A Screening System for the Assessment of Opacity Profusion in Chest Radiographs of Miners with Pneumoconiosis

The aim of this study was to develop a screening system of chest radiographs of miners with pneumoconiosis. Chest radiographs were of coal mine or silica dust exposed miners participating in a health screening program. A total of 236 regions of interest (ROIs) (166, 49, and 21 with profusions of category (shape and size) 0, 1(q), and 1(r), respectively) were identified from 74 digitized chest radiographs by two B-readers. Two different texture feature sets were extracted: spatial gray level dependence matrices (SGLDM), and gray level difference statistics (GLDS). The nonparametric Wilcoxon rank sum test was carried out to compare the different profusion categories versus that of profusion 0 (normal). Results showed that significant differences exist (at a=0.05) between 0 vs 1(q), and 0 vs 1(r) for 14, and 12 texture features respectively. For the screening system, the selforganizing map (SOM), the backpropagation (BP), and the radial basis function (RBF) neural networks classifiers, as well as the statistical k-nearest neighbour (KNN) classifier were used to classify two classes: profusion 0 and profusion 1(q and r). The highest percentage of correct classifications for the evaluation set (116 and 20 cases of profusion 0 and 1(q and r) respectively) was 75% for the BP classifier for the SGLDM feature set. These results compare favorably with interand intra-reader variability.