The Significance of Incidental Findings on Computed Tomography of the Chest

Computed tomography (CT) of the chest has replaced lung scans and pulmonary angiography as the criterion standard for the diagnosis of pulmonary embolism (PE). Most of these examinations are negative for PE, but they frequently have incidental findings that may require further evaluation.

In order to examine common incidental findings and their possible clinical ramifications and required workup, we reviewed data from relevant studies in which chest CTs were performed and incidental findings discovered.

The most common incidental findings on chest CT are pulmonary nodules and lymph nodes. Nodules are significantly more commonly found in smokers and are also more likely to be malignant in smokers. The recently updated 2017 Fleischner Society recommendations provide guidance to clinicians in deciding which nodules should be further evaluated. Enlarged lymph nodes similarly represent potential malignancy and most will need further evaluation with positron emission tomography scans or by transbronchial needle aspiration.

Enlarged lymph nodes and pulmonary nodules are both common incidental findings on chest CT. Each represents the potential for malignancy, and under certain conditions requires additional workup and further evaluation. The majority will be benign, even in high-risk populations. However, because of the increasing prevalence of the chest CT and the frequency with which incidental findings will be seen, it is important that the emergency physician be aware of common features and recommended subsequent evaluation.