Journal article
Airway fractal dimension predicts respiratory morbidity and mortality in COPD
The Journal of clinical investigation, Vol.128(12), pp.5374-5382
12/03/2018
DOI: 10.1172/JCI120693
PMCID: PMC6264725
PMID: 30256767
Abstract
Background: Chronic obstructive pulmonary disease (COPD) is characterized by airway remodeling. Characterization of airway changes on computed tomography has been challenging due to the complexity of the recurring branching patterns, and this can be better measured using fractal dimensions.
Methods: We analyzed segmented airway trees of 8,135 participants enrolled in the COPDGene cohort. The fractal complexity of the segmented airway tree was measured by the Airway Fractal Dimension (AFD) using the Minkowski-Bougliand box-counting dimension. We examined associations between AFD and lung function and respiratory morbidity using multivariable regression analyses. We further estimated the extent of peribronchial emphysema (%) within 5 mm of the airway tree, as this is likely to affect AFD. We classified participants into 4 groups based on median AFD, percentage of peribronchial emphysema, and estimated survival.
Results: AFD was significantly associated with forced expiratory volume in one second (FEV1; P < 0.001) and FEV1/forced vital capacity (FEV1/FVC; P < 0.001) after adjusting for age, race, sex, smoking status, pack-years of smoking, BMI, CT emphysema, air trapping, airway thickness, and CT scanner type. On multivariable analysis, AFD was also associated with respiratory quality of life and 6-minute walk distance, as well as exacerbations, lung function decline, and mortality on longitudinal follow-up. We identified a subset of participants with AFD below the median and peribronchial emphysema above the median who had worse survival compared with participants with high AFD and low peribronchial emphysema (adjusted hazards ratio [HR]: 2.72; 95% CI: 2.20-3.35; P < 0.001), a substantial number of whom were not identified by traditional spirometry severity grades.
Conclusion: Airway fractal dimension as a measure of airway branching complexity and remodeling in smokers is associated with respiratory morbidity and lung function change, offers prognostic information additional to traditional CT measures of airway wall thickness, and can be used to estimate mortality risk.
Details
- Title: Subtitle
- Airway fractal dimension predicts respiratory morbidity and mortality in COPD
- Creators
- Sandeep BodduluriAbhilash S Kizhakke PuliyakoteSarah E GerardJoseph M ReinhardtEric A HoffmanJohn D Jr NewellHrudaya P NathMeiLan K HanGeorge R WashkoRaúl San José EstéparMark T DransfieldSurya P BhattCOPDGene Investigators
- Resource Type
- Journal article
- Publication Details
- The Journal of clinical investigation, Vol.128(12), pp.5374-5382
- Publisher
- American Society for Clinical Investigation
- DOI
- 10.1172/JCI120693
- PMID
- 30256767
- PMCID
- PMC6264725
- ISSN
- 0021-9738
- eISSN
- 1558-8238
- Grant note
- K23HL133438,R01 HL089897,R01 HL089856,K24 HL138188 / ;
- Language
- English
- Date published
- 12/03/2018
- Academic Unit
- Roy J. Carver Department of Biomedical Engineering; Radiology; Internal Medicine
- Record Identifier
- 9984197153302771
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