Opportunistic Detection of Coronary Calcium on Dual-Energy Lateral Chest Radiograph

Heart disease remains the leading cause of death among men and women in the world. The majority of cardiac morbidity worldwide is secondary to atherosclerotic coronary disease. In this article, we discuss our experience using dual exposure, dual-energy lateral chest x-ray (CXR) technique to detect coronary calcium. Similar to other reports demonstrating opportunistic detection on imaging studies, here we demonstrate the added value of detection of coronary calcium on the lateral CXR. This technique reinforces the importance of "knowing where to look" and to recognize the appearance of coronary calcium wherein subtle cardiac motion can be a useful artifact in the accurate detection of coronary calcium. In addition, we discuss correlating coronary calcium burden with age, elaborate on the physics behind coronary calcium detection, and how best to optimize imaging technique. Lastly, we show other uses of dual-energy lateral CXR technique to illustrate where using material decomposition and subtle motion can better define contours in the mediastinum and lung.