Filling defect in a pulmonary arterial stump on CT after pneumonectomy: radiologic and clinical significance

Abstract

Objective: The objectives of our study were to determine the incidence of filling defects in pulmonary arterial stumps on CT after pneumonectomy and to evaluate their radiologic and clinical significance.

Materials and methods: We retrospectively reviewed 401 contrast-enhanced chest CT scans of 147 consecutive patients (male-female ratio, 123:24; mean age, 60 years) who underwent pneumonectomy (right, 60; left, 87) from 1996 to 2002 in our institution. CT findings were analyzed for the presence or absence of a filling defect in the vascular stump and its size, shape, and interval change on follow-up CT. CT findings were also evaluated for the length of the vascular stump and the presence of embolism in the contralateral pulmonary arteries, pneumonia, bronchopleural fistula, and bronchiolitis obliterans with organizing pneumonia. Intrathoracic or stump recurrence was also assessed in patients with lung cancer. The medical records of lung cancer patients were reviewed for the cause of pneumonectomy and stage and cell type of cancer at surgery. Statistical tests were performed to determine the relationship between the filling defect and other radiologic and clinical findings.

Results: A filling defect in the vascular stump was seen on CT scans of 18 patients after pneumonectomy (12%), and all had undergone the surgery for lung cancer. It was more frequently found in the right-sided stump (23.3%) than in the left-sided stump (4.6%) (p = 0.001). The vascular stump was longer in patients with a filling defect (37.2 +/- 6.8 [1 SD] mm) than those without this finding (25.0 +/- 12.5 mm) (p < 0.001). Other radiologic and clinical findings were not significantly related to the presence of the filling defect in the vascular stump.

Conclusion: A filling defect in the pulmonary arterial stump seen on CT after pneumonectomy is thought to be an in situ thrombus caused by stasis of blood flow and is not related to pulmonary embolism, tumor recurrence, or other complications after pneumonectomy.