Abstracts Poster Abstracts - Dr Falk

Imaging modalitiesProf. Riccardo LencioniUniversity of Pisa, ItalyDiagnostic confirmation and assessment of disease extent are crucial for properclinical management of patients with hepatocellular carcinoma (HCC). For years, thediagnosis of HCC was based on percutaneous biopsy, and intrahepatic tumor stagingrequired invasive procedures, such as angiography and Lipiodol computedtomography (CT). Currently, owing to the advances in imaging techniques, a reliablediagnostic assessment can be based in most instances on noninvasive examinationsin combination with clinical and laboratory findings. Nevertheless, imaging cirrhoticpatients with suspected HCC is a challenging issue. HCC shows a variety of imagingfeatures, that reflect the variable gross and microscopic characteristics of thismalignancy. In addition, pathologic changes inherent in cirrhosis - such as largeregenerative nodules and dysplastic nodules (DNs) - may be indistinguishable from asmall HCC. One of the key pathologic factors for differential diagnosis that isreflected in imaging appearances is the vascular supply to the lesion. Through theprogression from regenerative nodule, to low-grade DN, to high-grade DN, to frankHCC, one sees loss of visualization of portal tracts and development of new arterialvessels, termed nontriadal arteries, which become the dominant blood supply in overtHCC lesions. It is this neovascularity that allows HCC to be diagnosed and is the keyfor imaging cirrhotic patients. While ultrasound (US) is widely accepted for HCCsurveillance, spiral CT or dynamic magnetic resonance (MR) imaging are required fordiagnostic confirmation and intrahepatic tumor staging. However, despite recenttechnological advances, CT and MR imaging remain relatively insensitive for thedetection of tiny satellite lesions and tumor vascular invasion into peripheral portalvein branches.48