Application of PET-CT in monitoring residual and extrahepatic metastatic lesions for hepatocellular carcinoma with positive alpha fetoproteins after interventional therapy

Objective To investigate the value of positron emisson tomography-computed tomography ( PET-CT) in monitoring the residual lesions in lipiodol sedimentary region and extrahepatic metastastic lesions of hepatocellular carcinoma ( HCC) with alpha fetoproteins ( AFP) positive after interventional therapy. Methods The data of 20 cases with primary HCC confirmed by histopathology were retrospectively analyzed. Their AFP levels decreased to normal range after interventional treatments, but rose to abnormal high level during following-up. After the abdominal routine imaging examinations, the definite diagnosis of the residual lesions in lipiodol sedimentary region or extrahepatic lesions can't be made confidently. All cases were scanned by PET-CT, and according to their PET-CT results, the further treatments were given and the therapeutic results were monitored with radiology and AFP tests. Results In all 20 cases, 10 of them were detected to have the extrahepatic metastastic lesions by PET-CT, including 4 with abdominal wall metastasis upon the liver, 3 with solitary pulmonary metastasis with diameter less than 1 cm, 2 with mesenteric mestastasis, 1 with mestastasis of operative incisions, but these lesions were neglected by abdominal routine imaging examinations. Eight cases showed the uneven lipiodol sedimentary region in the primary lesion by CT or MRI examination, but can't be diagnosed whether it was residual lesion with other examinations including DSA. A definite diagnosis was obtained by PET-CT. In 2 cases, lymph nodes less than 1. 5 cm were found in the hepatic portal area(PHA) and retroperitoneum on CT images,which was determined to be metastatic by PET-CT. All the detected lesions were given further treatments of surgery or interventional therapy. Most patients showed decreased AFP levels except the 2 patients with lymph node metastasis. The imaging examinations also indicated that the treatments had a good effect on lesions. Conclusion In the patients with HCC and abnormal high levels of AFP, in addition to abdominal routine imaging examinations, PET-CT is beneficial for those who is suspected of residual lesions in lipiodol sedimentary region or extrahepatic metastasis. Key words: Positron-emisson tomography;  Tomography, X-ray computed;  Alpha-fetoproteins; Carcinoma, hepatocellular;  Radiology, interventional