FDG uptake on PET and enhancement on CT or MRI in hepatocellular carcinoma (HCC)

To correlate between FDG PET and enhancement pattern on CT and MRI and assess the factors affecting FDG uptake in HCC. Thirty seven nontreated HCC from 34 pts (M:F=30:4, mean age 53) were enrolled. All cases were histologically diagnosed and classified according to Edmonson and Steiner's grading. Tumor FDG uptake was visually assessed on a scale of 0 to 3 compared to the adjacent liver. (0liver and 3>>liver) and was semi-quantitatively analyzed using SUV. Enhancement pattern on CT and MRI was classified into 3 groups according to signal intensity or density in arterial and portal phase (GroupI: hyperintense-hypointense, GroupII: isointense-hypointense, GroupIII: hypointense-hypointense). Tumor FDG uptake was correlated with enhancement pattern, grade, size and serum aFP level. The tumor ranged from 1.5cm to 20cm. Of the 37 cases, 19(51%) had positive FDG uptake (2 or 3), while 18(49%) were negative (0 or 1). The correlation between FDG uptake and enhancement pattern was statistically insignificant. Lower FDG uptake was associated with lower tumor grade and/or smaller tumor size (P<0.005). FDG uptake of HCC seems to be useful in predicting the differentiation of the tumor and may be prognostic. Although the significance of dynamic enhancement pattern on CT or MRI is yet controversial, it has no specific correlation with FDG uptake and grade on the tumor in this study