Manual endocardial tracing using Simpson's method (MANUAL SIMP) provides an accurate assessment of left-ventricular ejection fraction (LVEF). We have previously demonstrated in patients who are difficult to image: (1) the incremental accuracy of contrast-enhanced power harmonic imaging and MANUAL SIMP in the calculation of LVEF; and (2) the use of intravenous contrast-combined MANUAL SIMP was the most accurate method of LVEF determination. However, MANUAL SIMP is time-consuming, requires accurate planimetry of the endocardial borders, and is difficult to apply routinely in the clinical situation. The current study prospectively studied the accuracy of intravenous contrast and a semiautomated endocardial border detection algorithm in the determination of LVEF in 51 patients with suboptimal images. LVEF was also calculated using contrast-enhanced power harmonic imaging and MANUAL SIMP. We demonstrated that there was good agreement between LVEF determined using both MANUAL SIMP and semiautomated endocardial border detection, and radionuclide angiography (standard of comparison).