Resting diffusing capacity and severity of radiographic disease predict gas exchange abnormalities with exercise in former US coal miners.

BACKGROUND: The US Department of Labor (DOL) does not fund diffusing capacity (DLCO) or metabolic measurements from cardiopulmonary exercise testing (CPET) for coal miners' disability evaluations. Although exercise arterial blood gas testing is covered, many miners are unable to perform maximal tests, and sampling at peak exercise can be challenging. We explored the relationship between resting DLCO, radiographic disease severity, and CPET abnormalities in former US coal miners. METHODS: We analyzed data from miners evaluated between 2005 and 2015. Multivariable linear and logistic regression analyses were used to examine relationships between percent predicted (pp) forced expiratory volume in 1 s (FEV1pp), DLCOpp, VO2maxpp, A-a oxygen gradient (A-a)pp, dead space fraction (Vd/Vt), disabling oxygen tension (PO2), and radiographic findings of pneumoconiosis. RESULTS: Data from 2015 male coal miners was analyzed. Mean tenure was 28 years (SD 8.6). Thirty-twopercent had an abnormal A-a gradient (>150 pp), 20% had elevated Vd/Vt (>0.33), and 34% a VO2max < 60 pp. DLCOpp strongly predicted a disabling PO2, with an odds ratio (OR) of 2.33 [2.09-2.60], compared to 1.18 [1.08-1.29] for FEV1. Each increase in subcategory of small opacity (simple) pneumoconiosis increased the odds of a disabling PO2 by 42% [1.29-1.57], controlling for age, body mass index, pack-years of tobacco smoke exposure, and years of coal mine employment. CONCLUSIONS: DLCO is the best resting pulmonary function test predictor of CPET abnormalities. Radiographic severity of pneumoconiosis was also associated with CPET abnormalities. These findings support funding DLCO testing for impairment and suggest the term "small opacity" should replace "simple" pneumoconiosis to reflect significant associations with impairment.

[Application of a light-weighted convolutional neural network for automatic recognition of coal workers' pneumoconiosis in the early stage].

Objective: To construct and verify a light-weighted convolutional neural network (CNN), and explore its application value for screening the early stage (subcategory 0/1 and stage Ⅰ of pneumoconiosis) of coal workers' pneumoconiosis (CWP) from digital chest radiography (DR) . Methods: A total of 1225 DR images of coal workers who were examined at an Occupational Disease Prevention and Control Institute in Anhui Province from October 2018 to March 2021 were retrospectively collected. All DR images were collectively diagnosed by 3 radiologists with diagnostic qualifications and gave diagnostic results. There were 692 DR images with small opacity profusion 0/- or 0/0 and 533 DR images with small opacity profusion 0/1 to stage Ⅲ of pneumoconiosis. The original chest radiographs were preprocessed differently to generate four datasets, namely 16-bit grayscale original image set (Origin16), 8-bit grayscale original image set (Origin 8), 16-bit grayscale histogram equalized image set (HE16) and 8-bit grayscale histogram equalized image set (HE8). The light-weighted CNN, ShuffleNet, was applied to train the generated prediction model on the four datasets separately. The performance of the four models for pneumoconiosis prediction was evaluated on a test set containing 130 DR images using measures such as the receiver operating characteristic (ROC) curve, accuracy, sensitivity, specificity, and Youden index. The Kappa consistency test was used to compare the agreement between the model predictions and the physician diagnosed pneumoconiosis results. Results: Origin16 model achieved the highest ROC area under the curve (AUC=0.958), accuracy (92.3%), specificity (92.9%), and Youden index (0.8452) for predicting pneumoconiosis, with a sensitivity of 91.7%. And the highest consistency between identification and physician diagnosis was observed for Origin16 model (Kappa value was 0.845, 95%CI: 0.753-0.937, P<0.001). HE16 model had the highest sensitivity (98.3%) . Conclusion: The light-weighted CNN ShuffleNet model can efficiently identify the early stages of CWP, and its application in the early screening of CWP can effectively improve physicians' work efficiency.

Prevalence and severity of abnormal lung function among US former coal miners with and without radiographic coal workers' pneumoconiosis.

