The correlation among 18F-FDG PET imaging, CT pattern of lipiodol retention and serum AFP in evaluating the effect of TACE for HCC

Objective: To investigate the relationship among 18F-fluorodeoxyglucose (FDG) PE, pattern of lipiodol retention CT and serum α-fetoprotein (AFP) in evaluating the effect of transcatheter arterial chemoembolization (TACE) for hepatocellular carcinoma (HCC). Methods: TACE was performed in thirty-five patients with HCC. 18F-FDG PET and lipiodol-CT examination were performed after TACE, and thus the patterns of lipiodol retention, and the tumor necrosis rates semi-quantitatively by 18F-FDG PET were obtained with simultaneous calculation of the decrease percentage of serum AFP before and after TACE. Results: The patterns of lipiodol retention were divided into four types; A. dense type (n=12), B. rarity type (n=13), C. scattering type (n=7) and D. empty type (n=3). The positive correlation between the tumor necrosis rate (7%-95%) and the decrease percentage of AFP(0-100%) were found (r=0.761 P<0.001). The difference of the decrease percentage of AFP was significant between the 14 cases with tumor necrosis rate above 75% and the other 27 cases with tumor necrosis rate below 75% (n=21) (t=6.212 P<0.001). In the 14 cases with tumor necrosis rate above 75%, the pattern of lipiodol retention of 12 cases were type A and 2 cases were type B. However, in 21 cases with tumor necrosis rate below 75%, type B occurred in 11 cases, type C in 7 cases and type D in 3. An uniform correlation was found among the tumor necrosis rates above 75%, the decrease percentage of AFP above 70% and the dense lipiodol retention. Conclusions: The decrease percentage of AFP is useful to evaluate the effectiveness of TACE for HCC. The decrease percentage of AFP above 70% or the dense lipiodol retention may be regarded as indexes to distinguish whether the TACE is effective or not. (authors)