title: The Role of Contrast-enhanced Ultrasound in Guiding Radiofrequency Ablation of Hepatocellular Carcinoma: A Retrospective Study.
abstract: OBJECTIVE
  The objective of the study was to determine the efficacy of contrast-enhanced ultrasound (CEUS) using ultrasound (US)-specific microbubbles in guiding radiofrequency ablation (RFA) of hepatocellular carcinoma (HCC).
  
  
  METHODS
  A retrospective analysis of 50 patients with HCC treated with CEUS guided RFA using perflutren at our institution was performed. CEUS images were first compared to B-mode US images performed at the same RFA session to determine the ability of CEUS to increase the conspicuity of lesions. A qualitative score (1 = poor, 2 = fair, 3 = excellent) was used to grade the ability to visualize the lesions. The preprocedure CEUS images were then evaluated using the most recent prior contrast enhanced computed tomography (CT) or magnetic resonance imaging (MRI). The efficacy of the treatment was evaluated with short-term follow-up imaging (median 1 month) for presence of residual or recurrent disease.
  
  
  RESULTS
  CEUS allows at least fair visualization (score ≥2) in 78% (reader 1) and 80% (reader 2) of the lesions not visualized by B-mode US, and 50% (reader 1) and 42% (reader 2) of the lesions poorly visualized by B-mode US. Lesion appearances on CEUS are largely concordant with those on CT or MRI: 88% for reader 1, 96% for reader 2. With CEUS-guided RFA, complete response was achieved in the vast majority of the lesions at short-term follow-up: 82% for reader 1, 94% for reader 2.
  
  
  CONCLUSIONS
  CEUS increases the conspicuity and provides better characterization of hypervascular HCC that are either not seen or poorly seen on B-mode US, and CEUS provides real-time guidance of RFA with good short-term treatment responses.
authors: Department of Radiology, University of British Columbia, Faculty of Medicine, Vancouver General Hospital, Vancouver, British Columbia, Canada. Electronic address: akwchan@gmail.com.
authors: Andy K W
authors: AK
authors: Chan
authors: Department of Radiology, University of British Columbia, Faculty of Medicine, Vancouver General Hospital, Vancouver, British Columbia, Canada.
authors: Chris
authors: C
authors: Hegarty
authors: Department of Radiology, University of British Columbia, Faculty of Medicine, Vancouver General Hospital, Vancouver, British Columbia, Canada.
authors: Darren
authors: D
authors: Klass
authors: Department of Hepatology, University of British Columbia, Faculty of Medicine, Vancouver General Hospital, Vancouver, British Columbia, Canada.
authors: Eric
authors: E
authors: Yoshida
authors: Department of Hepatobiliary Surgery, University of British Columbia, Faculty of Medicine, Vancouver General Hospital, Vancouver, British Columbia, Canada.
authors: Stephen
authors: S
authors: Chung
authors: Department of Radiology, University of British Columbia, Faculty of Medicine, Vancouver General Hospital, Vancouver, British Columbia, Canada.
authors: David M
authors: DM
authors: Liu
authors: Department of Radiology, University of British Columbia, Faculty of Medicine, Vancouver General Hospital, Vancouver, British Columbia, Canada.
authors: Stephen G F
authors: SG
authors: Ho
authors: Department of Radiology, University of British Columbia, Faculty of Medicine, Vancouver General Hospital, Vancouver, British Columbia, Canada.
authors: Alison C
authors: AC
authors: Harris
mesh_terms: D006528:Carcinoma, Hepatocellular / Q000000981:diagnostic imaging* / Q000601:surgery*; D017115:Catheter Ablation; D003287:Contrast Media / Q000627:therapeutic use; D005466:Fluorocarbons / Q000627:therapeutic use; D006801:Humans; D008113:Liver Neoplasms / Q000000981:diagnostic imaging* / Q000601:surgery*; D009364:Neoplasm Recurrence, Local / Q000000981:diagnostic imaging*; D018365:Neoplasm, Residual; D011859:Radiography; D012189:Retrospective Studies; D025321:Surgery, Computer-Assisted; D018084:Ultrasonography, Interventional / Q000379:methods*
chemical_list: D003287:Contrast Media; D005466:Fluorocarbons; C042852:perflutren
keywords: Contrast enhanced ultrasound; Gastrointestinal radiology; Hepatocellular carcinoma; Interventional radiology; Radiofrequency ablation; Ultrasound