High-resolution CT of benign asbestos-related diseases: clinical and radiographic correlation

Our plain-English summary of High-resolution CT of benign asbestos-related diseases: clinical and radiographic correlation, by D.R. Aberle, G. Gamsu, C.S. Ray (AJR. American Journal of Roentgenology, 1988).

The study

• Authors: D.R. Aberle, G. Gamsu, C.S. Ray
• Journal: AJR. American Journal of Roentgenology
• Published: 1988;151(5):883-91
• Cited by: 142 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. 003897).

Abstract

We prospectively analyzed benign asbestos-related pleural and parenchymal abnormalities on high-resolution CT scans and correlated them with clinical diagnoses in 100 asbestos-exposed workers. All subjects had high-resolution CT scans in conjunction with conventional CT at the time of clinical evaluation. To evaluate for asbestosis, we ranked high-resolution CT scans as high, intermediate, or low probability of asbestosis on the basis of the multiplicity and extent of observed parenchymal changes. By linear regression analysis, the most distinctive high-resolution CT features of asbestosis included thickened nondependent interstitial short lines and parenchymal bands. In 45 subjects satisfying clinical criteria of asbestosis, high-resolution CT probability of asbestosis was high in 38 (84%), intermediate in five (11%), and low in two (4%). In 20 (36%) of 55 subjects without clinical asbestosis, parenchymal abnormalities indicative of a high probability of asbestosis were observed on high-resolution CT. High-resolution CT probability scores had a strong positive correlation with chest radiographic profusion scores (p less than .0001) and asbestos-related pleural thickening (p less than .0001). Significant inverse correlations were seen with forced vital capacity (p less than .006) and single-breath diffusing capacity (p less than .03), both functional measures of restrictive interstitial lung disease. Neither clubbing nor rales were sufficiently prevalent to have statistical correlation with high-resolution CT scores. High-resolution CT is sensitive in detecting both pleural and parenchymal abnormalities in the asbestos-exposed subject. Asbestos-related pleural changes are observed more frequently on high-resolution CT than on conventional CT or chest radiography. The probability of asbestosis based on high-resolution CT parenchymal features has a significant correlation with existing clinical determinants of disease, and high-resolution CT can detect abnormality when other methods are not diagnostic.

In plain English

This prospective study compared high-resolution CT (HRCT) with conventional CT and X-rays in 100 asbestos-exposed workers. Eighty-five were exposed in shipyards and 15 in construction; in each case two outside B-readers had disagreed about their X-rays. Two radiologists independently scored each HRCT scan on a five-point scale; their averaged score was classed as low, intermediate or high probability of asbestosis. Of 45 workers meeting clinical criteria for asbestosis, HRCT probability was high in 38 (84%), intermediate in five (11%) and low in two (4%). Of 55 workers not meeting them, 20 (36%) had high-probability HRCT findings. Thickened interstitial short lines and parenchymal bands related most closely to the scores. HRCT showed unequivocal pleural plaques in 64 workers and minimal plaques in 29 more; X-rays showed plaques in 49. HRCT scores correlated with X-ray profusion scores and pleural thickening. They correlated inversely with forced vital capacity and diffusing capacity, not with smoking history. The authors had no tissue proof of disease in workers without clinical asbestosis. They concluded that HRCT can complement evaluation when other criteria are equivocal or absent.

