Left ventricular ejection fraction assessment by Tl-201 gated SPECT: a comparison with echocardiography

Abstract

Background: Few studies including only a limited number of patients have compared left ventricular ejection fraction (LVEF) assessed by 2-dimensional echocardiography (2-DE) and electrocardiography-gated Tl-201 single-photon emission computed tomography (SPECT).

Hypothesis: LVEF assessment by Tl-201 gated spect is comparable with LVEF assessed by 2-DE in two different echocardiographic laboratories.

Material and methods: Patients (n = 402) underwent Tl-201 gated SPECT in the same laboratory and 2-DE in 2 different laboratories. Patients were divided into 2 groups according to the study laboratory: group 1, at the tertiary hospital and group 2, at a community laboratory.

Results: LVEF evaluations were similar (mean LVEF: 50.73% +/- 11.67% by 2-DE vs 50.11% +/- 11.41% by SPECT in group 1 and 57.27% +/- 7.44% by 2-DE vs 57.41% +/- 8.37% by SPECT in group 2). All LVEF measurements were highly correlated (r = 0.7, P<.001). Baseline characteristics differed between the groups, with a higher prevalence of past myocardial infarction in the in-hospital vs the community echo group (46.7% vs 22.2%, P<.01), resulting in a higher LVEF in the latter, both by 2-DE (mean 50.7% +/- 11.7% vs 57.3% +/- 7.4%, P<.01) and SPECT (50.1% +/- 11.4% vs 57.4% +/- 8.4%, P<.01).

Conclusions: The Tl-201 gated SPECT is a reliable clinical tool for LVEF assessment, with good correlation when compared to 2-DE. It may be routinely used as an alternative for patients with poor acoustic visualization and should be performed systematically in patients undergoing myocardial perfusion imaging with Tl-201.