[Conventional x-ray techniques and computed tomography in the diagnosis of mediastinal lymph node involvement in non-small cell bronchogenic cancer. Which method is reliable?].

52 patients with bronchogenic carcinoma were studied preoperatively by means of conventional tomography and CT. The results were compared with surgical findings to evaluate the accuracy of these methods in detecting mediastinal lymph node involvement. 323 mediastinal lymph nodes were identified by CT and 237 of these were studied histologically. In 25% of lymph nodes with diameter between 0.5 and 1 cm metastases could be identified. On the other hand, 25% of lymph nodes measuring up to 3 cm did not contain metastases. The results varied in different regions (pre- and paratracheal, azygos region, aorto-pulmonary, subcarinal). The probability of involvement of small nodes was doubled if there were in regions neighbouring metastases. In view of the high incidence of false positive and false negative CT findings, conventional methods were sufficient in the presence of definite pathological findings.