OBJECTIVES: Examination of lung function abnormalities among coal miners has historically focused on actively working miners. This likely underestimates the true burden of chronic respiratory disease. The objective of this study was to characterise patterns and severity of lung function impairment among a population of former coal miners. METHODS: Cross-sectional data from 2568 former coal miners evaluated at eight US Black Lung clinics in a 12-month period were retrospectively analysed for patterns of prebronchodilator spirometric abnormality and severity of lung function impairment. Spirometry data from a subset of former miners with chest radiographs were analysed based on the presence and severity of coal workers' pneumoconiosis (CWP). RESULTS: Abnormal spirometry was identified in 56.6% of subjects. The age-standardised prevalence of airflow obstruction among miners aged ≥45 years was 18.9% overall and 12.2% among never smokers. Among 1624 subjects who underwent chest radiography, the prevalence and severity of abnormal spirometry increased with worsening radiographic category for pneumoconiosis. Of never-smoking former miners without radiographic CWP, 39.0% had abnormal spirometry; 25.1% had abnormally low forced expiratory volume in 1 s (FEV1), and 17.1% had moderate to severe FEV1 impairment. CONCLUSIONS: Abnormal spirometry is common among former coal miners. While ever-smoking former miners had higher rates of airflow obstruction, never-smoking former miners also demonstrated clinically significant airflow obstruction, including those without radiographic pneumoconiosis. These findings demonstrate the importance of recognising physiological as well as imaging manifestations of coal mine dust lung diseases in former miners.

Use data augmentation for a deep learning classification model with chest X-ray clinical imaging featuring coal workers' pneumoconiosis.

PURPOSE: This paper aims to develop a successful deep learning model with data augmentation technique to discover the clinical uniqueness of chest X-ray imaging features of coal workers' pneumoconiosis (CWP). PATIENTS AND METHODS: We enrolled 149 CWP patients and 68 dust-exposure workers for a prospective cohort observational study between August 2021 and December 2021 at First Hospital of Shanxi Medical University. Two hundred seventeen chest X-ray images were collected for this study, obtaining reliable diagnostic results through the radiologists' team, and confirming clinical imaging features. We segmented regions of interest with diagnosis reports, then classified them into three categories. To identify these clinical features, we developed a deep learning model (ShuffleNet V2-ECA Net) with data augmentation through performances of different deep learning models by assessment with Receiver Operation Characteristics (ROC) curve and area under the curve (AUC), accuracy (ACC), and Loss curves. RESULTS: We selected the ShuffleNet V2-ECA Net as the optimal model. The average AUC of this model was 0.98, and all classifications of clinical imaging features had an AUC above 0.95. CONCLUSION: We performed a study on a small dataset to classify the chest X-ray clinical imaging features of pneumoconiosis using a deep learning technique. A deep learning model of ShuffleNet V2 and ECA-Net was successfully constructed using data augmentation, which achieved an average accuracy of 98%. This method uncovered the uniqueness of the chest X-ray imaging features of CWP, thus supplying additional reference material for clinical application.

Early radiographic pneumoconiosis is associated with impaired exercise gas exchange among coal miners with normal resting spirometry.

RATIONALE: We sought to determine if radiographic pneumoconiosis predicts abnormal gas exchange during exercise in coal mine workers with preserved resting lung function. METHODS: We analyzed data from former coal miners seen between 2006 and 2014 in a single clinic specializing in black lung evaluations. We limited the analysis to those with normal resting spirometry and an A-a gradient at peak exercise ≥10 mmHg. We used multivariable logistic regression to estimate predictors of A-a gradient widened to >150% of the reference value. We focused on chest radiographs consistent with pneumoconiosis, taking into account higher silica exposure mining activities and years underground, and adjusting for cigarette smoking, obesity, and coronary artery disease. RESULTS: Of 5507 miners, we analyzed data for 742 subjects with normal spirometry and all key clinical variables available, of whom 372 (50.1%) had radiographic evidence of pneumoconiosis. All but 21 had small opacity profusion of less than 2/1. The median A-a gradient at peak exercise was 108% of reference value (interquartile range, 81%-141%). In the multivariable analysis, radiographic pneumoconiosis was associated with increased odds of widened A-a gradient (odds ratio [OR], 2.47; 95% confidence interval [CI], 1.7-3.7). Limited to 660 subjects with normal diffusing capacity for carbon monoxide, the odds were similarly increased (OR, 3.20; 95% CI, 1.5-3.6). DISCUSSION: Among coal miners with preserved resting lung function, radiographic evidence of early pneumoconiosis more than doubled the odds of abnormal exercise physiology. Impairment in pneumoconiosis occurs in early disease and may only be evident on exercise testing.

