RF ablation is an effective first-line treatment for cirrhotic patients with early-stage HCC who were excluded from surgery.

The development and progression of a hepatocellular carcinoma (HCC) in a chronically diseased liver, i.e., the carcinogenesis, comprise a multistep and long-term process. Morphologically, this process is associated with the presence of distinct nodular lesions in the liver that are called 'preneoplastic lesions.' These preneoplastic lesions are associated with and can precede the growth and progression of well-differentiated HCCs . The characterization of nodular lesions and demonstration of the multistep development of HCC in the cirrhotic liver by imaging modalities represent a challenging issue. The arterial hypervascular supply, depicted by different dynamic studies, represents a fundamental radiological criterion for the diagnosis of HCC in cirrhosis. Magnetic resonance (MR) imaging performed with tissue-specific contrast media can help to investigate the "grey area" of carcinogenesis, in which significant histological changes are already present without any imaging evidence of neoangiogenesis. The purpose of this review is to provide information on the properties of tissue-specific MR contrast agents and on their usefulness in the demonstration of the pathologic changes that take place at the level of the biliary and reticuloendothelial systems during the carcinogenetic process in liver cirrhosis.

Surgical resection is the standard of care for colorectal metastases isolated to the liver. However, only 10-25% of the patients are eligible for resection because of extent and location of the disease in the liver or concurrent medical conditions. Image-guided radiofrequency (RF) ablation is a minimally invasive technique that is emerging as a viable alternate treatment of nonsurgical patients with limited hepatic metastatic disease. Several series have shown that RF ablation can result in complete tumor eradication in properly selected candidates and have provided indirect evidence that the treatment improves survival. In a recent multicenter trial including 423 patients, overall survival of RF-ablation treated patients reached 47% at 3 years and 24% at 5 years. RF ablation technology is undergoing continuous improvement, and its clinical application has been successfully expanded to the treatment of colorectal metastases to the lung. Randomized trials comparing RF ablation with either surgical resection or chemotherapy protocols, however, are still missing. In this article, we review technique, indications, clinical results, and future prospects of RF ablation in the therapeutic management of metastatic colorectal cancer patients.

Imaging in liver interventional oncology plays a key role in the entire process starting from patient selection, leading to patient treatment and continuing with patient follow-up. Pre-procedural imaging evaluation is aimed to determine the indication for interventional therapies according to the size, number, and location of hepatic lesions, to the presence of major vascular invasion, nodal disease, and distant metastases, and to choose the most suitable approach according to tumor histology. Ideal qualities of a targeting technique include clear delineation of the tumor tissue and the surrounding anatomy, coupled with real-time imaging, multiplanar, and interactive capabilities. Moreover, the modality of image guidance should visualize therapy effects during the intervention to assess coverage of the targeted tissue and to prevent unintended thermal injury to critical structures in the surroundings of the target. Post-treatment imaging is then imperative to evaluate response to therapy by assessing for residual or recurrent disease, revising prognosis, and guiding future therapy. In this article, the role of imaging in patient selection and treatment planning will be discussed. Recently amended RECIST (mRECIST) for evaluation of tumor response in hepatocellular carcinoma and specific treatment-related findings after thermal ablation, trans-arterial chemoembolization, and radioembolization will be reviewed.

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