Profusion Of Small Opacities Research Articles

Compartmentalized immune response reflects clinical severity of beryllium disease.

Although beryllium disease has been associated with a bronchoalveolar lavage (BAL) lymphocytosis and T cell-mediated immune response, we do not know if either the BAL cellular profile or the compartmentalized pulmonary response to the antigen reflect the severity of the disease. We studied 110 subjects divided into three groups of subjects: beryllium disease patients (n = 55), beryllium-sensitized patients without disease (n = 8), and control subjects (n = 47). Evaluation included completion of a respiratory symptom questionnaire, clinical examination, chest radiograph, spirometry, body plethysmographic lung volumes, and diffusing capacity (DLCO). In the patient groups, we performed maximal exercise testing with an indwelling arterial line. In addition, we examined BAL and performed blood and BAL beryllium lymphocyte transformation tests (BeLT) as measures of the beryllium-specific T cell-mediated response in these two compartments. In beryllium disease patients we correlated the BAL cellular constituents with clinical parameters indicative of disease severity. Beryllium disease patients exhibited elevated numbers of white cells and lymphocytes in BAL compared with both other groups; however, this lymphocytic alveolitis was significantly obscured in smokers. The BAL cellular constituents correlated with BAL BeLT but not with the blood BeLT. BAL cellular constituents also correlated with the radiographic profusion of small opacities, FEV1/FVC, DLCO, maximal achievable work load, VO2max, and measures of gas exchange at rest and at maximum exercise. We conclude that the lymphocyte-predominant pulmonary inflammatory response in beryllium disease is related to the magnitude of the localized response to antigen and that BAL cellularity, differential cell count, and BeLT reflect beryllium disease clinical severity.(ABSTRACT TRUNCATED AT 250 WORDS)

Epidemiology of Pneumoconiosis in Coalminers of Nord-Pas de Calais in France

This was a longitudinal study of 3167 active or retired pneumoconiotic coalminers from Nord-Pas de Calais collieries (HBNPC, acronym in French) recognized through medico-legal decisions over three delined periods: 1942-1961, 1962-1981 and 1982-1987. Periodic medical examinations of pneumoconiotics are provided by the medical services of HBNPC for miners and exminers. Physicians involved in this follow-up programme are concerned with the high incidence of progressive massive fibrosis (PMF). The objectives of this study were to describe pneumoconiosis at time of compensation and examine factors related to the occurrence of PMF. For each subject, two radiological films were extracted from the medical files. They were reinterpreted according to the ILO classification (ILO, 1980) by three independent medical readers. Results indicated that radiological criteria for compensation had changed over time ; a marked predominice of category 212 small opacities was noted for cases compensated before 1962 and a predominice of category 1/1 among those compensated after 1981. Comparison of distribution of small opacity types in the 1942-1961 period with that in 1982-1987 confirmed the progressive fall, reported by other investigators, of proportions of predominant micronodular opacities accompanied by an increase in proportions of small irregular opacities at compensation [COCKCROFT and ANDERSON, Br. J. ind. Med. 44,484-487 (1987)]. When time interval between films was taken into account, profusion of small opacities at compensation greater than 1/1 was associated with a probability of 40% or more of developing PMF. Severity of coalworkers simple pneumoconiosis (CWSP) at compensation in HBNPC has been seen to decline since 1982 and the disease to occur mostly after retirement. The reported changes in small opacity types suggest a reduction in incidence of pure silicosis. Occurrence of PMF was correlated with profusion of small opacities at compensation.

Recognition and progression of coal workers' pneumoconiosis in the collieries of northern France.

In France, both active and retired coal miners take part in medical surveillance programs. Those compensated for pneumoconiosis are registered and receive annual chest X-rays and regular lung function assessments. A longitudinal study was done among 2719 pneumoconiotics from the Nord-Pas de Calais region Compensation Register, who received first compensation between 1942 and 1987 to study progression of CSWP. Chest radiographs taken at time of compensation and in 1987 were examined by three independent readers. There was a change over time in the characteristics of pneumoconiosis at the time of first compensation toward a low profusion of irregular opacities. In the period from 1982 to 1987, 645 pneumoconiotics developed progressive massive fibrosis (PMF). The occurrence of PMF was related to the date of compensation and the profusion of small opacities at detection (after controlling for time to follow-up). Two profiles for changes in coal workers' simple pneumoconiosis (CWSP) were observed: the first in the group of subjects with mild pneumoconiosis at compensation, who did not reach category 2 at follow-up and had a low attack rate of PMF; and the second in the group of those compensated for category 1/2 pneumoconiosis or higher, who reached severe CWSP and had a twofold attack rate for PMF at follow-up. The changes observed in the characteristics of pneumoconiosis at first compensation between 1942 and 1987 suggest a lessening of disease severity.