Progression of coal workers' pneumoconiosis absent further exposure.

OBJECTIVES: The natural history of coal workers' pneumoconiosis (CWP) after cessation of exposure remains poorly understood. METHODS: We characterised the development of and progression to radiographic progressive massive fibrosis (PMF) among former US coal miners who applied for US federal benefits at least two times between 1 January 2000 and 31 December 2013. International Labour Office classifications of chest radiographs (CXRs) were used to determine initial and subsequent disease severity. Multivariable logistic regression models were used to identify major predictors of disease progression. RESULTS: A total of 3351 former miners applying for benefits without evidence of PMF at the time of their initial evaluation had subsequent CXRs. On average, these miners were 59.7 years of age and had 22 years of coal mine employment. At the time of their first CXR, 46.7% of miners had evidence of simple CWP. At the time of their last CXR, 111 miners (3.3%) had radiographic evidence of PMF. Nearly half of all miners who progressed to PMF did so in 5 years or less. Main predictors of progression included younger age and severity of simple CWP at the time of initial CXR. CONCLUSIONS: This study provides further evidence that radiographic CWP may develop and/or progress absent further exposure, even among miners with no evidence of radiographic pneumoconiosis after leaving the industry. Former miners should undergo regular medical surveillance because of the risk for disease progression.

[Analysis on characteristic of patients with stage I coal worker's pneumoconiosis].

Objective: To compare the clinical and imaging characteristics of patients with stage I coal worker's pneumoconiosis (CWP) . Methods: All 347 cases of coal workers' pneumoconiosis diagnosed in the Third Hospital of Peking University from January 2014 to December 2018 were included in the study. According to different working posts, the subjects were divided into three categories: mining, tunneling and mixing workers. Dust exposure duration, initial dust exposure age, diagnosis age, latency, small shadow shape and lung regions distribution in X-ray chest film of different categories of CWP patients were analyzed. Results: Among the 347 patients, 216 were mining workers (62.2%) , 77 were tunneling workers (22.2%) and 54 were mixing workers (15.6%) . The dust exposure duration of mining, tunneling and mixing workers were (14.5±7.0) , (16.3±8.2) and (19.0±8.8) years, respectively. There are statistically significant differences in dust exposure duration between different categories of workers (P<0.05) . There were no significant difference in the age of diagnosis, initial dust exposure age and the latency between different categories of workers (P>0.05) . The X-ray films of mining, tunneling and mixing workers showed small round shadow, accounting for 50.9% (110/216) , 96.1% (74/77) and 96.3% (52/54) respectively. 48.1% (104/216) of the mining workers and 38.9% (21/54) of mixing workers, the distribution of small shadow in chest X-ray films reached middle and lower lung regions, while in the 48.1% (37/77) of the tunneling workers, the distribution of small shadow in chest X-ray films reached lower lung regions. There were differences in above indicators among workers with different categories (P<0.05) . Conclusion: The dust exposure duration, the shape and the distribution of lung area on chest X-ray films are different in stage I CWP patients of different occupational categories.

Deposits in the lungs of Kwäday Dän Ts'ìnchi man: Characterization by a combination of analytical microscopical methods.

