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Quantitative Assessment of Airway Narrowing, Wall Thickening, and Alteration of Branching Angle in Subjects with Cement Dust Exposure
Abstract   Open access   Peer reviewed

Quantitative Assessment of Airway Narrowing, Wall Thickening, and Alteration of Branching Angle in Subjects with Cement Dust Exposure

Sanghun Choi, Hyun Bin Cho, Taewoo Kim, Woo Jin Kim, Chang Hyun Lee, Kum Ju Chae, So Hyeon Bak, Sung Ok Kwon, Gong Yong Jin, Eun-Kee Park, …
American journal of respiratory and critical care medicine, A7906
Annual American Thoracic Society Meeting (05/15/2020–05/20/2020)
05/01/2020
DOI: 10.1164/ajrccm-conference.2020.201.1_meetingabstracts.a7906
url
https://doi.org/10.1164/ajrccm-conference.2020.201.1_meetingabstracts.a7906View
Published (Version of record) Open Access

Abstract

RATIONALE: Chronic dust exposure is known to be a risk factor for pulmonary diseases, leading to alterations of segmental airways and lung parenchyma. Previous studies have demonstrated the effects of dust exposure on airway wall thickness and emphysema burden but did not associate with its effects on airway diameter, branching angle, and more QCT imaging metrics. Here, we seek to utilize QCT to identify functional alterations in the lung which correspond to structural changes associated with cement dust exposure. METHODS: From a large dataset (N=778), we extracted QCT images for 58 cement dust exposed subjects and 142 non-cement dust exposed subjects. Subjects were limited to current non-smokers with normal PFT results and no prior diagnosis of asthma or pneumonia. Segmental structural variables of airway hydraulic diameter, wall thickness, and branching angle were extracted both at total lung capacity (TLC) and functional residual capacity (FRC), as well as their elongation ratio (strain) assessed by registering the FRC to the TLC image. The airway diameter and wall thickness were normalized by sex, age, and height. Through an image registration-based method, we also distinguished parenchyma as normal, emphysema (Emph%), air trapped (functional small airway disease: fSAD%). RESULTS: In both TLC and FRC scans, dust exposed subjects had smaller airway diameters and larger airway wall thicknesses at the 2 nd -5 th generation (p<0.001), and larger branching angles at the trachea (p<0.001, Figure), compared with non-dust exposed subjects. Dust exposed subjects also had smaller strains (elongation ratio) associated with the thickened walls of the 3 rd -4 th generation (p<0.05), indicating an airway stiffening. Unlike airway structural metrics, the parenchymal functional metrics were not noticeably different. We only found an elevation of Emph% of dust exposed subjects (p<0.01). However, the dust exposed subjects did not have an increased fSAD%. CONCLUSION: Segmental airways exposed by cement dusts are characterized by airway narrowing, airway wall thickening, alteration of branching angles, and airway wall stiffening. Unlike the alteration of segmental airway structure, parenchymal lung functional metrics were not noticeably different, except for a marginal increase of emphysema percentage. The unique airway structures in cement dust-exposed subjects may be associated with the large particle size of cement dust, leading to a different phenotype compared with subjects exposed to smaller particulate associated with cigarette smoke.
 Biomedical Engineering Materials Science Airway Branching angle Cement Dust exposure Quantitative assessment Thickening

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