Objective: To describe the computed tomography (CT) findings and clinical implications of pulmonary thromboembolism noted incidentally on CT.
Patients and methods: The authors reviewed the CT studies and medical records for nine patients in whom CT had shown clinically unsuspected pulmonary thromboembolism. The study group consisted of seven men and two women ranging in age from 51 to 75 years, who were referred for CT over a 5-year period for a variety of indications. The location of the emboli and the presence and location of parenchymal and pleural abnormalities were determined. Subsequent changes in patient care were analysed.
Results: The locations of the thromboemboli were described according to pulmonary zone. One case involved zone 1 (main pulmonary artery to a lung), all involved zone 2 (first-order branches), and four involved extension into zone 3 (second-order branches). No emboli were distinguished in zone 4 (beyond the segmental arteries). Four patients had pleural-based opacities characteristic of infarcts, and three had pleural effusions. Eight patients underwent confirmatory testing. A vena cava filter was placed in three patients, one of whom also received anticoagulation therapy. The other six patients were treated by anticoagulation alone. All of the patients survived and were discharged.
Conclusion: Radiologists should watch carefully for occult pulmonary thromboembolism when interpreting CT studies of the thorax. Establishing this diagnosis can result in immediate changes to treatment and possibly a reduction in the substantial morbidity and mortality associated with untreated pulmonary emboli.