OBJECTIVES: The approximately 250 years old remains of the Kwäday Dän Ts'ìnchi man were found in a glacier in Canada. Studying the state of preservation of the corpse, we observed black deposits in his lung. Following this observation we wanted to determine: (1) location of the deposits in the lung tissue, (2) composition and origins of the deposits. METHODS: By light microscopy (LM) and transmission electron microscopy (TEM), we studied the deposits in the Kwäday Dän Ts'ìnchi man' s lung and compared it with distribution of anthracotic deposits in contemporary samples from the David Harwick Pathology Centre (DHPC). To determine chemical composition of the inclusions we used Raman spectroscopy. Scanning electron microscopy and elemental mapping was used for determine the chemical elements. RESULTS: The histopathological identification of anthracosis in the Kwäday Dän Ts'ìnchi man's lung allowed us to distinguish crushed parenchyma from conducting airway tissue and identification of particles using LM and TEM. Crystal particles were found using TEM. Ordered carbonaceous material (graphene and graphite), disordered carbonaceous material (soot) and what might be minerals (likely conglomerates) were found with Raman spectrometry. Gold and lead particles in the lung were discovered with scanning electron microscopy and elemental mapping. CONCLUSIONS: Presence of soot particles in anthracotic areas in the Kwäday Dän Ts'ìnchi man's lung probably were due to an inhalation of particles in open fires. Gold and lead particles are most likely of an environmental origin and may have been inhaled and could have impacted his health and his Champagne and Aishihik First Nations (CAFN) contemporaries.

Element-based prognostics of occupational pneumoconiosis using micro-proton-induced X-ray emission analysis.

Pneumoconiosis is an occupational disease accompanied by long-term lung impairment, for which prediction of prognosis is poorly understood because of the complexity of the inhaled particles. Micro-proton-induced X-ray emission (micro-PIXE) analysis, which is advantageous for high-sensitivity, two-dimensional element mapping of lung tissues, was used to investigate element-based predictive factors of prognosis in Chinese patients with welder's and coal miner's pneumoconiosis. Chest radiographs and lung function tests showed that most of the coal miners deteriorated, whereas symptoms in some welders were alleviated after 5 yr, as determined by comparing percent vital capacity (%VC) and forced expiratory volume in the 1st second over forced vital capacity (FEV1.0/FVC) to values taken at the initial diagnosis. Micro-PIXE analysis suggested that the most abundant particulates in welder's pneumoconiosis were Fe, Mn, and Ti (metallic oxide),which were accompanied by particulates containing Si, Al, and Ca (aluminum silicate) or only Si (SiO2); the most abundant particulates in coal miner's pneumoconiosis were composed of C, Si, Al, K, and Ti, which were accompanied by particulates containing Ca or Fe. Particulates containing Al, Si, S, K, Ca, and Ti (orthoclase and anorthite) were correlated with severity of fibrosis. Multivariable linear regression suggested that long-term FEV1.0/FVC decrease was independently associated with Si and smoking index, whereas %VC decrease was associated with Si and Ti. A risk index comprised of these factors was developed to predict the prognosis of pneumoconiosis. Micro-PIXE analysis is feasible for the evaluation of elemental composition and dust exposure, especially for patients whose exposure is mixed or uncertain.

Radiographic disease progression in contemporary US coal miners with progressive massive fibrosis.

INTRODUCTION: Among contemporary US coal miners, there has been an increase in the prevalence and severity of pneumoconiosis, including its advanced form progressive massive fibrosis (PMF). We examine radiographic progression in Coal Workers' Health Surveillance Program (CWHSP) participants. METHODS: CWHSP participants with a final determination of PMF during 1 January 2000-1 October 2016 with at least one prior radiograph in the system were included. We characterised demographics, participation and progression patterns. RESULTS: A total of 192 miners with a PMF determination contributed at least one additional radiograph (total count: 2-10). Mean age at first radiograph was 28.8 years, 162 (84%) worked in Kentucky, Virginia or West Virginia and 169 (88%) worked exclusively underground. A total of 163 (85%) miners had a normal initial radiograph. Mean time from most recent normal radiograph to one with a PMF determination was 20.7 years (range: 1-43) and 27 (17%) progressed to PMF in less than 10 years. DISCUSSION: Dust exposure is the sole cause of this disease, and a substantial number of these miners progressed from normal to PMF in less than a decade. Participation in CWHSP is voluntary, and these findings are influenced by participation patterns, so for many miners it remains unclear how rapidly their disease progressed. The National Institute for Occupational Safety and Health recommends all working miners to participate in radiographic surveillance at 5-year intervals. Improved participation could allow more precise characterisation of the burden and characteristics of pneumoconiosis in US coal miners and provide an important early detection tool to prevent cases of severe disease.

