Left ventricular ejection fraction measured with Doppler color flow mapping techniques

Abstract

To determine if left ventricular (LV) ejection fraction (EF) can be accurately measured from the color Doppler examination, 11 patients (aged 0.4 to 22 years) underwent 2-dimensional and color Doppler examinations within 24 hours of cardiac catheterization. With use of a biplane Simpson's rule, LV end-diastolic volume, endsystolic volume and EF were measured from cineangiograms, 2-dimensional echocardiograms and color Doppler examinations. The 2-dimensional echocardiographic and color Doppler measurements were obtained from apical 4-chamber and long-axis views. The color Doppler examinations were performed by placing the color sector over the left ventricle only. The velocity scale was set at the lowest possible Nyquist limit (<0.17 m/s), and the highest possible carrier frequency was used to obtain this limit. With these settings, all flow signals in the LV chamber were aliased so that the entire chamber was filled with mosaic color Doppler signals. Motion of the surrounding LV walls gave rise to nonaliased (pure red-blue) signals. With use of an off-line analysis system equipped with a color frame grabber, the border of the mosaic color flow area was traced to obtain volumes and EF. End-diastolic and endsystolic volumes measured with color Doppler correlated well with those measured from 2-dimensional echocardiography (r = 0.99, standard error of the estimate [SEE] = 11.9 ml; r = 0.99, SEE = 4.4 ml, respectively) and cineangiography (r = 0.92, SEE = 16.8 ml; r = 0.90, SEE = 9.9 ml, respectively). Similarly, EF derived from color Doppler correlated extremely well with that measured from 2-dimensional echocardiography (r = 0.99, SEE = 1.6%) and cineangiography (r = 0.96, SEE = 3.4%). Thus, EF can be accurately measured from the color Doppler examination. With the addition of automatic edge-detecting algorithms, this technique has the potential for providing a quick and automatic on-line calculation of EF.