Using Routine Chest Computed Tomography to Diagnose Pulmonary Embolism.

Objective: This study investigated the use of routine contrast-enhanced chest computed tomography (CT) to diagnose unsuspected pulmonary embolism (PE).

Methods: All adult routine contrast-enhanced chest CTs performed at Montefiore in 2018 were included. Pulmonary artery enhancement was measured by placing regions of interest in the pulmonary vasculature. Adequate enhancement was defined as 200 Hounsfield units (HU) or greater. Presence or absence of PE was noted. Descriptive statistics and logistic regression analysis were performed.

Results: A total of 3164 CTs were evaluated (55.8% women; mean age, 63.2 years). Main pulmonary enhancement was highly correlated with peripheral enhancement. Of all cases, 28.7% (907 of 3164) reached the 200 HU threshold. Greater enhancement was associated with female sex, older age, outpatients, and contrast amount administered. Pulmonary embolism-positive cases comprised 1.8% (58 of 3164) of total cases. Furthermore, 39.7% (23 of 58) of PE-positive cases reached the 200 HU threshold.

Conclusions: Over one quarter of routine contrast-enhanced chest CT scans met the 200 HU threshold indicative of adequate pulmonary artery enhancement, including nearly half of the 2% of examinations positive for PE.