Detection of unsuspected central pulmonary embolism with conventional contrast-enhanced CT

When fast, nondynamic scanning techniques are used in combination with adequate intravenous injection of contrast material, good-quality images of the pulmonary artery (PA) can be obtained with routine computed tomography (CT). The purpose of this study was to evaluate PA filling defects detected on these CT scans. Twenty-two CT scans from 22 patients with PA filling defects were reviewed. A routine scanning technique was used. Thrombus was unilateral in 12 cases and bilateral in 10. All patients but one had a predisposition for pulmonary embolism (PE). However, only five patients underwent CT because there was a strong suspicion for PE. In 17 cases, PE was not the first choice of clinical diagnosis; in 13 cases, thrombus of the PA was not even considered. Diagnosis was confirmed in 11 patients with ventilation-perfusion scanning (n = 7), angiography (n = 3), and surgery (n = 1). In 11 patients, anticoagulation therapy was started without further diagnostic procedures. Diagnosis of thrombus of the PA is possible with routine nondynamic, contrast material-enhanced CT. Because PE is often unsuspected at clinical examination, every contrast-enhanced CT scan of the chest should be evaluated for the presence of filling defects in the PA.