title: Microwave ablation of liver tumors: degree of tissue contraction as compared to RF ablation.
abstract: To compare the amount of tissue contraction after microwave (MW) versus radiofrequency (RF) ablation of liver tumors.
  
  
  
  Seventy-five hepatic tumors in 65 patients who underwent percutaneous MW or RF ablations were included in this retrospective study. All patients underwent MRI within 6 months before the ablation and 24 h after the procedure. Two blinded radiologists, by consensus, performed measurements on the corresponding series of pre and post-ablation MRI. Absolute and relative contraction of liver, tumor, and control were calculated and compared.
  
  
  
  Thirty-one patients underwent MW ablations, and 44 patients underwent RF ablations. The absolute and relative contraction of the ablation zone were significantly greater with MW than RF ablation (p = 0.003 to <0.001). Thirty-two lesions were visible on both pre- and post-ablation MRI. MW ablation had significantly more tumor contraction as compared to RF ablation (p = 0.003 to 0.009). The control measurements demonstrated no significant difference in normal tissue variation between MW and RF groups.
  
  
  
  MW ablation of hepatic tumors produced significantly more contraction of tumor and ablated hepatic tissue compared to RF ablation. Tissue contraction should be taken into account during pre-procedural planning and assessing treatment response by comparing pre- and post-ablation images.
authors.affiliation: Department of Radiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.|Department of Radiology, Ewha Womans University, Seoul, Korea.
authors.forename: Jeong Kyong
authors.initials: JK
authors.lastname: Lee
authors.affiliation: Department of Radiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.|Department of Radiology, Chalubhorn Hospital, Bangkok, Thailand.
authors.forename: Surachate
authors.initials: S
authors.lastname: Siripongsakun
authors.affiliation: Department of Radiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.
authors.forename: Simin
authors.initials: S
authors.lastname: Bahrami
authors.affiliation: Department of Radiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.
authors.forename: Steven S
authors.initials: SS
authors.lastname: Raman
authors.affiliation: Department of Radiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA.|Department of Biostatistics, School of Public Health, UCLA, Los Angeles, CA, USA.
authors.forename: James
authors.initials: J
authors.lastname: Sayre
authors.affiliation: Department of Radiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA. dlu@mednet.ucla.edu.
authors.forename: David S
authors.initials: DS
authors.lastname: Lu
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017115:Catheter Ablation / Q000379:methods*; D003287:Contrast Media; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D008113:Liver Neoplasms / Q000000981:diagnostic imaging* / Q000601:surgery*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008872:Microwaves / Q000627:therapeutic use*; D008875:Middle Aged; D000078702:Radiofrequency Therapy; D012189:Retrospective Studies; D016896:Treatment Outcome
chemical_list: D003287:Contrast Media
keywords: Liver contraction; Liver tumor; Microwave ablation; Radiofrequency ablation