The importance of reporting incidental findings for non-cardiac chest CT

Non-cardiac chest computer tomography (CT) is one of the most commonly ordered diagnostic imaging examinations for an initial evaluation of thoracic disorders. Improvements in CT technology have decreased the number of artifacts caused by motion, enabling better evaluation of cardiac structures. As a result, incidental findings are becoming more visible.

Do radiologists report these incidental findings? If not, should they? A study published in Medicine conducted at the Università degli Studi di Milano in Milan, Italy, showed that nearly 70% of incidental findings visible on a non-cardiac chest CT scan were not reported. The authors explain what cardiac incidental findings should be reported and why non-cardiac radiologists need to pay attention to them.

The retrospective study conducted by radiologist Francesco Secchi, MD, PhD, and colleagues, was conducted to quantitatively and qualitatively evaluate the distribution of incidental findings in all consecutive patients who had a non-cardiac chest CT between February 2012 and August 2014. 237 cases were evaluated. None of the non-cardiac chest CT reports had been prepared by radiologists specializing in cardiac imaging.

For the study, a cardiovascular imaging specialized reviewed the 237 exams to report any incidental findings that could be seen, and a second specialist reviewed a subset of 50 exams so that inter-reader agreement could be estimated. Findings were compared to the original reports. The incidental findings of ascending aorta dilatation and pericardial effusion were considered to be clinically relevant.

A total of 229 incidental findings were identified, 86 of which were coronary calcifications. 158 of the incidental findings, or 69%, had not been mentioned in the original report. All six pericardial effusions were mentioned in the original reports, but eight out of 18, or 44%, of aorta dilatation were not mentioned. Inter-reader agreement was very high. As expected, a significant positive correlation was found between age category and the percentage of patients with at least one incidental finding: 78% for patients over 80 years of age compared to 35% for patients aged 50 to 59 years.

Incidental findings of potential clinical importance to report

The authors recommend that these incidental findings always be reported:

• Ascending aorta dilatation This condition may lead to aortic dissection or rupture, and requires monitoring or therapeutic intervention.
• Pericardial effusions The irregular pericardial thickening and mediastinal lymphadenopathy may suggest the presence of a malignant pericardial effusion.
• Cardiac valvular calcifications Common in patients with end-stage kidney disease, valvular calcifications are associated to induce myocardial ischemia in asymptomatic patients, and may be used to stratify patients at high risk of silent myocardial ischemia.
• Coronary calcification Minimal coronary calcification is the most common cardiac incidental finding and there seldom is the clinical need for immediate follow-up. However, because it can be a symptom that could lead to high risk of development of symptomatic coronary artery disease and major adverse cardiovascular events, referring physicians should be made aware of any degree of coronary calcification.
• Thoracic aorta atherosclerosis Published studies suggest that subclinical atherosclerosis can identify individuals at high cardiovascular risk who might benefit from therapeutic or preventive interventions.

REFERENCE

1. Secchi F, Di Leo G, Zanardo M, et al. Detection of incidental cardiac findings in noncardiac chest computed tomography. Medicine 2017 96; 29: e7531.