title: MRI contrast enhancement of malignant liver tumours following successful cryoablation.
abstract: OBJECTIVE
  To assess the incidence and degree of MRI contrast enhancement in liver tumours following successful percutaneous cryoablation.
  
  
  METHODS
  Thirty-eight patients with liver metastases (n = 29) or hepatocellular carcinoma (n = 9) underwent percutaneous cryoablation of 45 tumours between March 2004 and June 2009, with complete ablation zone coverage of the tumour and no local recurrence on follow-up imaging to date (range 3-60 months, mean 16). Contrast-enhanced MRI was used to assess 45 tumours at 24 h, 32 tumours at 2-4 months, and 21 tumours at 5-7 months. Percentage of tumours with contrast enhancement was assessed using dynamic spoiled gradient echo T1-weighted images.
  
  
  RESULTS
  Twenty-four hours post-cryoablation, 23 out of 45 tumours (51%) enhanced compared with 42 out of 43 (98%) pre-ablation (p < 0.001). Mean percentage tumour enhancement decreased from 157% (range 26-745%) pre-ablation, to 107% (27-260%) at 24 h (p = 0.003), and 43% (24-103%) at 2-4 months (p < 0.001). The incidence and degree of tumour enhancement decreased through 5-7 months.
  
  
  CONCLUSIONS
  Unlike previously reported studies of radiofrequency ablation, successful cryoablation of liver tumours is often associated with persistent tumour contrast enhancement on MRI performed at 24 h and decreasing over 2-7 months.
  
  
  CONCLUSIONS
  • Liver neoplasms often demonstrate MRI contrast enhancement following successful percutaneous cryoablation. • This differs from radiofrequency ablation techniques where contrast enhancement suggests residual tumour • This difference could potentially lead to important errors in follow up strategies.
authors: Abdominal Imaging and Intervention, Department of Radiology, Brigham and Women's Hospital, 75 Francis St., Boston, MA 02115, USA. pshyn@partners.org
authors: Paul B
authors: PB
authors: Shyn
authors: M Raquel
authors: MR
authors: Oliva
authors: Shaan H
authors: SH
authors: Shah
authors: Servet
authors: S
authors: Tatli
authors: Paul J
authors: PJ
authors: Catalano
authors: Stuart G
authors: SG
authors: Silverman
mesh_terms: D000328:Adult; D000368:Aged; D006528:Carcinoma, Hepatocellular / Q000175:diagnosis / Q000473:pathology / Q000628:therapy*; D003287:Contrast Media / Q000494:pharmacology*; D003452:Cryosurgery / Q000379:methods*; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D015994:Incidence; D008113:Liver Neoplasms / Q000175:diagnosis / Q000473:pathology* / Q000628:therapy*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D009364:Neoplasm Recurrence, Local; D012189:Retrospective Studies; D013997:Time Factors
chemical_list: D003287:Contrast Media