Black Lung Benefits Act: standards for chest radiographs. Final rule.

Physicians and adjudicators use chest radiographs (X-rays) as a tool in evaluating whether a coal miner suffers from pneumoconiosis (black lung disease). Accordingly, the Department's regulations implementing the Black Lung Benefits Act allow the submission of radiographs in connection with benefit claims and set out quality standards for administering and interpreting film-based chest radiographs. This final rule updates the Department's existing film-radiograph standards and provides parallel standards for digital radiographs. This rule also updates outdated terminology and removes certain obsolete provisions.

Pneumoconiosis and advanced occupational lung disease among surface coal miners--16 states, 2010-2011.

Coal workers' pneumoconiosis (CWP) is a chronic occupational lung disease caused by long-term inhalation of dust, which triggers inflammation of the alveoli, eventually resulting in irreversible lung damage. CWP ranges in severity from simple to advanced; the most severe form is progressive massive fibrosis (PMF). Advanced CWP is debilitating and often fatal. To prevent CWP, the Coal Mine Health and Safety Act of 1969 established the current federal exposure limit for respirable dust in underground and surface coal mines. The Act also established a surveillance system for assessing prevalence of pneumoconiosis among underground coal miners, but this surveillance does not extend to surface coal miners. With enforcement of the exposure limit, the prevalence of CWP among underground coal miners declined from 11.2% during 1970-1974 to 2.0% during 1995-1999, before increasing unexpectedly in the last decade, particularly in Central Appalachia. Exposure to respirable dust is thought to be less in surface than underground coal miners. Although they comprise 48% of the coal mining workforce, surface coal miners have not been studied since 2002. To assess the prevalence, severity, and geographic distribution of pneumoconiosis among current surface coal miners, CDC obtained chest radiographs of 2,328 miners during 2010-2011 through the Coal Workers' Health Surveillance Program of the National Institute for Occupational Safety and Health (NIOSH). Forty-six (2.0%) of 2,257 miners with >1 year of surface mining experience had CWP, including 37 who had never worked underground. Twelve (0.5%) had PMF, including nine who had never worked underground. A high proportion of the radiographs suggested silicosis, a disease caused by inhalation of crystalline silica. Surface coal mine operators should monitor worker exposures closely to ensure that both respirable dust and silica are below recommended levels to prevent CWP. Clinicians should be aware of the risk for advanced pneumoconiosis among surface coal miners, in addition to underground coal miners, to facilitate prompt disease identification and intervention.

Lung transplantation in patients with coal workers' pneumoconiosis.

Patients with coal workers' pneumoconiosis (CWP) can develop chronic respiratory failure and require lung transplantation. A retrospective review was performed of the 712 referrals and 143 patients undergoing unilateral or bilateral lung transplantation at the University of Kentucky Medical Center between January 1999 and July 2009. Twenty-one of the 712 referrals (3%) had a diagnosis of CWP with eight patients eventually undergoing lung transplant (six single, two bilateral). The mean age of the cohort was 53 ± 5 (mean ± SD) yr (range 45-59). There was no increased risk of perioperative or postoperative complications. Six patients (75%) remain alive after a mean follow-up of 1013 ± 857 d with the two deaths attributable to sepsis 683 and 145 d after transplant, respectively. There were no pulmonary complications because of the native lung in patients after a single lung transplant, with otherwise good clinical outcomes seen after lung transplantation.

Anthracofibrosis involving lung parenchyma: CT findings and long-term follow-up.

OBJECTIVE: To describe computed tomographic (CT) findings of anthracofibrosis involving lung parenchyma. METHODS: Retrospectively reviewed CT findings of 34 patients with anthracofibrosis involving lung parenchyma, showing deposition of anthracotic pigmentation with focal fibrotic lesions on histologic examination. RESULTS: Types included nodules (41.2%), masses (55.9%), and fibrotic consolidation (2.9%). The mean size was 26.8 mm. The most common location was right upper lobe (n = 10). Satellite nodules were identified in 5 patients, calcification was identified in 11 patients, necrotic low attenuation was identified in 9 patients, and marginal spicule was identified in 26 patients (76.5%). The CT images showed airway manifestation of anthracofibrosis in 13 patients, nodal manifestation in 11 patients, and inactive tuberculosis in 14 patients. Initial radiologic diagnosis included tuberculosis (n = 10), lung cancer (n = 9), organized pneumonia (n = 7), nonspecific pulmonary nodule (n = 7), and anthracofibrosis (n = 1). CONCLUSION: Anthracofibrosis involving lung parenchyma appears as a nodule, mass, or fibrotic consolidation, surrounded by long spicule. It may be the spectrum of bronchial anthracofibrosis involving small airway of lung parenchyma.

