[Evaluation of mediastinal lymph nodes by computed tomography in lung cancer].

It is important to evaluate hilar and mediastinal lymph node metastasis accurately, since the findings are used to determine the indications for therapies and to estimate the patient's prognosis. Computed tomography (CT) is a useful method for this purpose, but it is known that healthy people may also have lymphadenopathy up to 10 to 15 mm, and metastasis is sometimes observed in lymph nodes less than 10 mm in cases of adenocarcinoma. For this reason, it is necessary to establish an optimal criteria for measured values of lymph nodes on CT images. In this study, we compared the size of mediastinal lymph nodes on CT images and histological findings in 425 lymph nodes of 153 primary lung cancer patients resected in our hospital from 1984 to 1991. Criteria were expressed as possible criteria which can be obtained from ROC analysis with compatibility of sensitivity and specificity, and definite criteria which offer highest efficiency. We analyzed these two criteria by minor axis, major axis, their sum, and their product. As a result, minor axis offered the best criteria. The value of possible criteria was 8.7 mm (sensitivity: 73%, specificity: 70%) and definite criteria was 13 mm (efficiency: 88%) in 425 lymph nodes. Analyzed by histological type, the criteria of epidermoid carcinoma (possible criteria: 9.5 mm, definite criteria: 13 mm) were larger than those of adenocarcinoma (possible criteria: 8.3 mm, definite criteria: 11 mm). Analysed by anatomical region and histological type, the criteria of epidermoid carcinoma varied by with the location of lymph nodes, but those of adenocarcinoma were almost constant.(ABSTRACT TRUNCATED AT 250 WORDS)