Profusion Of Small Opacities Research Articles

Comparison of Digital Direct Readout Radiography with Conventional Film‐screen Radiography for the Recognition of Pneumoconiosis in Dust‐exposed Chinese Workers

Pneumoconiosis in China remains a disease with substantial public health significance. Diagnostic standards for the pneumoconioses are based on traditional film-screen radiography (FSR). However, FSR is increasingly being replaced with digital radiographic imaging, which has become the predominant technology available in Chinese clinical practice. To evaluate the applicability of digital direct readout radiography (DR) images in the recognition of pneumoconioses, we compared the profusion of small opacities and large opacities between FSR and DR radiographs. We enrolled 161 pneumoconioses patients and 31 dust-exposed workers during the course of the study, with FSR and DR images obtained from all participants. Each chest film was interpreted by five readers using the Chinese Diagnostic Criteria classification of radiographs of pneumoconiosis, as were DR images displayed on medical-grade computer monitors. No statistically significant differences were observed when the data were analyzed by small opacity profusion subcategory except for 1/1. The overall intermodality agreement of small opacities was good, with a weighted kappa (κ) of 0.77. DR images with soft copy display are equivalent with respect to image quality and the recognition and classification of small parenchymal lung opacities. Additionally, we observed likeness between modalities with respect to the classification of large opacities. Overall, our study findings demonstrate that in a population of Chinese workers with pneumoconiosis, direct readout digital systems are equivalent to traditional film-screen radiography in the recognition and classification of small pneumoconiotic opacities.

Pulmonary lesions and serum levels of soluble Fas (sCD95) in former hard coal miners

ObjectiveFas/APO-1 (CD95) and Fas Ligand (FasL) is a major mediator system that activates programmed cell death (apoptosis) and is most important for pulmonary cellular homeostasis. Another form of Fas, circulating soluble Fas (sCD95), produced by alternative mRNA splicing antagonizes the cell-surface Fas function. It was the aim of the study to test the hypothesis that the Fas/FasL system is implicated in the development of silica-induced pulmonary nodular lesions.Materials and methodsWe investigated the serum levels of sCD95 in 55 former hard coal miners. Coal workers' pneumoconiosis (CWP) was assumed when the profusion of small round opacities according to the ILO 2000 classification system was 1/1 or greater. Analyses of sCD95 were performed by a sandwich ELISA.ResultsRadiologic CWP was found in 34 of the 55 individuals. The age of subjects with and without CWP was similar (73.5 (SD 7.2) years vs. 73.5 (7.1) years; P = 0.924). sCD95 could be quantified in all samples; significantly higher levels were observed in subjects with radiologic signs of CWP (914 (752-1251) pg/ml vs. 632 (509-804) pg/ml, P < 0.001). However, there was no relationship between sCD95 serum concentrations and the quantity of profusion according to ILO.ConclusionsThe hypothesis of elevated sCD95 concentrations in CWP was corroborated. The usefulness of sCD95 for prevention and diagnosis of CWP and other forms of silica-induced fibrosis needs to be established By epidemiological studies.

Comparison of storage phosphor computed radiography with conventional film-screen radiography in the recognition of pneumoconiosis

Traditional film-screen radiography (FSR) has been useful in the recognition and evaluation of interstitial lung diseases, but is becoming increasingly obsolete. To evaluate the applicability of storage phosphor digital computed radiography (CR) images in the recognition of small lung opacities, we compared image quality and the profusion of small opacities between FSR and CR radiographs. We screened 1,388 working coal miners during the course of the study with FSR and CR images obtained on the same day from all participants. Each traditional chest film was independently interpreted by two of eight experienced readers using the International Labour Office (ILO) classification of radiographs of pneumoconiosis, as were CR images displayed on medical-grade computer monitors. The prevalence of small opacities (ILO category 1/0 or greater) did not differ between the two imaging modalities (5.2% for FSR and 4.8% for soft copy CR; p>0.50). Inter-reader agreement was also similar between FSR and CR. Significant differences between image modalities were observed in the shape of small opacities, and in the proportion of miners demonstrating high opacity profusion (category 2/1 and above). Our results indicate that, with appropriate attention to image acquisition and soft copy display, CR digital radiography can be equivalent to FSR in the identification of small interstitial lung opacities.

