title: Coagulation areas produced by cool-tip radiofrequency ablation and microwave ablation using a device to decrease back-heating effects: a prospective pilot study.
abstract: OBJECTIVE
  To compare the ablation area produced by a single application of a microwave ablation (MWA) system, equipped with a miniaturized device on the tip of the antenna entrapping reflected microwaves, with that produced by an internally cooled radiofrequency ablation (RFA) system.
  
  
  METHODS
  Forty patients with primary or secondary inoperable liver tumors, selected to undergo percutaneous thermal ablation, were randomly assigned to MWA or RFA procedure. The ablation areas produced by a single application of MWA (ablation time 10 min) or RFA (ablation time 12 min) energy were assessed by contrast-enhanced ultrasonography immediately after the end of the procedure. The long- and short-axis diameters of the ablation areas were measured and compared using Student t test.
  
  
  RESULTS
  Long- and short-axis diameters of the ablation areas produced by MWA were significantly greater than those produced by RFA: 48.5 ± 6.7 versus 30.9 ± 1.1 mm (p < 0.0001) and 38.5 ± 4.6 versus 26.8 ± 2.9 mm (p < 0.0001), respectively.
  
  
  CONCLUSIONS
  The MWA system can achieve significantly larger ablation areas than the internally cooled RFA system. Broader randomized trials are strongly warranted to investigate whether such superiority can translate into better long-term outcome of the ablation procedure.
authors.affiliation: Section of Interventional Ultrasound, Department of Internal Medicine, St. Anna Hospital, Via a. Moro 8, Cona, 44100, Ferrara, Italy, fradiv12@libero.it.
authors.forename: Francesca
authors.initials: F
authors.lastname: Di Vece
authors.forename: Paola
authors.initials: P
authors.lastname: Tombesi
authors.forename: Francesca
authors.initials: F
authors.lastname: Ermili
authors.forename: Cinzia
authors.initials: C
authors.lastname: Maraldi
authors.forename: Sergio
authors.initials: S
authors.lastname: Sartori
mesh_terms: D006528:Carcinoma, Hepatocellular / Q000000981:diagnostic imaging* / Q000601:surgery*; D017115:Catheter Ablation / Q000295:instrumentation / Q000379:methods*; D003287:Contrast Media; D005260:Female; D006801:Humans; D008113:Liver Neoplasms / Q000000981:diagnostic imaging* / Q000556:secondary / Q000601:surgery*; D008297:Male; D008872:Microwaves; D008875:Middle Aged; D010865:Pilot Projects; D011446:Prospective Studies; D011846:Radio Waves; D016896:Treatment Outcome; D014463:Ultrasonography
chemical_list: D003287:Contrast Media