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 correlating high-resolution CT findings with clinical diagnosis, chest radiographs and conventional CT
• Who was studied: 100 asbestos-exposed workers being evaluated for effects of asbestos exposure, in each of whom two ILO B-readers had disagreed about the chest X-ray findings; 85 exposed in shipyards and 15 in construction; average age 62 (range 34-85); 27 had never smoked; 29 had been included in an earlier report by the authors. Location and dates of enrollment are not stated.
• Exposure: Documented occupational asbestos exposure (fiber types not specified) in shipyards or construction; mean duration of exposure 21 years (range 2-45); mean latency from first exposure 37 years (range 12-59), at least 10 years in all subjects
• Main results:
  • Each of the two radiologists independently scored every HRCT scan on a five-point scale (1 = normal to 5 = high probability of asbestosis); the two scores were averaged into a consensus score, which was then classed as high, intermediate (3-3.5) or low (below 3) probability
  • Among 45 subjects meeting clinical criteria for asbestosis, HRCT probability of asbestosis was high in 38 (84%), intermediate in five (11%), and low in two (4%)
  • Among 55 subjects not meeting criteria for clinical asbestosis (none with an abnormal chest X-ray by ILO standards), HRCT probability was high in 20 (36%), intermediate in 10 (18%), and low in 25 (45%)
  • Of individual HRCT features, nondependent (prone) thickened interstitial short lines were most highly correlated with the probability score (r = .74, p less than .0001); parenchymal bands in the prone (r = .55) and supine (r = .52) positions were also strongly correlated. Dependent density and curvilinear subpleural lines had no significant correlation.
  • Pleural plaques were seen on chest radiographs in 49 subjects. Conventional CT showed unequivocal plaques in 56 and minimal plaques in 25 more. HRCT showed unequivocal plaques in 64 and minimal plaques in 29 more; only seven subjects were free of pleural abnormality on HRCT.
  • Pleural calcification was seen in 13 subjects on chest radiography, 16 on conventional CT, and 20 on HRCT
  • HRCT probability scores correlated most with ILO chest radiographic profusion score (r = .49, p less than .0001) and with pleural disease on conventional CT (r = .47, p less than .0001); inverse correlations with forced vital capacity (r = -.28, p less than .006) and single-breath diffusing capacity (r = -.22, p less than .03). Rales (14 subjects) and clubbing (6 subjects) had no significant correlation.
  • Latency had a small but significant correlation with HRCT score (r = .32, p less than .002); duration of exposure, smoking history and tests of airflow obstruction did not correlate with HRCT scores
  • All seven subjects with diffuse pleural thickening had a high HRCT probability score for asbestosis
  • The two radiologists' five-point HRCT scores were identical in 65 subjects, differed by one point in 32, and by two points in three
• The authors' conclusion: The authors concluded that HRCT can complement the evaluation of asbestos-exposed subjects when other criteria for parenchymal fibrosis are equivocal or absent
• Limitations the authors state:
  • No pathologic (tissue) proof of parenchymal disease in the subjects without clinical asbestosis who had abnormal HRCT findings
  • Parenchymal abnormalities like those described may occur in other interstitial diseases, such as idiopathic interstitial fibrosis
  • The specificity of HRCT remains to be defined by longitudinal follow-up and tissue analysis
  • Diffuse pleural thickening was present in too few patients for strong statistical correlation
  • Honeycombing was seen in only seven subjects, too few to contribute to the diagnostic correlations

Topics

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

Medical terms in this study, explained in our Lexicon: High-Resolution CT (HRCT), Interstitial, Pleural Thickening, Diffusing Capacity (DLCO), Interstitial Lung Disease, Clubbing.

Related studies

• Conventional and high resolution computed tomography in the diagnosis of asbestos-related diseases — D.A. Lynch, G. Gamsu, et al. (1989)
• Asbestos-related pleural and parenchymal fibrosis: detection with high-resolution CT — D.R. Aberle, G. Gamsu, et al. (1988)
• Asbestos-related focal lung masses: manifestations on conventional and high-resolution CT scans — D.A. Lynch, G. Gamsu, et al. (1988)
• High-resolution computed tomography of asbestos-related diseases — D.R. Aberle (1991)
• High-resolution CT in the diagnosis of asbestos-related pleuroparenchymal disease — G. Gamsu (1989)
• Asbestos-related disease: progression of parenchymal abnormalities on high-resolution CT — C.I. Silva, N.L. Müller, et al. (2008)

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