Head-to-head comparison of ⁶⁸ Ga-FAPI-46 PET/CT, ¹⁸F-FDG PET/CT, and contrast-enhanced CT for the detection of various tumors

FAPI-PET/CT exhibits high tumor uptake and low background accumulation, enabling high-sensitivity tumor detection. We compared the diagnostic performance of ⁶⁸ Ga-FAPI-46 PET/CT plus contrast-enhanced CT (CE-CT), ¹⁸F-FDG PET/CT plus CE-CT, and standalone CE-CT in patients with various malignancies.

232 patients underwent ⁶⁸ Ga-FAPI-46 PET/CT,¹⁸F-FDG PET/CT, and CE-CT each within 4 weeks. Detection rates were assessed by a blinded reader, with ≥ 2 weeks between scans of the same patient to avoid recall bias. A sub-analysis of diagnostic performance was performed for 490 histopathologically validated lesions. Detection rates were compared using McNemar's test.

Lesion-based detection rates in ⁶⁸ Ga-FAPI-46 PET/CT plus CE-CT, ¹⁸F-FDG PET/CT plus CE-CT, and CE-CT alone were 91.2% (1540/1688), 82.5% (1393/1688) and 60.2% (1016/1688). The detection rates were significantly higher for ⁶⁸ Ga-FAPI-46 PET/CT plus CE-CT than for ¹⁸F-FDG PET/CT plus CE-CT (p < 0.02 for primary lesions and p < 0.001 for total, abdominopelvic nodal, liver and other visceral lesions) and CE-CT (p < 0.0001 for total, primary, cervicothoracic nodal, abdominopelvic nodal, liver, other visceral, and bone lesions). In the sub-analysis, sensitivity, specificity, positive and negative predictive value, and accuracy were 61.3%, 96.7%, 81.4%, 91.4% and 90.0% for ⁶⁸ Ga-FAPI-46 PET/CT plus CE-CT, 57.0%, 95.7%, 75.7%, 90.5% and 88.4% for ¹⁸F-FDG PET/CT plus CE-CT, and 51.6%, 97.2%, 81.4%, 89.6% and 88.6% for CECT, respectively.

⁶⁸ Ga-FAPI-46 PET/CT plus CE-CT demonstrates a higher tumor detection rate than ¹⁸F-FDG PET/CT plus CE-CT and CE-CT in a diverse spectrum of malignancies, especially for primary, abdominopelvic nodal, liver, and other visceral lesions. Further studies on which entities draw particular benefit from ⁶⁸ Ga-FAPI-46 PET/CT are warranted to aid appropriate diagnostic workup.

A total of N = 232 patients were analyzed. Of these, N = 50 patients were included in a prospective interventional trial (NCT05160051), and N = 175 in a prospective observational trial (NCT04571086) for correlation and clinical follow-up of PET findings; N = 7 patients were analyzed retrospectively.