Pneumoconiosis: comparison of digitized and conventional radiographs.

The classification of pneumoconiosis on 108 paired radiographs obtained in coal miners was compared by using conventional radiograph film images and digitized images of those conventional film images. Conventional film images and digitized images were each independently read in a random order in two separate sessions by three radiologists certified as "B" readers. Overall, the digitized images were perceived as being of better quality than the conventional film images (radiograph quality grade 1, 48% [617 of 1,292 classifications] vs 37% [482 of 1,296], respectively; P < .001). The mean International Labour Office (ILO) scores for small-opacity profusion were similar between the digitized images and conventional film images (3.14 vs 3.24, respectively; P = .19). The mean absolute differences in small-opacity profusion score between radiograph pairs were also similar (0.74 vs 0.77, respectively; P = .50). No difference in the ILO type of opacity was noted between the display modes. Interpretation of digitized images for pneumoconiotic small opacities was shown to be an acceptable alternative to interpretation of conventional film images; the important problem of reader variability affects both display modes.

Chest x ray films from construction workers: International Labour Office (ILO 1980) classification compared with routine readings.

The extent of agreement between International Labour Office (ILO) and clinical readings of chest x ray films from construction workers was studied. From a survey of 5898 workers 258 subjects with a profusion of small opacities of > or = 1/1 and a stratified sample of subjects with profusion < 1/1 were selected. Only 41% of the films classified as ILO profusion category > or = 1/1 were clinically recorded as non-normal for the parenchyma. The proportion of films recorded as pneumoconiotic (or possibly so) was especially low for irregular opacities (22%), but increased with the profusion category (both rounded and irregular) as well as with the size of rounded opacities (p 3/11, q 12/25, r 3/4). Only with the profusion category > or = 2/1 were most of the films recorded as pneumoconiotic. The specificity and sensitivity were highest in the geographical areas where a few clinical readers had assessed many films each. The proportion of false negative clinical reports was low for circumscribed pleural thickening of the chest wall (9%) and diaphragmatic pleural thickening (6%). For calcified pleural changes and for the combination of diffuse pleural thickening and obliteration of the costophrenic angle, false negative reports were absent. The present study shows an unsatisfactory sensitivity for clinical compared with ILO readings as a means for screening the parenchyma of workers with a risk of pneumoconiosis.

Serum angiotensin converting enzyme activity in chronic beryllium disease.

Serum angiotensin converting enzyme (SACE) activity is used as a marker of sarcoidosis activity and severity, but in chronic beryllium disease (CBD) the studies of SACE give conflicting results. We examined SACE activity in 23 CBD patients, five patients with beryllium sensitization, and 25 beryllium-exposed control subjects. CBD patients underwent complete clinical evaluation, including physical examination, pulmonary function testing, exercise physiology testing, chest radiography, and bronchoscopy with bronchoalveolar lavage and biopsy. CBD SACE activity was systematically compared with these clinical markers of disease severity. Of CBD patients, 22% had elevated SACE activity. The test did not discriminate CBD patients from those in the beryllium-sensitized or beryllium-exposed groups. However, SACE activity in CBD correlated with the extent of pulmonary granulomatous inflammation as reflected by the symptom of breathlessness, the number of white cells in bronchoalveolar lavage (r = 0.44), the number of lavage lymphocytes (r = 0.58), the lavage lymphocyte percentage (r = 0.55), and the profusion of small opacities on chest radiograph (r = 0.41). The test-retest reliability of the assay was high (r = 0.84), as was the agreement between fresh and -70 degrees C frozen sera (r = 0.93). We conclude that SACE activity levels may reflect the extent of pulmonary granulomatous inflammation in CBD but that the test does not help discriminate disease from nondisease.

