title: Diagnostic performance of contrast-enhanced computed tomography in the immediate assessment of radiofrequency ablation success in colorectal liver metastases.
abstract: BACKGROUND
  To determine the accuracy of contrast-enhanced multislice computed tomography (CT) in the assessment of treatment success immediately after CT-guided radiofrequency (RF) ablation.
  
  
  METHODS
  26 patients with 38 Colorectal liver metastasis (CRM) were treated by CT-guided RF ablation. Pre-contrast and portal phase CT features before and immediately after ablation were retrospectively evaluated quantitatively and qualitatively: Influence of attenuation characteristics, safety margin, congruency between tumor and coagulation, and morphological criteria (shape, margin distinction, margin configuration, and margin continuity) were investigated. Findings were statistically analyzed with regard to local tumor progression.
  
  
  RESULTS
  Mean observation period for follow-up scans was 6.4 months (range: 3-40 months). Attenuation characteristics, safety margin, and congruency had no significant effect on the probability of local tumor progression. Coagulations whose margin was categorized as "discontinuous" were significantly more often associated with local recurrence (p = 0.038). No significant influence on local recurrence could be detected regarding coagulation shape, margin distinction, and configuration.
  
  
  CONCLUSIONS
  Computed tomography imaging immediately after RF ablation allows for morphological characterization of the coagulation and provides a valid baseline status for follow-up imaging. However, in CRM, morphological image criteria and attenuation characteristics have limited predictive value for immediate detection of persistent tumor.
authors.affiliation: Department of Diagnostic and Interventional Radiology, University Hospital of Tuebingen, Hoppe-Seyler-Str. 3, Tuebingen, 72076, Germany. christina.schraml@med.uni-tuebingen.de
authors.forename: Christina
authors.initials: C
authors.lastname: Schraml
authors.forename: Stephan
authors.initials: S
authors.lastname: Clasen
authors.forename: Nina F
authors.initials: NF
authors.lastname: Schwenzer
authors.forename: Ingmar
authors.initials: I
authors.lastname: Koenigsrainer
authors.forename: Tina
authors.initials: T
authors.lastname: Herberts
authors.forename: Claus D
authors.initials: CD
authors.lastname: Claussen
authors.forename: Philippe L
authors.initials: PL
authors.lastname: Pereira
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017115:Catheter Ablation / Q000379:methods*; D015179:Colorectal Neoplasms / Q000473:pathology*; D003287:Contrast Media; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007472:Iohexol / Q000031:analogs & derivatives; D008099:Liver / Q000000981:diagnostic imaging*; D008113:Liver Neoplasms / Q000000981:diagnostic imaging / Q000556:secondary* / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D011856:Radiographic Image Enhancement / Q000379:methods*; D015641:Radiography, Interventional / Q000379:methods; D015203:Reproducibility of Results; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods*; D016896:Treatment Outcome
chemical_list: D003287:Contrast Media; D007472:Iohexol; C038192:iopromide