Head-to-head comparison of the detection performance and tumor uptake of 68Ga-FAPI-04 and 18F-FDG PET/CT in liver metastases from malignant tumors of different types

Abstract Objective We sought to compare the detection performance and tumor uptake of 68 Ga-FAPI-04 and 18 F-FDG in liver metastases from malignant tumors of different types. Methods A total of 76 patients were included between May 2020 and April 2023. The detection performance of 18 F-FDG and 68 Ga-FAPI-04 PET/CT was determined via visual evaluation. Differences in the maximum standardized uptake value (SUVmax) and tumor-to-background ratio (TBR) were also analyzed between 18 F-FDG and 68 Ga-FAPI-04 PET/CT. Results For detecting liver metastases, the sensitivity (94.80% vs. 69.94%, p < 0.001) and accuracy (91.53% vs. 70.37%, p < 0.001) of 68 Ga-FAPI-04 PET/CT were significantly greater than those of 18 F-FDG PET/CT in malignant tumors (76 patients), the sensitivity (97.87% vs. 73.05%, p < 0.001) and accuracy (96.05% vs. 74.34%, p < 0.001) of 68 Ga-FAPI-04 PET/CT were significantly greater than those of 18 F-FDG PET/CT in carcinoma (65 patients), and the sensitivity (81.25% vs. 56.25%, p = 0.021) of 68 Ga-FAPI-04 PET/CT was significantly greater than that of 18 F-FDG PET/CT in sarcoma (11 patients). On semiquantitative analysis, the SUVmax of 68 Ga-FAPI-04 was significantly greater than that of 18 F-FDG for carcinoma (mean, 6.33 vs. 5.39; p = 0.017). The TBR of 68 Ga-FAPI-04 was significantly greater than that of 18 F-FDG for malignant tumors (median, 4.60 vs. 1.67; p < 0.001), carcinoma (median, 4.83 vs. 1.69; p < 0.001), and sarcoma (median, 3.25 vs. 1.49; p < 0.001). Conclusion 68 Ga-FAPI-04 PET/CT has significantly better detection performance than 18 F-FDG PET/CT for detecting liver metastases in carcinoma.