title: Automatic detection method of hepatocellular carcinomas using the non-rigid registration method of multi-phase liver CT images.
abstract: BACKGROUND
  Multi-phase CT images are obtained sequentially after the injection of contrast agents so that there is a large amount of local deformation between images due to the respiratory and heart motion. Therefore, a non-rigid registration technique is required in order to establish the anatomical correspondence between the multi-phase CT images for liver CAD (computer-aided diagnosis).
  
  
  OBJECTIVE
  In this paper, we propose the automatic detection method of hepatocellular carcinomas using the non-rigid registration method of multi-phase CT images.
  
  
  METHODS
  Global movements between multi-phase CT images are aligned by rigid registration based on normalized mutual information. Local deformations between multi-phase CT images are modeled by non-rigid registration based on B-spline deformable model. After the registration of multi-phase CT images, hepatocellular carcinomas are automatically detected by analyzing the original and subtraction information of the registered multi-phase CT images.
  
  
  RESULTS
  We applied our method to twenty five multi-phase CT datasets. Experimental results showed that the multi-phase CT images were accurately aligned. All of the hepatocellular carcinomas including small size ones in our 25 subjects were accurately detected using our method.
  
  
  CONCLUSIONS
  We conclude that our method is useful for detecting hepatocellular carcinomas.
authors.affiliation: School of Computer Science and Engineering, Soongsil University, Dongjak-Gu, Seoul, Korea.
authors.forename: Jeongjin
authors.initials: J
authors.lastname: Lee
authors.affiliation: Department of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Songpa-ku, Seoul, Korea.
authors.forename: Kyoung Won
authors.initials: KW
authors.lastname: Kim
authors.affiliation: Department of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Songpa-ku, Seoul, Korea.
authors.forename: So Yeon
authors.initials: SY
authors.lastname: Kim
authors.affiliation: Department of Systems Management Engineering, Sungkyunkwan University, Seobu-ro, Jangan-gu, Suwon-si, Gyeong gi-do, Korea.
authors.forename: Juneseuk
authors.initials: J
authors.lastname: Shin
authors.affiliation: School of Computer Science and Engineering, Soongsil University, Dongjak-Gu, Seoul, Korea.
authors.forename: Kyung Jun
authors.initials: KJ
authors.lastname: Park
authors.affiliation: Department of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Songpa-ku, Seoul, Korea.
authors.forename: Hyung Jin
authors.initials: HJ
authors.lastname: Won
authors.affiliation: Department of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Songpa-ku, Seoul, Korea.
authors.forename: Yong Moon
authors.initials: YM
authors.lastname: Shin
mesh_terms: D006528:Carcinoma, Hepatocellular / Q000000981:diagnostic imaging*; D006801:Humans; D008113:Liver Neoplasms / Q000000981:diagnostic imaging*; D011857:Radiographic Image Interpretation, Computer-Assisted / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000379:methods*
keywords: B-spline deformable model; Multi-phase liver CT; cancer detection; hepatocellular carcinoma; non-rigid registration; normalized mutual information; rigid registration