title: High-intensity focused ultrasound ablation for the treatment of colorectal liver metastases during an open procedure: study on the pig.
abstract: OBJECTIVE
  To demonstrate in a porcine model that high-intensity focused ultrasound (HIFU) with toroid-shaped emitters may have a role in treating unresectable colorectal liver metastases.
  
  
  BACKGROUND
  Surgical resection is the only curative option for colorectal hepatic metastases. Only 20% of patients are suitable for surgery. Many ablative techniques have been assessed but several limitations have been documented: traumatic puncture of the parenchyma, limited size of lesions, and inability to monitor the treatment in real time.
  
  
  METHODS
  A HIFU device with 256 toroid-shaped emitters and integrated ultrasound imaging probe was used. Single lesions, induced in 40 seconds, and juxtaposition of 6 single lesions were created under ultrasound guidance on 13 pigs. The lesions were studied on sonograms, macroscopically and microscopically up to 30 days after the treatment.
  
  
  RESULTS
  Ninety percent of the HIFU lesions were immediately hypoechoic on ultrasound imaging. The average coagulated volume obtained from a 40 seconds total exposure in the liver was 7.0 +/- 2.5 cm (1.5-20.0), average diameter: 19.5 +/- 3.8 mm (10.0-29.0). Using the real-time visualization of the treated region, single lesions were easily juxtaposed to produce larger lesions up to 6 cm in diameter without any major complication.
  
  
  CONCLUSIONS
  This toroid HIFU device allows short treatment times, noninvasiveness regarding the liver and real time ultrasound guidance. It seems to be simpler and more reliable to use than current ablative methods. Additionally, lesions through large vessels (up to 5 mm) being feasible, treatment of some juxta-vascular metastases should be possible.
authors.affiliation: INSERM, U556, Lyon, France.
authors.forename: Hubert
authors.initials: H
authors.lastname: Parmentier
authors.forename: Parmentier
authors.initials: P
authors.lastname: Hubert
authors.forename: David
authors.initials: D
authors.lastname: Melodelima
authors.forename: Melodelima
authors.initials: M
authors.lastname: David
authors.forename: Apoutou
authors.initials: A
authors.lastname: N'Djin
authors.forename: N'Djin
authors.initials: N
authors.lastname: Apoutou
authors.forename: Sabrina
authors.initials: S
authors.lastname: Chesnais
authors.forename: Chesnais
authors.initials: C
authors.lastname: Sabrina
authors.forename: Jean Yves
authors.initials: JY
authors.lastname: Chapelon
authors.forename: Chapelon Jean
authors.initials: CJ
authors.lastname: Yves
authors.forename: Michel
authors.initials: M
authors.lastname: Rivoire
authors.forename: Rivoire
authors.initials: R
authors.lastname: Michel
mesh_terms: D000818:Animals; D015179:Colorectal Neoplasms / Q000473:pathology*; D004867:Equipment Design; D008099:Liver / Q000473:pathology / Q000601:surgery; D008113:Liver Neoplasms / Q000556:secondary* / Q000601:surgery / Q000628:therapy*; D013552:Swine; D014464:Ultrasonic Therapy / Q000295:instrumentation