Abstract 3264: Combined Computed Tomography Coronary Angiography and Perfusion Imaging Accurately Detects the Physiological Significance of Coronary Stenoses in Patients with Chest Pain
Background: Multidetector computed tomography angiography (MDCTA) can non-invasively detect coronary atherosclerosis. However, in its current form, it cannot assess the physiologic significance of coronary stenoses. Our lab has recently shown in an animal model of coronary stenosis that adenosine stress MDCT myocardial imaging can measure differences in myocardial perfusion induced by coronary stenosis. The aim of this study is to test the hypothesis that the functional significance of coronary stenoses caused by atherosclerosis can be assessed during adenosine stress MDCTA in patients with chest pain.
Methods and Results: Seven patients referred for invasive coronary angiography (ICA) with chest pain and abnormal radionuclide myocardial perfusion imaging (MPI) were enrolled. One to seven days prior to ICA, patients underwent 64-slice MDCT during adenosine infusion (0.14 mg/kg/min) for five minutes according to the following protocol: iopamidol (90–100 ml, 370 mgI/ml) injected at 5 ml/sec, 0.5 mm X 64 collimation, 120 kV, 400 mA, beam pitch and rotation time (heart rate dependent). MDCT myocardial perfusion images were reconstructed with a 3 mm slice thickness in the cardiac short axis at a cardiac phase of 80%. Normally perfused myocardium was defined by myocardium supplied by an artery with no significant stenoses by MDCTA and no identified perfusion deficit. Using custom perfusion analysis software, perfusion deficits were defined as myocardium meeting a density threshold of one standard deviation below the normal myocardial signal intensity. Radionuclide MPI was assessed for perfusion deficits according to standard protocol. On a per-vessel basis, MDCTA (visual assessment) and ICA (standard quantitative coronary angiography) were assessed for stenoses <or ≥50%. The density of normal myocardium was 124.6±25.7 Hounsfield units (HU) while the density of perfusion deficits was 64.0±26.9 HU, p<0.001. The sensitivity and specificity for perfusion deficits identifying stenoses < or ≥ 50% was 83% and 100% for MDCT and 67% and 80% for radionuclide MPI, respectively.
Conclusion: First-pass, adenosine stress helical MDCT can accurately assess coronary atherosclerosis and its physiological significance in patients with chest pain.