Radiological and pathological correlations in asbestosis in the Republic of South Africa and the United Kingdom. II. A preliminary study of observer variation in the classification of radiographs of asbestos-exposed workers and the relation of pathology and x-ray appearances

Our plain-English summary of Radiological and pathological correlations in asbestosis in the Republic of South Africa and the United Kingdom. II. A preliminary study of observer variation in the classification of radiographs of asbestos-exposed workers and the relation of pathology and x-ray appearances, by A. Caplan, J.C. Gilson, K.F. Hinson, et al (Annals of the New York Academy of Sciences, 1965).

The study

• Authors: A. Caplan, J.C. Gilson, K.F. Hinson, J.C. McVittie, J.C. Wagner
• Journal: Annals of the New York Academy of Sciences
• Published: 1965;132(1):379-86
• Cited by: 8 articles, as counted by NIH iCite
• Read it: PubMed · Publisher
• In J-M's library: Johns-Manville's company medical library held a copy (J-M no. 002499).

In plain English

This preliminary study tested an extended I.L.O. system for classifying chest X-rays of workers diagnosed with asbestosis. It used 114 X-rays of men applying for compensation: 50 from the South African Pneumoconiosis Bureau in Johannesburg and 64 from a London panel. Readers from both countries read the films separately, then agreed a final reading. Before meeting, the two groups agreed on linear markings in 70 films. The final reading found linear markings in 57 per cent of films, large opacities in 14 per cent and small opacities in 20 per cent. When 20 films were reread, one observer reported pleural thickening in 13 and another in all 20. In 54 London cases, X-rays were compared with autopsy findings. Of 45 cases with linear markings on X-ray, 37 (82 per cent) showed asbestosis to the naked eye. Pleural calcification seen on 7 X-rays was confirmed at autopsy in 3. The authors concluded that the results were encouraging enough to warrant a larger study. They noted that lung tumors in about half the autopsy cases, and incomplete pathology records, complicated interpretation.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Preliminary study of agreement between and within X-ray readers using an extended I.L.O. classification, with a comparison of X-ray readings against autopsy pathology
• Who was studied: 114 chest radiographs of men with diagnosed asbestosis who had recently applied for compensation: 50 from the South African Pneumoconiosis Bureau in Johannesburg and 64 from the London Pneumoconiosis Panel of the Ministry of Pensions and National Insurance. Autopsy reports were available for 54 London cases. Women, cases with tuberculosis, and cases of mixed pneumoconioses or other pulmonary fibrosis were excluded. Lung cancer cases were not excluded from the UK series.
• Exposure: Asbestos-exposed workers diagnosed with asbestosis. Fiber types, jobs and doses are not stated. Some cases had also been exposed to other toxic dusts.
• Main results:
  • Before the final meeting, South African and United Kingdom readers agreed on linear markings in 70 of the 114 films.
  • In the final agreed reading of the 114 films, 57 per cent showed linear markings.
  • Large opacities were present in 14 per cent of the 114 films in the final agreed reading. The authors noted this was of interest because such appearances have often been assumed not to occur in asbestosis.
  • In the final agreed reading, 20 per cent of the films showed small opacities, and agreement between the two reader groups before meeting was reasonably good.
  • For pleural thickening (all sites), the two reader groups reported very similar prevalence. The final agreed reading gave a figure rather lower than either group's, but still over 60 per cent.
  • When three observers reread 20 of the films, agreement with their own earlier readings was described as fairly high. However, individual readings could differ appreciably from the final agreed reading: for pleural thickening, observer two reported it in only 13 of the 20 films, while observer three reported it in all 20.
  • Separating linear markings into fine and coarse was too poorly reproducible, within and between observers, to be usable.
  • In the London autopsy comparison, pleural thickening was reported on X-ray in 45 cases and confirmed at autopsy in three-quarters of them. In seven further cases it was found at autopsy but not reported on the X-ray.
  • Pleural calcification was seen on the X-ray in seven cases, and only three of these were confirmed at autopsy.
  • Of 45 cases with linear markings on the X-ray, 37 (82 per cent) showed asbestosis to the naked eye at autopsy. Eight cases had linear markings but no visible asbestosis at autopsy, and another eight had asbestosis at autopsy but no linear markings recorded. The pattern was very similar for asbestosis seen under the microscope.
• The authors' conclusion: The authors judged the results encouraging enough to warrant a larger study, with films covering the full range of abnormality and coming from several countries and occupational groups. They considered that a useful system for classifying asbestosis could be built on the 1958 I.L.O. Classification by recording linear markings by lung zone, making pleural thickening a main category recorded by site, and recording calcified pleural plaques separately by site.
• Limitations the authors state:
  • A tumor was present at autopsy in about half the cases, which often made it difficult to separate fibrosis due to asbestos from fibrosis caused by collapse and infection.
  • The pathology records were incomplete and had not been made with this investigation in mind. This may partly explain why few X-ray calcifications were confirmed at autopsy.
  • Lungs were not always inflated, and because some autopsies were done elsewhere, the parietal pleura was not always available for examination.
  • Lung cancer was so common in the UK series that those cases could not be excluded.
  • Exposure to other toxic dusts in some cases, and radiotherapy in one case, made interpretation difficult.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Asbestosis.

Medical terms in this study, explained in our Lexicon: Pathology.

Related studies

• Radiological and pathological correlations in asbestosis in the Republic of South Africa and the United Kingdom. I. A proposed radiological classification of asbestosis — G.K. Sluis-Cremer, C.P. Theron (1965)
• Radiological classification of pulmonary asbestosis — H. Bohlig (1965)
• Asbestosis in South Africa--certain geographical and environmental considerations — G.K. Sluis-Cremer (1965)
• A study of the histological cell types of lung cancer in workers suffering from asbestosis in the United Kingdom — F. Whitwell, M.L. Newhouse, et al. (1974)
• Correlation between lung asbestos count at necropsy and radiological appearances — P. Macpherson, J.K. Davidson (1969)
• Excess mortality from stomach cancer, lung cancer, and asbestosis and/or mesothelioma in crocidolite mining districts in South Africa — J.L. Botha, L.M. Irwig, et al. (1986)

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