Absence of left-sided predominance in asbestos-related pleural plaques: a CT study

Our plain-English summary of Absence of left-sided predominance in asbestos-related pleural plaques: a CT study, by J.C. Gallego (Chest, 1998).

The study

• Author: J.C. Gallego
• Journal: Chest
• Published: 1998;113(4):1034-6
• Cited by: 3 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Study Objectives: Differences between the number and areas of pleural plaques in every hemithorax could not be expected a priori. However, previous studies based on chest radiographs reported an unexplained left-sided predominance. In this paper, a comparison of summed surfaces and location of plaques calculated from CT studies was performed.

Patients And Methods: Thoracic CT scans from 40 adults with asbestos exposure and pleural plaques were analyzed. The surface area of every plaque was calculated, and summed areas were recorded separately for every hemithorax. The statistical analysis was performed with t-tests for paired samples. Emphasis was placed on measurement differences.

Measurements And Results: The results show lack of significant predominance for any hemithorax. A total of 668 plaques (352 right and 316 left) were measured, with an average area (+/-SD) of 47.81+/-47.72 cm2 for the right plaques and 45.34+/-67.32 cm2 for the left. The mean of differences (left minus right areas) was -2.56+/-53.68 and slightly statistically different from zero (p=0.652).

Conclusions: Left-sided predominance of asbestos-related pleural plaques is not supported by this study.

In plain English

This study from a hospital radiology department in Ferrol, Spain, used CT scans to test whether asbestos-related pleural plaques are bilateral and symmetric. Some earlier chest X-ray studies had reported a predominance of left-sided pleural disease. The author retrospectively reviewed CT scans of 40 adult men aged 42 to 80 who had pleural plaques and occupational asbestos exposure. All were current or former shipyard workers who had started work at least 20 years earlier. Each plaque's area was estimated by treating it as an ellipse, and areas were added up separately for each side of the chest. In total, 668 plaques were measured: 352 right and 316 left. The mean summed area was 47.81 square centimetres on the right and 45.34 on the left. The mean left-minus-right difference, minus 2.56 square centimetres, was not statistically significant (p = 0.652). Two patients had plaques on one side only. The author concluded that the study does not support left-sided predominance, while noting that the measurement method was imprecise and that 40 patients may be too few to detect uncommon asymmetry.

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: Retrospective review of chest CT scans, comparing right and left pleural plaque areas within each patient (paired t test)
• Who was studied: 40 adult men with asbestos exposure and pleural plaques, aged 42 to 80 (mean 64.37), scanned at the Department of Radiology, Hospital Arquitecto Marcide, Ferrol, Spain; 10 other patients with previous pleural disease were excluded; study dates not given
• Exposure: Occupational asbestos exposure as current or former shipyard workers who had begun working at least 20 years earlier; fiber types and doses not reported
• Main results:
  • 668 plaques were measured in the 40 patients: 352 on the right and 316 on the left
  • Mean summed plaque area was 47.81 cm2 (SD 47.72) on the right and 45.34 cm2 (SD 67.32) on the left
  • The mean left-minus-right difference was -2.56 cm2 (SD 53.68). It was not statistically different from zero (p = 0.652).
  • Only two patients had small plaques on one side only, one right (12.25 cm2) and one left (25.08 cm2)
• The authors' conclusion: The author concluded that left-sided predominance of asbestos-related pleural plaques is not supported by this study, and that it supports symmetry as the rule in the extent of plaque formation
• Limitations the authors state:
  • Plaques were assumed to be elliptical, but their real shape may differ
  • The front-to-back diameter is underestimated because the chest wall is curved, and the top-to-bottom diameter can be affected by breathing movements and partial volume effect
  • The small number of patients may be insufficient to detect asymmetry that occurs only rarely

Topics

Medical terms in this study, explained in our Lexicon: Pleural Plaques, Hemithorax, Chest X-Ray, CT Scan, Asbestos Exposure.

Related studies

• The left-sided predominance of asbestos-related pleural disease — H. Hu, L. Beckett, et al. (1993)
• Roentgenographic evidence for predominant left-sided location of unilateral pleural plaques — B.F. Withers, A.M. Ducatman, et al. (1989)
• Inter-reader agreement in HRCT detection of pleural plaques and asbestosis in participants with previous occupational exposure to asbestos — F. Laurent, C. Paris, et al. (2014)
• Do asbestos-related pleural plaques on HRCT scans cause restrictive impairment in the absence of pulmonary fibrosis? — B. Clin, C. Paris, et al. (2011)
• Asbestos-related cancer risk in patients with asbestosis or pleural plaques — J. Ameille, P. Brochard, et al. (2011)
• Intensity-modulated radiation therapy with simultaneous integrated boost in unresected left-sided pleural mesothelioma: a case report — S. Cilla, C. Digesú, et al. (2010)

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