Comparative Accuracy of Semiconductor Single-Photon Emission Computed Tomography (SPECT) Versus Cardiac Magnetic Resonance (CMR) for Myocardial Viability Assessment

Background Evaluating myocardial viability is critical for developing optimal strategies for ischemic cardiomyopathy. While semiconductor single-photon emission computed tomography (D-SPECT) demonstrated higher image quality than conventional Anger cameras for assessing myocardial viability, its accuracy compared to cardiac magnetic resonance (CMR) in the same patient cohort is still unknown. Methods We conducted a retrospective study on patients with known or suspected coronary artery disease who underwent D-SPECT and CMR within 100 days. Rest deficit score on D-SPECT and depth of contrast enhancement on late gadolinium enhancement (LGE) in CMR were classified and compared using a 16-segment analysis. Follow-up echocardiography was performed about a year after the initial examinations, detecting whether the optimal medical therapy (OMT) was followed by invasive therapy (coronary artery bypass grafting [CABG] or percutaneous coronary intervention [PCI]). The five-year survival rates were also compared. Results The study comprised 336 segments from 21 consecutive patients collected between January 2015 and December 2017. Using LGE as a viability criterion, a D-SPECT score of three had the highest diagnostic accuracy (area under the curve: 0.97). Follow-up echocardiography showed significant improvements in left ventricular ejection fraction in patients receiving OMT + PCI/CABG compared to OMT alone (OMT vs. OMT + PCI/CABG; 1.5% ± 3.4% vs. 7.1% ± 5.0%, p = 0.008); five-year survival rate did not significantly differ between the groups. Conclusions Deficits observed at rest on D-SPECT and LGE extent on CMR showed a strong correlation in evaluating myocardial viability, implying that D-SPECT is a viable alternative to CMR for this purpose.