Contrast-enhanced quantitation of left ventricular ejection fraction: what is the best method?

The need to enhance the echocardiographic determination of left ventricular ejection fraction (LVEF) is greatest in patients with suboptimal images. We have previously demonstrated that in difficult-to-image patients, contrast-enhanced power harmonic imaging resulted in accurate calculation of LVEF by using Simpson's method. However, the incremental accuracy of contrast enhancement with other methods of determining LVEF has not been examined. This study prospectively assessed the comparative accuracy of LVEF determination by using the Quinones' method with fundamental imaging (FU), tissue harmonic imaging (TH), contrast-enhanced harmonic imaging [TH(CON)], as well as Quinones' method with contrast-enhanced power harmonic imaging [POW(QUIN)] in 62 patients with suboptimal images. LVEF was also calculated by using contrast-enhanced power harmonic imaging and Simpson's method [POW(SIMP)] in these patients. We demonstrated that LVEF calculated from the POW(QUIN) mode had the best agreement with radionuclide angiography (standard of comparison) compared with FU, TH, and TH(CON). However, POW(SIMP) was even more accurate. In conclusion, when the Quinones' method was used to calculate LVEF in difficult-to-image patients, POW(QUIN) mode was the most accurate. However, POW(SIMP) was even more accurate and should be the method of choice when a high degree of quantitative accuracy is required.

Feasibility and accuracy of left ventricular volumes and ejection fraction determination by fundamental, tissue harmonic, and intravenous contrast imaging in difficult-to-image patients.

The need to enhance the echocardiographic determination of left ventricular ejection fraction is greatest in patients with suboptimal images. Intravenous contrast (CON) and tissue harmonic imaging (THI) are 2 important methods for enhancing endocardial border definition. However, the comparative feasibility and accuracy of THI and contrast-enhanced power harmonic imaging in difficult-to-image patients have not been examined. We assessed the comparative accuracy of THI and CON in determining EF and ventricular volumes in patients with suboptimal fundamental images. We demonstrated that CON is feasible and exhibits a greater correlation with ejection fraction and ventricular volumes determined by radionuclide angiography (standard of comparison) than THI in this difficult-to-image population, with no reported side effects. For both ejection fraction and ventricular volumes, the observer variability was least for CON, intermediate with THI, and greatest for fundamental imaging.