction of tw o-dimensional color Doppler images of the proximal jet to quantify the effective area of an orifice in an in vitro model. Steady and pulsati le flows were directed through various orifices; orifice vena contract a areas were quantified with laser flow visualization, thus providing gold standard effective orifice areas. Three-dimensional areas followe d vena contracta areas well, although variations in color Doppler gain and 3D gray levels for thresholding produced significant changes in r econstructed images. These variations were minimized by using minimum color gain and 50% gray level threshold. At these settings, 3D areas s till overestimated vena contracta areas by approximately 25% because o f the poor lateral resolution of the color Doppler system, which cause d bleeding of the now signal past the edges of the proximal jet. Never theless, 3D now images provided a superior format for qualitative and quantitative appreciation of proximal jet shape and dimensions.