A comprehensive computational model of sound transmission through the porcine lung.

Zoujun Dai,Richard H Sandler,Ying Peng,Brian M Henry,Hansen A Mansy,Thomas J Royston

doi:10.1121/1.4890647

Abstract

A comprehensive computational simulation model of sound transmission through the porcine 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 used in comsol FE software to simulate the vibroacoustic response of the lung to sound input at the trachea. The FE simulation model is validated by comparing simulation results to experimental measurements using scanning laser Doppler vibrometry on the surface of an excised, preserved lung. The FE model can also be 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 of a local tumor on the lung acoustic response is simulated and visualized using the FE model. In the future, this type of visualization can be compared and matched with experimentally obtained elastographic images to better quantify regional lung material properties to noninvasively diagnose and stage disease and response to treatment.

Highlights

The lung parenchyma is modeled as a poroviscoelastic material using Biot theory
The finite element (FE) model is used to calculate and visualize vibroacoustic pressure and motion inside the lung and its airways caused by the acoustic input
The FE simulations were validated by comparisons with experimental measurements obtained using scanning laser Doppler vibrometry on the surface of an excised, preserved lung

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.

Objectives

Results

Conclusion