Computed tomography analysis of the anterior mediastinal fat after left upper lobectomy.

Rationale And Objectives: The authors evaluate changes in the anterior mediastinal fat (AMF) after left upper lobectomy.

Methods: In 36 carcinoma patients undergoing left upper lobectomy, the area and volume of AMF were measured using computed tomography before and after surgery, and their relations to postoperative mediastinal deviation were examined.

Results: The postoperative AMF distribution was changed distinctly, showing marked increase from the aortic arch to the main pulmonary arterial level, with converse decrease at upper and lower slices, but no significant postoperative change was noted in total AMF volume. There was a close correlation between changes in AMF area and mediastinal deviation after lobectomy. In two patients, a pseudotumor composed of AMF was depicted on frontal radiograph postoperatively, pseudotumor was thought to appear when the postoperative mediastinal deviation was marked but unaccompanied by marginal fluid or fibrosis.

Conclusions: The AMF distribution is distinctly changed postoperatively, the displaced AMF redistribution is considered to be the main cause of seemingly increased fat or pseudotumor.