title: Classification of Benign and Malignant Breast Tumors in Ultrasound Images with Posterior Acoustic Shadowing Using Half-Contour Features.
abstract: Posterior acoustic shadowing (PAS) can bias breast tumor segmentation and classification in ultrasound images. In this paper, half-contour features are proposed to classify benign and malignant breast tumors with PAS, considering the fact that the upper half of the tumor contour is less affected by PAS. Adaptive thresholding and disk expansion are employed to detect tumor contours. Based on the detected full contour, the upper half contour is extracted. For breast tumor classification, six quantitative feature parameters are analyzed for both full contours and half contours, including standard deviation of degree (SDD), which is proposed to describe tumor irregularity. Fifty clinical cases (40 with PAS and 10 without PAS) were used. Tumor circularity (TC) and SDD were both effective full- and half-contour parameters in classifying images without PAS. Half-contour TC [74 % accuracy, 72 % sensitivity, 76 % specificity, 0.78 area under the receiver operating characteristic curve (AUC),p> 0.05] significantly improved the classification of breast tumors with PAS compared to that with full-contour TC (54 % accuracy, 56 % sensitivity, 52 % specificity, 0.52 AUC,p> 0.05). Half-contour SDD (72 % accuracy, 76 % sensitivity, 68 % specificity, 0.81 AUC,p< 0.05) improved the classification of breast tumors with PAS compared to that with full-contour SDD (62 % accuracy, 80 % sensitivity, 44 % specificity, 0.61 AUC,p> 0.05). The proposed half-contour TC and SDD may be useful in classifying benign and malignant breast tumors in ultrasound images affected by PAS.
authors.affiliation: Biomedical Engineering Center, College of Life Science and Bioengineering, Beijing University of Technology, Beijing, 100124 China.
authors.forename: Zhuhuang
authors.initials: Z
authors.lastname: Zhou
authors.affiliation: Biomedical Engineering Center, College of Life Science and Bioengineering, Beijing University of Technology, Beijing, 100124 China.
authors.forename: Shuicai
authors.initials: S
authors.lastname: Wu
authors.affiliation: Department of Surgery, Cheng Ching General Hospital, Chung Kang Branch, Taichung, 407 Taiwan.|Department of Surgery, National Taiwan University Hospital, Taipei, 10048 Taiwan.
authors.forename: King-Jen
authors.initials: KJ
authors.lastname: Chang
authors.affiliation: Department of Electrical Engineering, Yuan Ze University, Chung Li, 32003 Taiwan.
authors.forename: Wei-Ren
authors.initials: WR
authors.lastname: Chen
authors.affiliation: Department of Electrical Engineering, Yuan Ze University, Chung Li, 32003 Taiwan.
authors.forename: Yung-Sheng
authors.initials: YS
authors.lastname: Chen
authors.affiliation: Department of Surgery, National Taiwan University Hospital, Taipei, 10048 Taiwan.
authors.forename: Wen-Hung
authors.initials: WH
authors.lastname: Kuo
authors.affiliation: Department of Computer Science and Information Engineering, Chang Gung University, Taoyuan, 33302 Taiwan.
authors.forename: Chung-Chih
authors.initials: CC
authors.lastname: Lin
authors.affiliation: Department of Medical Imaging and Radiological Sciences, College of Medicine, Chang Gung University, Taoyuan, 33302 Taiwan.|Institute of Radiological Research, Chang Gung University and Hospital, Taoyuan, 33302 Taiwan.
authors.forename: Po-Hsiang
authors.initials: PH
authors.lastname: Tsui
keywords: Breast tumor; Half-contour feature; Posterior acoustic shadowing (PAS); Standard deviation of degree (SDD); Ultrasound