Observer variation in computed tomography of pleural lesions in subjects exposed to indoor asbestos

Our plain-English summary of Observer variation in computed tomography of pleural lesions in subjects exposed to indoor asbestos, by H. De Raeve, J.A. Verschakelen, P.A. Gevenois, et al (The European Respiratory Journal, 2001).

The study

• Authors: H. De Raeve, J.A. Verschakelen, P.A. Gevenois, P. Mahieu, G. Moens, B. Nemery
• Journal: The European Respiratory Journal
• Published: 2001;17(5):916-21
• Cited by: 15 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

To assess the reliability of computed tomography (CT) in detecting discrete pleural lesions, the interobserver and intra-observer variability in reading the conventional and high-resolution CT (HRCT) scans of 100 volunteers, who had worked for > or = 10 yrs in a building with known asbestos contamination, was evaluated. In the first session, pleural abnormalities were detected by a single radiologist (A1) in 13 subjects. In the second session, the scans were read again independently by the same radiologist (A2) and two other experienced radiologists (B, C). The final decision for the presence of pleural lesions was made in a final consensus reading. This gave a diagnosis of pleural abnormalities in 18 subjects, of whom eight (44%) had been detected by all three readers, five (28%) by two readers and four (22%) by only one reader; one scan, rated normal by all readers during the second session, was reconsidered because pleural abnormalities had been noted at the first reading (A1). The intra-observer agreement for reader A was good (kappa (kappa) 0.68) but the interobserver agreement between the readers was only fair to moderate (weighted kappa: A2-B=0.43, A2-C = 0.45, B-C = 0.26) in the second reading session. In conclusion, when looking for the prevalence of pleural lesions in indoor asbestos exposed subjects, the potential lack of consistency in reporting the presence of small pleural abnormalities must be borne in mind and strict precautions must be taken.

In plain English

This study measured how consistently radiologists read chest CT scans for small abnormalities of the pleura, the lining around the lungs. The subjects were the first 100 volunteers in a health screening of EU staff who had worked at least 10 years in the Brussels Berlaymont building, evacuated in 1991 because of indoor asbestos pollution. One radiologist first found pleural abnormalities in 13 people. That radiologist and two others reread all scans independently, then reached a consensus. By consensus, 18 people had pleural abnormalities: 7 judged more likely due to past tuberculosis or pleurisy, and 11 judged pleural plaques of low, moderate or high probability. Eight of the 18 were spotted by all three readers. The first radiologist agreed well with their earlier reading (kappa 0.68), but agreement between reader pairs was only fair to moderate: weighted kappa 0.43 (95% confidence interval 0.19 to 0.66), 0.45 (0.27 to 0.64) and 0.26 (0.07 to 0.44). The authors concluded that inconsistent reporting of small pleural abnormalities must be borne in mind. They noted the study could not show whether the lesions were asbestos-related.

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-variability study: repeated and independent readings of CT scans from a health screening study, with agreement measured by kappa statistics
• Who was studied: First 100 consecutive volunteers (45 males, 55 females, mean age 54 years) who were present or former EU civil servants and had worked at least 10 years in the Berlaymont building, Brussels. They were examined at University Hospitals Gasthuisberg, Leuven, Belgium.
• Exposure: Indoor asbestos exposure from working in the Berlaymont building, which housed EU offices from 1968 until its evacuation in 1991 because of asbestos pollution. Fiber type was not stated. The subjects had worked there for an average of 16 years.
• Main results:
  • No overt cases of pulmonary fibrosis, diffuse pleural thickening, bronchial cancer or mesothelioma were detected by HRCT in the 100 subjects.
  • At the first reading, radiologist A found a pleural abnormality in 13 of the 100 subjects.
  • By consensus, pleural abnormalities were found in 18 subjects. Of these, eight (44%) had been detected by all three readers, five (28%) by two readers and four (22%) by only one reader. One further scan had been rated normal by all readers at the second session and was reconsidered because of the first reading.
  • Of the 18 subjects with pleural abnormalities, 7 were considered not related to asbestos but more likely to past tuberculosis or pleurisy. The remaining 11 were considered pleural plaques of low (2), moderate (4) or high (5) probability.
  • Intra-observer agreement for reader A between the first and second readings was good (kappa 0.68).
  • Inter-reader agreement in the second reading session (weighted kappa, 95% confidence intervals) was fair to moderate: A2 versus B 0.43 (0.19 to 0.66), moderate; B versus C 0.26 (0.07 to 0.44), fair; A2 versus C 0.45 (0.27 to 0.64), moderate.
  • The first single reading (A1) and the consensus reading agreed in 95% of cases. The consensus reading detected five additional cases of pleural abnormalities.
  • The detected lesions were small, from a few millimetres to at most one centimetre in length. In 7 of the 18 subjects, they were found on one side only.
• The authors' conclusion: The authors concluded that, when looking for the prevalence of pleural lesions in people exposed to indoor asbestos, the potential lack of consistency in reporting small pleural abnormalities must be borne in mind and strict precautions must be taken. They also stated that a reading by three radiologists increased the detection rate of small pleural lesions compared with a single reader.
• Limitations the authors state:
  • There is no gold standard (such as surgical, autopsy or pathological evidence) for minor pleural plaques, so accuracy could not be tested, only agreement between and within readers.
  • The detected lesions do not all necessarily correspond to the classical definition of pleural plaques.
  • Some lesions may have been due to tuberculosis or pleurisy, making it difficult to say they were asbestos-related.
  • The study did not answer whether the lesions were asbestos-related. A control group of 100 unexposed subjects was still being analysed.

Topics

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

Medical terms in this study, explained in our Lexicon: High-Resolution CT (HRCT).

Related studies

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• Low-dose chest computed tomography screening of subjects exposed to asbestos — K. Kato, K. Gemba, et al. (2018)
• Computed tomography features in malignant pleural mesothelioma and other commonly seen pleural diseases — M. Metintas, I. Ucgun, et al. (2002)
• The diagnostic performance of routinely acquired and reported computed tomography imaging in patients presenting with suspected pleural malignancy — S. Tsim, D.B. Stobo, et al. (2017)

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