Abstract 4718: Combined Adenosine Stress Perfusion and Coronary Angiography Using 320-Row Detector Dynamic Volume Computed Tomography in Patients with Suspected Coronary Artery Disease
Dynamic volume 320-row detector computed tomography (CT), with full cardiac coverage, allows for the combination of non-invasive angiography (CTA) performed at rest with myocardial perfusion imaging (MPI) during adenosine stress. The purpose of this study was to test the accuracy of combined CTA and MPI using dynamic volume 320-row detector CT to identify atherosclerosis causing territorial ischemia. Eighteen patients with chest pain and intermediate to high pre-test likelihood of coronary artery disease (CAD) underwent rest CTA and stress CT-MPI following radionuclide MPI using the following prospective ECG-gated protocol: Rest CTA: 320 × 0.5mm, 120 kV, 400 mA, 70 – 80% R-R interval followed by Stress CT-MPI: adenosine (140μg/kg/min), 320 × 0.5mm, 120 kV, 400 mA, 70 – 80% R-R interval. CT-MPI images were reconstructed in the short axis with a 3 mm slice thickness. The transmural perfusion ratio (TPR) was calculated by dividing the endocardial attenuation density (AD) by the epicardial AD in each sector. Ischemia was defined as a TPR <0.99 on adenosine stress CT-MPI that normalized on the rest CTA images. CTA was analyzed for stenoses ≥50% and radionuclide MPI was analyzed for fixed and reversible perfusion abnormalities. Using a 17-segment model in a territory/vessel based analysis, the combination of CTA + CT-MPI was compared with CTA 3 radionuclide MPI (gold standard) for its ability to detect atherosclerosis causing territorial ischemia. Mean TPRs in ischemic and normal territories were 0.90±0.09 and 1.13±0.10, respectively (p<0.001). The sensitivity, specificity, positive (PPV) and negative predictive value (NPV) for CTA + CT-MPI were 86%, 85%, 67, and 94% compared with the gold standard; respectively. However, when adjusting for balanced multivessel disease the sensitivity, specificity, PPV, and NPV were 89%, 94%, 89%, and 94%; respectively. Mean effective radiation dose for the combined rest (4.9±0 mSv) and stress (8.5±0.5mSv) protocols was 13.4±0.5 mSv. The combination of CTA and CT -MPI, using 320-row detector dynamic volume CT, is capable of accurately identifying myocardial ischemia in the presence of obstructive atherosclerosis and compares well with CTA/radionuclide MPI.