Chest ultrasonography in health surveillance of asbestos related pleural disease

Our plain-English summary of Chest ultrasonography in health surveillance of asbestos related pleural disease, by S. Scarlata, P. Finamore, G. Giannunzio, et al (Lung Cancer, 2017).

The study

• Authors: S. Scarlata, P. Finamore, G. Giannunzio, S. Santangelo, R. Antonelli Incalzi
• Journal: Lung Cancer
• Published: 2017;111:139-142
• Cited by: 3 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

High resolution computed tomography, (HRCT), is currently considered the diagnostic gold standard to diagnose early stage malignant pleural mesothelioma and other non-malignant pleural conditions, but it is expensive and exposes the patient to radiation dose. In a screening and population medicine perspective, Thoracic Ultrasounds may become a valuable alternative because it can detect minimal changes in pleural surface, is widely available and safe. On these bases, we therefore validated thoracic US in subjects with history of exposure to asbestos, having HRCT as the reference standard. One hundred-fifty subjects were screened and 117 were recruited. Pleural abnormalities at US and/or HRCT were detected in 66 out of 117 subjects (prevalence=57%), and their prevalence was unrelated to both mansion and smoking habit, while mean age and mean length of exposure were higher in those having pleural abnormalities (age=47±5 vs 44±6years, p<0.05;years of exposure=20±7 vs 17±5, p<0.05). Thirteen out of 19 subjects with pleural abnormalities at HRCT were also identified by thoracic US, whereas 47 participants had lesions seen at US, but not at the HRCT scan. Positive and negative percent agreement were 66.6% and 51.8%, respectively; the McNemar's test for equality showed a p-value <0.001. In conclusion, chest US might complement HRCT in the health surveillance of asbestos exposed population to detect earlier lesions or to follow up US approachable lesions. Further research is needed to clarify whether this approach may enhance early recognition of pleural mesothelioma and ameliorate prognosis.

Copyright © 2017 Elsevier B.V. All rights reserved.

In plain English

This proof-of-concept study in Rome, Italy, compared chest ultrasound with high resolution CT (HRCT) for finding pleural abnormalities. HRCT was treated as the reference standard. The participants were men with long occupational exposure to chrysotile asbestos in the aircraft and automotive industry. Of 150 men screened between January 2016 and February 2017, 117 were included, and their mean exposure was 20 years. Pleural abnormalities were seen on ultrasound, HRCT or both in 66 of the 117 men (57%), and these men were on average older and had been exposed longer. Of the 19 men with abnormalities on HRCT, 13 were also identified by ultrasound, while 47 men had lesions seen only on ultrasound. Four of the six lesions seen only on HRCT were in areas ultrasound could virtually not reach. The authors concluded that chest ultrasound might complement HRCT in health surveillance of asbestos-exposed people. They noted three limits: without follow-up, the meaning of the ultrasound findings is unknown; a single operator performed all the ultrasound examinations; and a definitive accuracy estimate would need thoracoscopy or biopsy.

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: Proof-of-concept diagnostic comparison study: chest ultrasound compared with HRCT as the reference standard in people screened for asbestos-related pleural disease
• Who was studied: 150 consecutively screened men, 117 of them included in the analysis. All were men working in the aircraft and automotive industry, referred to Campus Bio Medico University and Teaching Hospital, Rome, Italy, and enrolled January 2016 to February 2017. Mean age was 46.8 years.
• Exposure: Documented occupational exposure to chrysotile asbestos (spelled 'crysotile' or 'crysothile' in the article), prolonged and continuous for over 15 years. Mean length of exposure was 20 years.
• Main results:
  • Pleural abnormalities were seen on ultrasound and/or HRCT in 66 of 117 participants (prevalence 57%).
  • Participants with pleural abnormalities were older on average (47 plus or minus 5 vs 44 plus or minus 6 years, p less than 0.05) and had longer exposure (20 plus or minus 7 vs 17 plus or minus 5 years, p less than 0.05). The prevalence of abnormalities was unrelated to job role and smoking.
  • Of the 19 participants with pleural abnormalities on HRCT, 13 were also identified by ultrasound.
  • 47 participants had lesions seen on ultrasound but not on HRCT.
  • Of the six lesions seen only on HRCT, four were virtually not reachable by ultrasound (retro-scapular, retro-sternal and paravertebral areas). The other two, along the axillary space, were theoretically visible by ultrasound.
  • Agreement between ultrasound and HRCT was 54% overall, 66.6% positive and 51.8% negative. McNemar's test gave p less than 0.001.
  • Lesion sizes by group: ultrasound-only lesions 4.2 (plus or minus 7.5) millimeters, HRCT-only lesions 6.8 (plus or minus 4.2), lesions seen by both methods 6.6 (plus or minus 7.4). The difference was not statistically significant (p = 0.541).
  • Among the 13 lesions seen by both methods, size measurements agreed with Cohen's k = 0.81 for lesions over 8 mm and 0.69 for lesions under 8 mm.
  • Spirometry was normal in 108 participants (93%).
• The authors' conclusion: The authors concluded that chest ultrasound might complement HRCT in health surveillance of asbestos-exposed populations, to detect earlier lesions or to follow up lesions ultrasound can reach. They called for further research on whether this improves early recognition of pleural mesothelioma.
• Limitations the authors state:
  • Follow-up is pending, so the biological and clinical meaning of pleural thickness detected by ultrasound remains unknown.
  • The chest ultrasound examinations were all performed by a single operator, so the effect of differences between observers could not be checked.
  • A definitive estimate of ultrasound accuracy would require thoracoscopy and/or biopsy rather than HRCT as the reference.

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: High-Resolution CT (HRCT), Pleural Mesothelioma, Ultrasound, Habit, P-Value, Prognosis.

Related studies

• Chest ultrasonography in health surveillance of asbestos-related lung diseases — A. Smargiassi, G. Pasciuto, et al. (2017)
• Early detection of malignant pleural mesothelioma in asbestos-exposed individuals with a noninvasive proteomics-based surveillance tool — R.M. Ostroff, M.R. Mehan, et al. (2012)
• Asbestos-related pleural disease and asbestosis: a comparison of CT and chest radiography — A.C. Friedman, S.B. Fiel, et al. (1988)
• Ultrasonography and computed tomography of peritoneal mesothelioma — H.C. Yeh, A.P. Chahinian (1980)
• The usefulness of computed tomography in detecting asbestos-related pleural abnormalities in people who had indeterminate chest radiographs: the Libby, MT, experience — O.I. Muravov, W.E. Kaye, et al. (2005)
• Asbestos-related chest diseases: plain radiographic findings — W.T. Miller, W.B. Gefter, et al. (1992)

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