Chest ultrasonography in health surveillance of asbestos-related lung diseases

Our plain-English summary of Chest ultrasonography in health surveillance of asbestos-related lung diseases, by A. Smargiassi, G. Pasciuto, I. Pedicelli, et al (Toxicology and Industrial Health, 2017).

The study

• Authors: A. Smargiassi, G. Pasciuto, I. Pedicelli, E. Lo Greco, M. Calvello, R. Inchingolo, G. Schifino, P. Capoluongo, P. Patriciello, M. Manno, A. Cirillo, G.M. Corbo, G. Soldati, I. Iavicoli
• Journal: Toxicology and Industrial Health
• Published: 2017;33(6):537-546
• Cited by: 7 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

Objectives: Exposure to asbestos fibers can lead to different lung diseases, such as pleural thickening and effusion, asbestosis, mesothelioma, and lung cancer. These diseases are expected to peak in the next few years. The aim of the study was to validate ultrasonography (US) as a diagnostic tool in the management of lung diseases in subjects with a history of occupational exposure to asbestos.

Methods: Fifty-nine retired male workers previously exposed to asbestos were enrolled in the study. Chest US was performed in all the subjects. The US operator was blinded to earlier performed computed tomography (CT) scan reports and images. The sonographic pathological findings were pleural thickening (with or without calcifications), peripheral lung consolidation, and focal sonographic interstitial syndrome and diffuse pneumogenic sonographic interstitial syndrome (pulmonary asbestosis). Significant US findings were recorded, stored, and subsequently compared with CT scans.

Results: With some patients falling into more than one category, on CT scan, pleural thickening was reported in 33 cases (56%, 26 with calcifications), focal interstitial peripheral alterations in 23 (39%), asbestosis in 6 (10%), and peripheral lung consolidation in 13 cases (22%). Comparing each pathological condition to CT scan reports, US findings had high levels of sensitivity, specificity, positive, and negative predictive values. US did not prove effective for the detection of central lung nodules or diaphragmatic pleural thickenings. Chest US was considered to be the best technique to detect minimal pleural effusions (six subjects, 10%).

Conclusions: Chest US might be considered an additional tool to follow up subjects occupationally exposed to asbestos who have already undergone CT scan examination and whose pathology is detectable by US as well.

In plain English

This study from the Campania region of Italy tested whether chest ultrasound could detect asbestos-related lung and pleural changes found by low-dose CT scans. Fifty-nine retired male workers, randomly recruited by mail from a regional list of workers exposed to asbestos before 1992, had both tests on the same day. The ultrasound operator did not know the CT results. Using CT as the reference, ultrasound found 29 of 33 cases of pleural thickening, all 6 cases of diffuse changes the authors identified as pulmonary asbestosis, 22 of 23 focal interstitial changes and 10 of 13 peripheral lung consolidations. It detected none of 8 central lung nodules and none of 14 diaphragmatic pleural thickenings. It found five minimal pleural effusions that CT did not easily show. The authors noted the small sample, the limited number of asbestosis cases, and parts of the chest that ultrasound cannot reach. The authors concluded that chest ultrasound might be an additional follow-up tool for workers already examined by CT, and called the work preliminary.

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: Diagnostic accuracy comparison of chest ultrasound against low-dose CT (the reference standard) in the same subjects on the same day, with the ultrasound operator blinded to CT results
• Who was studied: 59 retired male workers with a mean age of 66 years (range 53 to 82). They were randomly recruited by mail from a list of 12,622 previously asbestos-exposed workers held by the Campania Region, Italy, and were examined at ASL Napoli 3 Sud, Pompei, from November 2015 to February 2016.
• Exposure: Documented but variable occupational asbestos exposure before 1992 in various industries. Mean years of exposure were 24.6 and mean time since first exposure was 44.1 years. Main job categories were shipyard worker, asbestos production worker, mechanical and electrical maintenance worker, and lathe operator. Fiber types were not specified.
• Main results:
  • Pleural thickening: ultrasound identified 29 of 33 CT-detected cases (sensitivity 88%, specificity 100%, 26/26)
  • Pleural thickening with calcifications: ultrasound recognized indirect signs of calcification in 22 of 26 CT cases (sensitivity 85%, specificity 97%, 32/33)
  • Pulmonary asbestosis (diffuse sonographic interstitial syndrome): ultrasound confirmed all 6 CT-detected cases (sensitivity and specificity 100%)
  • Focal sonographic interstitial syndrome: ultrasound identified 22 of 23 CT cases (sensitivity 96%) and ruled it out in 24 of 36 CT-negative subjects (specificity 67%)
  • Peripheral subpleural lung consolidations: ultrasound detected 10 of 13 CT cases (sensitivity 77%, specificity 100%, 46/46)
  • Apical lung alterations: ultrasound detected 25 of 27 CT cases (sensitivity 93%, specificity 84%, 27/32)
  • Ultrasound did not detect any of the 8 central lung nodules or any of the 14 diaphragmatic pleural thickenings seen on CT
  • Of six subjects with pleural effusions, five had minimal free-flowing effusions that CT scans did not easily detect but ultrasound reported. One large loculated effusion was found by both methods.
  • Subjects with pleural thickening had more years of exposure than those without (26.6 vs. 22.3 years, p = 0.019) and a longer time since first exposure (45.9 vs. 42 years, p = 0.012)
  • Subjects with nodular lung opacities had a significantly longer time since first exposure than those without (47.7 vs. 42.6 years, p = 0.0025)
• The authors' conclusion: The authors concluded that chest ultrasound might be considered an additional tool for following up asbestos-exposed workers who have already had a CT scan, when their disease can also be seen by ultrasound. They described their work as a preliminary study needing confirmation in larger groups.
• Limitations the authors state:
  • The number of subjects was small, and six asbestosis cases were too few to adequately determine sensitivity and specificity
  • The high accuracy values were biased by the high prevalence of disease in the subjects
  • Ultrasound cannot assess the mediastinal and diaphragmatic pleura, lung tissue behind the shoulder blades, or the central lung
  • The authors described the work as preliminary and said larger studies are needed

Topics

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

Medical terms in this study, explained in our Lexicon: Pleural Thickening, Mesothelioma, Lung Cancer, Occupational Exposure, Consolidation, Interstitial, Asbestosis, CT Scan.

Related studies

• Chest ultrasonography in health surveillance of asbestos related pleural disease — S. Scarlata, P. Finamore, et al. (2017)
• Agreement between chest radiography and high-resolution computed tomography in diagnosing dust-related interstitial lung fibrosis — R.R. Tiwari (2015)
• Comparison of chest digital tomosynthesis and chest radiography for detection of asbestos-related pleuropulmonary disease — G. Lee, Y.J. Jeong, et al. (2013)
• Findings from high resolution computed tomography of the lung and pleura of symptom free workers exposed to amosite who had normal chest radiographs and pulmonary function tests — S. Neri, A. Antonelli, et al. (1994)
• Inter-reader variability in chest radiography and HRCT for the early detection of asbestos-related lung and pleural abnormalities in a cohort of 636 asbestos-exposed subjects — E. Ochsmann, T. Carl, et al. (2010)
• Asbestos-related pleural disease and asbestosis: a comparison of CT and chest radiography — A.C. Friedman, S.B. Fiel, et al. (1988)

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