Rangayyan Rangaraj M, Banik Shantanu, Desautels J E Leo
Department of Electrical and Computer Engineering, Schulich School of Engineering, University of Calgary.
J Vis Exp. 2013 Aug 30(78):50341. doi: 10.3791/50341.
We demonstrate methods for the detection of architectural distortion in prior mammograms of interval-cancer cases based on analysis of the orientation of breast tissue patterns in mammograms. We hypothesize that architectural distortion modifies the normal orientation of breast tissue patterns in mammographic images before the formation of masses or tumors. In the initial steps of our methods, the oriented structures in a given mammogram are analyzed using Gabor filters and phase portraits to detect node-like sites of radiating or intersecting tissue patterns. Each detected site is then characterized using the node value, fractal dimension, and a measure of angular dispersion specifically designed to represent spiculating patterns associated with architectural distortion. Our methods were tested with a database of 106 prior mammograms of 56 interval-cancer cases and 52 mammograms of 13 normal cases using the features developed for the characterization of architectural distortion, pattern classification via quadratic discriminant analysis, and validation with the leave-one-patient out procedure. According to the results of free-response receiver operating characteristic analysis, our methods have demonstrated the capability to detect architectural distortion in prior mammograms, taken 15 months (on the average) before clinical diagnosis of breast cancer, with a sensitivity of 80% at about five false positives per patient.
我们展示了基于乳腺钼靶图像中乳腺组织模式方向分析来检测间期癌病例既往乳腺钼靶片中结构扭曲的方法。我们假设在肿块或肿瘤形成之前，结构扭曲会改变乳腺钼靶图像中乳腺组织模式的正常方向。在我们方法的初始步骤中，使用Gabor滤波器和相位图分析给定乳腺钼靶片中的定向结构，以检测放射状或相交组织模式的节点样部位。然后使用节点值、分形维数以及专门设计用于表示与结构扭曲相关的毛刺状模式的角离散度测量值来表征每个检测到的部位。我们的方法使用为表征结构扭曲而开发的特征、通过二次判别分析进行模式分类以及采用留一患者法进行验证，对56例间期癌病例的106张既往乳腺钼靶片和13例正常病例的52张乳腺钼靶片的数据库进行了测试。根据自由响应接收器操作特征分析的结果，我们的方法已证明能够在乳腺癌临床诊断前（平均）15个月获取的既往乳腺钼靶片中检测到结构扭曲，每位患者约有五个假阳性时灵敏度为80%。
