[Clinical evaluation on the diagnosis of chest disease using CRT units]

To investigate the diagnostic efficacy of two CRT systems in pulmonary diseases, two clinical studies were performed. One of the CRTs has 1,750 x 2,000 resolution (CRT-A), and the other has 1,280 x 1,024 (CRT-B). In the first run, five conventional PA chest X-ray films in which diagnosis was already confirmed, were digitized by a 5 pixels/mm aperture with 8 bits/pixel, processed using four variant methods, and stored on a magnetic disk. These images were displayed on the CRTs and interpreted for normal structures and abnormalities by 24 chest specialists. Among the results of statistical analysis concerning image reading, it was concluded that suitable spatial frequency images using CRT-A can be used for interpretation of normal structures without clavicles and intermediate bronchial images. On the late run, four conventional chest X-ray films were digitized with 10 bits/pixel, processed for spatial frequency, and interpreted for anatomical sites and kinds of pulmonary diseases indicated by nodules, diffusion, opacity, etc., by 22 chest specialists. ROC analysis was performed with the answers of image reading. However, the results of the data analysis were not significantly different from those of conventional X-ray films.