For the entire group, TEE findings were considered to be positive for aortic invasion in 61 patients, negative in 129 patients, and inconclusive in 11 patients, while CT scan findings were considered to be positive in 14 patients, negative in 12 patients, and inconclusive in 66 patients. In 109 patients, there was no comment at all with respect to aortic invasion by CT scanning. Of more interest are the data from the 97 patients with confirmation of a pathologic condition. Of the 12 patients with definite aortic invasion at surgery, 10 patients were correctly staged by TEE, 1 patient was understaged, and the staging for 1 patient was inconclusive. In contrast, CT scanning allowed correct staging in only 2 patients, 1 patient was understaged, and the staging in 9 patients was inconclusive. Of the 85 patients without aortic invasion at surgery, 79 patients were correctly identified by TEE, 2 were overcalled, and the staging in 4 patients was inconclusive. For the same group, only 4 patients received correct diagnoses by CT scanning, 6 patients were overstaged, and the staging in 75 patients was inconclusive. The authors correctly concluded that TEE is far superior to conventional CT scanning in the evaluation of the involvement of the thoracic aorta in cancer of the left lung.