Imaging review of hepatocellular carcinoma after thermal ablation: The good, the bad, and the ugly.

Image-guided thermal ablation is a well-established locoregional technique for the treatment of hepatocellular carcinoma (HCC). HCC surveillance programs have led to an increase in the number of patients diagnosed at an early stage of the disease who are eligible for thermal ablation. Tumor response is assessed on imaging and requires extensive follow-up; thus, radiologists play a key role in defining the technical success and efficacy of treatment as well as identifying progressive disease. Although they are rare, complications, such as secondary infections, must also be identified. Several contrast-enhanced imaging techniques can be used at different postprocedural timepoints but magnetic resonance imaging (MRI) and computed tomography (CT), which allow both liver-centered and whole-body imaging are the cornerstones of follow-up. This review describes the imaging features of HCC following thermal ablation. After describing the basic technical elements of follow-up imaging, imaging findings are divided into three groups: normal and expected features (the good), abnormal features, uncontrolled disease, and complications (the bad), and atypical or rare presentations (the ugly). J. Magn. Reson. Imaging 2016;44:1070-1090.