Spectral graph theory efficiently characterises ventilation heterogeneity in lung airway networks

Research output: Contribution to journalArticle

  • External authors:
  • Peter Latimer
  • Jim M. Wild
  • Guilhem J. Collier

Abstract

This paper introduces a linear operator for the purposes of quantifying the spectral properties of transport within resistive trees, such as airflow in lung airway networks. The operator, which we call the Maury matrix, acts only on the terminal nodes of the tree and is equivalent to the adjacency matrix of a complete graph summarising the relationships between all pairs of terminal nodes. We show that the eigenmodes of the Maury operator have a direct physical interpretation as the relaxation, or resistive, modes of the network. We apply these findings to both idealised and image-based models of ventilation in lung airway trees and show that the spectral properties of the Maury matrix characterise the flow asymmetry in these networks more concisely than the Laplacian modes, and that eigenvector centrality in the Maury spectrum is closely related to the phenomenon of ventilation heterogeneity caused by airway narrowing or obstruction. This method has applications in dimensionality reduction in simulations of lung mechanics, as well as for characterisation of models of the airway tree derived from medical images.

Bibliographical metadata

Original languageEnglish
Pages (from-to)1-18
Number of pages18
JournalJournal of the Royal Society. Interface
Early online date29 Jul 2020
DOIs
Publication statusE-pub ahead of print - 29 Jul 2020