PURPOSE: Estimation of left ventricular ejection fraction (LVEF) with equilibrium 99MTc-HSA equilibrium radionuclide angiography (MUGA) is frequently used for assessing cardiac function. The purpose of this study was to compare intra- and interobserver variation between three different gamma cameras.

MATERIALS AND METHODS: Eighty-two patients, scanned in the same sequential order on the three cameras. Each acquisition was analyzed twice by two technologists. Inter- and intraobserver variations were calculated as the coefficient of variation and the 95% confidence interval for limits of agreement between each sequence of analyses for each of the three cameras.

RESULTS: The lowest intraobserver variations in LVEF for the two NaI-detector cameras were 3.1% (-4.0% to 3.5%) for the planar and 3.4% (-4.2% to 4.5%) for SPECT (P ≤ 0.001-0.019), the highest result for the CZT SPECT camera was 2.6% (-2.9% to 3.1%). Similarly, interobserver variation was 4.8% (-4.8% to 6.4%) and 4.9% (-5.4% to 7.5%), respectively, for each of the NaI-detector cameras and 3.3% (-3.4% to 4.3%) for the CZT SPECT camera (P ≤ 0.001-0.008).

DISCUSSION: The CZT detector camera was superior to both NaI detector cameras regarding intra- and interobserver variation. The CZT SPECT camera may identify changes in LVEF with greater certainty than its NaI detector-equipped counterparts.