Performance of [⁶⁸Ga]Ga-FAPI-04 PET/CT imaging in hepatic vascular-associated mesenchymal tumor: comparison with [¹⁸F]FDG PET/CT.

Abstract

To assess the efficacy of [⁶⁸Ga]Ga-FAPI-04 PET/CT in detecting hepatic vascular-associated mesenchymal tumor (HVAMT), including hepatic hemangioma (HH), hepatic epithelioid hemangioendothelioma (HEHE), and hepatic perivascular epithelioid cell tumor (PEComa), and to compare its efficacy with that of [¹⁸F]FDG PET/CT. A retrospective analysis was conducted on 31 cases of HVAMTs from a prospective parent study (ChiCTR2000039099), including 25 cases of HH (35 lesions), 2 cases of HEHE (18 lesions), and 4 cases of PEComa (6 lesions). All patients underwent both [¹⁸F]FDG and [⁶⁸Ga]Ga-FAPI-04 PET/CT within one week of each other. The detection rates of both imaging modalities in detecting HVAMTs were compared. SUVmax, tumor-to-background ratio (TBR), and correlation between the longest diameter (LD) of lesions and SUVmax were analyzed. The imaging results were validated with pathological evaluations and follow-up examinations. The detection rate for each tumor type by [¹⁸F]FDG and [⁶⁸Ga]Ga-FAPI-04 PET/CT was as follows: HH (2.9% [1/35] vs. 54.3% [19/35], p < 0.001); HEHE (27.8% [5/18] vs. 88.9% [16/18], p = 0.001); PEComa (83.3% [5/6] vs. 100% [6/6]); HVAMT (18.6% [11/59] vs. 69.5% [41/59], p < 0.001). Although [⁶⁸Ga]Ga-FAPI-04 PET/CT yielded lower median SUVmax than [¹⁸F]FDG PET/CT in HH (1.30 vs. 2.30, p < 0.001) and HVAMT (1.60 vs. 2.70, p = 0.001), it exhibited higher TBR than the latter for HH (1.83 vs. 1.07, p < 0.001), HEHE (2.13 vs. 1.19, p < 0.001), PEComa (8.85 vs. 2.28, p = 0.088), and HVAMT (2.25 vs. 1.14, p < 0.001), respectively. In addition, the SUVmax of [⁶⁸Ga]Ga-FAPI-04 PET/CT showed a significant positive correlation with the LD of lesion in HH (r = 0.777, p < 0.001), HEHE (r = 0.836, p < 0.001), PEComa (r = 0.829, p = 0.042), and HVAMT (r = 0.676, p < 0.001). No such correlation was observed in [¹⁸F]FDG PET/CT. [⁶⁸Ga]Ga-FAPI-04 PET/CT was more sensitive than [¹⁸F]FDG PET/CT in HVAMTs detection. However, the possibility of lesions being HVMATs should also be evaluated when detecting other common liver tumors using [⁶⁸Ga]Ga-FAPI-04 PET/CT. Chinese Clinical Trial Registry ChiCTR2000039099. Registered 17 October 2020.