Comparison of echocardiography with technetium 99m-gated single photon emission computed tomography as diagnostic tools for left ventricular ejection fraction

Left ventricular ejection fractions (LVEF) are routinely measured and result in critical decision-making algorithms in cardiology. This study was conducted to compare the accepted standard two-dimensional (2-D) echocardiogram ejection fraction (EF_ECHO) with single photon emission computed tomography rest ejection fraction (EF_SPECT). Data were acquired and analyzed from 51 inpatients. EF_ECHO was obtained using modified Simpson's rule in the four-chamber apical view, and gated EF_SPECT was computed by an automated method (Siemens ICON software). Comparison between EF_ECHO and EF_SPECT was done by linear regression, Bland-Altman, and receiver operator characteristic (ROC) analyses. Linear regression analysis revealed EF_SPECT = 1.12 × EF_ECHO - 3.6%, r = 0.93, n = 51, P < 0.0001. Bland-Altman analysis showed that the limits of 95% confidence for the difference between EF_SPECT and EF_ECHO were - 12% to 18%. Ninety-eight percent of the datapoints were within the limits of confidence. The ROC analysis showed that the sensitivity and specificity for detecting abnormal EF (≤ 50%) were 85% and 86% with EF_SPECT, and 91% and 90% with EF_ECHO. This study showed good correlation as well as agreement between SPECT and two-dimensional echocardiograms in measuring EF.