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BioMed Research International
Volume 2016 (2016), Article ID 6893712, 11 pages
http://dx.doi.org/10.1155/2016/6893712
Research Article

Cross-Sectional Nakagami Images in Passive Stretches Reveal Damage of Injured Muscles

1Department of Biomedical Engineering, National Cheng Kung University, No. 1, University Road, Tainan 701, Taiwan
2Department of Computer Science and Information Engineering, National Cheng Kung University, No. 1, University Road, Tainan 701, Taiwan
3Department of Occupational Therapy, I-Shou University, No. 1, Sec. 1, Syuecheng Road, Dashu District, Kaohsiung, Taiwan
4Department of Cell Biology and Anatomy, National Cheng Kung University, No. 1, University Road, Tainan 701, Taiwan
5Institute of Basic Medical Sciences, National Cheng Kung University, No. 1, University Road, Tainan 701, Taiwan
6Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089, USA
7Medical Device and Innovation Center, National Cheng Kung University, No. 1, University Road, Tainan 701, Taiwan

Received 13 August 2015; Revised 5 November 2015; Accepted 9 November 2015

Academic Editor: Bo Zuo

Copyright © 2016 Shih-Ping Lin et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Muscle strain is still awanting a noninvasive quantitatively diagnosis tool. High frequency ultrasound (HFU) improves image resolution for monitoring changes of tissue structures, but the biomechanical factors may influence ultrasonography during injury detection. We aim to illustrate the ultrasonic parameters to present the histological damage of overstretched muscle with the consideration of biomechanical factors. Gastrocnemius muscles from mice were assembled and ex vivo passive stretching was performed before or after injury. After injury, the muscle significantly decreased mechanical strength. Ultrasonic images were obtained by HFU at different deformations to scan in cross and longitudinal orientations of muscle. The ultrasonography was quantified by echogenicity and Nakagami parameters (NP) for structural evaluation and correlated with histological results. The injured muscle at its original length exhibited decreased echogenicity and NP from HFU images. Cross-sectional ultrasonography revealed a loss of correlation between NP and passive muscle stretching that suggested a special scatterer pattern in the cross section of injured muscle. The independence of NP during passive stretching of injured muscle was confirmed by histological findings in ruptured collagen fibers, decreased muscle density, and increased intermuscular fiber space. Thus, HFU analysis of NP in cross section represents muscle injury that may benefit the clinical diagnosis.