A comprehensive computational model of sound transmission through the porcine lung

Ying Peng,Brian Henry,Zoujun Dai,Hansen Mansy,Thomas Royston

doi:10.1121/1.4831141

Abstract

A comprehensive computational simulation model of sound transmission through the porcine airways and lung is introduced and experimentally evaluated. This “subject-specific” model utilizes parenchymal and major airway geometry derived from x-ray CT images. The lung parenchyma is modeled as a poroviscoelastic material using Biot theory. A finite element (FE) mesh of the lung that includes airway detail is created, and COMSOL FE software is used to simulate the vibroacoustic response of the lung to sound input at the trachea. The FE model is validated by comparing simulation results with experimental measurements using scanning laser Doppler vibrometry on the surface of an excised and preserved lung. The FE model is also used to calculate and visualize vibroacoustic pressure and motion inside the lung and its airways caused by the acoustic input. The effect of diffuse lung fibrosis and a tumor on the lung acoustic response is simulated and visualized using the FE simulation. In the future, this type of visualization can be compared and matched with experimentally-obtained elastographic images in order to better quantify lung material properties. [Work supported by NIH Grant EB012142.]

Highlights

The lung parenchyma is modeled as a poroviscoelastic material using Biot theory
The finite element (FE) model can be used to calculate and visualize vibroacoustic pressure and motion inside the lung and its airways caused by the acoustic input
The FE model is used to calculate and visualize vibroacoustic pressure and motion inside the lung and its airways caused by the acoustic input

Summary

Introduction

The lungs are a unique, multiphase porous structure that have defied conventional noninvasive medical imaging methods and our ability to contrast and quantify changes in macroscopic properties that can be indicative of disease and be fundamentally linked to pathophysiologic and structural changes at the microscopic level. A wide range of pulmonary ailments can result in significant changes, locally or diffusely, to the stiffness or density of lung tissue with findings that include inflammation, fibrosis, edema, consolidation, or a mass effect (e.g., tumors). These changes often are not identifiable by currently available imaging modalities.

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