RESEARCH ARTICLE
In-vitro Strain and Modulus Measurements in Porcine Cervical Lymph Nodes
Queeny Wing-Han Yuen, Yong-Ping Zheng*, Yan-Ping Huang, Jun-Feng He, James Chung-Wai Cheung, Michael Ying
Article Information
Identifiers and Pagination:
Year: 2011Volume: 5
First Page: 39
Last Page: 46
Publisher ID: TOBEJ-5-39
DOI: 10.2174/1874120701105010039
Article History:
Received Date: 07/09/2010Revision Received Date: 07/01/2011
Acceptance Date: 07/01/2011
Electronic publication date: 30/03/2011
Collection year: 2011
open-access license: This is an open access article licensed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted, non-commercial use, distribution and reproduction in any medium, provided the work is properly cited.
Abstract
Cervical lymph nodes are common sites of metastatic involvement in head and neck cancers. These lymph nodes are superficially located and palpation is a common practice for assessing nodal hardness and staging cancer which is, however, too subjective and with limited accuracy. In this study, the mechanical properties of pig lymph node tissues were investigated using ultrasound elastography and indentation test. Lymph nodes were excised from fresh pork pieces and embedded in an agar-gelatin phantom for strain imaging by elastography. A strain ratio reflecting the strain contrast of lymph node over agar-gelatin phantom was used to assess the elasticity of the lymph node. A cutting device was then custom-designed to slice the phantom into uniform slices for indentation test. The measurements revealed that there were significant differences in both the strain ratio and Young’s modulus between the peripheral and middle regions of the lymph nodes (both p < 0.05); however, the results appeared contradictory. Correlation between the results of the two measurements (modulus ratio vs. inversed strain ratio) showed their association was moderate for both the peripheral and middle regions (R2 = 0.437 and 0.424 respectively). As the tests were only performed on normal lymph nodes, comparison in stiffness between healthy and abnormal lymph nodes could not be made. Future studies should be conducted to quantify the stiffness change in abnormal lymph nodes.