Comparison of Digital Radiographs with Film Radiographs for the Classification of Pneumoconiosis 1

Digital chest imaging has replaced film chest radiographs in many centers, but the International Labour Organization classification system, which is the most widely used system for recognition and classification of dust-related abnormalities, is predicated on film chest radiographs. The purpose of this study was to evaluate the equivalency of digital chest radiographs (including both hard copy and soft copy) with film radiographs for the recognition and quantification of abnormalities consistent with pneumoconiosis using the International Labour Organization classification system. Digital chest images and film images, obtained from 107 subjects with a range of parenchymal and pleural abnormalities, were classified in random order by six B readers. Readings of film and soft copy images were equivalent for small opacity profusion; readings of hard copy images had significantly greater prevalence of small opacities compared to film and soft copy. The prevalence of large opacities differed significantly among all three image formats: hard copy greater than film greater than soft copy. However, film and soft copy readings for large opacities did not differ significantly when images demonstrating the coalescence of small opacities that had not yet become a large opacity were grouped with large opacities. The prevalence of pleural abnormalities differed significantly among all three image formats: film greater than hard copy greater than soft copy. Film and soft copy images can be recommended for the recognition and classification of dust-related parenchymal abnormalities using International Labour Organization classifications. The role of digital radiography in reading for pleural abnormalities requires additional investigation.

Variability in Interpretation among B-Readers in the U.S. Navy Asbestos Medical Surveillance Program

U.S. Navy Asbestos Medical Surveillance Program B-reading reports were analyzed for variability in identifying pneumoconiosis in 278,944 chest radiographs done from 1990 to 2004 using commercial database and statistical software. Reported presence of pneumoconiosis by 33 B-readers ranged from 1.85 to 32.28%. The reported presence of parenchymal abnormalities ranged from 0.11 to 15.07%; increased profusion (to 1/0 or greater) of small parenchymal opacities ranged from 0.10 to 17.70%; presence of large opacities ranged from 0.00 to 0.67%; and presence of pleural abnormalities ranged from 1.08 to 23.93%. Ranges appear to be decreasing slightly as rates of abnormal findings are diminishing. Differences between U.S. East Coast, West Coast, and midcontinent were not statistically significant.

Pulmonary malignancy in silicosis: Factors associated with radiographic detection

The aim was to assess radiographic features of pulmonary malignancies in silicosis and to reveal confounding factors in their detection. A total of 501 silicosis patients were followed up between 1982 and 2003. Sixty pulmonary malignancies were pathologically confirmed in 54 (10.8%) patients. Two radiologists reviewed serial radiographs of these patients to determine radiographic features of tumor (size, margin, nodule or consolidation, localization, overlying structures) and silicosis (profusion of pneumoconiotic opacities, progressive massive fibrosis (PMF), hilar lymphadenopathy). Eleven tumors were radiographically negative. Forty-nine tumors were retrospectively visible with radiograph. Of these, 15 tumors were clinically detected with radiograph, but 25 were missed. The remaining nine tumors became radiographically positive after positive sputum cytology. There were no differences between missed and detected nodules in terms of radiographic findings. The mean tumor size was 30 mm (range: 15–90 mm) and was significantly larger in patients with PMF or hilar lymphadenopathy than in those without (35 mm vs. 24 mm, p = 0.006; 33 mm vs. 24 mm, p = 0.038, respectively). This was correlated with background profusion of small pneumoconiotic opacities ( r = 0.433, p = 0.024). Retrospective reading tests by three radiologists showed correct localization of tumor in 75%, however, the correct diagnosis with a high confidence was reached in only 54%. In conclusion, radiographic detection of malignancy in silicosis proved a difficult task and no single radiographic finding was found to be associated with missing the tumor. The presence of PMF, hilar lymphadenopathy and profusion of small pneumoconiotic nodules affected tumor size at detection.

