The objective of this study was to assess the incremental value of myocardial wall motion and thickening compared with perfusion alone obtained from gated single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) in diagnosing myocardial viability in patients with ischemic heart failure.
Eighty-three consecutive patients with ischemic heart failure who underwent both Tc-MIBI gated SPECT MPI and F-FDG positron emission tomography (PET) myocardial metabolic imaging were retrospectively enrolled. SPECT/PET myocardial viability was defined as the reference standard. Segmental myocardial perfusion, wall motion, and thickening were measured by an automated algorithm from gated SPECT MPI. Univariate and stepwise multivariate analysis were conducted to establish an optimal multivariate model for predicting hibernating myocardium and scar.
Among the 1411 segments evaluated, 774 segments had normal perfusion and 637 segments had decreased perfusion. The latter were classified by F-FDG PET into 338 hibernating segments and 299 scarred segments. The multivariate regression analysis showed that the model that combined myocardial perfusion uptake with wall motion and thickening scores had the optimal predictive efficiency to distinguish hibernating myocardium from scar in the segments with decreased perfusion. The model had the largest C-statistic (0.753 vs 0.666, P < 0.0001), and the global chi-square was increased from 53.281 to 111.234 when compared with perfusion alone (P < 0.001).
Assessment of myocardial wall motion and thickening in addition to conventional perfusion uptake in the segments with decreased perfusion enables better differentiation of hibernating myocardium from scar in patients with ischemic heart failure. Considering wide availability and high cost-effectiveness, regional myocardial function integrated with perfusion on gated SPECT MPI has great promise to become a clinical tool in the assessment of myocardial viability.