Extracardiac findings on coronary CT angiograms: Limited versus complete image review

Cardiac CT often reveals findings outside the heart and great vessels. A few cardiologists have suggested that the field of interpretation be restricted to avoid false-positive diagnoses. Radiologists generally favor a comprehensive review to avoid false-negative findings. The purpose of this study was to examine this tradeoff by comparing broad and focused approaches with viewing coronary CT angiograms.

Outpatient coronary CT angiography was performed on consecutively registered patients. In the broad approach to review, both the large field-of-view and small field-of-view image sets, including lung windows, were evaluated. In the focused approach, attention was centered on the heart, great vessels, and immediately adjacent structures and did not include lung windows. Each finding was classified as necessitating immediate therapy, timely additional workup, longer-term follow-up, or no action.

Among 6,920 patients, 1,642 (23.7%) had one or more extracardiac findings for a total of 1,901 findings in the broad viewing scheme. Of the 6,920 patients, 16.2% had a finding necessitating therapy, workup, or follow-up. In the focused viewing scheme, 90.9% of the findings necessitating therapy, 64.1% necessitating workup, and 51.2% necessitating follow-up were missed. Use of the focused approach resulted in fewer false-positive diagnoses, but five malignant tumors of the breast, 88 lung infiltrates, 43 cases of adenopathy, two cases of polycystic kidney disease, one breast abscess, and one case of splenic flexure diverticulitis were missed.

Almost one fourth of all patients who underwent diagnostic coronary CT angiography in this study had extracardiac findings. Several serious diagnoses were missed with the limited viewing approach, but use of the broad viewing approach led to more workup and follow-up imaging.