Radiological Progression and Mortality among Silica Flour Packers: A Longitudinal Study

There are few longitudinal studies that investigated the radiological progression of silicosis among different occupational groups. Inhalation exposure to very high levels of crystalline silica can lead to acute silicosis. This longitudinal study was designed to determine association between mortality and radiological progression among individuals with rapidly progressive silicosis. Twenty-three subjects with silicosis had previously worked in the same stone-grinding factories, where they had been exposed to high airborne concentrations of silica powder dust. The diagnosis of rapidly progressive form of silicosis was made according to the National Institute for Occupational Safety and Health definition. The subjects were entered into the study if chest radiography films with acceptable quality showed small opacity shadowing of at least 1/0 profusion grade. Chest radiographs of the start and end of follow-up were independently reviewed at different times by two readers. For paired comparison, the side-by-side method of presenting radiographs was used. Data analysis was carried out by using the t-test, Fisher's exact test, and logistic regression. It was found that 65.2% of workers showed evidences of radiological progression during a period of follow up (mean 30.3 mo). The age of death for the 10 workers who died of silicosis ranged between 21 and 35 yr, with the mean and median age of 27.30 (SD 4.77) and 28.50 yr, respectively. There was a significant association between mortality and both size and profusion progression of small opacities. In conclusion, we quantified the risk of death from rapidly progressive forms of silicosis in a group of workers heavily exposed to silica. We conclude that young adult age, rapid progression in the size, and profusion of small opacities are risk factors for the development of advanced silicosis. Death occurs more quickly in silicotic patients with these criteria.

A Flat‐Panel Detector Digital Radiography and a Storage Phosphor Computed Radiography: Screening for Pneumoconioses

Storage phosphor computed radiography (SR) and flat-panel detector (FPD) radiography are two types of digital X-ray utilizing different techniques. We compared these two techniques with conventional analogue chest radiograph (AR) among pneumoconiotic patients and healthy controls. Thirty individuals consisting of 20 silica-exposed ex-workers and 10 healthy controls without occupational exposure to any mineral dust were examined with chest X-ray by AR, SR and FPD. Three occupational physicians, including one NIOSH B reader, assessed the digital and conventional radiographs by the side-by-side method according to the ILO 2000 International Classification of Radiograph of Pneumoconioses (ILO/ICRP). No significant difference was shown between the subjective film qualities by AR and FPD. Inter-reader agreement of the profusion of small opacities on radiographs was high in the order of SR (kappa=0.64), FPD (kappa=0.62), and AR (kappa=0.55). The profusions of small opacity for AR and FPD by the 12-point scaled profusion of ILO/ICRP did not show a statistically significant difference, but those for AR and SR showed a significant difference. The areas under the receiver operator curves (ROC) using clinical diagnosis by a pulmonologist as the reference showed no statistically significant difference among the three radiographic techniques. FPD gives image quality as good as that of AR, and it has acceptable agreement with AR in small profusion categories, which consequently assures its application to pneumoconiosis screening. SR showed less profusion than FPD and AR, which can be fixed with image modification.

Meta-analysis of silicosis and lung cancer

This study examined the association between silicosis and lung cancer in a systematic review (and meta-analysis) of the epidemiologic literature, with special reference to the methodological quality of observational studies. We searched Medline, Toxline, BIOSIS and Embase (1966-May 2004) for original articles published in any language and systematically reviewed the bibliographies of the retrieved articles. Observational studies (cohort and case-control studies) were selected if they reported a measure of association [standardized mortality ratio (SMR), relative risk or odds ratio] relating lung cancer to silicosis. Thirty-one studies (27 cohort studies, 4 case-control studies) met the inclusion criteria of the meta-analysis. Without any adjustment for smoking, the meta-analysis of the cohort studies indicated that the common SMR was 2.45 [95% confidence interval (95% CI) 1.63-3.66; homogeneity P<0.0001]. When the results of the cohorts for which mortality data were adjusted for smoking were pooled, the common SMR was 1.60 (95% CI 1.33-1.93; homogeneity P=0.52). In a "dose-response" analysis, the profusion of small and large opacities found in chest X-rays correlated with the risk of death from lung cancer. Overall, the case-control studies were more conservative in their conclusions. Because of biases inherent to observational studies, it is likely that the risk of lung cancer among silicosis patients is overestimated in the current literature. There is nevertheless evidence, from data restricted to never-smokers and from a "dose-response" analysis, that silicosis and lung cancer are associated.

