Incremental value of an integrated adenosine stress-rest MDCT perfusion protocol for detection of obstructive coronary artery disease.

BACKGROUND: Preliminary studies have shown the potential of myocardial computed tomography perfusion (CTP) analysis for ischemia detection in both animals and humans.

OBJECTIVE: To provide validation data on stress-rest CTP protocols as additive tools to improve the accuracy of multidetector computed tomography (MDCT) for coronary artery disease (CAD) in symptomatic patients.

METHODS: Ninety symptomatic patients with suspected CAD (62 ± 8 years, 66% males) underwent both MDCT and invasive coronary angiography (XA). The MDCT protocol included a prospective calcium score acquisition, a helical acquisition with retrospective gating during infusion of adenosine (140 μg/kg/min) and a prospective scan for computed tomography angiography (CTA) at rest (total effective radiation dose: 5.1 ± 0.8 mSv). Significant and higher-grade CADs were defined by the presence of ≥50% or ≥70% stenosis in at least one coronary artery, as evaluated by quantitative coronary angiography (QCA) using XA images.

RESULTS: On a patient-based model, CTA sensitivity, specificity, and positive (PPV) and negative predictive values (NPV) to detect ≥50% or ≥70% stenosis were 98%, 71%, 80%, and 97% (global accuracy 86%) and 100%, 60%, 64%, and 100% (accuracy 77%), respectively. An integrative approach of CTA and CTP results had the best performance for detection of CAD with sensitivity of 83%, specificity of 98%, PPV of 98%, and NPV of 84% (accuracy 84%) for detection of 50% stenosis and 97%, 90%, 88%, and 98% (accuracy 93%), respectively, for the 70% threshold. The integration of results had the best overall performance in all scenarios but was particularly advantageous in the prediction of higher-grade CAD, with an area under the curve of 0.93, compared with 0.80 for isolated CTA and 0.82 for CTP and in patients with severe calcifications (sensitivity 92%, specificity 87%, overall accuracy of 90%).

CONCLUSIONS: The integration of functional and morphological data using CTA and CTP improved MDCT accuracy for detection of clinically relevant CAD at both thresholds of 50% and 70% in this intermediate to high pretest probability population.