Lung function and radiographic signs of pulmonary fibrosis in oil exposed workers in a cable manufacturing company: a follow up study.

Thirty seven workers employed for at least three years in oil impregnation of cables during 1963-83 were followed up in 1990 to study the development of pulmonary fibrosis and consequences for lung function. They had been exposed to concentrations of mineral oil vapours of 50-100 mg/m3, and concentrations of oil mist of 0.5-1.5 mg/m3. All 29 living persons were traced. For each person one control matched for age, height, and smoking habits was selected. Among 25 workers followed up with radiographic studies, 10 cases of pulmonary fibrosis were found, by contrast with one case in the control group (p less than 0.01). Chest radiographs from 1979-80 and 1989-90 were reviewed. The profusion of small opacities increased in seven of 16 persons during 10 years without exposure. Seventeen workers had lung function tests. The bellows function (VC, FEV1, MVV) and lung volumes (TLC, RV) did not differ from those in the matched controls (p greater than 0.05), but the carbon monoxide transfer factor (TLCO) was decreased. The largest reduction of TLCO (1.5 mmol/kPa/min) was found among workers exposed for 10 years or more (p less than 0.05). Arterial blood gases were not affected at rest, but during maximum tread mill exercise, PO2 and HbO2 were reduced in exposed workers compared with controls, particularly among those exposed for at least 10 years (p less than 0.05). Exposure to low viscosity oil mist and vapour is the most plausible cause of the fibrosis. Unaffected bellows function, reduced TLCO, and decreased arterial blood oxygen during exercise is compatible with peribronchiolar fibrosis.

Relationship of Pulmonary Function to Radiographic Interstitial Fibrosis in 2,611 Long-term Asbestos Insulators: An Assessment of the International Labour Office Profusion Score

Radiographic evidence of interstitial fibrosis (IF) secondary to asbestos inhalation (using the International Labour Office [ILO] profusion of small irregular opacities) was compared with FVC as an independent indicator of IF. In addition, spirometric indices of airflow (FEV1/FVC and FET25-75%) were correlated with the radiographic profusion score. A study of 2,611 long-term insulators was well designed for these analyses since all subjects were from the same trade, there were sufficient (n = 515) nonsmokers to assess the effects of asbestos exposure in the absence of smoking, most (60%, n = 1,557) of the workers had parenchymal abnormalities (scores greater than or equal to 1/0), and there was a greater prevalence of high scores than in other published series (347 workers or 13.3% had scores greater than or equal to 2/1). Looking at all subjects, the FVC decreased as profusion score increased. The FVC was abnormal (88.0% of predicted) even when the profusion score was clearly normal (0/0). The FVC was lower at any score in smokers and in workers with pleural thickening (more so with diffuse thickening). There was, however, no difference in FVC between intermediate scores 0/1 versus 1/0 and 1/2 versus 2/1. Airflow increased with greater profusion, tending to overcome a decrease seen at lesser profusion scores. These results provide a greater understanding of the relationships among profusion scores, smoking, pleural diseases, and pulmonary function.

A comparison of pneumoconiosis interpretation between Chinese and American readers and classifications

As a preliminary step in joint Sino-American pneumoconiosis research efforts, a formal chest X-ray pneumoconiosis reading trial was conducted among Chinese and American radiologists. Twelve Chinese readers from different institutions located in south central China used the 1986 Chinese Roentgenodiagnostic Criteria of Pneumoconioses. Three American radiologists, centified as NIOSH "B" readers, used the International Labour Office Classification of Pneumoconioses. The chest X-ray study set consisted of 150 posterior-anterior films. One-half were Chinese X-rays of silica-exposed workers, and the other half were American films of variously exposed workers but primarily coal miners. All readings were done independently. The results showed that the inter-reader variability among the Chinese was similar to that of the American readers, both being in an acceptable range. In addition, there was general agreement between the Chinese and American interpretations. For small opacity profusion, the Chinese readers tended to read slightly more diseases than their American counterparts, although there was exact agreement as to the major category in two-thirds of the films. Agreement for film quality, and pleural disease was less, but was not different from reported variation among American "B" readers. Overall, the results suggest that despite the use of two different classification systems, a valid correspondence exists between the Chinese and American Interpretations, which is suitable for use in epidemiologic research.

