[Diagnosis and treatment of primary lung carcinoma--CT diagnosis of N-factor].

We applied CT to the diagnosis of the intrathoracic lymph nodes metastases from the lung carcinoma. We defined nodes with a diameter larger than 1 cm as indicating presence of metastasis. In the diagnosis of the mediastinal lymph nodes metastases, the overall accuracy was 61%. There were many over-estimations in epidermoid carcinomas and some under--estimations in adenocarcinomas because of the presence of inflammatory hyperplastic nodes in the former and several small metastatic nodes in the latter. In the diagnosis of the hilar lymph nodes metastases, the CT detectability of the positive nodes was low. There were many under-estimations because of the presence of small metastatic nodes in adenocarcinomas and difficulty of separating the nodes from the primary tumors in epidermoid carcinomas. In the diagnosis of the intrathoracic lymph nodes metastases, CT is useful to decrease under-estimations, but is apt to increase some over-estimations. We should make a further evaluation for the relationship between the lymph nodes size, location and histology of primary tumors.