3D VCA analysis
Three-dimensional color Doppler dataset was acquired to perform off-line
analysis of 3D vena contracta area (VCA). Care was taken to include the
entire proximal convergence region in the data set with the highest
volume rate. The Nyquist limit was controlled within 50–60 cm/s for
optimal visualization of the MR jet. Using the commercial software 3DQ
(Cardiac 3D Quantification; Philips Medical Systems), the two-orthogonal
long-axis planes were aligned parallel with the direction of the
proximal MR jet. The transverse plane was then scanned proximally to
distally in order to identify the narrowest portion of the jet
immediately distal to the regurgitant orifice. The resultant short-axis
image of the VC was traced to obtain the 3D
VCA.[14]