Pulmonary asbestosis: CT study of subpleural curvilinear shadow. Work in progress

Our plain-English summary of Pulmonary asbestosis: CT study of subpleural curvilinear shadow. Work in progress, by H. Yoshimura, M. Hatakeyama, H. Otsuji, et al (Radiology, 1986).

The study

• Authors: H. Yoshimura, M. Hatakeyama, H. Otsuji, M. Maeda, H. Ohishi, H. Uchida, H. Kasuga, H. Katada, N. Narita, R. Mikami
• Journal: Radiology
• Published: 1986;158(3):653-8
• Cited by: 81 articles, as counted by NIH iCite
• Read it: PubMed · Publisher
• In J-M's library: Johns-Manville's company medical library held a copy (J-M no. 000452).

Abstract

High-resolution computed tomographic scans of 19 patients with pulmonary asbestosis revealed a subpleural curvilinear shadow (SCLS) parallel to the inner chest wall in the lungs of 15 (78.9%) patients. Most (46.7%) SCLS measured greater than 5 cm but less than 10 cm in length and occurred less than 1 cm from the inner chest wall in all cases. SCLS was distributed mainly in the lower lobe in patients with mild pulmonary fibrosis and in segments where fibrosis was mild in patients with honeycomb shadows. This may reflect initiation of pulmonary fibrosis leading to the formation of a honeycomb shadow. Radiologic-pathologic correlation, achieved in one postmortem specimen, seemed to indicate that SCLS was associated with the initial change of fibrosing bronchioloalveolitis, which is characteristic of pulmonary asbestosis.

In plain English

Researchers at Nara Medical University, Japan, reviewed high-resolution CT scans of 19 patients with pulmonary asbestosis. The patients had long-term work exposure to asbestos dust in asbestos manufacturing factories. The authors described a thin curved line just inside the chest wall, which they named a subpleural curvilinear shadow (SCLS). It appeared in 15 of the 19 patients (78.9%). Of these 15, 7 (46.7%) had shadows over 5 cm but under 10 cm long; in all cases the shadow lay less than 1 cm from the inner chest wall. In patients with mild lung scarring it lay mainly in the lower lobe. Where honeycomb-pattern scarring had developed, it was found more in areas where scarring was milder. In a comparison group of ten patients with idiopathic interstitial pneumonia, one (10%) had the shadow. In one patient studied after death, the shadow matched a band of scarring with flattened, collapsed air sacs near the lung surface. The authors concluded that the shadow may reflect the early phase of scarring that later becomes honeycombing. They said it remained to be seen how specific the finding is.

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: Descriptive CT study of patients with asbestosis (labelled 'work in progress'), with a small comparison group and radiologic-pathologic correlation in one postmortem lung
• Who was studied: 19 patients judged to have pulmonary asbestosis by ILO classification: 18 men and one woman, aged 41 to 68 (mean 55). By ILO category, 11 were category 1, six category 2 and two category 3. All had long-term occupational exposure in asbestos manufacturing factories. The comparison group was 10 patients with idiopathic interstitial pneumonia. The study was from Nara Medical University, Japan, published 1986.
• Exposure: Occupational asbestos dust in asbestos manufacturing factories, with a mean exposure duration of 30 years. Fiber type is not specified.
• Main results:
  • The subpleural curvilinear shadow was found in 15 of the 19 asbestosis patients (78.9%).
  • By the authors' CT severity types, the shadow was seen in all 6 type I patients, 6 of 9 type II patients, both type III patients and 1 of 2 type IV patients.
  • Of the 15 patients with the shadow, 7 (46.7%) had shadows longer than 5 cm but shorter than 10 cm (Table 2). In all cases the shadow was less than 1 cm from the inner chest wall.
  • In the mildest type (type I), the shadow tended to concentrate in the lower lobe.
  • In types II to IV, the shadow disappeared from the lower segments as honeycomb shadowing increased.
  • In the comparison group of 10 patients with idiopathic interstitial pneumonia, the shadow was seen in 1 (10%).
  • In one patient examined after death (a 55-year-old man with 15 years of exposure), a streaky structure was found where the shadow had been on CT. Under the microscope it showed a fibrosing alveolitis pattern.
• The authors' conclusion: The authors concluded that the subpleural curvilinear shadow seen in pulmonary asbestosis may reflect the initial phase of lung fibrosis that later develops into a honeycomb pattern.
• Limitations the authors state:
  • The authors stated that how specific the finding is remains to be seen.
  • The authors stated that the cause of the shadow is not yet known.
  • The authors stated that further CT and tissue studies of asbestosis and other interstitial lung diseases 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: Asbestosis, Subpleural Curvilinear Line, Pulmonary Fibrosis, Fibrosis.

Related studies

• Transient subpleural curvilinear shadow caused by pulmonary congestion — K. Arai, T. Takashima, et al. (1990)
• Health progress in an asbestos textile works — J. Mitchell (1961)
• Teachers Union Organizes Members to Enforce AHERA Law--A Work in Progress — M.P. Sireci, C. Levenstein, et al. (2016)
• The comparison of high-resolution computed tomography findings in asbestosis and idiopathic pulmonary fibrosis — M. Akira, K. Morinaga (2016)
• Specificity of high-resolution CT findings in pulmonary asbestosis: do patients scanned for other indications have similar findings? — C.J. Bergin, R.A. Castellino, et al. (1994)
• Some observations of the dust content and composition in lungs with asbestosis, made during work on coal miners pneumoconiosis — G. Nagelschmidt (1965)

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