title: Silicon carbide-enhanced microwave ablation in an ex-vivo bovine liver model - effects on heat distribution and ablation volume.
abstract: OBJECTIVE
  Evaluation of the maximum temperatures and ablation volumes in microwave ablation (MWA) after injection of different concentrations of silicon carbide (SiC) particles in an ex-vivo bovine liver model.
  
  
  METHODS
  15 ml of different concentrations of SiC particles (20 vol% SiC; 50 vol% SiC) mixed with 2 % gelatin were injected into an ex-vivo bovine liver. As a reference group, 2 % gelatin without SiC was injected. MWA was performed using a clinical MWA system with different generator settings (10 - 45 W/10 minutes). The temperature was measured at a distance of 5 mm and 10 mm from the applicator. Afterwards the liver tissue was sliced along the short and long axis, the ablation zones were measured on the x, y and z-axis and the ablation volume was calculated. All experiments were performed 5 times (total: 40 experiments).
  
  
  RESULTS
  The average maximum temperatures measured at a generator setting of 45 W at a distance of 5 mm from the applicator were 103.4 ± 4.6 °C (20 vol% SiC), 103.3 ± 6.5 °C (50 vol% SiC) and 96.0 ± 4.2 °C in the control group (0 vol% SiC). At 45 W, injection of 20 vol% SIC caused a significantly higher maximum temperature than that achieved in the control group (p = 0.016). No significant temperature increase compared to the control group could be measured using 50 vol% SiC. The mean ablation volumes at 45 W and 20 vol% SiC and 50 vol% SiC were significantly larger (172.7 ± 31.5 ml and 171.0 ± 34.7 ml, respectively) than those achieved in the control group (111.2 ± 23.8 ml) (p = 0.027 and p = 0.045).
  
  
  CONCLUSIONS
  In an ex-vivo bovine liver model, the SiC particles demonstrated an enhancing effect of MWA with respect to maximum temperatures and ablation volume. Therefore, SiC is a promising candidate for enhancing MWA in vivo.
authors.affiliation: Department of Diagnostic and Interventional Radiology, University Hospital RWTH Aachen, Germany. isfort@rad.rwth-aachen.de
authors.forename: P
authors.initials: P
authors.lastname: Isfort
authors.forename: T
authors.initials: T
authors.lastname: Penzkofer
authors.forename: P
authors.initials: P
authors.lastname: Bruners
authors.forename: T
authors.initials: T
authors.lastname: Schmitz-Rode
authors.forename: C K
authors.initials: CK
authors.lastname: Kuhl
authors.forename: A H
authors.initials: AH
authors.lastname: Mahnken
mesh_terms: D000818:Animals; D001672:Biocompatible Materials; D017554:Carbon Compounds, Inorganic / Q000008:administration & dosage*; D017115:Catheter Ablation / Q000295:instrumentation* / Q000379:methods*; D002417:Cattle; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D066298:In Vitro Techniques; D007267:Injections; D008099:Liver / Q000601:surgery*; D008872:Microwaves; D010316:Particle Size; D017655:Silicon Compounds / Q000008:administration & dosage*; D013696:Temperature
chemical_list: D001672:Biocompatible Materials; D017554:Carbon Compounds, Inorganic; D017655:Silicon Compounds; C022088:silicon carbide