[68Ga]Ga-PSMA-617 PET/MRI for imaging patients suspected of hepatocellular carcinoma

Purpose

Radiolabeled probes targeting prostate-specific membrane antigen (PSMA) have been used in prostate cancer. Moreover, PSMA is also overexpressed on neovessels in hepatocellular carcinoma (HCC). This study aimed to preliminarily evaluate the diagnostic effectiveness of [⁶⁸Ga]Ga-PSMA-617 PET/MRI for HCC.

Methods

Patients suspected of HCC were prospectively enrolled in this single-center study (NCT05006326, 2021-08-16) to perform [⁶⁸Ga]Ga-PSMA-617 PET/MRI, along with contrast enhanced CT (ceCT) or ceMRI. The main suspicious intrahepatic lesions were resected and pathologically verified. Visual evaluation of [⁶⁸Ga]Ga-PSMA-617 PET/MRI images was performed on all lesions. Maximum standard uptake value (SUVmax), mean standard uptake value (SUVmean), tumor-to-liver ratio (TLR), tumor-to-blood ratio (TBR), and tumor-to-parotid ratio (TPR) were measured or calculated. The diagnostic efficiency of different modalities was summarized. PSMA expression was evaluated by immunohistochemistry and the correlation of PSMA expression and [⁶⁸Ga]Ga-PSMA-617 uptake in HCC primary tumors was quantitatively analyzed.

Results

A total of 12 patients (ten men and two women; mean age 58.75 ± 12.08 years) were included. Ten patients were diagnosed with HCC, 2 with intrahepatic cholangiocarcinoma (ICC), and 4 with hemangioma. The SUVmax, TLR, TBR, and TPR of HCC primary tumors were higher than those of ICC and hemangioma. The diagnostic accuracy of [⁶⁸Ga]Ga-PSMA-617 PET/MRI for primary HCC was 82.4%. When combined with ceCT or ceMRI, the accuracy increased to 88.2%. A moderate correlation was observed between SUVmax and mean PSMA expression in HCC primary tumors (R = 0.788).

Conclusion

Utilizing a hybrid PET/MRI system to combine [⁶⁸Ga]Ga-PSMA-617 PET/MRI with ceMRI is a promising one-stop solution for the accurate diagnosis of HCC.

Trial Registration

NCT05006326. Registered August 16, 2021, https://clinicaltrials.gov/study/NCT05006326.