Imaging diagnosis and evaluation of early recurrence in postoperative hepatocellular carcinoma        JIA Hu-liang，QIN Lun-xiu. Liver Cancer Institute & Zhongshan Hospital, Fudan University, Shanghai 200032，China
Corresponding author：QIN Lun-xiu，E-mail：qin.lunxiu@zs-hospital.sh.cn
Abstract    Imaging diagnostic techniques play very important roles in the early detection and diagnosis of postoperative recurrence of hepatocellular carcinoma（HCC）. Because of its cost-effectiveness, ultrasonography (US) still keeps a preferred place for routine screening of HCC in patients with liver disease as well as for surveillance in postoperative patients. Compared with US, computed tomography (CT) has a higher sensitivity in small HCC diagnosis, and is widely used to detect and characterize liver lesions. Due to the technical advances in hardware and software that allow the acquisition of images with excellent anatomic detail, and the novel tissue-specific contrast agents, magnetic resonance imaging (MRI) has played more and more significant roles in the early detection of HCC recurrence, which has been the first choice. MRI has been proved to be more sensitive and specific than CT, particularly for the detection of very small nodules of HCC recurrences. Positron emission tomography (PET) is not proved to be more useful and sensitive in diagnosis, prognosis and therapeutic effect judgement of HCC. It usually suggests the HCC patients receive regular serum AFP detection and US every two months, and enhanced CT or MRI each year during the follow-up after  operation; when the tumor recurrence is suspected by the AFP and US, enhanced MRI/CT is recommended to make the diagnosis.