title: Intra-operative ultrasound elasticity imaging for monitoring of hepatic tumour thermal ablation.
abstract: BACKGROUND
  Thermal ablation is an accepted therapy for selected hepatic malignancies. However, the reliability of thermal ablation is limited by the inability to accurately monitor and confirm completeness of tumour destruction in real time. We investigated the ability of ultrasound elasticity imaging (USEI) to monitor thermal ablation.
  
  
  OBJECTIVE
  Capitalizing on the known increased stiffness that occurs with protein denaturation and dehydration during thermal therapy, we sought to investigate the feasibility and accuracy of USEI for monitoring of liver tumour ablation.
  
  
  METHODS
  A model for hepatic tumours was developed and elasticity images of liver ablation were acquired in in vivo animal studies, comparing the elasticity images to gross specimens. A clinical pilot study was conducted using USEI in nine patients undergoing open radiofrequency ablation for hepatic malignancies. The size and shape of thermal lesions on USEI were compared to B-mode ultrasound and post-ablation computed tomography (CT).
  
  
  RESULTS
  In both in vivo animal studies and in the clinical trial, the boundary of thermal lesions was significantly more conspicuous on USEI when compared with B-mode imaging. Animal studies demonstrated good correlation between the diameter of ablated lesions on USEI and the gross specimen (r = 0.81). Moreover, high-quality strain images were generated in real time during therapy. In patients undergoing tumour ablation, a good size correlation was observed between USEI and post-operative CT (r = 0.80).
  
  
  CONCLUSIONS
  USEI can be a valuable tool for the accurate monitoring and real-time verification of successful thermal ablation of liver tumours.
authors.affiliation: Department of Surgery, Johns Hopkins School of Medicine, Johns Hopkins University, Baltimore, MD 21287, USA.
authors.forename: Mark G
authors.initials: MG
authors.lastname: Van Vledder
authors.forename: Emad M
authors.initials: EM
authors.lastname: Boctor
authors.forename: Lia R
authors.initials: LR
authors.lastname: Assumpcao
authors.forename: Hassan
authors.initials: H
authors.lastname: Rivaz
authors.forename: Pezhman
authors.initials: P
authors.lastname: Foroughi
authors.forename: Gregory D
authors.initials: GD
authors.lastname: Hager
authors.forename: Ulrike M
authors.initials: UM
authors.lastname: Hamper
authors.forename: Timothy M
authors.initials: TM
authors.lastname: Pawlik
authors.forename: Michael A
authors.initials: MA
authors.lastname: Choti
mesh_terms: D000818:Animals; D017115:Catheter Ablation; D004548:Elasticity; D054459:Elasticity Imaging Techniques; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007430:Intraoperative Care; D008113:Liver Neoplasms / Q000000981:diagnostic imaging* / Q000601:surgery*; D010865:Pilot Projects; D013552:Swine; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome