title: A microbubble contrast agent improves prediction of ablated areas during radiofrequency ablation: a rabbit liver study.
abstract: OBJECTIVE
  The purpose of this study was to explore the effects of a microbubble contrast agent (SonoVue; Bracco SpA, Milan, Italy) on the spread of gas generated by heating during radiofrequency ablation in vivo.
  
  
  METHODS
  Radiofrequency ablation was performed with or without SonoVue on 2 areas per rabbit liver in 20 rabbits under sonographic guidance. They were divided into groups 1 and 2 on the basis of ablation with and without SonoVue. In group 1, SonoVue (0.05 mL/kg) was injected as an intravenous bolus. After radiofrequency ablation, 3 orthogonal diameters of hyperechogenicity and defects of enhancement on contrast-enhanced sonography were measured sonographically. Coagulated zones and ablation times were also evaluated.
  
  
  RESULTS
  There were no significant differences in the sizes of the hyperechoic areas, defects, or coagulated zones between the groups (P > .05). However, the total number of ablations with clearly visualized hyperechogenicity was 15 in group 1 versus 7 in group 2, as opposed to ablations with partial or not clearly visualized hyperechogenicity (P< .05). A comparison between hyperechoic and pathologic volumes provided correlation values of r(2) = 0.803 and r(2) = 0.624 for groups 1 and 2, respectively. In addition, the ablation time for group 1 was significantly shorter (P < .05).
  
  
  CONCLUSIONS
  A microbubble agent would not change the size of the ablated area, but it can improve prediction of ablated areas and reduce the ablation time for achieving the same effects. Therefore, it might be useful to prevent unfavorable ablation of adjacent organs and vessels.
authors.affiliation: Department of Ultrasound, Nanfang Hospital, Southern Medical University, Guangzhou, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Hu
authors.forename: Fenglin
authors.initials: F
authors.lastname: Wu
authors.forename: Yang
authors.initials: Y
authors.lastname: Sui
authors.forename: Tingting
authors.initials: T
authors.lastname: Xu
mesh_terms: D017115:Catheter Ablation / Q000379:methods*; D003287:Contrast Media; D007089:Image Enhancement / Q000379:methods*; D008099:Liver / Q000000981:diagnostic imaging* / Q000601:surgery*; D045423:Microbubbles; D010743:Phospholipids; D011379:Prognosis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013459:Sulfur Hexafluoride; D025321:Surgery, Computer-Assisted / Q000379:methods*; D014463:Ultrasonography / Q000379:methods*
chemical_list: D003287:Contrast Media; D010743:Phospholipids; C420843:contrast agent BR1; D013459:Sulfur Hexafluoride