[Pulmonary nodule detection of chest phantom with CRT images--comparison with conventional radiography (film-screen system) and FCR (Fuji Computed Radiography) hardcopy].

Conventional Radiography, Fuji Computed Radiography (FCR) hardcopy and CRT images were evaluated about the detectability of pulmonary nodule using the chest phantom. Conventional and digitized chest radiographs (FCR) were used, including 45 normal cases and 45 abnormal cases with a variety pulmonary nodule. Observer performance tests were conducted to compare the effects on diagnostic accuracy of Conventional Radiography, FCR hardcopy and CRT images, and diagnostic accuracy was determined with receiver operating characteristic (ROC) analysis. ROC study was performed in which six radiologists were asked to locate nodule on three modalities. Two CRT monitors were used to observed CRT images. The left side CRT monitor was divided into two parts and displayed two images which were done as same image processing as FCR hardcopy. The right side CRT monitor was divided into four parts and displayed four images as a subsidiary diagnosis. The upper two images were displayed to diagnose the nodule of cardiac and diaphragmatic area, and lower two images were displayed to diagnose the nodule of the lung field. The results were summarized as follows: 1) CRT images were superior in sensitivity (78.5%) to the others, and FCR hardcopys were superior in specificity (95.9%). 2) About the accuracy of 5 and 8 mm in diameter nodule detection, there was no significant difference among three modalities. 3) Diagnostic accuracy of 3 mm in diameter nodule detection was significantly greater with digitized radiographs (FCR 44.4%, CRT images 54.4%) than with conventional radiograph (17.7%).(ABSTRACT TRUNCATED AT 250 WORDS)