Missed pulmonary embolism on abdominal CT.

OBJECTIVE

The purpose of this study is to evaluate a series of missed pulmonary emboli (PE) identified on abdominal CT and to describe their characteristics and the clinical scenario.

MATERIALS AND METHODS

All reports of chest CT scans performed during a 12-month period were searched for keywords indicative of PE. Among patients with PE, patients who also underwent an enhanced abdominal CT within 3 months were assessed for missed PE. Three radiologists reviewed the abdominal CT to confirm the presence of a missed PE. Missed PEs were classified as unknown or known. Each study was assessed for characteristics of the missed PE and the image quality of the PE study. The electronic medical record was used to document the clinical context in which the PE occurred.

RESULTS

Eighteen patients (12 men and six women; average age, 58.8 years) were identified as having missed PE on abdominal CT. In seven patients (38.9%), the PE had not been previously diagnosed. Most of the missed PEs were segmental, but three missed PEs occurred in lobar vessels. In a slight majority of the cases, the reviewing radiologists judged the contrast bolus as good. The abdominal CT on which PE was overlooked was obtained for a variety of reasons, most commonly because of abdominal pain or to follow up a preexisting condition.

CONCLUSION

This study shows that missed PE can occur on abdominal CT. It is recommended that interpretation include a careful search of the lower pulmonary arterial vasculature on contrast-enhanced abdominal CT scans.