Objectives: To assess the incidence and degree of MR1 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%) preablation, 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 2-7months.Key Points · 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.