Estimation of left ventricular ejection fraction by semiautomated edge detection

Left ventricular (LV) volume and ejection fraction estimation from two-dime nsional echocardiograms requires off-line analysis and time-consuming manua l tracing. LV volumes may be estimated on-line with a semiautomated edge de tection echocardiographic system [also known as acoustic quantification (AQ )], but there are few data that compare volumes obtained from the AQ method with volumes derived front off-line manual tracing of conventional two-dim ensional echocardiograms. Echocardiograms were performed in 48 patients at two medical centers. LV volumes were measured from the apical view with the method of discs and area-length formulae and from the parasternal short-ax is view with the modified ellipsoid model. Based on the criterion of greate r than or equal to 75% endocardial visualization, 25 (52%) of the short-axi s views and 14 (29%) of the apical views were analyzed by a single investig ator. End-diastolic and end-systolic LV volumes derived on line with the AQ system showed a very strong linear association with off-line, manually tra ced volumes (r = 0.96-0.99). Correlations for ejection Faction also were st rong (r = 0.90-0.96). End-diastolic and end-systolic LV volumes, measured f rom the apical views, were underestimated by the AQ method. However, becaus e the error was in the same direction, ejection fractions measured with the AQ system and by manual tracing of conventional echocardiograms were simil ar. Estimation of ejection fraction using a semiautomated edge detection ec hocardiographic system is a promising method for noninvasive evaluation of systolic function in carefully selected patients.