Abstract
BACKGROUND: Prostate-specific membrane antigen (PSMA) is expressed in hepatocellular carcinoma (HCC). Recently, (18)F-PSMA-1007 has been used for tumor imaging in positron emission tomography/computed tomography (PET/CT). This study aimed to compare the diagnostic performances of (18)F-PSMA-1007 PET/CT and (18)F-FDG PET/CT in HCC, and to assess factors associated with the sensitivity of (18)F-PSMA-1007 PET/CT in detecting HCC and intrahepatic tumor lesions. MATERIALS AND METHODS: Forty-four patients with suspected HCC undergoing both (18)F-FDG and (18)F-PSMA-1007 PET/CT were prospectively enrolled. Two experienced nuclear medicine physicians independently interpreted imaging results. The mean standardized uptake values (SUV(mean)) were measured in the intrahepatic lesions (T), liver background (L), abdominal aorta (A), and right medial gluteal muscle (M), respectively. The tumor-to-background ratio (T/L, T/A, T/M) was then calculated as the SUV(mean) of the intrahepatic lesion (T) divided by the SUV(mean) of the background regions (L, A, M). RESULTS: Sixty-two intrahepatic lesions in 41 patients with HCC were finally involved in the statistical analysis. (18)F-PSMA-1007 PET/CT demonstrated higher sensitivity than (18)F-FDG PET/CT in detecting HCC patients (85.4% vs. 61.0%, P = 0.041), particularly in identifying well- or moderately differentiated HCC patients (92.9% vs. 14.3%, P = 0.003). (18)F-PSMA-1007 PET/CT showed a higher sensitivity than (18)F-FDG PET/CT in detecting intrahepatic HCC lesions (82.3% vs. 50.0%, P = 0.001), including in small (≤ 2 cm in diameter; 62.5% vs. 25.0%, P = 0.049) and well- or moderately differentiated (88.9% vs. 14.8%, P < 0.001) lesions. The sensitivity of (18)F-PSMA-1007 PET/CT was associated with tumor size (P = 0.005). The SUV(mean) values for the intrahepatic lesions (T) and liver background (L) from (18)F-PSMA-1007 PET/CT were significantly higher compared with those from (18)F-FDG PET/CT (both P < 0.001). Background uptake in the abdominal aorta (A) and right medial gluteal muscle (M) for (18)F-PSMA-1007 was significantly lower than that for (18)F-FDG (both P < 0.001). T/L, T/A and T/M values from (18)F-PSMA-1007 were significantly higher than those from (18)F-FDG PET/CT (all P < 0.001). CONCLUSIONS: (18)F-PSMA-1007 PET/CT exhibits higher sensitivity than (18)F-FDG PET/CT for detecting HCC and has lower background uptake in blood and muscle tissues. The sensitivity of (18)F-PSMA-1007 is correlated mainly with tumor size.