Pleural plaques in asbestos-exposed workers: reproducibility of a new high-resolution CT visual semiquantitative measurement method

Our plain-English summary of Pleural plaques in asbestos-exposed workers: reproducibility of a new high-resolution CT visual semiquantitative measurement method, by G.S. Meirelles, J.I. Kavakama, D. Jasinowodolinski, et al (Journal of Thoracic Imaging, 2006).

The study

• Authors: G.S. Meirelles, J.I. Kavakama, D. Jasinowodolinski, L.E. Nery, M. Terra-Filho, R.T. Rodrigues, J.A. Neder, L.M. Napolis, E. Bagatin, G. D'Ippolito, N.L. Müller
• Journal: Journal of Thoracic Imaging
• Published: 2006;21(1):8-13
• Cited by: 12 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Objective: To assess the reproducibility of a new high-resolution computed tomography (CT) visual semiquantitative method for pleural plaques in asbestos-exposed workers.

Material And Methods: We performed thin-section CT in 752 chrysotile asbestos mining workers and ex-workers. Institutional review board approval and signed written informed consent from subjects were obtained. Two readers independently evaluated the 752 CT scans and identified 57 workers (mean age +/- SD, 61.8 years +/- 8.1; range, 37 to 81 years) who had pleural plaques and no other pleural or parenchymal abnormality. Three independent radiologists then quantified the plaque burden in these 57 workers using a scoring system based on the evaluation of the maximum thickness of parietal pleural plaques and percentage of parietal pleural surface involvement. We also calculated the proportion between the number of CT slices with diaphragmatic plaques and the total number of slices in which the diaphragm was seen (pdiaph). The intraobserver and interobserver agreements were analyzed using weighted Kappa coefficient.

Results: Interobserver agreements were good for the pleural plaque score (k = 0.61, 0.75, and 0.79) and ranged from good (k = 0.61) to excellent (k = 0.86) for the pdiaph. Intraobserver agreements ranged from good to excellent for the pleural plaque score (k = 0.79 and 1.00) and for the pdiaph (k = 0.79 and 0.93).

Conclusion: The method proposed for high-resolution CT pleural plaque quantification in asbestos-exposed workers has a high reproducibility.

In plain English

This study built a new way to score pleural plaques on high-resolution (thin-section) CT scans. It tested whether different readers, and the same reader on two occasions, scored the scans alike. Between January 2002 and September 2003, 752 chrysotile asbestos mining workers and ex-workers in Brazil had CT scans. Readers picked out 57 men who had pleural plaques and no other pleural abnormality or sign of asbestosis. The authors stated these men were exposed only to chrysotile, for a mean of 13 years. Three radiologists split each scan image into four quadrants. In each quadrant they graded how much of the chest-wall lining the plaques covered and how thick the thickest plaque was. Plaques on the diaphragm were measured separately. Agreement between readers on the plaque score gave kappa values of 0.61, 0.75 and 0.79. For diaphragm plaques the values ranged from 0.61 to 0.86. On re-reading, two readers scored 0.79 and 1.00 for the plaque score and 0.79 and 0.93 for diaphragm plaques. The authors concluded the method has high reproducibility.

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: Observer-agreement (reproducibility) study of a new visual scoring method for pleural plaques on high-resolution CT
• Who was studied: 752 chrysotile asbestos mining workers and ex-workers in Brazil scanned January 2002 to September 2003; 57 men (mean age 61.8 years, range 37 to 81) with pleural plaques and no other pleural abnormality or evidence of asbestosis were scored
• Exposure: Chrysotile asbestos from mining work only; mean exposure time 13 years (range 3 months to 40 years)
• Main results:
  • Agreement between readers on the parietal pleural plaque score: kappa 0.61, 0.75 and 0.79
  • Agreement between readers on the diaphragmatic plaque proportion (pdiaph): kappa ranged from 0.61 to 0.86
  • Agreement of the same reader on re-reading after 30 to 90 days (two readers): kappa 0.79 and 1.00 for the plaque score and 0.79 and 0.93 for pdiaph
  • The authors classed kappa 0.61 to 0.80 as good and 0.81 to 1.00 as excellent
  • Agreement between readers was slightly lower for diaphragmatic plaques than for parietal plaques
  • Mediastinal plaques were very uncommon (0 to 4) and were not analysed statistically
• The authors' conclusion: The authors concluded that the proposed CT plaque-scoring method has high reproducibility and could be used to correlate with clinical and functional findings

Topics

The National Library of Medicine indexes this study under subjects our site covers: Pleural plaques and thickening.

Medical terms in this study, explained in our Lexicon: Pleural Plaques, High-Resolution CT (HRCT), Chrysotile, Informed Consent, CT Scan, Diaphragm.

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