Mediastinal lymph node metastases from nonsmall cell bronchogenic carcinoma: reevaluation with CT.

We evaluated the sensitivity of CT for detecting mediastinal lymph node metastases in patients with nonsmall cell bronchogenic carcinoma. Computed tomography of 208 cases of surgically proven bronchogenic carcinoma from three institutes was evaluated retrospectively using specific diagnostic criteria. These consisted of two size thresholds for specific mediastinal node regions: 13 mm short transverse diameter for nodes in the subcarinal, precarinal, and tracheobronchial regions and 10 mm for other regions. Based on these criteria, the overall sensitivity of CT was 69%, specificity 94%, and accuracy 86% for detection of metastasis. In cases of adenocarcinoma, sensitivity was 61%, specificity 93%, and accuracy 81%, and in those of squamous cell carcinoma the respective values were 86, 94, and 92%. Comparison between the results using the present criteria with the former criterion of 10 mm short transverse diameter for all mediastinal nodes revealed that the number of false-positive cases decreased markedly. We conclude that more accurate CT evaluation of mediastinal lymph node metastasis in nonsmall cell bronchogenic carcinoma can be achieved with specific size criteria for specific mediastinal regions.