title: Role of contrast-enhanced ultrasound (CEUS) in evaluation of thermal ablation zone.
abstract: Thermal ablation has emerged as a mainstay therapy for primary and metastatic liver malignancy. Percutaneous thermal ablation is usually performed under CT and/or ultrasound guidance. CT guidance frequently utilizes iodinated contrast for tumor targeting, with additional radiation and contrast required at the end of the procedure to ensure satisfactory ablation margins. Contrast-enhanced ultrasound (CEUS) is an imaging technique utilizing microbubble contrast agents to demonstrate blood flow and tissue perfusion. In this study, we performed a retrospective review to assess the utility of CEUS in the immediate post ablation detection of residual tumor.
  
  
  
  Sixty-four ablations were retrospectively reviewed. 6/64 ablations (9.4%) had residual tumor on the first follow-up imaging after thermal ablation. There were two groups of patients. Group 1 underwent standard protocol thermal ablation with CT and/or ultrasound guidance. Group 2 not only had thermal ablation with a protocol identical to group 1, but also had CEUS assessment at the conclusion of the procedure to ensure satisfactory ablation zone.
  
  
  
  The residual tumor rate in group 1 was 16.7% and the residual tumor rate in group 2 was 0%. The difference between the groups was statistically significant with a p value of 0.023. The results suggest that using CEUS assessment immediately after the ablation procedure reduces the rate of residual tumor after thermal ablation.
  
  
  
  CEUS evaluation at the end of an ablation procedure is a powerful technique providing critical information to the treating interventional radiologist, without additional nephrotoxic contrast or ionizing radiation.
authors.affiliation: Department of Radiology, Keck School of Medicine, University of Southern California, 1500 San Pablo Street, Second Floor Imaging, Los Angeles, CA, 90033, USA.
authors.forename: Ilya
authors.initials: I
authors.lastname: Lekht
authors.affiliation: Department of Radiology, Keck School of Medicine, University of Southern California, 1500 San Pablo Street, Second Floor Imaging, Los Angeles, CA, 90033, USA.
authors.forename: Mittul
authors.initials: M
authors.lastname: Gulati
authors.affiliation: Department of Radiology, Keck School of Medicine, University of Southern California, 1500 San Pablo Street, Second Floor Imaging, Los Angeles, CA, 90033, USA. mnayyar@usc.edu.
authors.forename: Megha
authors.initials: M
authors.lastname: Nayyar
authors.affiliation: Department of Radiology, Keck School of Medicine, University of Southern California, 1500 San Pablo Street, Second Floor Imaging, Los Angeles, CA, 90033, USA.
authors.forename: Michael D
authors.initials: MD
authors.lastname: Katz
authors.affiliation: Department of Radiology, Keck School of Medicine, University of Southern California, 1500 San Pablo Street, Second Floor Imaging, Los Angeles, CA, 90033, USA.
authors.forename: Ramon
authors.initials: R
authors.lastname: Ter-Oganesyan
authors.affiliation: Department of Radiology, Keck School of Medicine, University of Southern California, 1500 San Pablo Street, Second Floor Imaging, Los Angeles, CA, 90033, USA.
authors.forename: Mary
authors.initials: M
authors.lastname: Marx
authors.affiliation: Department of Radiology, Keck School of Medicine, University of Southern California, 2001 North Soto Street, Soto Building 210B, Los Angeles, 90089, USA.
authors.forename: Steven Y
authors.initials: SY
authors.lastname: Cen
authors.affiliation: Department of Radiology, Keck School of Medicine, University of Southern California, 1500 San Pablo Street, Second Floor Imaging, Los Angeles, CA, 90033, USA.
authors.forename: Edward
authors.initials: E
authors.lastname: Grant
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D006528:Carcinoma, Hepatocellular / Q000000981:diagnostic imaging* / Q000601:surgery*; D017115:Catheter Ablation / Q000379:methods*; D003287:Contrast Media; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D008099:Liver / Q000000981:diagnostic imaging / Q000601:surgery; D008113:Liver Neoplasms / Q000000981:diagnostic imaging* / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D018365:Neoplasm, Residual; D012189:Retrospective Studies; D016896:Treatment Outcome; D014463:Ultrasonography / Q000379:methods*
chemical_list: D003287:Contrast Media
keywords: Computed tomography (CT); Contrast-enhanced ultrasound (CEUS); Hepatocellular carcinoma (HCC); Radiofrequency ablation (RFA)