Hybrid SPECT/CT for Attenuation Correction of Stress Myocardial Perfusion Imaging

Background: This study aimed to determine whether attenuation correction using the Hybrid SPECT/CT reduced attenuation artifacts. Methods and Results: Ninety-nine patients (55 men and 44 women) underwent coronary angiography and electrocardiography gated stress/rest myocardial perfusion imaging using Tc-99m sestamibi (MIBI) with CT-attenuation correction (CT-AC) for stress scans. Visual semi-quantitative analysis of the CT-AC and noncorrected perfusion images was performed. In this study, there was 39.3% moderate or severe misregistration. The overall specificity, sensitivity, and accuracy for noncorrected versus CT-AC were 62.9% versus 79.0% (P = 0.041), 94.6% versus 91.9% (P = NS), and 74.7% versus 83.8% (P = 0.035), respectively. CT-AC increased specificity in the right coronary artery region, from 77.9% to 98.7% (P = 0.000), accompanied by a decrease in specificity in the left anterior descending region, from 94.1% to 82.4% (P = 0.008). CT-AC significantly reduced defect scores in the inferior wall. This was more obvious in men than in women (P = 0.027). In the anterior wall, although a tendency for defect scores to increase with CT-AC was observed only in men, no significant difference was found between the gender (P = 0.049). Conclusion: Attenuation correction using Hybrid SPECT/CT improved specificity in the right coronary artery, but decreased specificity in the left anterior descending. This technique is likely to be more useful in men than in women.