title: Early PET/CT after radiofrequency ablation in colorectal cancer liver metastases: is it useful?
abstract: BACKGROUND
  Morphologic imaging after radiofrequency ablation (RFA) of liver metastases is hampered by an inflammatory response in the ablation margin, making the identification of local tumor progression (LTP) difficult. The aim of this study was to evaluate the efficacy of early (18)F-FDG PET/CT scanning to monitor the effectiveness of RFA in colorectal liver metastases.
  
  
  METHODS
  Twelve patients with 20 metastases were treated with RFA for colorectal liver metastases. They underwent PET/CT within 2 weeks before RFA and within 24 hours after RFA (so termed "early PET/CT"). PET/CT was repeated at 1, 3, and 6 months, and then every 6 months after ablation. The standard of reference was based on available clinical and radiological follow-up data.
  
  
  RESULTS
  Early PET/CT revealed total photopenia in 16 RFA-treated metastases, which were found to be without residual tumor on the final PET/CT scan. Three RFA-treated metastases with focal uptake were identified as local tumor progression, which necessitated further treatment. One RFA-treated metastasis with rim-shaped uptake was regarded as inflammation. The results of the early PET/CT scanning were consistent with the findings of the final follow-up.
  
  
  CONCLUSIONS
  PET/CT performed within 24 hours after RFA can effectively detect whether residual tumor exists for colorectal cancer liver metastases. The results can guide further treatment, and may improve the efficacy of RFA.
authors.affiliation: Department of Radiology, Shengjing Hospital of China Medical University, Shenyang, Liaoning 110004, China. liuzy@sj-hospital.org
authors.forename: Zhao-Yu
authors.initials: ZY
authors.lastname: Liu
authors.forename: Zhi-Hui
authors.initials: ZH
authors.lastname: Chang
authors.forename: Zai-Ming
authors.initials: ZM
authors.lastname: Lu
authors.forename: Qi-Yong
authors.initials: QY
authors.lastname: Guo
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017115:Catheter Ablation; D015179:Colorectal Neoplasms / Q000150:complications* / Q000000981:diagnostic imaging / Q000628:therapy*; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000627:therapeutic use; D006801:Humans; D008113:Liver Neoplasms / Q000000981:diagnostic imaging / Q000556:secondary* / Q000628:therapy*; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D019788:Fluorodeoxyglucose F18