Jg. Myers et al., Color Doppler velocity accuracy proximal to regurgitant orifices: Influence of orifice aspect ratio, ULTRASOUN M, 25(5), 1999, pp. 771-792
Many noninvasive methodologies used for the accurate evaluation of valvular
regurgitation require precise velocity measurements from ultrasound instru
ments. Previous studies have indicated that velocity measurements from colo
r Doppler (CD) instruments are susceptible to errors due to the interaction
of the ultrasound beam and the proximal orifice flow field. This study exa
mined the influence of high aspect ratio (AR) orifices on the CD velocity e
rror. Center line velocity error distributions for orifices ranging from 7.
07 to 78.5 mm(2), varying in shape from circular to an AR = 8 ellipse, were
evaluated using a numerical model of the ultrasound beam and the simulated
regurgitant flow field. An in vitro study was also performed and confirmed
the findings of the numerical model. The study showed that increasing AR d
oes not significantly change the error characteristics. The study confirmed
that orifice size is the dominant factor in the error distribution, and th
at corrections speculated for circular orifices can be extended to elliptic
al orifices without significant errors, (C) 1999 World Federation for Ultra
sound in Medicine & Biology.