title: Utility of FDG-PET for investigating unexplained serum AFP elevation in patients with suspected hepatocellular carcinoma recurrence.
abstract: The aim of this study was to evaluate the potential role of positron emission tomography (PET) with 18F-fluorodeoxyglucose (FDG) in patients with unexplained rising serum alpha-fetoprotein (AFP) levels after the treatment of hepatocellular carcinoma (HCC).
  
  
  METHODS
  Thirty-one FDG-PET studies were performed in 26 patients (age range, 45-83; 21 men and 5 women), who had undergone either surgical resection or interventional therapy for HCC, but were subsequently noted to have high AFP serum levels on routine follow-up examinations, although imaging studies and physical examinations were normal. The FDG-PET results were correlated with histological findings, as well as long-term radiological and clinical follow-up (shortest follow-up period after FDG-PET was 6 months).
  
  
  RESULTS
  FDG-PET was abnormal in 22 of the 31 studies (71.0%) among the 26 patients. Intrahepatic lesions were detected in 20 of a total 30 lesions (66.7%) in 18 studies of FDG-PET among 26 patients. Ten FDG-PET studies among 9 patients identified one intrahepatic lesion, while 3 studies among 3 patients identified more than one intrahepatic lesion. Extrahepatic metastases were found in 9/31 studies of FDG-PET (29.0%) among 8 patients. These metastatic foci, composed of increased FDG accumulation, were identified in several locations; lung (4 studies among 4 patients), bone (2 studies among 2 patients) and the peritoneum (4 studies among 3 patients). Overall, FDG-PET for detecting HCC recurrence demonstrated 22 true-positives, 8 false-negatives, 1 true-negative and 0 false-positive results., The sensitivity, specificity and accuracy of FDG-PET for detecting HCC recurrence was 73.3%, 100% and 74.2%, respectively.
  
  
  CONCLUSIONS
  When conventional examinations are normal, FDG-PET is a valuable imaging tool in patients who have rising AFP levels after HCC treatment. FDG-PET whole-body scan also provides an important and valuable imaging study for detecting extrahepatic metastasis.
authors.affiliation: Department of Nuclear Medicine and PET Center, Shin Kong Wu Ho-Su Memorial Hospital, Taipei and China Medical University, Taichung, Taiwan.
authors.forename: Yen-Kung
authors.initials: YK
authors.lastname: Chen
authors.forename: Dar-Shih
authors.initials: DS
authors.lastname: Hsieh
authors.forename: Chao-Sheng
authors.initials: CS
authors.lastname: Liao
authors.forename: Chyi-Huey
authors.initials: CH
authors.lastname: Bai
authors.forename: Chen-Tau
authors.initials: CT
authors.lastname: Su
authors.forename: Yeh-You
authors.initials: YY
authors.lastname: Shen
authors.forename: Jih-Fang
authors.initials: JF
authors.lastname: Hsieh
authors.forename: Alfred C
authors.initials: AC
authors.lastname: Liao
authors.forename: Chia-Hung
authors.initials: CH
authors.lastname: Kao
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D006528:Carcinoma, Hepatocellular / Q000097:blood* / Q000000981:diagnostic imaging* / Q000473:pathology / Q000628:therapy; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000493:pharmacokinetics; D006801:Humans; D008113:Liver Neoplasms / Q000097:blood* / Q000000981:diagnostic imaging* / Q000473:pathology / Q000628:therapy; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000097:blood / Q000000981:diagnostic imaging; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D012189:Retrospective Studies; D000509:alpha-Fetoproteins / Q000378:metabolism*
chemical_list: D019275:Radiopharmaceuticals; D000509:alpha-Fetoproteins; D019788:Fluorodeoxyglucose F18