Abstract 16897: Morphologic and Functional Assessment of Coronary Artery Disease: Potential Application of CT Angiography and Myocardial Perfusion Imaging

Abstract

Purpose: Now that the technological advances have substantially and favorably allowed reduction in radiation burden both from CT angiography (CTA) and myocardial perfusion imaging (MPI) by single-photon emission computed tomography (SPECT), and because CT-SPECT combination is becoming a mainstream investigative tool, we evaluated the role of combined evaluation of MPI and CTA in coronary artery disease (CAD). For CTA, we evaluated both, the extent of luminal stenosis as also the features of high-risk plaques (HRP, including positive remodeling and low attenuation. Methods: 280 patients (65±11 years, mean f/u: 26 months) underwent both CTA and MPI. Patients without significant stenosis on CTA, or suspected of stenosis by CTA but normal MPI findings were classified as normal, and patients with significant CTA stenosis and reversible defect on MPI were classified as abnormal. On CTA, HRP was also reported regardless of luminal stenosis. Patients were classified into group 1: abnormal CTA and MPI (n=81), group 2: normal CTA and MPI but with HRP (n=25), and group 3: normal by CTA and MPI and also no HRP (n=174). Cardiac events were defined as percutaneous coronary intervention (PCI) or bypass surgery (CABG) after CTA and MPI, and unexpected coronary event. Results: Cardiac event was observed in 56 patients; 43 PCI or CABG, and 13 unexpected events. CTA+MPI showed higher diagnostic accuracy than CTA or MPI (sensitivity, specificity, positive (PPV) and negative predictive value (NPV) were 89, 44, 28, 94%, 83, 69, 37, 91%, and 70, 81, 48, 92%, respectively). The prognosis of group1, 2, and 3 were significantly different (logrank: p<0.0001) (figure). Unexpected events were also more frequent in group1 and 2 than group3 (9%vs16%vs1%, p=0.0006). Conclusion: The combination of CTA and MPI was more accurate than MPI alone for risk stratification in patients suspected CAD. Furthermore, plaque detection by CTA would be the additional valuable information to predict the cardiac event.