Factors associated with massive fibrosis in silicosis.

Data on 1432 patients with silicosis on a register in Hong Kong were analysed to examine the association of massive fibrosis with possible predisposing factors. Detailed occupational and clinical histories, clinical records, radiographic readings according to the International Standard Classification of Radiographs of Pneumoconioses, and environmental dust measurements from hygiene surveys were used to obtain information for several variables--namely, age at first exposure, relative dust exposure level, duration of exposure, smoking, previous recorded history of tuberculosis, and background profusion of small opacities. The most significant risk factors associated with massive fibrosis were high relative dust exposure level, a history of tuberculosis, and increased background profusion of small opacities.

Pulmonary effects of polyvinyl chloride dust exposure on compounding workers.

Spirometry, chest radiography, environmental measurements, and a questionnaire on respiratory symptoms were used to evaluate the effects of exposure to polyvinyl chloride (PVC) dust on 171 Chinese and Malay PVC compounding workers in comparison with an unexposed reference group. Workers with high cumulative PVC dust exposure had a lower forced expiratory volume in 1 s and forced vital capacity, and a higher prevalence of radiological profusion of small opacities. Wheezing or chest tightness was also significantly more frequent in this group. Unlike previous studies, the PVC compounding workers in this study were exposed to only negligible amounts, if any, of vinyl chloride monomer or thermal degradation products of PVC such as hydrogen chloride, phosgene, or chlorine. The conclusion was drawn that a low grade of pneumoconiosis and a small degree of lung function impairment is associated with PVC dust exposure. Reversible airways obstruction is also likely and warrants further investigation.

Comparison of chest radiograph reading methods for assessing progress of pneumoconiosis over 10 years in Wittenoom crocidolite workers.

Thirty three pairs of chest radiographs taken up to 10 years apart were obtained for 33 subjects suffering from asbestosis who had applied for compensation to the Pneumoconiosis Medical Board of Western Australia. Multiple films from the period before the first radiograph in each pair, from the intervening period between the two, and from the period subsequent to the second radiograph were also available and all films were read by two independent readers according to the 1980 ILO classification of pneumoconiosis. Films were read twice as side by side pairs ten years apart, twice as two separate randomly ordered films ten years apart, and once as part of the full series of all available chest radiographs on each subject to assess which method provided the best consistency (between reader variation) and repeatability (within reader variation). Judging by consistency, the full series method performed as well as either of the other methods when assessing radiographic changes and significantly better when assessing the level of profusion of small opacities. There was little to choose between the other two methods either judging by consistency or repeatability, which could not be estimated for the full series method. Use of all available films for a subject is recommended for assessing single films, as in a prevalence study, as well as for documenting change in a longitudinal study.

Relationship of lung function to radiographic reading (ILO) in patients with asbestos related lung disease.

The 1980 International Labour Office (ILO) classification of posteroanterior chest radiographs was used to obtain the scores for profusion of small opacities and pleural abnormalities of 172 men with confirmed or suspected disease of the lungs due to asbestos. After allowance had been made for age, stature, and smoking habit the quantitative score for area of diffuse pleural thickening seen in profile on both lateral chest walls contributed to reductions in inspiratory capacity, expiratory reserve volume, and forced expiratory flow rates. Occlusion of one or both costophrenic angles in the presence of diffuse thickening was associated with further reduction in inspiratory capacity. Profusion of small opacities was associated with a reduction in transfer factor. Diffuse pleural thickening and occlusion of costophrenic angles were associated with relatively low values for the forced expiratory flow rates (MEF50FVC) and FEV1/FVC, whereas small opacities were associated with relatively high values. Thus overall increased, normal, or reduced values of MEF50FVC and FEV1/FVC might occur, depending on the distribution of the radiographic abnormalities. The findings contribute to the validation of the ILO pleural scores; those for diffuse pleural thickening and occlusion of costophrenic angles should be used jointly with the scores for profusion of parenchymal small opacities in interpreting the lung function of persons exposed to asbestos.

