Comprehensive Non-contrast CT Imaging of the Vulnerable Patient

Atherosclerotic cardiovascular disease is the leading cause of death in developed countries. Every year, one million people in the US experience a heart attack or sudden cardiac death. A large percentage of these patients have no prior symptoms of any kind but suffer from silent heart disease, which may cause a heart attack at any time. Currently, there is no reliable screening method to identify the “vulnerable patient” who may have silent heart disease and therefore is at the risk of suffering a cardiovascular event such as a heart attack. Non-contrast cardiac CT is used worldwide to assess coronary artery calcium, a subclinical marker of coronary atherosclerosis. It has been recommended for screening asymptomatic individuals with intermediate-high Framingham risk, due to its high prognostic value, low radiation burden, and simplicity. In this chapter, we review technical aspects of imaging coronary calcium and techniques for “coronary calcium scoring” and review its value in prognostic studies. The non-contrast cardiac CT scan provides three-dimensional images of the heart and contains important additional information regarding the patient's cardiovascular risk, beyond the coronary calcium score. These include pericardial and thoracic fat, aortic calcification, aortic and left ventricular size, spotty calcification pattern, and the number of calcified lesions. These markers are, however, not considered in routine clinical analysis. In this chapter, we summarize the methods to quantify these markers of cardiovascular risk and the growing evidence regarding their clinical and prognostic significance. Automated algorithms to identify and quantify these markers may help in identifying the vulnerable patient with silent heart disease.