Rapidly progressive coal workers’ pneumoconiosis in the United States: geographic clustering and other factors

Background: Despite significant progress made in reducing dust exposures in underground coal miners in the United States, severe cases of coal workers’ pneumoconiosis (CWP), including progressive massive fibrosis (PMF), continue...

High-Resolution CT in Silicosis

To assess high-resolution computed tomography (HRCT) findings in silicosis and to better define the role of HRCT in early detection of parenchymal abnormalities in silica-exposed workers. Forty-one stone carvers were evaluated with chest radiographs (CR), HRCT, and pulmonary function tests (PFT). Inter-reader agreement was calculated using the kappa statistic (k). Correlation between radiographic and HRCT profusion scores and PFT was assessed using the Spearman correlation coefficient. The most common HRCT findings were branching centrilobular structures, seen in 28/41 workers (68.3%). Nodules consistent with silicosis were detected in 53.7% workers on CR and in 56.1% workers on HRCT. Inter-reader agreement for diagnosis of silicosis was better on HRCT (k = 0.84) than on CR (k = 0.54). Small opacity profusion on HRCT correlated inversely with total lung capacity and FVC%. Profusion of opacities on HRCT correlates with functional impairment. The presence of branching centrilobular structures may be helpful in early recognition of silicosis.

Comparison of “B” readers' interpretations of chest radiographs for asbestos related changes

The purpose of this study was to determine if chest radiographic interpretations by physicians retained by attorneys representing persons alleging respiratory changes from occupational exposure to asbestos would be confirmed by independent consultant readers. For 551 chest radiographs read as positive for lung changes by initial "B" readers retained by plaintiffs' attorneys, 492 matching interpretative reports were made available to the authors. Six consultants in chest radiology, also B readers, agreed to re-interpret the radiographs independently without knowledge of their provenance. The film source, patient name, and other identifiers on each film were masked. The International Labor Office 1980 Classification of Chest Radiographs(ILO 80) was used with forms designed by the US National Institute of Occupational Safety and Health to record the consult-ants' findings. The results were compared with initial readings for film quality, complete negativity, parenchymal abnormalities,small opacities profusion, and pleural abnormalities using chi-square tests and kappa statistics.Results. Initial readers interpreted study radiographs as positive for parenchymal abnormalities (ILO small opacity profusion category of 1/0 or higher) in 95.9% of 492 cases. Six consultants classified the films as 1/0 or higher in 4.5% of 2,952 readings. Statistical tests of these and other comparable data from the study showed highly significant differences between the interpretations of the initial readers and the findings of the consultants. The magnitude of the differences between the interpretations by initial readers and the six consultants is too great to be attributed to interobserver variability. There is no support in the literature on x-ray studies of workers exposed to asbestos and other mineral dusts for the high level of positive findings recorded by the initial readers in this report.

An epidemiological study of the respiratory health of workers in the European refractory ceramic fibre industry

OBJECTIVESTo investigate possible relations between respiratory health and past airborne exposure to refractory ceramic fibres (RCFs) and respirable dust in workers at six European factories, studied previously in 1987.METHODSThe target...

Radiological progression and its predictive risk factors in silicosis

OBJECTIVESTo investigate the risk factors predicting radiological progression in silicosis in a prospective cohort study of patients with silicosis who were previously exposed to silica from granite dust.METHODSFrom among a...

Follow-up of asbestosis patients and predictors for radiographic progression.

