The Potential Utility of 68Ga-FAPI-04 As a Novel Broad-spectrum Tumor and Inflammatory Imaging Agent - Comparison With 18F-FDG

Abstract Objective: This study aimed to compare the diagnostic performance of 68Ga-FAPI-04 and 18F-FDG PET/CT in the patients with various oncological and non-oncological lesions. Patients and Methods: A total of 123 patients underwent contemporaneous 68Ga-FAPI-04 and 18F-FDG PET/CT were included in this prospective study. The maximum standard uptake value (SUVmax) was measured to compare oncological and non-oncological lesion uptake. The sensitivity, specificity, predictive values and accuracy of 18F-FDG and 68Ga-FAPI-04 PET/CT for detecting primary, metastatic, and non-oncological lesions were calculated and compared to evaluate the diagnostic efficacy. Results: The study subjects consisted of 123 patients (69 men and 54 women; mean age: 56.11±11.94). A total of 84 patients with 88 solid primary malignant tumors, 58 patients with 376 nodal metastases, 43 patients with 406 distant metastases, 8 patients with hematological neoplasms and 52 patients with 145 non-oncological lesions and benign tumors were detected. 68Ga-FAPI-04 PET/CT demonstrated a significantly higher uptake and detection rate for the primary (SUVmax: 10.98±5.83 vs. 8.36±6.43, p＜0.001; X2=0.538, p=0.021), nodal (SUVmax: 10.50±5.98 vs. 8.20±6.29, p=0.011; X2=2.067, p＜0.001) and distant metastatic lesions (SUVmax: 6.74±4.83 vs. 9.64±6.45; p＜0.001; X2=4.897, p＜0.001) of solid tumor than did 18F-FDG PET/CT. 68Ga-FAPI-04 PET/CT demonstrated a lower activity (SUVmax: 6.84±4.67 vs. 13.09±7.29, p＜0.001) and detection rate (X2=5.166, p＜0.001) for multiple myeloma and lymphoma compared to 18F-FDG PET/CT. 68Ga-FAPI-04 and 18F-FDG PET/CT PET/CT demonstrated a comparative diagnostic efficacy (SUVmax: 6.40±3.95 vs. 5.74±15.78, p = 0.729; X2 = 9.460, p = 0.007) for non-oncological lesion and benign tumor detection. Conclusions: Except for myeloma and lymphoma, 68Ga-FAPI-04 PET/CT showed a superior diagnostic efficacy for detecting various primary and metastatic lesions than 18F-FDG PET/CT. A comparative diagnostic utility for non-oncological lesion detection was obtained with both tracers. 68Ga-FAPI-04 could be used as a broad-spectrum tumor and inflammatory imaging agent in the clinical especially for various solid tumors and non-oncological lesions.