title: Computer-aided detection system for masses in automated whole breast ultrasonography: development and evaluation of the effectiveness.
abstract: OBJECTIVE
  The aim of this study was to evaluate the performance of a proposed computer-aided detection (CAD) system in automated breast ultrasonography (ABUS).
  
  
  METHODS
  Eighty-nine two-dimensional images (20 cysts, 42 benign lesions, and 27 malignant lesions) were obtained from 47 patients who underwent ABUS (ACUSON S2000). After boundary detection and removal, we detected mass candidates by using the proposed adjusted Otsu's threshold; the threshold was adaptive to the variations of pixel intensities in an image. Then, the detected candidates were segmented. Features of the segmented objects were extracted and used for training/testing in the classification. In our study, a support vector machine classifier was adopted. Eighteen features were used to determine whether the candidates were true lesions or not. A five-fold cross validation was repeated 20 times for the performance evaluation. The sensitivity and the false positive rate per image were calculated, and the classification accuracy was evaluated for each feature.
  
  
  RESULTS
  In the classification step, the sensitivity of the proposed CAD system was 82.67% (SD, 0.02%). The false positive rate was 0.26 per image. In the detection/segmentation step, the sensitivities for benign and malignant mass detection were 90.47% (38/42) and 92.59% (25/27), respectively. In the five-fold cross-validation, the standard deviation of pixel intensities for the mass candidates was the most frequently selected feature, followed by the vertical position of the centroids. In the univariate analysis, each feature had 50% or higher accuracy.
  
  
  CONCLUSIONS
  The proposed CAD system can be used for lesion detection in ABUS and may be useful in improving the screening efficiency.
authors.affiliation: Department of Radiology, Ewha Womans University Mokdong Hospital, Ewha Womans University School of Medicine, Seoul, Korea.
authors.forename: Jeoung Hyun
authors.identifier: 0000-0003-3504-9595
authors.initials: JH
authors.lastname: Kim
authors.affiliation: Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Joo Hee
authors.identifier: 0000-0002-1446-8195
authors.initials: JH
authors.lastname: Cha
authors.affiliation: Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Namkug
authors.identifier: 0000-0002-3438-2217
authors.initials: N
authors.lastname: Kim
authors.affiliation: Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Yongjun
authors.identifier: 0000-0001-9289-1282
authors.initials: Y
authors.lastname: Chang
authors.affiliation: Health Screening and Promotion Center, Asan Medical Center, Seoul, Korea.
authors.forename: Myung-Su
authors.identifier: 0000-0003-1891-8445
authors.initials: MS
authors.lastname: Ko
authors.affiliation: Korea Electrotechnology Research Institute, Ansan, Korea.
authors.forename: Young-Wook
authors.identifier: 0000-0002-9657-1873
authors.initials: YW
authors.lastname: Choi
authors.affiliation: Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Hak Hee
authors.identifier: 0000-0002-2956-9212
authors.initials: HH
authors.lastname: Kim
keywords: Computer-assisted radiographic image interpretation; Mass screening; Three-dimensional imaging