Evaluation On Digital Radiograph And A Chest X-Ray Reading And Recording System For Pneumoconiosis Diagnosis

Part A Evaluation on Digital Radiograph for Pneumoconiosis Diagnosis[Objective] The aim of this study was to evaluate the equivalency and accuracy of hard copies (printed on films) of digital radiograph (DR) images with conventional chest films of film-screen radiography (FSR) for the recognition and classification of pneumoconiosis, and to determine the key quality control techniques for diagnosing pneumoconiosis using hard copies of DR.[Method] The quality control plan for the recognition and classification of pneumoconiosis using hard copies of DR was designed by a literature search and reviews, expert consults, and preliminary experiments. In four institutions for occupational health examinations and diagnoses, the dust-exposed workers participated in the occupational health examinations and subjects with pneumoconiosis in different categories were enrolled and all subjects gave informed consent. The high-kV postero-anterior FSR and DR chest films of each subject were obtained at the same time. The subjects were diagnosed in according with the diagnostic criteria of pneumoconiosis by these four institutions, and the results of which were used as a reference standard. The DR and FSR chest films of372subjects satisfied the requirements of the plan and were enrolled in this study as follows: silicosis,87; coal worker’s pneumoconiosis,145; asbestosis,41; foundry worker’s pneumoconiosis,1; and healthy controls,98. Six certified physicians for occupational disease diagnosis who have abundant experience in the diagnosis of pneumoconiosis were separated into two groups (A and B) as readers, with three physicians in each group. The hard copies of DR and FSR films were read and classified under a X-ray view box side-by-side with the pneumoconiosis diagnosis standard and complying with the principles of randomized and double-blind. The data were inputted using Epidata3.02, and were logically checked and statistically analyzed using SPSS20.0. The analytic method included a descriptive analysis, accuracy evaluation, analysis of screening tests, logistic analysis, ROC analysis, and weighted and kappa identity test analysis.[Result] Using the reference diagnosis results as a gold standard, the sensitivity, specificity, Youden’s index, and likelihood ratio of DR and FSR screening of pneumoconiosis were almost equal. The areas under the ROC curve (Az) were0.816(95%CI,0.781to0.852) and0.866(95%CI,0.834to0.897), respectively, but not significantly different (z=-1.82, P>0.05). The main factors that affected the accuracy of pneumoconiosis diagnoses by hard copies of DR included the diagnosing physician group, the medical examination centers (the parameters of the DRs and the printing effects of chest films), the quality of the chest films, whether or not the optical density under the diaphragm of the hard copy of DR was<0.4, the production voltage, the size of the chest film printed, whether or not asbestosis subjects, whether or not predominated by a p or s small opacity, the total intensity and the gold standard. Using the diagnostic results of FSR as the gold standard, in which chest films were of first-class quality, the sensitivity, specificity, and positive likelihood ratio of diagnosing pneumoconiosis by hard copies of DR were95.0%,84.6%, and6.18, respectively; the Az was0.935(95%CI,0.896to0.973). When the quality of chest films of DR were first or second class, and the quality of the chest films of FSR were first class, the value of the linear weighted kappa (kw) between hard copies of DR with FSR films was0.759(95%CI,0.671to0.847) using a5-point scale (normal, suspected case, pneumoconiosis in category1, pneumoconiosis in category2, and pneumoconiosis in category3), and the diagnostic difference between DR and FSR was not significantly different (X2=2.855, P>0.05).[Conclusion] The diagnosis of pneumoconiosis using hard copies of DR had good consistency with FSR films. We suggest using≥120kV for DR radiographs, an optical density under the diaphragm<0.4, and an image appearance of DR chest films consistent with FSR chest films as much as possible by controlling the parameters of the DR equipment before radiographing if pneumoconiosis images are classified using hard copies of DR and read under the view box with FSR standard chest films. We also suggest developing standard digital images of DR, and providing training for DR radiographing, DR recognition and classification. Part B Evaluation on a Chest X-Ray Reading and Recording System to Aid in the Diagnosis of Pulmonary Tuberculosis in Workers Exposed to Dust[Objective] The aim of this study was to develop a chest X-ray reading and recording system for workers exposed to dust, and to improve the accuracy of diagnosing pulmonary tuberculosis by physicians during occupational examinations.[Method] By combining the classification of pulmonary tuberculosis in the Diagnostic Criteria for Pulmonary Tuberculosis(WS288-2008) with the semi-quantitative diagnostic method of pneumoconiosis in the Diagnostic Criteria for Pneumoconiosis (GBZ70-2009), a chest X-ray reading and recording system for workers exposed to dust was developed. The chest films from51typical cases of pulmonary tuberculosis and27healthy controls were obtained to assess the applicability of this system. Eight certified physicians for occupational disease diagnosis and two certified physicians for pulmonary tuberculosis diagnosis were separated into two groups evenly. The physicians read and diagnosed the films twice with the randomized and double-blind trials. The first time, a conventional diagnosing method was used. The second time, a chest X-ray reading and recording system was used to aid in the diagnosis, and the two reading sessions were carried out with an interval of1month. The recoding system was edited after evaluation. In several institutions for occupational health examinations,2278cases with abnormal chest shadows on films in previous occupational health examinations, and10,524workers exposed to dust who participated in the occupational health examinations regularly were enrolled as research objects successively and all subjects gave informed consent. The chest X-ray reading and recording system was used to aid in the diagnosis and validation of the cases and controls. The data were recorded using Epilate3.02, and checked logically and statistically analyzed using SPSS20.0. The analytic method included a descriptive analysis, an evaluation of accuracy, analysis of screening tests, logistic analysis, ROC analysis, and weighted kappa identity test analysis.[Result] After using the chest X-ray reading and recording system as an aid in the diagnosis of pulmonary tuberculosis for workers exposed to dust, the sensitivity and specificity of the two groups of physicians increased from47.1%and29.6%to90.2%and85.2%, respectively. The kappa value increased from0.452(95%CI,0.295to0.609) to0.567(95%CI,0.459to0.575). The validation results for a retrospective investigation and cross-sectional study showed that the chest X-ray reading and recording system could aid physicians in distinguishing pulmonary tuberculosis, pneumoconiosis, and silicotuberculosis effectively, help the physicians to classify pulmonary tuberculosis, and improve the accuracy of pulmonary tuberculosis diagnosis. The area under the ROC curve (Az) was0.951(95%CI,0.938to0.964) and0.955(95%CI,0.916to0.994).[Conclusion] The chest X-ray reading and recording system for workers exposed to dust could aid physicians for occupational disease diagnosis in the screening of pulmonary tuberculosis, and increase the accuracy and identity of diagnostics. The objectivity and scientific value of the diagnostic results were assured if the results of analysis and diagnosis of pulmonary tuberculosis in the chest films of cases could be standardized and recorded.