We followed a group of 85 Finnish asbestosis patients radiographically for an average of 6.5 (range 2-10) years to examine the progression of the disease and to assess possible explanations for the progression. The examinations included full-size chest radiographs and a blood specimen analysis. The radiographs were classified according to the 1980 International Labor Office (ILO) classification. Progression was accepted if the second or third radiography was estimated (in a side-by-side comparison) to have more profusion of small opacities qualitatively than the first, even if the radiographs were classified into the same profusion category. In all, 38% of the patients showed progression during the follow-up period. The average progression of small opacities ranged from ILO 1/1 to ILO 2/2 (0.4 minor ILO categories/year). The asbestosis was progressive more often among the sprayers than among the insulators and asbestos factory workers [cross-tabulation, odds ratio (OR) 5.0, 95% confidence interval (95% CI) 1.2-20]. In the logistic regression model the ILO classification category at the beginning of the follow-up (OR 1.54; 95% CI 0.96-2.47), the fibronectin (OR 1.01; 95% CI 1.00-1.01) and angiotensin-converting enzyme (ACE; OR 1.10; 95% CI 1.00-1.20) levels, and the erythrocyte sedimentation rate (ESR; OR 1.05; 95% CI 1.00-1.10) were statistically associated with the radiographic progression of small opacities. Abnormalities of the pleura were found to progress more often among the patients with progressive parenchymal opacities. For the progression of small-opacity profusion the significant predictors in the logistic regression model were the ILO profusion category at the beginning of the follow-up period, the fibronectin level, the ACE value, and the ESR. The model correctly classified 94% of the patients with progression and 65% of those without progression. The differences in the mean values recorded for the biomarkers between the progressors and nonprogressors, however, were small and may therefore not be of any importance to the clinician.

Observer variation in classifying chest radiographs for small lung opacities and pleural abnormalities in a population sample.

The purpose of this study was to assess inter-and intraobserver variation in the radiographic categories of small lung opacities (profusion) and pleural abnormalities classified according to the ILO classification of pneumoconioses with some modifications. Chest radiographs derived from a representative adult population sample (n = 7,095) were classified by two radiologists. Observer variation was assessed on the basis of kappa (kappa)-type statistics. The observers agreed on profusion categories in 69% of cases of the total material. Up to 98% of the classifications fell into the same category or deviated by no more than one category. The corresponding kappa (kappa) coefficient was 0.48 (95% CI = 0.46=0.49) and the weighted kappa 0.72. When a selected subsample was reclassified by the observers, the proportions of crude agreement on profusion of small opacities ranged from 42% to 47% (weighted kappa 0.52-0.55). The proportions of agreement on the main pleural abnormalities were 92% or over, and the corresponding kappa coefficients at least 0.73. The classification of lung opacities was subject to considerable observer variation, which calls for caution when results from different studies are compared. This variation, however, rarely exceeded one category, and thus appears to be small enough for meaningful comparisons between groups, at least within a single study.

Progression of Asbestosis Predicts Lung Cancer

To explore whether the progression of asbestosis correlates with the risk of lung cancer among patients with asbestosis. A group of 85 asbestosis patients (78 men and 7 women) were radiographically followed up between 1979 and 1987. Two or three posteroanterior radiographs taken from each patient in 1978 to 1979, 1983 to 1984, and 1986 to 1987 were classified according to the International Labour Office 1980 classification and were used to divide the patients into progressors and nonprogressors. Follow-up for cancer was done automatically through the files of the Finnish Cancer Registry from the time of determination of the progression status to December 31, 1994. Predictors of lung cancer risk were studied with a logistic regression model, and the standardized incidence ratio (SIR) was calculated for lung cancer. Of the 24 male patients with progressive small opacity profusion, 11 (46%) developed lung cancer, as opposed to 5 (9%) of the 54 male patients without progression. The SIR for lung cancer was 37 (95% confidence interval, 18 to 66) for the progressors and 4.3 (1.4 to 9.9) for the nonprogressors. In both groups, all the lung cancer cases occurred among smokers or ex-smokers. None of the seven female patients showed progressive small opacity profusion. One of them developed lung cancer. In the logistic regression model including all 85 asbestosis patients, radiographic progression of small opacity profusion (p=0.0009) and current smoking (0.0021) were significant predictors of lung cancer morbidity. Asbestosis patients with radiographic progression of small opacity profusion over a few years are at a higher risk of lung cancer than those with a less aggressive course of the disease. The progression of pulmonary fibrosis may be an independent risk factor that, in addition to smoking history and the intensity of asbestos exposure, could be used to estimate lung cancer risk.

