The Framingham Heart Study: Populational CT-based phenotyping in the lungs and mediastinum

Our plain-English summary of The Framingham Heart Study: Populational CT-based phenotyping in the lungs and mediastinum, by T. Araki, G.R. Washko, M.L. Schiebler, et al (European Journal of Radiology Open, 2020).

The study

• Authors: T. Araki, G.R. Washko, M.L. Schiebler, G.T. O'Connor, H. Hatabu
• Journal: European Journal of Radiology Open
• Published: 2020;7:100260
• Type of article: Review
• Cited by: 7 articles, as counted by NIH iCite
• Read it: PubMed · Publisher · Free full text

Abstract

The Framingham Heart Study (FHS) is one of the largest and established longitudinal populational cohorts. CT cohorts of the FHS since 2002 provided a unique opportunity to assess non-cardiac thoracic imaging findings. This review deals with image-based phenotyping studies from recent major publications regarding interstitial lung abnormalities (ILAs), pulmonary cysts, emphysema, pulmonary nodules, pleural plaques, normal spectrum of the thymus, and anterior mediastinal masses, concluding with the discussion of future directions of FHS CT cohorts studies in the era of radiomics and artificial intelligence.

© 2020 The Author(s).

In plain English

This article was a review, not a new study. The authors summarized earlier research using CT scans from the Framingham Heart Study in Framingham, Massachusetts, focusing on the lungs and mediastinum rather than the heart. Third Generation and Offspring participants had cardiac CT from 2002 to 2005 and full chest CT from 2009 to 2011. An earlier Framingham study found pleural plaques or thickening in 1.5% of participants (40 of 2633). The authors described these findings as typically associated with asbestos exposure. That rate was less than half of the 3.9% reported earlier from chest X-rays in the NHANES II cohort (1976 to 1980). In the Framingham study, pleural abnormalities were associated with older age, male sex and cigarette smoking. The authors noted that asbestos is difficult to assess directly and that CT findings can help infer exposure. The review also summarized other findings, including interstitial lung abnormalities, pulmonary cysts, emphysema and anterior mediastinal masses, plus unpublished preliminary data on lung nodules. The authors concluded that the Framingham CT cohorts offered an opportunity, distinct from screening cohorts, to study lung and mediastinal conditions.

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: Review of earlier published studies (mostly by the same research group) that used CT scans from the Framingham Heart Study, plus some unpublished preliminary data on lung nodules
• Who was studied: Framingham Heart Study Third Generation and Offspring cohort participants in Framingham, Massachusetts, USA. They had cardiac CT from 2002 to 2005 (MDCT1) and full chest CT from 2009 to 2011 (MDCT2). Most findings are reported out of 2633 participants, aged 34 to 92 years.
• Exposure: The review reports no exposure measurements. Its asbestos-relevant part concerns pleural plaques and diffuse pleural thickening seen on CT, which the authors describe as typically associated with asbestos exposure. The authors note that direct assessment of asbestos is difficult. They present CT findings in the general population as a useful way to infer occupational or general exposure.
• Main results:
  • An earlier Framingham study (Araki et al., reference 17) found pleural plaques or thickening on CT in 1.5% of participants (40 of 2633) in 2009 to 2011. This was less than half of the 3.9% reported from chest X-rays in the NHANES II cohort (1976 to 1980).
  • In that earlier Framingham study (reference 17), pleural abnormalities were associated with older age, male sex and cigarette smoking.
  • In the Framingham participants with pleural plaques or thickening, the plaques were often at the back of the chest (88 to 93%), and involvement at the front was also common (78%).
  • Earlier Framingham studies found interstitial lung abnormalities in 7% of participants (177 of 2633), associated with older age and MUC5B gene polymorphism. Progression of these abnormalities was associated with lung function decline and increased risk of death.
  • Pulmonary cysts were found in 7.6% of Framingham participants (200 of 2633). They were more common in older participants and were not seen in those under 40.
  • Pure paraseptal emphysema was seen in 3% of Framingham participants (86 of 2633), and mixed paraseptal and centrilobular emphysema in 8% (214 of 2633).
  • Unpublished preliminary Framingham data showed non-calcified lung nodules in 37.5% of the 2633 participants: solid nodules in 35.1% and subsolid nodules in 2.4%.
  • Anterior mediastinal masses were found in 0.9% of Framingham participants (23 of 2571). Over 5 to 7 years of observation, six of eight masses grew in size.
• The authors' conclusion: The authors concluded that the Framingham CT cohorts provide an opportunity to investigate lung and mediastinal diseases that is distinct from screening cohorts. They also concluded that the cohorts suit the study of preclinical conditions, age-related changes and incidental findings.
• Limitations the authors state:
  • Most earlier Framingham CT studies relied on visual assessment using yes-or-no or semi-quantitative classification. Only a few used quantitative measures.
  • The earlier cardiac CT scans (MDCT1) did not cover the entire lungs.

Topics

Medical terms in this study, explained in our Lexicon: Mediastinum, Interstitial, Emphysema, Pleural Plaques.

Related studies

• Pleural abnormalities in the Framingham Heart Study: prevalence and CT image features — T. Araki, M. Yanagawa, et al. (2017)
• Author reply: 'Response to: Pleural abnormalities in the Framingham Heart Study: prevalence and CT image features' by Araki et al — T. Araki, G.M. Hunninghake, et al. (2018)
• Fine needle aspirate flow cytometric phenotyping characterizes immunosuppressive nature of the mesothelioma microenvironment — P.H. Lizotte, R.E. Jones, et al. (2016)
• Solitary fibrous tumor of the mediastinum. A report of 14 cases — G.B. Witkin, J. Rosai (1989)
• A biphasic tumor of the mediastinum with features of synovial sarcoma. A report of four cases — G.B. Witkin, M. Miettinen, et al. (1989)
• Solitary fibrous tumor of the mediastinum — N. Weidner (1991)

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