title: Internally cooled antenna for microwave ablation: results in ex vivo and in vivo porcine livers.
abstract: OBJECTIVE
  To evaluate the performance of microwave ablation with an internally cooled antenna in ex vivo and in vivo porcine livers.
  
  
  METHODS
  Microwave ablations were performed in ex vivo and in vivo porcine livers with a 1.9 mm-diameter 2450 MHz microwave needle antenna. Four power settings (50, 60, 70 and 80 W) were used in this study, while application time was fixed at 10 min. Diameters of the coagulation zone were observed on gross specimens.
  
  
  RESULTS
  Excessive elongation of coagulation along the needle shaft was not encountered in all ablations. An arrow-shaped charring was observed. As the power increases, the long-axis coagulation diameter for in vivo liver increased significantly (P<.05). The short-axis coagulation diameter for in vivo liver was significantly smaller than that for ex vivo liver (P<.05) but not statistically different among the four power settings. After 10 min of ablation at 80 W, the short-axis and long-axis coagulation diameter for in vivo liver was 4.92+/-0.15 cm and 2.37+/-0.10 cm, respectively.
  
  
  CONCLUSIONS
  The internally cooled microwave antenna may be advantageous to minimize collateral damages.
authors.affiliation: Department of Ultrasound, Chinese PLA General Hospital, 28 Fuxing Road, Beijing 100853 China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Ultrasound, Chinese PLA General Hospital, 28 Fuxing Road, Beijing 100853 China.
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Sun
authors.affiliation: Department of Ultrasound, Chinese PLA General Hospital, 28 Fuxing Road, Beijing 100853 China.
authors.forename: Lei
authors.initials: L
authors.lastname: Feng
authors.affiliation: Department of Ultrasound, Chinese PLA General Hospital, 28 Fuxing Road, Beijing 100853 China.
authors.forename: Yongyan
authors.initials: Y
authors.lastname: Gao
authors.affiliation: Department of Ultrasound, Chinese PLA General Hospital, 28 Fuxing Road, Beijing 100853 China.
authors.forename: Xiaoxia
authors.initials: X
authors.lastname: Ni
authors.affiliation: Department of Ultrasound, Chinese PLA General Hospital, 28 Fuxing Road, Beijing 100853 China. Electronic address: liangping301@hotmail.com.
authors.forename: Ping
authors.initials: P
authors.lastname: Liang
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D017115:Catheter Ablation / Q000295:instrumentation / Q000379:methods*; D066298:In Vitro Techniques; D008099:Liver / Q000601:surgery*; D008872:Microwaves / Q000627:therapeutic use*; D013552:Swine