Imaging: focus on hepatocellular carcinoma and liver transplantation

The choice of management for the patient with HCC hinges on precise localization and staging of the disease process. All the major imaging modalities are employed to achieve this end. US is frequently the initial means of detection of the lesion. Since percutaneous needling may lead to tumour dissemination, the temptation to proceed to imaging-guided biopsy should be resisted until a full evaluation has been completed and it is clear that neither curative surgery nor transplantation is a therapeutic option. CT scanning is considered to be superior to ultrasound both in detection and staging of the disease. A variety of modifications to the technique, including CT arterio-portography and lipiodol-CT, is used to obtain optimum results. The role of MRI has not yet been established but initial results suggest that this may be the optimum means of scanning the patient following percutaneous or intra-arterial therapy. Angiography is generally performed prior to resection and may be combined with the delivery of chemotherapeutic and embolic agents pre-operatively or as a definitive palliative procedure. Imaging-guided percutaneous alcohol is also a useful palliative measure where the lesion is small. In the majority of cases, resection is not feasible. In a selected few liver transplantation is an option. Imaging requirements of the potential liver transplant candidate depend on the nature of the underlying liver problem. A general assessment including a chest X-ray and US with Doppler imaging of the hepatic vascular structures is sufficient in the majority. In children with complex structural anomalies and in patients with bile duct disease or tumours, the full range of investigations is required. US, cholangiography CT and angiography may all be required in the diagnosis and management of post-transplant complications.