Role of MRI in the assessment of treatment response after radiofrequency and microwave ablation therapy for hepatocellular carcinoma

PurposeThe purpose of this study was to assess the role of dynamic contrast enhanced and diffusion MR imaging in the detection of tumor viability after radiofrequency and microwave ablation therapy of hepatocellular carcinoma.Subjects and methodsThe study was done on 50 patients with HCC underwent radiofrequency or microwave ablation. Patients were classified into resolved group if there’s no MRI evidence of tumor viability at the ablated lesion and unresolved group if there’s evidence of tumor viability.ResultsIn the early 1 month post-ablation period, heterogenous signal of the ablation zone in the precontrast T1 and T2 images was noted that gradually become more homogenous in the 3–12 months follow-up. Ill defined persistent perilesional enhancement is considered as a benign finding that was present in 100% of patients imaged within the 1st month and persists only in 5% after 9–12 months. The mean ADC value of the malignant lesions was 0.91 ± 0.09 × 10−3 mm2/s, while the mean ADC value of the benign post-ablation parenchymal changes was 1.29 ± 0.12 × 10−3 mm2/s with a cutoff value of 1.05 × 10−3 mm2/s.ConclusionMRI provides a powerful tool in the assessment of treatment response after RFA and MWA of hepatocellular carcinoma.