AN IN-VITRO ANALYTICAL INVESTIGATION ON THE EFFECTS OF MOMENTUM ON COLOR DOPPLER JET AREA

In regurgitant lesions the appearance of color Doppler flow (CD) image s may be related to the momentum delivered (M). In order to investigat e this relationship, a commercially available CD system (Toshiba 65A, 3.75 Mhz transducer) was used for imaging regurgitant jets in an in vi tro model. The phantom model consisted of a compliant chamber of 90 cc at rest in which jets were created through an orifice by gravity usin g a blood mimicking fluid. Four orifice diameters were tested: .64, .4 8, .32, and .16 cm2. Peak and mean velocities at the orifice ranged fr om 51 to 515 cm/sec. Mean flow rates ranged from 5 to 61 cc/sec. CD im ages were videotaped and digitized off line on an image processing com puter for the calculation of jet area integrated over .5 second of the injection period. Momentum was calculated as orifice area . mean velo city2. Result: A good correlation was found between momentum and jet a rea (R = .85, SEE = 7.8) for all orifices studied. Conclusion: Momentu m of regurgitant jets correlates in our in vitro model with jet areas obtained by color Doppler flow images. Momentum is an important determ inant of color Doppler jet areas.