Comparison of the diagnostic efficacy of Ga-FAPI-04 PET/MR and F-FDG PET/CT in patients with pancreatic cancer.

PURPOSE

We sought to assess the performance of  Ga-FAPI-04 PET/MR for the diagnosis of primary tumours as well as metastatic lesions in patients with pancreatic cancer and to compare the results with those of F-FDG PET/CT.

METHODS

Prospectively, we evaluated 33 patients suspected to have pancreatic adenocarcinoma, of whom thirty-two were confirmed by histopathology, and one had autoimmune pancreatitis confirmed by needle biopsy and glucocorticoid treatment. Within 1 week, each patient underwent both  Ga-FAPI-04 PET/MR and F-FDG PET/CT. Comparisons of the detection abilities for primary tumours, lymph nodes, and metastases were conducted for the two imaging approaches. The original maximum standard uptake values (SUV) and normalised SUV (SUV/SUV) of paired lesions on  Ga-FAPI-04 PET/MR and F-FDG PET/CT were measured and compared.

RESULTS

Thirty pancreatic cancer patients and three pancreatitis patients were enrolled.  Ga-FAPI-04 PET/MR and F-FDG PET/CT exhibited equivalent (100%) detection rates for primary tumours. The original/normalised SUV of primary tumours on  Ga-FAPI-04 PET was markedly higher than that on F-FDG (p < 0.05). Sixteen pancreatic cancer patients had pancreatic parenchymal uptake, whereas F-FDG PET images showed parenchymal uptake in only four patients (53.33% vs. 13.33%, p < 0.001).  Ga-FAPI-04 PET detected more positive lymph nodes than F-FDG PET (42 vs. 30, p < 0.001), while F-FDG PET was able to detect more liver metastases than  Ga-FAPI-04 (181 vs. 104, p < 0.001). In addition, multisequence MR imaging helped explain ten pancreatic cancers that could not be definitively revealed due to  Ga-FAPI-04 inflammatory uptake and identified more liver metastases than F-FDG (256 vs. 181, p < 0.001).

CONCLUSION

Ga-FAPI-04 PET might be better than F-FDG PET in the detection of suspicious lymph node metastases. MR multiple sequence imaging of  Ga-FAPI-04 PET/MR was helpful for explaining pancreatic lesions in patients with obstructive inflammation and detecting tiny liver metastases.