Incidental pulmonary emboli detected at helical CT: effect on patient care

To evaluate incidental pulmonary emboli detected at helical computed tomography (CT) and the effect on patient care.

A computer search of reports from 1,879 consecutive contrast material-enhanced helical CT scans identified 28 cases in which pulmonary emboli were suggested. These 28 scans were rereviewed by three radiologists to confirm intraluminal defects. Six cases were excluded (three because of tumor invasion, two arterial stump thrombi after pneumonectomy, one artifact). In four cases, pulmonary emboli were clinically suspected or diagnosed prior to CT. Pulmonary embolus was not suspected at CT in the remaining 18 patients who constituted the study group. The medical records were reviewed for predisposing factors, suspicion of pulmonary embolism, adjuvant studies, and resultant therapy.

All 18 patients in the study group had predisposition for thromboembolic disease. Seven of these patients underwent confirmatory or correlative studies (angiography, radionuclide studies, or autopsy), and four patients had supportive studies documenting deep venous thrombosis. Eleven patients received anticoagulants or caval filter placement as a result of CT findings.

Incidental pulmonary emboli were detected in approximately 1% of patients who underwent contrast-enhanced CT of the chest. All of these patients were at high risk for emboli. Therapeutic intervention was undertaken in 61% of these patients. While ultimate patient outcome is uncertain, the incidental CT diagnosis of pulmonary emboli appears accurate and affects patient care.