ECG-gated CT angiography of the thoracic aorta: the importance of evaluating the coronary arteries

Abstract

To evaluate the feasibility of coronary artery disease (CAD) evaluation using electrocardiogram-gated computed tomography CT of the thoracic aorta. A total of 477 patients, who underwent CT angiography of the thoracic aorta, were included retrospectively. Dose-length products (DLP) were recorded. Two blinded readers graded image quality of the coronary arteries on a three-point scale. Coronary artery stenosis has only been reported if considered significant, i.e., ≥50%. The type of plaque responsible for the stenosis was considered. The normal distribution of the data was assessed using Shapiro-Wilk and Anderson-Darling tests. Results were expressed as means and standard deviations and percentages. Inter-reader agreements were analysed by calculating the intraclass correlation coefficient, and by using Cohen kappa statistics. The mean DLP was 566±90.4mGy∙cm, corresponding to an effective dose of 9.6±1.5mSv. Five point three percent of asymptomatic patients were positive for CAD with stenosis ≥50%. All patients with coronary stenosis presented with a soft plaque. Two anomalous coronary origins were found. The inter-reader agreement was excellent in defining both the quality of the examination and the degree of coronary stenosis (k=0.85). The opportunity to prove the presence of CAD in asymptomatic patients during a ECG-gated CT of the thoracic aorta can have an extremely important clinical impact, promoting the best therapeutic pathway for the patient. Therefore, coronary arteries should always be analysed carefully and reported in ECG-gated CT angiography of the thoracic aorta.