Imaging Diagnosis Riccardo Lencioni, M.D., 1,2 Dania Cioni, M.D., 2 Clotilde Della Pina, M.D., 2 Laura Crocetti, M.D., 2 and Carlo Bartolozzi, M.D. 2 ABSTRACT The diagnosis of hepatocellular carcinoma (HCC) is based on imaging examina- tions in combination with clinical and laboratory findings. Despite technological advances, imaging cirrhotic patients remains a challenging issue because nonmalignant hepatocellular lesions, such as dysplastic nodules, mimic a small HCC. One of the key pathologic factors for differential diagnosis that is reflected in imaging appearances is the vascular supply to the lesion. It is accepted that imaging techniques may establish the diagnosis of HCC in nodules larger than 2 cm showing characteristic arterial hypervascularization. In lesions ranging from 1 to 2 cm, biopsy is still recommended, although a negative response can never be used to rule out malignancy completely. Although ultrasonography is widely accepted for HCC surveillance, spiral computed tomography (CT) or dynamic magnetic resonance imaging is required for diagnostic confirmation and intrahepatic tumor staging. These examinations have replaced invasive procedures, such as lipiodol CT, but remain relatively insensitive for the detection of tiny HCC lesions and tumor vascular invasion into peripheral portal vein branches. KEYWORDS: Ultrasonography, computed tomography, magnetic resonance imaging, percutaneous biopsy Objectives: Upon completion of this article, the reader will be able to (1) recognize and characterize imaging findings of hepatocellular carcinoma and dysplastic nodules in cirrhosis, (2) discuss advantages and limitations of current imaging techniques for intrahepatic tumor staging, and (3) select the most appropriate diagnostic work-up for patients with suspected hepatocellular carcinoma. Accreditation: Tufts University School of Medicine (TUSM) is accredited by the Accreditation Council for Continuing Medical Education to provide continuing medical education for physicians. Credit: TUSM designates this educational activity for a maximum of 1 Category 1 credit toward the AMA Physicians Recognition Award. Each physician should claim only those credits that he/she actually spent in the educational activity. Diagnostic confirmation and assessment of disease extent are crucial for proper clinical management of patients with hepatocellular carcinoma (HCC). For years, the diagnosis of HCC was based on percuta- neous biopsy, and intrahepatic tumor staging required invasive procedures, such as angiography and lipiodol computed tomography (CT). Currently, owing to advances in imaging techniques, a reliable diagnostic assessment can be based in most instances on noninva- sive examinations in combination with clinical and laboratory findings. 1 Nevertheless, imaging cirrhotic patients with sus- pected HCC is a challenging issue. HCC shows a variety of imaging features that reflect the variable gross and microscopic characteristics of this malignancy. In ad- dition, pathologic changes inherent in cirrhosis—such Hepatocellular Carcinoma; Editor in Chief, Paul D. Berk, M.D.; Guest Editor, Jordi Bruix, M.D. Seminars in Liver Disease, volume 25, number 2, 2005. Address for correspondence and reprint requests: Prof. Riccardo Lencioni, Division of Diagnostic and Interventional Radiology, Pisa University Hospital, Via Roma 67, I-56125 Pisa, Italy. E-mail: Lencioni@do.med.unipi.it. 1 Professor, 2 Division of Diagnostic and Interventional Radiology, Department of Oncology, Transplants and Advanced Technologies in Medicine, University of Pisa, Pisa, Italy. Copyright # 2005 by Thieme Medical Publishers, Inc., 333 Seventh Avenue, New York, NY 10001, USA. Tel: +1(212) 584-4662. 0272-8087,p;2005,25,02,162,170, ftx,en; sld00332x. 162 Downloaded by: Vanderbilt University. Copyrighted material.