Small pneumoconiotic opacities on U.S. coal worker surveillance chest radiographs are not predominantly in the upper lung zones.

BACKGROUND: Radiographic shadows of coal workers' pneumoconiosis (CWP) are commonly described as predominantly in the upper lung zones. METHODS: We evaluated the lung distribution of small opacities on surveillance chest radiographs (CXRs) taken between 1981 and 2010 among 2,467 underground US coal miners. All had evidence of pneumoconiosis (category ≥1/0), based on the contemporary International Labour Office Classification of Radiographs of Pneumoconioses. RESULTS: Small opacity involvement was approximately equal over all lung zones, with 30.7% of the total involvement reported in the upper zones, 37.1% in the middle zones, and 32.1% in the lower zones. Primarily rounded opacities were seen in 62.1% of miners and primarily irregular opacities were seen in 37.9%. Miners with primarily rounded opacities had a distribution with moderate upper zone predominance (upper = 36.8%, middle = 36.5%, and lower = 27.2%). In contrast, miners with primarily irregular opacities showed a lower zone preponderance (upper = 20.5%, middle = 38.4%, and lower = 41.1%). CONCLUSION: The distribution of small pneumoconiotic opacities on surveillance CXRs of working US coal miners is not consistent with the conventional expectations of upper lung zone predominance.

Specifications for medical examinations of underground coal miners. Final rule.

This final rule modifies the Department of Health and Human Services (HHS) regulations for medical examinations of underground coal miners. Existing regulations established specifications for providing, interpreting, classifying, and submitting film-based roentgenograms (now commonly called chest radiographs or X-rays) of underground coal miners. The revised standards modify the requirements to permit the use of film-based radiography systems and add a parallel set of standards permitting the use of digital radiography systems. An additional amendment requires coal mine operators to provide the National Institute for Occupational Safety and Health (NIOSH) with employee rosters to assist the Coal Workers' Health Surveillance Program in improving participation by miners.

[The analysis of consistency between digital radiography and high-kV chest radiographs in diagnosis pneumoconiosis].

OBJECTIVE: To study the consistency between DR and high-kV chest radiographs in diagnosis of pneumoconiosis and to explore the feasibility of DR chest radiograph in the diagnosis of pneumoconiosis. METHODS: Twenty five coal miners were examined with DR and high-kV chest radiographs at the same time. Image post-processing parameters (density, contrast, etc.) were set to ensure the quality of DR chest radiograph in Philips Essenta DR machine. In order to avoid the repetitive numbers, 50 chest radiographs were numbered at random. Pneumoconiosis diagnosis was conducted by six independent certified occupational physicians of pneumoconiosis by blind method. The consistency between 2 kinds of chest films was assessed. RESULTS: All chest radiographs (25 cases, 50 chest films) were excellent. The diagnosis results of six readers on the 15 pairs of DR and high-kV chest radiographies were summarized. For high-kV chest radiographs, the consistency of pneumoconiosis classification for 12 pairs of readers was more than 68%, the consistency of total density for 11 pairs of readers was more than 68%. For DR chest radiographs, the consistency of pneumoconiosis classification for 13 pairs of readers was more than 60%, the consistency of total density for 14 pairs of readers was more than 60%. The consistency of pneumoconiosis classification between two chest radiographs was 72% (value: 0.69, 95% CI: 0.46-0.92), the consistency of total density between two chest radiographs was 80% (value: 0.78, 95% CI: 0.61-0.95). CONCLUSION: When the chest radiograph quality was good and the difference of reading films was low, there was a good consistency of pneumoconiosis diagnosis between DR chest radiographs and high-kV chest radiographs.