Quantitative CT image-based structural and functional changes during asthma acute exacerbations

Joonwoo Park; Sujeong Kim; Jae-Kwang Lim; Kwang Nam Jin; Min Suk Yang; Kum Ju Chae; Gong Yong Jin; Tae-Bum Kim; Hee-Kyoo Kim; Kyeong Eun Lee; Chang Hyun Lee; Sanghun Choi

doi:10.1152/japplphysiol.00743.2020

Quantitative CT image-based structural and functional changes during asthma acute exacerbations

J Appl Physiol (1985). 2021 Sep 1;131(3):1056-1066. doi: 10.1152/japplphysiol.00743.2020. Epub 2021 Aug 12.

Authors

Joonwoo Park¹, Sujeong Kim², Jae-Kwang Lim³, Kwang Nam Jin⁴, Min Suk Yang⁵, Kum Ju Chae⁶, Gong Yong Jin⁶, Tae-Bum Kim⁷, Hee-Kyoo Kim⁸, Kyeong Eun Lee⁹, Chang Hyun Lee¹⁰, Sanghun Choi¹

Affiliations

¹ School of Mechanical Engineering, College of Engineering, Kyungpook National University, Daegu, South Korea.
² Department of Internal Medicine, School of Medicine, Kyungpook National University, Kyungpook National University Hospital, Daegu, South Korea.
³ Department of Radiology, School of Medicine, Kyungpook National University, Kyungpook National University Hospital, Daegu, South Korea.
⁴ Department of Radiology, Seoul Metropolitan Government Seoul National University Boramae Medical Center, Seoul, South Korea.
⁵ Department of Internal Medicine, Seoul Metropolitan Government Seoul National University Boramae Medical Center, Seoul, South Korea.
⁶ Department of Radiology, Institute of Medical Science, Research Institute of Clinical Medicine of Chonbuk National University-Biomedical Research Institute of Chonbuk National University Hospital, Jeonju, South Korea.
⁷ Department of Allergy and Clinical Immunology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea.
⁸ Department of Internal Medicine, Kosin University Gospel Hospital, Kosin University College of Medicine, Busan, South Korea.
⁹ Department of Statistics, College of Natural Sciences, Kyungpook National University, Daegu, South Korea.
¹⁰ Department of Radiology, College of Medicine, Seoul National University, Seoul National University Hospital, Seoul, South Korea.

PMID: 34382839
DOI: 10.1152/japplphysiol.00743.2020

Abstract

Asthma acute exacerbations (AE) have been investigated using quantitative computed tomography (QCT)-based imaging metrics, but QCT has not yet been used to investigate a comprehensive set of imaging metrics during AE. This study aims to explore imaging features, captured both at segmental and parenchymal scales, during asthma AE compared with those in stable asthma (SA). Two sets of the QCT images at total lung capacity (TLC) and functional residual capacity (FRC) were captured for 14 subjects during asthma AE and in SA phase, respectively. We calculated airway wall thickness (WT), hydraulic diameter (D_h), and airway circularity (Cr) of the 36 segmental airways; percentage of functional small airway disease (fSAD%); percentage of emphysema; tissue fraction (β_tiss); and coefficient of variation of β_tiss (CV of β_tiss). We performed Spearman correlation tests for changes in QCT metrics and pulmonary function tests, measured in AE and SA. During asthma AE, structural metrics, that is, WT, D_h, and Cr, were not changed significantly. In functional metrics, CV of β_tiss at FRC indicating the heterogeneity of lung tissue distribution was significantly increased, whereas the mean of β_tiss at FRC did not change during AE. An increase of fSAD% during AE was most correlated with a decrease of forced expiratory volume in 1 s and forced vital capacity, especially in the lower lobes. This study demonstrates that the heterogeneous feature of β_tiss measured at lower lobes is more noticeable during asthma AE, compared with other traditional imaging metrics. This metric could be utilized to identify unique features during asthma AE.NEW & NOTEWORTHY Using two sets of inspiration and expiration images, the difference of segmental airway structure and parenchymal lung function is assessed by comparing the QCT images during asthma acute exacerbations with those in stable asthma. This study also introduces a useful application of an imaging-based metric, estimating the heterogeneity of tissue distribution. This could be a phenotype for the asthma acute exacerbation.

Keywords: asthma acute exacerbations; coefficient of variation; functional heterogeneity; stable asthma; tissue fraction.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Asthma* / diagnostic imaging
Forced Expiratory Volume
Humans
Lung / diagnostic imaging
Pulmonary Disease, Chronic Obstructive*
Tomography, X-Ray Computed

Associated data

figshare/10.6084/m9.figshare.14009891.v2