International classification trial of AIA set of 100 radiographs of asbestos workers.

A series of 100 full size radiographs illustrating the range of asbestos related radiographic changes was collected by the Asbestos International Association to provide a demonstration and teaching supplement to the ILO 1980 International Classification of the Radiographic Appearances of Pneumoconioses. Each film was read by 12 experienced readers from ten countries; the readings have been summarised by a median reading, with the range covered by two thirds of the readers. The occupational histories and some relevant clinical information are also available. It is proposed that, in the use of this set, readers should classify each film using the ILO classification rules, particularly without reference to the summary reading or the additional information. Comparing the individual readings by the 12 readers, most of the variation in reading the profusion of small opacities was ascribable only to random variation, with little consistent bias between readers. By contrast, two readers recorded pleural changes much more frequently than their colleagues. This illustrated a major problem with the ILO 1980 Classification. Several others which occurred in this reading trial are also discussed.

The relation among pulmonary function, chest roentgenographic abnormalities, and smoking status in an asbestos-exposed cohort.

To clarify the clinical value of the International Labor Office (ILO) roentgenographic classification of pneumoconiosis in assessing asbestos-exposed persons, we determined the relationships among spirometric values, radiographic evidence of parenchymal pulmonary fibrosis and/or pleural thickening, and cigarette smoking history in 684 consecutively enrolled male plumbers and pipefitters participating in a larger cross-sectional prevalence study. The subjects were mainly marine pipefitters (35%), plumbers (24%), and steamfitters/welders (23%); 28% had never smoked, 39% were ex-smokers, and 33% currently smoked cigarettes. Mean values for FVC and FEV1 were 95.0 and 91.9% of predicted, respectively, with mean FEV1/FVC ratio 77.7%; by standard criteria, 7.8% had restrictive impairment, and 21.7%, obstructive defects. Chest radiographs were normal in 63% and showed pleural abnormalities only in 17%, parenchymal abnormalities only in 7%, and both pleural and parenchymal abnormalities in 12%. Both FVC and FEV1 correlated with the degree of small opacity profusion, as assessed by ILO grade. Pleural abnormalities were associated with lower FVC values, independently of ILO profusion grade for Grades less than or equal to 1/0, and were unexplained by smoking status. In addition, there was a positive association between smoking history and degree of ILO parenchymal abnormality, particularly in those with the heaviest cumulative smoking history. Our results suggest that the ILO classification of pneumoconiosis, although a useful epidemiologic tool, should be applied with caution in persons with asbestos exposure, and that pleural abnormalities may be associated with physiologic impairment in such persons.

Irregularly shaped small shadows on chest radiographs, dust exposure, and lung function in coalworkers' pneumoconiosis.

The predominant shapes of small opacities on the chest radiographs of 895 British coalminers have been studied. The aims were to determine whether irregular (as distinct from rounded) small opacities can be identified reproducibly, whether their occurrence is related to dust exposure, and whether they are associated with excess prevalence of respiratory symptoms or impairments of lung function. Six of the doctors responsible for regular radiological surveys of all British coalminers each classified all 895 radiographs twice and independently, using the International Labour Organisation's 1980 classification system. The majority view was that 39 films showed predominantly irregular small opacities, 131 showed predominantly small rounded opacities, and 587 showed no small opacities. Readers' opinions varied about the presence and shapes of shadows on the other 138 films. In general, consistency between readers (and within readers on repeated viewings) was satisfactory. The occurrence and profusion of irregular shadows were related significantly both to the men's ages and additionally to their cumulative exposure to respirable coalmine dust as determined from 15 years' dust monitoring close to where the miners had worked. For any given level of exposure, the average level of profusion of the small irregular opacities was less than the corresponding profusion of small rounded opacities. The prevalence rates of chronic cough and phlegm, and of breathlessness, were higher in those with small irregular opacities than in those with no small opacities (category 0/0), but the differences were not statistically significant after adjustment for other factors including smoking habits. The presence of irregular (but not rounded) small shadows was associated with an impairment in respiratory function averaging about 190 ml deficits in both FEV1 and FVC. These deficits were not explicable in terms of the men's ages, body sizes, and smoking habits and they were in addition to the lung function losses attributable to the miners' dust exposure as such. It is concluded that the presence and profusion of small irregular opacities should be taken into consideration when assessing the severity of coalworkers' simple pneumoconiosis.

