title: Microwave ablation assisted by a computerised tomography-ultrasonography fusion imaging system for liver lesions: an ex vivo experimental study.
abstract: OBJECTIVE
  To investigate the feasibility and validity of real-time guidance using a fusion imaging system that combines ultrasonography (US) and computerised tomography (CT) information in the targeting and subsequent microwave ablation of a liver target inconspicuous on US.
  
  
  METHODS
  The study was an experimental ex vivo study in calf livers with internal targets, simulating a focal liver lesion, focused on the accuracy of real-time US using a multimodality fusion imaging system in combination with 15 gauge (G) microwave antennae. US image and pre-procedural CT image were fused by the external markers registration procedure. Microwave antennae were inserted into the liver to ablate the target assisted by the CT-US fusion imaging system. Finally, a post-procedural CT with needles in situ and multiplanar reconstructions were performed to compare with pre-procedural CT information in order to calculate the accuracy of positioning (distance between the needle tip and the target).
  
  
  RESULTS
  Eight insertions were planned and eight ablations were performed in four calf livers. The calf livers were undertaken successfully on external markers registration procedure. The mean registration error in the four livers was 2.1 ± 0.1 mm, 2.8 ± 0.1 mm, 3.4 ± 0.1 mm and 2.3 ± 0.1 mm, respectively. The accuracy of the matched US-CT images was very satisfactory in the fact that it was found there was a mean discrepancy of 1.63 ± 1.06 mm.
  
  
  CONCLUSIONS
  Real-time registration and fusion of pre-procedural CT volume images with intraprocedural US is feasible and accurate for microwave (MW) ablation in experimental setting. Further studies are warranted to validate the system under clinical conditions.
authors.affiliation: Department of Interventional Ultrasound, Chinese PLA General Hospital, Beijing, China. dyuxl301@yahoo.com.cn
authors.forename: Xiaoling
authors.initials: X
authors.lastname: Yu
authors.forename: Fangyi
authors.initials: F
authors.lastname: Liu
authors.forename: Ping
authors.initials: P
authors.lastname: Liang
authors.forename: Alex Dell
authors.initials: AD
authors.lastname: Era
authors.forename: Zhigang
authors.initials: Z
authors.lastname: Cheng
authors.forename: Zhiyu
authors.initials: Z
authors.lastname: Han
mesh_terms: D055011:Ablation Techniques; D000818:Animals; D002417:Cattle; D008099:Liver / Q000000981:diagnostic imaging / Q000601:surgery; D008113:Liver Neoplasms / Q000601:surgery*; D008872:Microwaves / Q000627:therapeutic use*; D025321:Surgery, Computer-Assisted / Q000379:methods; D014057:Tomography, X-Ray Computed / Q000379:methods; D018084:Ultrasonography, Interventional