Computer tomography in the evaluation of pulmonary asbestosis. Preliminary experiences with the EMI general purpose scanner

Our plain-English summary of Computer tomography in the evaluation of pulmonary asbestosis. Preliminary experiences with the EMI general purpose scanner, by L. Kreel (Acta Radiologica: Diagnosis, 1976).

The study

• Author: L. Kreel
• Journal: Acta Radiologica: Diagnosis
• Published: 1976;17(4):405-12
• Cited by: 69 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. 002295).

Abstract

Thirteen individuals with varying lengths of exposure to asbestosis were examined by computer tomography with the EMI Scanner. Various pleuroparenchymal abnormalities were found, many not being seen on standard chest films. In some cases, with normal chest radiography, definite pleural involvement could be demonstrated, particularly that in the posterior sulci on the diaphragm and at the mediastinum. Tissue attenuation measurements in regions of parenchymal involvement reached 90 EMI units above normal lung tissue. The normal gravity effect is abolished in cases of parenchymal disease caused by asbestosis. Parenchymal disease was much more obvious on the CT scans than on conventional chest films.

In plain English

This 1976 report from Harrow, England, described early experience using computer tomography (CT) with the EMI general purpose scanner in 13 patients exposed to asbestos for between one and 40 years. Each had 5 to 8 CT sections, which were compared with their chest X-rays. Pleural plaques were seen on CT in 11 of 13 patients but on chest films in only 8 of 13. CT also showed changes not seen on chest films, including subpleural infiltrates in 3 patients and thick soft-tissue 'bands' in 3 patients. In patients with lung tissue disease, the normal increase in blood flow to the lower-lying (gravity-dependent) parts of the lung was absent. The author considered this probably a sign of interstitial fibrosis. Lung tissue density reached up to 90 EMI units above normal. No chest film showed an abnormality that CT did not. The author concluded that lung tissue disease was much more obvious on CT than on chest films. The author stated that the cause of the bands, and whether the raised density reflected fibrosis or silicates, was not yet known.

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: Small preliminary case series: imaging study comparing CT scans with conventional chest films in 13 patients, with no comparison group
• Who was studied: 13 referred patients known to have been exposed to asbestos. Their chest films ranged from normal to fine linear structures in the mid and lower zones, and many had pleural plaques, some calcified. The author's department was in Harrow, England (Clinical Research Centre and Northwick Park Hospital). Where and when the patients were examined is not otherwise stated, beyond submission in January 1976.
• Exposure: Asbestos exposure lasting from one to 40 years. Fiber types, products and jobs were not stated.
• Main results:
  • Pleural plaques were present on CT in 11 of 13 patients, but on chest films in only 8 of 13
  • Marked irregularity, straightening or blurring of the heart margin (mediastinal pleural irregularity) was seen in 5 of the 13 patients
  • Subpleural infiltrates were seen on CT in 3 patients and could not be seen on conventional chest films
  • Thick soft-tissue 'bands' were seen on CT in 3 patients, with no counterpart on standard chest films
  • Where chest films showed thin linear structures, CT showed large patches of honeycomb appearance
  • A large dense area near the lesser fissure was found in 2 patients, and areas considered to be bullae were found in 2 patients
  • In patients with asbestosis, the normal gravity-related increase in blood flow to the lower-lying parts of the lung was abolished
  • Tissue attenuation (density) in affected lung reached up to 90 EMI units above normal lung tissue
  • In none of the patients did the chest film show an abnormality that could not be seen on CT
• The authors' conclusion: The author concluded that parenchymal (lung tissue) disease was much more obvious on CT scans than on conventional chest films, and that pleural involvement could be shown on CT in some patients with normal chest X-rays. The author considered the loss of the gravity effect on blood flow to be probably a sign of interstitial fibrosis.
• Limitations the authors state:
  • The author stated that the pathologic abnormalities causing the 'bands' seen on CT are not known
  • The author stated it was not possible to tell whether the raised tissue density was due to fibrosis or to the presence of silicates
  • The author stated that the reason for the loss of the gravity effect on blood flow was not yet known

Topics

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

Medical terms in this study, explained in our Lexicon: Asbestosis, Chest X-Ray, Diaphragm, Mediastinum, CT Scan.

Related studies

• Computed tomography in pulmonary asbestosis — D. Katz, L. Kreel (1979)
• 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)
• Pleural calcification in pancreatitis demonstrated by computed tomography — G.M. Bydder, L. Kreel (1981)
• The comparison of high-resolution computed tomography findings in asbestosis and idiopathic pulmonary fibrosis — M. Akira, K. Morinaga (2016)
• Assessment of therapy responses and prediction of survival in malignant pleural mesothelioma through computer-aided volumetric measurement on computed tomography scans — F. Liu, B. Zhao, et al. (2010)
• Computer-assisted classification system for chest X-ray and computed tomography findings in occupational lung disease — T. Kraus, H.J. Raithel, et al. (1997)

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