Incidental and Underreported Pleural Plaques at Chest CT: Do Not Miss Them-Asbestos Exposure Still Exists

Our plain-English summary of Incidental and Underreported Pleural Plaques at Chest CT: Do Not Miss Them-Asbestos Exposure Still Exists, by M.A. Mazzei, F. Contorni, F. Gentili, et al (BioMed Research International, 2017).

The study

• Authors: M.A. Mazzei, F. Contorni, F. Gentili, S. Guerrini, F.G. Mazzei, A. Pinto, N. Cioffi Squitieri, A.G. Sisinni, V. Paolucci, R. Romeo, P. Sartorelli, L. Volterrani
• Journal: BioMed Research International
• Published: 2017;2017:6797826
• Cited by: 20 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

Pleural plaques (PPs) may be a risk factor for mortality from lung cancer in asbestos-exposed workers and are considered to be a marker of exposure. Diagnosing PPs is also important because asbestos-exposed patients should be offered a health surveillance that is mandatory in many countries. On the other hand PPs are useful for compensation purposes. In this study we aimed to evaluate the prevalence, as incidental findings, and the underreporting rate of PPs in chest CT scans (CTs) performed in a cohort of patients (1512) who underwent chest CT with a slice thickness no more than 1.25 mm. PPs were found in 76 out of 1482 patients (5.1%); in 13 out of 76 (17,1%) CTs were performed because of clinical suspicion of asbestos exposure and 5 of them (38%) were underreported by radiologist. In the remaining 63 cases (82.9%) there was no clinical suspicion of asbestos exposure at the time of CTs (incidental findings) and in 38 of these 63 patients (60.3%) PPs were underreported. Reaching a correct diagnosis of PPs requires a good knowledge of normal locoregional anatomy and rigorous technical approach in chest CT execution. However the job history of the patient should always be kept in mind.

In plain English

This retrospective study from a university hospital in Siena, Italy, measured how often pleural plaques showed up on chest CT scans and how often the original radiology report left them out. The authors reviewed 1,482 thin-slice chest CT scans taken between January and June 2016. Two radiologists, who did not know the patients' job histories, examined every scan. Pleural plaques were found in 76 of the 1,482 patients (5.1%). In 13 of these 76, the scan had been ordered because asbestos exposure was suspected, and the plaques were not reported in 5 of them. In the other 63, nobody suspected asbestos exposure when the scan was done. For 38 of these 63 patients (60.3%), the final CT report did not mention the plaques. A history of asbestos exposure was later established in 53 of the 63. Plaque width did not differ significantly between reported and unreported plaques. The authors concluded that plaques can be detected on CT even without suspicion of asbestos exposure, but are often underreported.

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 from one hospital's radiology database, with blinded re-reading by two radiologists
• Who was studied: 1,512 chest CT scans with slice thickness no more than 1.25 mm, taken at the Diagnostic Imaging Unit of the Azienda Ospedaliera Universitaria Senese (Siena, Italy) from January to June 2016. 30 were excluded for motion artefacts, insufficient image resolution or partially explored lung, leaving 1,482 patients.
• Exposure: Asbestos exposure was not measured and no fiber types are named. After the blinded image review, the authors established a history of asbestos exposure for 66 of the 76 patients with plaques, using work histories, clinical reports and information from patients. Jobs listed in Table 1 included bricklayers (21), metal workers (9), asbestos insulation removers (7), plumbers (5), shipyard workers (5), and others.
• Main results:
  • Pleural plaques were found in 76 of the 1,482 patients (5.1%).
  • In 13 of the 76 patients with plaques, the CT was ordered because asbestos exposure was suspected. In 5 of these 13 (38%), the plaques were underreported.
  • In the 63 patients whose plaques were incidental findings (no suspicion of asbestos exposure at the time of the CT), the plaques were not mentioned in the final CT report in 38 of 63 (60.3%).
  • Among those 63 incidental cases, a history of asbestos exposure was established in 53 (84.1%) after the blinded image analysis.
  • Of the 63 incidental cases, 43 had at least one earlier CT whose report was negative for pleural findings, including plaques.
  • Of the 66 patients with a history of asbestos exposure, 65 had multiple plaques on both sides. Of the 10 patients without a history of occupational asbestos exposure, 6 of the 8 with a single plaque were attributed to pleuritis from earlier pneumonia, and 2 were probably due to bleeding into the chest after trauma. For the remaining 2, who had multiple plaques on both sides, the authors considered environmental asbestos exposure plausible.
  • Mean plaque width did not differ significantly between reported and underreported plaques: 5.4 plus or minus 2.7 mm versus 5.5 plus or minus 3.3 mm, p greater than 0.05.
• The authors' conclusion: The authors concluded that pleural plaques can be detected on CT scans even when asbestos exposure is not suspected, but they are often underreported. In their view, knowing the typical appearance and location of plaques, and keeping the patient's job history in mind, is crucial.
• Limitations the authors state:
  • The study population may not be large enough to fully understand whether and how radiologists report pleural findings on standard chest CTs.

Topics

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

Medical terms in this study, explained in our Lexicon: Pleural Plaques, Asbestos Exposure, Lung Cancer, CT Scan.

Related studies

• Focal pleural thickening mimicking pleural plaques on chest computed tomography: tips and tricks — K.M. Alfudhili, D.A. Lynch, et al. (2016)
• Risk and significance of chest radiograph and pulmonary function abnormalities in an elderly cohort of former nuclear weapons workers — M.A. Mikulski, P.G. Hartley, et al. (2011)
• Pleural plaques and exposure to mineral fibres in a male urban necropsy population — A. Karjalainen, P.J. Karhunen, et al. (1994)
• Relationship between number of asbestos bodies in autopsy lung and pleural plaques on chest X-ray film — T. Kishimoto, T. Ono, et al. (1989)
• Pleural plaques in asbestos-exposed workers: reproducibility of a new high-resolution CT visual semiquantitative measurement method — G.S. Meirelles, J.I. Kavakama, et al. (2006)
• Ultra low dose CT screen-detected non-malignant incidental findings in the Western Australian Asbestos Review Programme — C.P. Murray, P.M. Wong, et al. (2016)

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