Possible Effects of the Introduction of the 1969 Asbestos Regulations

Abstract This paper describes a study of a sample of the chest radiographs collected between 1971 and 1978 in the course of the Health and Safety Executive's survey of asbestos workers. Each radiograph was read by three doctors from a panel of 18. Despite a wide disparity in readers' assessments of the radiographs, three radiological signs were consistently observed: (1) profusion of small opacities; (2) diffuse pleural thickening, and (3) obliteration of the costophrenic angle. Of these, the first showed a relationship both with age and with smoking, the second with age and the third with neither. The risk of showing any one of these signs in those whose exposure began before 1971 was estimated to be at least twice that of those whose exposure started only after the introduction of the regulations.

Chronic beryllium disease: diagnosis, radiographic findings, and correlation with pulmonary function tests.

Patients with suspected chronic beryllium disease underwent bronchoscopy and bronchoalveolar lavage. Their bronchoalveolar lymphocytes were incubated with beryllium salts, and quantitative lymphocyte transformation was measured. Seventeen patients with a positive lymphocyte proliferation test were evaluated radiographically with the International Labour Office classification. The most common radiographic abnormalities included diffuse small round and reticular opacities. Hilar adenopathy, linear scars, lung distortion, bullae, and pleural thickening were found less commonly. Specific radiographic findings were compared with pulmonary function abnormalities. The extent of radiographic profusion of small opacities and the presence of linear scars did not correlate with pulmonary function abnormalities. There was, however, a significant correlation between extensive pleural disease and reduced vital capacity in this small group of patients.

Coalworkers' pneumoconiosis: correlation between opacity profusion and number and type of dust lesions with special reference to opacity type.

The relation between the profusion and predominant type of small rounded opacities on chest radiographs taken within four years of death and the postmortem counts of dust lesions in four classes (macules, "pinhead" fibrotic nodules, nodules 1-3 mm, and nodules greater than 3-9 mm in diameter) has been examined for 71 coalworkers without progressive massive fibrosis. The radiographs were categorised by four readers independently, according to the ILO classification. For subjects considered by each reader to present predominantly p type opacities, increasing opacity profusion was exclusively and significantly associated with an increase in the number of pinhead fibrotic nodules. Numbers of nodules measuring 1-3 mm and greater than 3-9 mm in diameter both showed significant linear associations with opacity profusion category in subjects presenting predominantly q opacities, the closer association being observed with the smaller lesions. These observations held true for all readers. Opacities of type r were rarely considered to be the predominant type. For the reader who recorded the maximum number of such cases, opacity profusion was not significantly related to the numbers of dust lesions in any of the lesion classes. Nevertheless, the closest association was observed with nodules measuring greater than 3-9 mm in diameter. An overall significant linear association between total lung dust content and opacity profusion was found to be due mainly to subjects presenting predominantly p type opacities and to a lesser extent to those with predominantly q opacities.

Serum type III procollagen peptide: indicator for pulmonary fibrosis: II. Application in 80 asbestos insulation workers.

An assay for type III procollagen peptide (P-III-P) was applied to serum from 80 asbestos insulation workers in order to evaluate its relationship with pulmonary and pleural fibrosis. The serum peptide levels of 16 control workers were 7.8 +/- 2.0 ng/ml (mean +/- SD). An association between the serum values of P-III-P and the profusion of small irregular opacities on chest X-rays was noted. The levels in the group with moderate interstitial pulmonary fibrosis [profusion category 2(2/1, 2/2, and 2/3)] and with marked interstitial pulmonary fibrosis [profusion category 3(3/3)] were 9.9 +/- 2.3 ng/ml (n = 5) and thus tended to be higher than those of 16 control workers (p less than 0.1). On the other hand, there was not correlation between serum peptide levels and pleural lesions nor between the former and duration of asbestos exposure. From the results of the investigation [part I of which is reported elsewhere (Okazaki et al, 1986)] this assay may be useful for detecting individuals with a more marked tendency for progression of interstitial pulmonary fibrosis due to asbestos exposure in insulation work.