Quantitative CT-derived vessel metrics in idiopathic pulmonary fibrosis: A structure-function study

Joseph Jacob; Michael Pienn; Christian Payer; Martin Urschler; Maria Kokosi; Anand Devaraj; Athol U Wells; Horst Olschewski

doi:10.1111/resp.13485

Quantitative CT-derived vessel metrics in idiopathic pulmonary fibrosis: A structure-function study

Respirology. 2019 May;24(5):445-452. doi: 10.1111/resp.13485. Epub 2019 Feb 20.

Authors

Joseph Jacob^{1

2}, Michael Pienn³, Christian Payer⁴, Martin Urschler^{4

5}, Maria Kokosi⁶, Anand Devaraj⁷, Athol U Wells⁶, Horst Olschewski^{3

8}

Affiliations

¹ Department of Respiratory Medicine, University College London, London, UK.
² Centre for Medical Image Computing, University College London, London, UK.
³ Ludwig Boltzmann Institute for Lung Vascular Research, Graz, Austria.
⁴ Institute of Computer Graphics and Vision, Graz University of Technology, Graz, Austria.
⁵ Ludwig Boltzmann Institute for Clinical-Forensic Imaging, Graz, Austria.
⁶ Interstitial Lung Disease Unit, Royal Brompton Hospital, London, UK.
⁷ Department of Radiology, Royal Brompton Hospital, London, UK.
⁸ Division of Pulmonology, Department of Internal Medicine, Medical University of Graz, Graz, Austria.

Abstract

Background and objective: This study aimed to investigate whether quantitative lung vessel morphology determined by a new fully automated algorithm is associated with functional indices in idiopathic pulmonary fibrosis (IPF).

Methods: A total of 152 IPF patients had vessel volume, density, tortuosity and heterogeneity quantified from computed tomography (CT) images by a fully automated algorithm. Separate quantitation of vessel metrics in pulmonary arteries and veins was performed in 106 patients. Results were evaluated against readouts from lung function tests.

Results: Normalized vessel volume expressed as a percentage of total lung volume was moderately correlated with functional indices on univariable linear regression analysis: forced vital capacity (R² = 0.27, P < 1 × 10^-6 ), diffusion capacity for carbon monoxide (DL_CO ; R² = 0.12, P = 3 × 10^-5 ), total lung capacity (TLC; R² = 0.45, P < 1 × 10^-6 ) and composite physiologic index (CPI; R² = 0.28, P < 1 × 10^-6 ). Normalized vessel volume was correlated with vessel density but not with vessel heterogeneity. Quantitatively derived vessel metrics (and artery and vein subdivision scores) were not significantly linked with the transfer factor for carbon monoxide (K_CO ), and only weakly with DL_CO . On multivariable linear regression analysis, normalized vessel volume and vessel heterogeneity were independently linked with DL_CO , TLC and CPI indicating that they capture different aspects of lung damage. Artery-vein separation provided no additional information beyond that captured in the whole vasculature.

Conclusion: Our study confirms previous observations of links between vessel volume and functional measures of disease severity in IPF using a new vessel quantitation tool. Additionally, the new tool shows independent linkages of normalized vessel volume and vessel heterogeneity with functional indices. Quantitative vessel metrics do not appear to reflect vasculopathic damage in IPF.

Keywords: interstitial lung disease; lung fibrosis; radiology and other imaging; respiratory structure and function.

Publication types

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

MeSH terms

Adult
Aged
Aged, 80 and over
Algorithms*
Carbon Monoxide
Female
Humans
Idiopathic Pulmonary Fibrosis / diagnostic imaging*
Idiopathic Pulmonary Fibrosis / physiopathology*
Male
Middle Aged
Pulmonary Artery / diagnostic imaging*
Pulmonary Artery / physiopathology*
Pulmonary Diffusing Capacity
Radiographic Image Interpretation, Computer-Assisted
Severity of Illness Index
Tidal Volume
Tomography, X-Ray Computed / methods*
Vital Capacity

Substances

Carbon Monoxide

Abstract

Publication types

MeSH terms

Substances

Grants and funding