Risks of silicosis in coalworkers exposed to unusual concentrations of respirable quartz.

OBJECTIVES: To describe the radiographic changes in coalworkers exposed to unusual concentrations of respirable quartz during the 1970s, and to relate these to exposure measurements. METHODS: Men who had worked...

New composite ('quadrant') standard films for classifying radiographs of pneumoconioses.

120 chest radiographs of dust exposed persons were classified twice by each of 39 physicians, and three times by 37 of them. All film readers used both the 22 standard films accompanying the current International Labour Office's (1980) Classification of Radiographs of Pneumoconioses, and a modified set that reproduced selected parts from some of them as quadrants of full-size films. Variability within and between readers in small opacity profusion classifications was high, but similar when using the two sets of standards. Some readers recognised irregularly shaped small opacities more frequently, in low profusion categories, when using the quadrant standards. Small rounded opacities were classified more frequently higher on the scale when using the current standards. The effects found were small although the test films included a high proportion with some small opacities. It is concluded that use of the new quadrant standards is unlikely to introduce any important bias into results from occupational health surveys.

Comparision of Chest Radiographs and Pulmonary Function in Coal Workers' Pneumoconiosis and Welders' Lung

Background: Chest X-ray of coal workers' pneumoconiosis and shipyard welders' lung show similar and regular opacities mostly, it is very difficult that we distinguish the former from the latter by only chest X-ray. so we performed this study to understand the progression of the disease and to provide the disease by considering pulmonary function and other factors in proportion to the profusion of small regular opacities of chest X-ray in both groups. Method: 430 coal workers' pneumoconiosis were compared with 311 shipyard welders' lung by the number, the age, the duration of dust exposure, %vital capacity(%VC), %FEV1.0, the type of ventilatory impairment, the combined pulmonary disease according to the profusion of small regular opacities on the chest radiographs, which were classified into category 0/1, category 1, and category 2. Result: 1) the percent of category 2 in coal workers' pneumoconiosis was 54.4%. the percent of category 1, and category 2 in welders' lung were 60.0%, 7.4%. the progression to the category 2 was higher in coal workers' pneumoconiosis than in welders' lung 2) The mean age was higher in coal workers' pneumoconiosis than in welders' lung, significantly increased in proportion to the progresion of profusion of small regular opacities in both groups 3) There was no difference in the duration of dust exposure by category 1/0, but the duration of dust exposure by category 1, 2 in coal workers' pneumoconiosis more significantly increased than in welders' lung. the duration in the proportion of category 2 to category 0/1, 1 significantly increased in the proportion to small regular opacities in coal workers' pneumoconiosis. but there was no significant difference in the proportion to small regular opacities in duration of dust exposure in welders' lung. 4) There was no significant difference of mean values of %VC(%vital capacity)in both groups except for category 1. the mean values of %VC had no relationship between the progression of small regular opacities in both groups. 5) The mean values of %FEV1.0 decreased more significantly in coal workers' pneumoconiosis than in welders' lung except for category 0/1. and decreased significantly in proportion to the profusion of small regular opacities in coal workers' pneumoconiosis. there was significant difference of %FEV1.0 in the proportion of category 2 to category 011 in welders' lung. 6) there were no significant difference of %FEV1.0, %VC in smoker and nonsmoker in both groups. 7) With regard to the type of ventilation in both groups in coal workers' pneumoconiosis 21.4 percent of patients belonged to the restrictive type, 11.6 percent to the obstructive type, 5.6 percent to the combined type, but in welders' lung 21.8 percent to the restrictive type, 2.9 percent to the obstructive type, 1.9 percent to the combined type. 8. in the pulmonary disease, the incidence of the pulmonary tuberculosis was the most in both groups, was more in coal workers' pneumoconiosis than welders' lung Conclusion: If we compare coal workers' pneumoconiosis with electric arc welders'lung by considering pulmonary function and other factors in proportion to the profusion of chest X-ray, I think that we will have the better result in understanding the progression of the disease and provision of the disease in both groups.