[The efficacy of X-ray signs for differential diagnosis of small lung cancer and tuberculoma. Committee for Lung Cancer Mass Screening, JATA].

In order to evaluate the efficacy of X-ray signs for the differential diagnosis of small lung cancer from tuberculoma, a cooperative study was carried out. X-ray films of 64 cases (lung cancer 35, tuberculoma 29) were read by 11 experienced chest physicians independently. The positivity of various X-ray signs were assessed respectively and obtained data were analysed with ROC analysis method. "Ill defined contour", "unevenness of density", "paleness" were proved to be relatively useful as a diagnostic tool, but "notch", "pleural indentation" were not useful in differentiating lung cancer from tuberculoma. It was also noted that great interindividual variations existed on the judgements of X-ray signs among chest specialists, and the conquest of which may be a crucial key for the universal validity of these signs.