Computed tomography of mediastinal lymph nodes in nonsmall cell lung cancer. A new approach based on the lymphatic pathway of tumor spread.

Computed tomography was used to evaluate mediastinal lymph nodes in 97 patients with nonsmall cell lung cancer. All patients had thorough surgical-pathological determination of mediastinal node status. Twenty-three patients were found to have metastatic lymph nodes. The usual lymphatic pathways of tumor spread into the mediastinum were defined using the node mapping scheme suggested by the American Thoracic Society. We considered mediastinal nodes abnormal when the short axis of the largest mediastinal node in the lymphatic drainage territory of the cancer was greater than or equal to 10 mm and the difference between this node and the largest node in the other territories is greater than 5 mm. The sensitivity was 78%, the specificity 99%, the positive predictive value 95%, the negative predictive value 94%, and the accuracy 94%. Comparing our method to those that used the size criterion alone, the number of false positives was reduced.