Research Article A Normalized Shear Deformation Indicator for Ultrasound Strain Elastography in Breast Tissues: An In Vivo Feasibility Study Jingfeng Jiang 1,2 and Bo Peng 3 1 Department of Biomedical Engineering, Michigan Technological University, 1400 Townsend Drive, Houghton, MI 49931, USA 2 Department of Medical Physics, University of Wisconsin-Madison, Madison, WI 53705, USA 3 School of Computer Science, Southwest Petroleum University, Chengdu 610500, China Correspondence should be addressed to Jingfeng Jiang; jjiang1@mtu.edu Received 17 September 2017; Revised 9 December 2017; Accepted 9 January 2018; Published 12 February 2018 Academic Editor: Weibao Qiu Copyright © 2018 Jingfeng Jiang and Bo Peng. Tis 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. Te shear deformation under loads contains useful information for distinguishing benign breast lesions from malignant ones. In this study, we proposed a normalized shear deformation indicator (NSDI) that was derived from the concept of principal strains. Since the NSDI requires both high-quality axial and lateral (parallel and perpendicular to the beam, resp.) displacement estimates, a strategy combining high-quality speckle tracking with signal “denoising” was employed. Both techniques were previously published by our group. Finite element (FE) models were used to identify possible causes for elevated NSDI values in and around breast lesions, followed by an analysis of ultrasound data acquired from 26 biopsy-confrmed in vivo breast lesions. We found that, theoretically, the elevated NSDI values could be attributed to two factors: signifcantly hardened tissue stifness and increasing heterogeneity. Te analysis of in vivo data showed that the proposed NSDI values were higher ( < 0.05) among malignant cancers as compared to those measured from benign ones. In conclusion, our preliminary results demonstrated that the calculation of NSDI value is feasible and NSDI could add value to breast lesion diferentiation with current clinical equipment as a postprocessing tool. 1. Introduction According to the US National Institute of Cancer, an esti- mated 252,710 new cases of invasive breast cancer are expected to be diagnosed in 2017. In light of the widespread use of the ultrasound, American College of Radiology has developed a BI-RADS lexicon to standardize the charac- terization of breast lesions under ultrasound [1]. Trough analyzing BIRADS 3–5 lesions, Hille et al. reported that the sensitivity and specifcity were 92% and 85%, respectively [2]. Teir result suggested that ultrasound probably should not be used alone as the frst line of imaging. In the last two decades, a lot of eforts have been devoted to ultrasound strain elastography (SE) [3]. In Ultrasound SE, tissue displacements are frst tracked by correlating radio frequency (RF) signals before and afer compression. Ten, axial (parallel to the acoustic beam direction) strain defned by the change in length divided by the length before compres- sion can be used as a surrogate for relative tissue elasticity. Ultrasound SE has been successfully applied to noninvasive diferentiation of breast tumors [4–7] with several identifed metrics: area ratio, elasticity score, strain ratio, and length ratio. Te frst metric is known as the area ratio which was defned as the ratio between the tumor area measured from the axial strain elastogram and the tumor area appearing on the B-mode image [4, 5, 7]. Typically, a large area ratio (e.g., >1.0) is correlated to an increasing possibility of malignancy. Te second metric used a scoring system [6], in which the overall tumor appearance on the axial strain elastogram was rated between 1 and 5 based on a set of graphic criteria. Te strain ratio between the tumor and a selected region containing background tissue was also adopted by numerous studies [4, 8, 9]. Te fourth metric is the length ratio. Te length ratio is defned as the lesion length measured from the Hindawi BioMed Research International Volume 2018, Article ID 2053612, 11 pages https://doi.org/10.1155/2018/2053612