¹⁸F-PSMA-1007 versus ¹⁸F-FDG PET/CT in the detection of hepatocellular carcinoma

Prostate-specific membrane antigen (PSMA) is expressed in hepatocellular carcinoma (HCC). Recently, ¹⁸F-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 ¹⁸F-PSMA-1007 PET/CT and ¹⁸F-FDG PET/CT in HCC, and to assess factors associated with the sensitivity of ¹⁸F-PSMA-1007 PET/CT in detecting HCC and intrahepatic tumor lesions.

Forty-four patients with suspected HCC undergoing both ¹⁸F-FDG and ¹⁸F-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).

Sixty-two intrahepatic lesions in 41 patients with HCC were finally involved in the statistical analysis. ¹⁸F-PSMA-1007 PET/CT demonstrated higher sensitivity than ¹⁸F-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). ¹⁸F-PSMA-1007 PET/CT showed a higher sensitivity than ¹⁸F-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 ¹⁸F-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 ¹⁸F-PSMA-1007 PET/CT were significantly higher compared with those from ¹⁸F-FDG PET/CT (both P < 0.001). Background uptake in the abdominal aorta (A) and right medial gluteal muscle (M) for ¹⁸F-PSMA-1007 was significantly lower than that for ¹⁸F-FDG (both P < 0.001). T/L, T/A and T/M values from ¹⁸F-PSMA-1007 were significantly higher than those from ¹⁸F-FDG PET/CT (all P < 0.001).

¹⁸F-PSMA-1007 PET/CT exhibits higher sensitivity than ¹⁸F-FDG PET/CT for detecting HCC and has lower background uptake in blood and muscle tissues. The sensitivity of ¹⁸F-PSMA-1007 is correlated mainly with tumor size.