Asbestos-related pleural and parenchymal fibrosis: detection with high-resolution CT

Our plain-English summary of Asbestos-related pleural and parenchymal fibrosis: detection with high-resolution CT, by D.R. Aberle, G. Gamsu, C.S. Ray, et al (Radiology, 1988).

The study

• Authors: D.R. Aberle, G. Gamsu, C.S. Ray, I.M. Feuerstein
• Journal: Radiology
• Published: 1988;166(3):729-34
• Cited by: 200 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. 000183).

Abstract

Twenty-nine subjects with occupational asbestos exposure and clinical asbestosis were examined with high-resolution computed tomography (HRCT) to determine its sensitivity, relative to that of conventional computed tomography (CT), for detection of benign asbestos-related disease. Thin-section HRCT scans were obtained at five discrete levels through the mid and lower thorax in both prone and supine positions. The same technique was used in 34 age-similar control patients. Parenchymal abnormalities were seen most frequently in the posterior portion of the lung bases in the asbestos-exposed subjects. HRCT prone scans enabled basal structural abnormalities to be reliably distinguished from gravity-related physiologic phenomena in 25 asbestos-exposed subjects. HRCT was more sensitive than CT in detection of both pleural and parenchymal fibrosis. In subjects with clinical asbestosis, HRCT demonstrated parenchymal abnormality in 96%, compared with 83% for CT. Similarly, pleural thickening was shown in 100% of subjects at HRCT, compared with 93% at CT. HRCT could be an important adjunct in the evaluation of asbestos-related pleuroparenchymal fibrosis. An HRCT study including prone scans is a sensitive, reliable means of detecting thoracic abnormalities in asbestos-exposed individuals.

In plain English

This study compared high-resolution CT (HRCT) with conventional CT in 29 people who had a clinical diagnosis of asbestosis and at least 10 years of occupational asbestos exposure. They came from a larger group of shipyard workers, longshoremen and construction workers. HRCT used very thin slices at five levels of the mid and lower chest, taken with patients lying face up and face down. Conventional CT and HRCT were also done in 34 control patients without occupational asbestos exposure; only 17 of them were scanned face down as well. HRCT showed lung-tissue (parenchymal) abnormality in 96% of the asbestosis subjects, compared with 83% on conventional CT. It showed pleural plaques in all 29 subjects, compared with 93% on conventional CT. Face-down scans helped separate fixed scarring from gravity-related changes. Honeycombing appeared in five asbestosis subjects and in no controls. HRCT found diffuse pleural thickening in only two of the four subjects in whom conventional CT showed it. The authors noted that the HRCT findings are not specific for asbestosis. They concluded that HRCT can complement clinical and radiologic assessment.

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: Prospective imaging study comparing high-resolution CT with conventional CT and chest radiographs in subjects with clinical asbestosis, with a control group
• Who was studied: 29 subjects (mean age 65.8 years, plus or minus 8.2) with a clinical diagnosis of asbestosis and at least 10 years of occupational asbestos exposure, drawn from a larger cohort of shipyard workers, longshoremen and construction workers; 24 of 29 had a significant smoking history. Controls were 34 patients without occupational asbestos exposure (mean age 54.6 years, plus or minus 14.0), referred for other conditions such as known or suspected metastatic disease, lymphoma or solitary lung nodules. 17 controls had supine-only HRCT and 17 had both supine and prone HRCT. A 35th control was excluded after a remote occupational exposure was found. Department of Radiology, University of California, San Francisco; study dates not given.
• Exposure: Occupational asbestos exposure of at least 10 years in shipyard, longshore and construction work; fiber types and doses not specified
• Main results:
  • Parenchymal disease was identified on HRCT in 96% of subjects with clinical asbestosis, compared with 83% on conventional CT, even though conventional CT covered the whole lung
  • HRCT changes were rated high probability for asbestosis in 25 of 29 subjects (86%) and intermediate in 3 (10%). Conventional CT rated 18 high (62%), 6 intermediate (21%) and 5 low (17%, disease absent).
  • Conventional CT probability ratings in the 29 asbestosis subjects
  • On HRCT, pleural plaques were seen in all 29 asbestosis subjects (100%). Conventional CT showed them in 93%; in two subjects plaques were not seen on conventional CT.
  • Conventional CT missed pleural plaques in two of the 29 asbestosis subjects
  • Pleural calcification was seen on HRCT in 11 asbestosis subjects (38%), compared with 9 (31%) on conventional CT
  • Thickened septal and core lines were seen in 28 of 29 asbestosis subjects (97%). In control subjects the septal lines were uniform and thin in 27 (79%).
  • Subpleural dependent density was seen in 17 of 29 asbestosis subjects (59%) and in 10 of 34 controls (29%). In the six controls with prone scans, the density disappeared and normal lung was seen beneath it.
  • Subpleural honeycombing was seen in five asbestosis subjects (17%) and in no control subjects
• The authors' conclusion: The authors concluded that HRCT can complement the clinical and radiologic assessment of asbestos-exposed people and could be used when plain radiographs are equivocal. They concluded that a limited thin-section study, done with patients lying both face up and face down, reliably distinguishes fixed structural abnormalities from functional variations.
• Limitations the authors state:
  • Because HRCT sampled only five levels, it may be limited for diffuse pleural thickening. HRCT identified it in only two of the four subjects in whom conventional CT showed it; the authors said this needs confirmation in a larger series.
  • The HRCT abnormalities described are not considered specific for asbestosis
  • The specificity of the findings for asbestosis, and how they compare with other interstitial lung diseases, has not yet been analyzed
  • Prone and supine images were not always taken at identical planes

Topics

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

Medical terms in this study, explained in our Lexicon: Parenchymal Fibrosis, High-Resolution CT (HRCT), Asbestos Exposure, Thorax, Pleural Thickening, Fibrosis.

Related studies

• Asbestos-related pleural and parenchymal fibrosis: detection with high-resolution CT — T.C. McLoud (1989)
• Agreement between chest radiography and high-resolution computed tomography in diagnosing dust-related interstitial lung fibrosis — R.R. Tiwari (2015)
• Asbestos-related disease: progression of parenchymal abnormalities on high-resolution CT — C.I. Silva, N.L. Müller, et al. (2008)
• Asbestos-related focal lung masses: manifestations on conventional and high-resolution CT scans — D.A. Lynch, G. Gamsu, et al. (1988)
• High-resolution CT of benign asbestos-related diseases: clinical and radiographic correlation — D.R. Aberle, G. Gamsu, et al. (1988)
• Early detection of interstitial lung disease in asbestos exposed non-smoking workers by mid-expiratory flow rate and high resolution computed tomography — Z. Dujić, J. Tocilj, et al. (1991)

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