Non-malignant findings of focal 68Ga-FAPI-04 uptake in pancreas

Abstract

Purpose

68Ga-Labelled Fibroblast Activation Protein Inhibitor (68Ga-FAPI) has shown promise in tumour positron emission tomography (PET) imaging, including malignant pancreatic lesions. Here, we showed several non-malignant findings of focal 68Ga-FAPI-04 uptake in the pancreas which were occasionally found by PET/MR. The study aimed to investigate the reasons for the focal uptake and remind caution for the diagnosis.

Methods

We retrospectively analysed imaging data of 103 patients who underwent 68Ga-FAPI-04 PET/MR at our institute from May 22 to July 8, 2020. Seven patients had focally elevated uptake of 68Ga-FAPI-04 in the pancreas; four of these underwent simultaneous 18F-FDG PET/CT scans. The clinical data, PET/MR imaging features, pathological, and follow-up results were further collected and analysed.

Results

The cases showed that 68Ga-FAPI-04 accumulation can occur in any part of the pancreas, with corresponding negative 18F-FDG uptake. Most lesions were small with no significant changes in CT or MR signals. The SUVmax value of 68Ga-FAPI-04 had a wide range of 3.1–9.1. All the pancreatic lesions were proven to be non-neoplastic by pathology confirmation or follow-up imaging. Lesions with uptake were identified including pancreatic pseudocysts, sites of prior pancreatitis, and foci of IgG 4-related disease.

Conclusion

Though 68Ga-FAPI-04 demonstrates great potential for oncological diagnosis, focal 68Ga-FAPI-04 uptake could occur in benign pancreatic lesions and should be carefully evaluated. Fortunately, combined with MR, 68Ga-FAPI-04 PET/MR may potentially avoid the misdiagnosis of some pancreatic lesions.

Clinical Trial Registration: NCT04554719 and NCT04605939. Registered September 13, 2020 and October 25, 2020, respectively.

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Data availability

Not applicable.

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Funding

This work was supported by National Natural Science Foundation of China (No. 82030052, and 81901783).

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Authors

Contributions

X. L. conceived and designed the study devised, and supervised the project. X. Z. and W. S. wrote the manuscript. C. Q. and F. L. analysed the image data. X. Z. and W. S. contributed to the follow-up of the patients.

Corresponding author

Correspondence to Xiaoli Lan.

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All procedures involving human participants were carried out in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards.

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This article is part of the Topical Collection on Oncology - Digestive tract.

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Zhang, X., Song, W., Qin, C. et al. Non-malignant findings of focal 68Ga-FAPI-04 uptake in pancreas. Eur J Nucl Med Mol Imaging (2021). https://doi.org/10.1007/s00259-021-05194-6

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Keywords

  • 68Ga-FAPI-04
  • PET/MRI
  • 18F-FDG
  • Non-malignant
  • Pancreas