THE VALUE OF 18F-FDG PET/CT SCAN IN DIAGNOSIS OF HEPATOCELLULAR CARCINOMA: 1140

Abstract

Background: The value of 18F-FDG PET/CT scan in detection of primary hepatocellular carcinoma (HCC) and extrahepatic metastases has been evaluated, but detailed reports are still limited. We analyzed the sensitivity, specificity, and accuracy between conventional imaging modalities and 18F-FDG PET/CT scan. Methods: A total of 138 patients with HCC who had both conventional imaging modalities (abdomen computed tomography (CT)/magnetic resonance imaging (MRI), chest CT, bone scan) and 18F-FDG PET/CT scan done between November 2006 and March 2011 were enrolled. Diagnostic value for detection of extrahepatic metastases between conventional imaging modalities and 18F-FDG PET/CT scan were evaluated and tumor characteristics including 18F-FDG PET/CT scan findings were analyzed as risk factors for metastases by univariate and multivariate methods. Result: 1) The sensitivity, specificity and accuracy for detection of lung metastases in 18F-FDG PET/CT scan were 60.9%, 99.1%, and 92.6%, respectively and 100%, 98.2%, and 98.5%, respectively in chest CT. 2) The detection rate of metastatic pulmonary nodule ≥ 1 cm was 12/13 (92.3%), when < 1cm was 2/10 (20%) in 18F-FDG PET/CT scan. 3) The sensitivity, specificity and accuracy for detection of bone metastases were 100%, 100%, and 100%, respectively in 18F-FDG PET/CT scan and 63.6%, 96.8% and 94.1%, respectively in bone scan. 4) In multivariate analysis, increased tumor size (≥ 5cm) (p=0.042) and increased average standardized uptake value (SUV) uptake (≥ 3.4) (p=0.028) were predictive factors for extrahepatic metastases. Isometabolic HCC in 18F-FDG PET scan was inversely correlated in multivariate analysis (p=0.035). Conclusion: 18F-FDG PET/CT scan is invaluable for detection of lung metastases larger than 1 cm and bone metastases. Primary HCC having larger than 5 cm and increased average SUV uptake more than 3.4 should be considered for extrahepatic metastases.