⁶⁸Ga-DOTA-FAPI-04 and ¹⁸F-FDG PET/CT: a head-to-head comparison for peritoneal carcinomatosis diagnostic accuracy

The study aimed to compare the diagnostic accuracy of ⁶⁸Ga-DOTA-FAPI-04 (⁶⁸Ga-FAPI) and ¹⁸F-FDG PET/CT for peritoneal carcinomatosis (PC) in patients with various types of cancer.

The study enrolled 113 patients with suspected peritoneal malignancy, each of whom underwent ⁶⁸Ga-FAPI and ¹⁸F-FDG PET/CT scans. Lesions in all patients were confirmed through pathology or radiological follow-up. The evaluation and comparison of diagnostic performance, visual scores, maximum standardized uptake value (SUV_max), mean tumor-to-background ratio (TBR), and the peritoneal cancer index (PCI) score were conducted.

Compared to ¹⁸F-FDG, ⁶⁸Ga-FAPI PET/CT presented higher sensitivity, negative predictive value, and accuracy for detecting PC on a patient-level (100% vs. 93.2%, 100% vs. 22.22% and 93.81% vs. 86.73%, respectively). Semi-quantitative evaluation revealed that ⁶⁸Ga-FAPI PET/CT had significantly higher SUV_max and TBR for PC [(6.06 ± 3.04 vs. 4.82 ± 2.75, P = 0.001) and (8.50 ± 5.01 vs. 2.92 ± 1.67, P < 0.001)]. The PCI_-FAPI score for PC was higher than the PCI_-FDG score (11.28 ± 7.10 vs. 5.69 ± 5.15, P < 0.001).

⁶⁸Ga-FAPI has demonstrated superior diagnostic accuracy compared to ¹⁸F-FDG PET/CT in detecting PC with various types of cancer, particularly gastric cancer. Additionally, ⁶⁸Ga-FAPI has shown significantly higher uptake and PCI score in PC compared to ¹⁸F-FDG, indicating its potential importance in clinical.