Comparison of Poroviscoelastic Models for Sound and Vibration in the Lungs

    Authors

    Z. J. Dai; Y. Peng; H. A. Mansy; R. H. Sandler;T. J. Royston

    Comments

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    Abbreviated Journal Title

    J. Vib. Acoust.-Trans. ASME

    Keywords

    MAGNETIC-RESONANCE ELASTOGRAPHY; MR ELASTOGRAPHY; VISCOELASTIC; PROPERTIES; MECHANICAL-PROPERTIES; COMPRESSIONAL WAVE; RESPIRATORY; SYSTEM; SHEAR STIFFNESS; FREQUENCY RANGE; BREAST-LESIONS; ELASTIC-MODULI; Acoustics; Engineering, Mechanical; Mechanics

    Abstract

    Noninvasive measurement of mechanical wave motion (sound and vibration) in the lungs may be of diagnostic value, as it can provide information about the mechanical properties of the lungs, which in turn are affected by disease and injury. In this study, two previously derived theoretical models of the vibroacoustic behavior of the lung parenchyma are compared: (1) a Biot theory of poroviscoelasticity and (2) an effective medium theory for compression wave behavior (also known as a "bubble swarm" model). A fractional derivative formulation of shear viscoelasticity is integrated into both models. A measurable "fast" compression wave speed predicted by the Biot theory formulation has a significant frequency dependence that is not predicted by the effective medium theory. Biot theory also predicts a slow compression wave. The experimentally measured fast compression wave speed and attenuation in a pig lung ex vivo model agreed well with the Biot theory. To obtain the parameters for the Biot theory prediction, the following experiments were undertaken: quasistatic mechanical indentation measurements were performed to estimate the lung static shear modulus; surface wave measurements were performed to estimate lung tissue shear viscoelasticity; and flow permeability was measured on dried lung specimens. This study suggests that the Biot theory may provide a more robust and accurate model than the effective medium theory for wave propagation in the lungs over a wider frequency range.

    Journal Title

    Journal of Vibration and Acoustics-Transactions of the Asme

    Volume

    136

    Issue/Number

    5

    Publication Date

    1-1-2014

    Document Type

    Article

    Language

    English

    First Page

    11

    WOS Identifier

    WOS:000341761500006

    ISSN

    1048-9002

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