Karuppanan Udayakumar, Unni Sujatha Narayanan, Angarai Ganesan R
Indian Institute of Technology Madras , Department of Applied Mechanics, Biophotonics Lab, Chennai, India.
Indian Institute of Technology Madras , Department of Physics, Applied Optics Lab, Chennai, India.
J Med Imaging (Bellingham). 2017 Jan;4(1):016001. doi: 10.1117/1.JMI.4.1.016001. Epub 2017 Feb 1.
Assessment of mechanical properties of soft matter is a challenging task in a purely noninvasive and noncontact environment. As tissue mechanical properties play a vital role in determining tissue health status, such noninvasive methods offer great potential in framing large-scale medical screening strategies. The digital speckle pattern interferometry (DSPI)-based image capture and analysis system described here is capable of extracting the deformation information from a single acquired fringe pattern. Such a method of analysis would be required in the case of the highly dynamic nature of speckle patterns derived from soft tissues while applying mechanical compression. Soft phantoms mimicking breast tissue optical and mechanical properties were fabricated and tested in the DSPI out of plane configuration set up. Hilbert transform (HT)-based image analysis algorithm was developed to extract the phase and corresponding deformation of the sample from a single acquired fringe pattern. The experimental fringe contours were found to correlate with numerically simulated deformation patterns of the sample using Abaqus finite element analysis software. The extracted deformation from the experimental fringe pattern using the HT-based algorithm is compared with the deformation value obtained using numerical simulation under similar conditions of loading and the results are found to correlate with an average %error of 10. The proposed method is applied on breast phantoms fabricated with included subsurface anomaly mimicking cancerous tissue and the results are analyzed.
在纯粹的非侵入性和非接触环境中评估软物质的力学性能是一项具有挑战性的任务。由于组织力学性能在确定组织健康状况方面起着至关重要的作用，这种非侵入性方法在制定大规模医学筛查策略方面具有巨大潜力。本文所述的基于数字散斑图案干涉术（DSPI）的图像采集和分析系统能够从单个采集的条纹图案中提取变形信息。在对软组织施加机械压缩时，由于散斑图案具有高度动态的特性，因此需要采用这种分析方法。制作了模拟乳腺组织光学和力学性能的软质体模，并在DSPI面外配置设置中进行了测试。开发了基于希尔伯特变换（HT）的图像分析算法，以从单个采集的条纹图案中提取样品的相位和相应变形。发现实验条纹轮廓与使用Abaqus有限元分析软件对样品进行数值模拟得到的变形模式相关。使用基于HT的算法从实验条纹图案中提取的变形与在相似加载条件下使用数值模拟获得的变形值进行比较，结果发现两者的平均误差为10%，具有相关性。将所提出的方法应用于包含模拟癌组织的地下异常的乳腺体模，并对结果进行了分析。
