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Proceedings Paper

Identifying viscoelastic parameters of tissue specimens using Hertz contact mechanics
Author(s): Nikan K. Namiri; Ashkan Maccabi; Neha Bajwa; Karam W. Badran; Maie A. St. John; Zachary D. Taylor; Warren S. Grundfest; George N. Saddik
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Paper Abstract

The unique viscoelastic properties of tissues throughout the human body can be utilized in a variety of clinical applications. Palpation techniques, for instance, enable surgeons to distinguish malignancies in tissue composition during surgical procedures. Additionally, imaging devices have begun utilizing the viscoelastic properties of tissue to delineate tumor margins. Vibroacoustography (VA), a non-invasive, high resolution imaging modality, has the ability to detect sub-millimeter differences in tissue composition. VA images tissue using a low frequency acoustic radiation force, which perturbs the target and causes an acoustic response that is dependent on the target’s viscoelastic properties. Given the unique properties specific to human and animal tissues, there are far-reaching clinical applications of VA. To date, however, a comprehensive model that relates viscoelasticity to VA tissue response has yet to be developed. Utilizing tissue-mimicking phantoms (TMPs) and fresh ex vivo tissues, a mechanical stress relaxation model was developed to compare the viscoelastic properties of known and unknown specimens. This approach was conducted using the Hertz theory of contact mechanics. Fresh hepatic tissue was obtained from porcine subjects (n=10), while gelatin and agar TMPs (n=12) were fabricated from organic extracts. Each specimen’s elastic modulus (E), long term shear modulus (η), and time constant (τ) were found to be unique. Additionally, each specimen’s stress relaxation profiles were analyzed using Weichert-Maxwell viscoelastic modeling, and retained high precision (R2>0.9) among all samples.

Paper Details

Date Published: 19 February 2018
PDF: 6 pages
Proc. SPIE 10486, Design and Quality for Biomedical Technologies XI, 1048606 (19 February 2018); doi: 10.1117/12.2289831
Show Author Affiliations
Nikan K. Namiri, Univ. of California, Los Angeles (United States)
Ashkan Maccabi, Univ. of California, Los Angeles (United States)
Neha Bajwa, Ctr. for Advanced Surgical and Interventional Technology (United States)
Karam W. Badran, David Gellen School of Medicine, Univ. of California, Los Angeles (United States)
Maie A. St. John, Univ. of California, Los Angeles (United States)
Zachary D. Taylor, Univ. of California, Los Angeles (United States)
Warren S. Grundfest, Univ. of California, Los Angeles (United States)
George N. Saddik, Univ. of California, Los Angeles (United States)

Published in SPIE Proceedings Vol. 10486:
Design and Quality for Biomedical Technologies XI
Ramesh Raghavachari; Rongguang Liang, Editor(s)

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