Mediastinal invasion by bronchogenic carcinoma: CT signs.

Purpose: To determine the accuracy of computed tomographic (CT) signs in assessment of direct mediastinal invasion by primary bronchogenic carcinoma.

Materials And Methods: In 90 patients with primary bronchogenic carcinoma who underwent CT with thoracic surgical staging and thoracotomy, the pathologic and CT findings in 14 mediastinal structures were compared retrospectively. The degree of contact of the primary tumor with each structure and whether the structure was distorted or contained intraluminal tumor were recorded. A total of 785 mediastinal structures (25 with tumor invasion) were analyzed.

Results: When greater than 90 degrees of contact was considered a positive CT finding, the sensitivity of CT was 40% (10 of 25 structures); specificity, 99% (752 of 760 structures); and positive and negative predictive values, 56% and 98%. All structures with > 180 degrees of contact had pathologic involvement, but only 11 of 17 distorted structures (65%) and five of seven structures with intraluminal tumor (71%) were involved.

Conclusion: CT is insensitive in detection of mediastinal invasion by primary bronchogenic carcinoma. The positive predictive value may be higher, depending on the criteria used.