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

It is well known that [18F]FDG PET has a low sensitivity in the detection of hepatocellular carcinoma (HCC). We prospectively compared [11C]acetate PET/CT results with those of [18F]FDG PET/CT in patients with HCCs.Thirteen patients (M:F=11:2, mean age of 51±12) with suspicious or confirmed HCCs underwent [11C]acetate PET/CT with or without [18F]FDG PET/CT (both [11C]acetate and [18F]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. [18F]FDG PET/CT showed markedly increased uptake in only two patients, moderately increased uptake in another two and negative in six. [11C]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 [11C]acetate PET/CT. For detection of HCC, [11C]acetate PET/CT showed a high sensitivity of 83%, whereas [18F]FDG PET/CT only of 40%.The study results demonstrated that [18F]FDG PET/CT has a limitation in detection of HCC and [11C]acetate PET/CT has a complementary role to [18F]FDG PET/CT. When primary HCC showed low [18F]FDG uptake, it was [11C]acetate-avid, and vice versa. It may be useful to combine both [18F]FDG and [11C]acetate PET/CT for detection of HCCs.