title: Imaging of peripheral cholangiocarcinoma with low-mechanical index contrast-enhanced sonography and SonoVue: initial experience.
abstract: OBJECTIVE
  The purpose of this study was to investigate the imaging findings of peripheral cholangiocarcinoma with low-mechanical index (MI) contrast-enhanced sonography.
  
  
  METHODS
  Eighteen nodules of peripheral cholangiocarcinoma proved by pathologic examination in 18 patients were evaluated with contrast-enhanced sonography. A low-MI real-time contrast-enhanced sonographic mode (ie, contrast pulse sequencing) and a sulfur hexafluoride-filled microbubble contrast agent (SonoVue [BR1]; Bracco SpA, Milan, Italy) were used.
  
  
  RESULTS
  On contrast-enhanced sonographic images, all 18 nodules (100%) of peripheral cholangiocarcinoma showed inhomogeneous enhancement during the arterial phase, and the emergence of nodule enhancement was earlier in 3 nodules (16.7%), simultaneous in 13 (72.2%), and later in 2 (11.1%), respectively, when compared with the adjacent liver tissue. During the arterial phase, 8 nodules (44.4%) showed irregular peripheral rimlike hyperenhancement, 2 (11.1%) showed inhomogeneous hyperenhancement, and 8 (44.4%) showed inhomogeneous hypoenhancement. In portal and late phases, all 18 nodules (100%) showed hypoenhancement. When contrast-enhanced sonography was added for analysis, the confidence levels of the investigators were improved in 15 (83.3%) of 18 nodules, and 17 (94.4%) of 18 peripheral cholangiocarcinomas were correctly characterized.
  
  
  CONCLUSIONS
  The imaging findings of peripheral cholangiocarcinoma had some characteristics on low-MI contrast-enhanced sonography. Knowledge of these characteristics might be beneficial for improving the diagnostic performance of sonography in evaluating this entity.
authors.affiliation: Department of Medical Ultrasonics, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, China.
authors.forename: Hui-Xiong
authors.initials: HX
authors.lastname: Xu
authors.forename: Ming-De
authors.initials: MD
authors.lastname: Lu
authors.forename: Guang-Jian
authors.initials: GJ
authors.lastname: Liu
authors.forename: Xiao-Yan
authors.initials: XY
authors.lastname: Xie
authors.forename: Zuo-Feng
authors.initials: ZF
authors.lastname: Xu
authors.forename: Yan-Ling
authors.initials: YL
authors.lastname: Zheng
authors.forename: Jin-Yu
authors.initials: JY
authors.lastname: Liang
mesh_terms: D000328:Adult; D000368:Aged; D001650:Bile Duct Neoplasms / Q000000981:diagnostic imaging*; D001653:Bile Ducts, Intrahepatic; D018281:Cholangiocarcinoma / Q000000981:diagnostic imaging*; D003287:Contrast Media; D005260:Female; D006801:Humans; D008297:Male; D045423:Microbubbles; D008875:Middle Aged; D010743:Phospholipids; D013459:Sulfur Hexafluoride; D014463:Ultrasonography
chemical_list: D003287:Contrast Media; D010743:Phospholipids; C420843:contrast agent BR1; D013459:Sulfur Hexafluoride