Journal of Nuclear Cardiology | 2019
Incidental findings on cardiac computed tomography: No new emergencies to declare!
Abstract
Coronary computed tomography angiography (CCTA) is now an established modality to assess low to intermediate risk patients with acute and stable chest pain. Its utilization has increased over time and has even become the first-line test in some regions of the world. It is also recommended in many guidelines. Compared to other modalities, CCTA has the potential to identify non-cardiac causes of chest pain such as pulmonary embolism and aortic disorders. CCTA can also identify subclinical atherosclerosis as well, possibly resulting in more frequent implementation of statin therapy and improved outcomes. With the increased adoption of CCTA, newly discovered incidental findings have become the topic of frequent discussions. These incidental findings have also been the focus of numerous investigations, with lung nodules being the most commonly identified. The concern about the impact of these nodules on management, cost and resource utilization have led to fierce debates related to image acquisition and reconstruction protocols as well as the specialty of the interpreting physicians. Whether CCTA reconstructions should include a wide field of view is still debatable. In addition, the impact of downstream–potentially hazardous– testing on outcomes and cancer detection is not clear. Previous reports did show that follow-up of incidentally detected pulmonary nodules may reduce lung cancer mortality. This benefit, however, was associated with greater down-stream cost and resource utilization. Incidental findings on CCTA are common, particularly in the population being referred for CCTA. There are multiple shared risk factors between coronary artery disease (CAD) and cancer, which increases the incidence of these findings in the populations being tested. These incidental finings can even be more challenging when discovered on CCTA performed for transcatheter aortic valve replacement (TAVR) planning, due to potential delays in treating a critical condition in a minority of patients. In a meta-analysis of thirteen studies with a total of 11,703 patients undergoing CCTA, the average prevalence of extracardiac findings was 41% of which 16% were considered to be clinically significant. Malignant extra-cardiac findings accounted for only 0.3% of these findings. In the Scottish COmputed Tomography of the HEART Trial (SCOT-HEART) trial which was performed in stable chest pain patients, CCTA was performed in 1778 patients and noncardiac findings were identified in 38% of these patients. Clinically significant findings were reported in 10% of patients and were the cause of symptoms in 3%. New malignancy was diagnosed in seven patients (0.4%). Similarly, incidental findings can be seen in lowdose CT performed for attenuation correction (CTAC) during nuclear imaging, Qureshi and colleagues showed that incidental findings were common on CTAC (135 clinically significant findings in 1139 patients, 12%) and associated with cancer-specific mortality after adjustment. Similarly, in a study of 1506 patients who underwent CT attenuation-corrected SPECT, 830 (55.1%) and 212 (14.1%) patients had minor and major extra-cardiac findings, respectively. Among patients with major extra-cardiac findings, the abnormality was previously unknown in 113 (53.3%) patients. These findings are summarized in Table 1. In the current issue of the Journal, Goldman et al provides an interesting analysis on incidental findings Reprint requests: Mouaz H. Al-Mallah, MD, MSc, FASNC, Houston Methodist DeBakey Heart and Vascular Center, 6550 Fannin Street, Smith Tower Suite 1801, Houston, TX, 77030; [email protected] J Nucl Cardiol 2020;27:2316–9. 1071-3581/$34.00 Copyright 2019 American Society of Nuclear Cardiology.