Evaluation of patients with hepatocellular carcinomas using [(11)C]acetate and [(18)F]FDG PET/CT: A preliminary study

It is well known that [(18)F]FDG PET has a low sensitivity in the detection of hepatocellular carcinoma (HCC). We prospectively compared [(11)C]acetate PET/CT results with those of [(18)F]FDG PET/CT in patients with HCCs. Thirteen patients (M:F=11:2, mean age of 51+/-12) with suspicious or confirmed HCCs underwent [(11)C]acetate PET/CT with or without [(18)F]FDG PET/CT (both [(11)C]acetate and [(18)F]FDG PET/CT were performed in 10 patients). HCC was confirmed by histopathology or clinical criteria in 12 patients and one benign liver lesion. Both PET/CT images were interpreted by two experienced nuclear physicians, supported by standardized uptake value (SUV). A total of 12 patients were confirmed to have initial or recurrent HCCs. [(18)F]FDG PET/CT showed markedly increased uptake in only two patients, moderately increased uptake in another two and negative in six. [(11)C]acetate PET/CT demonstrated markedly increased uptake in seven patients, moderately increased uptake in three and negative in only two. One HCC metastatic lesion was detected only by [(11)C]acetate PET/CT. For detection of HCC, [(11)C]acetate PET/CT showed a high sensitivity of 83%, whereas [(18)F]FDG PET/CT only of 40%. The study results demonstrated that [(18)F]FDG PET/CT has a limitation in detection of HCC and [(11)C]acetate PET/CT has a complementary role to [(18)F]FDG PET/CT. When primary HCC showed low [(18)F]FDG uptake, it was [(11)C]acetate-avid, and vice versa. It may be useful to combine both [(18)F]FDG and [(11)C]acetate PET/CT for detection of HCCs.