Stent-Induced [⁶⁸Ga]Ga-FAPI Diffuse Expression in a Patient with Pancreatic Cancer: Navigating Non-oncologic Challenges

Excerpt

A 52-year-old gentleman with a known history of stage Ib poorly differentiated pancreatic adenocarcinoma was treated with pylorus-preserving pancreaticoduodenectomy, vascular reconstruction, and pancreatic duct stent insertion. Following surgery, the patient underwent chemotherapy followed by a [⁶⁸Ga]Ga-fibroblast activation protein inhibitor (FAPI) positron emission tomography/computed tomography (PET/CT) scan (Fig. 1). Posttreatment evaluation with [⁶⁸Ga]Ga-FAPI PET/CT was offered after elevated carbohydrate antigen 19–9. All other conducted laboratory tests to assess hematologic, pancreatic, and liver profiles were unremarkably normal. [⁶⁸Ga]Ga-FAPI PET/CT took place 3 weeks after recent pancreatic stent replacement. The scan revealed increased [⁶⁸Ga]Ga-FAPI activity at the pancreatic uncinate process, indicative of local disease recurrence (Fig. 1a, b; arrowheads). Additionally, diffuse [⁶⁸Ga]Ga-FAPI activity around the pancreatic stent in the body and tail of the pancreas was observed (Fig. 1a, c, d; arrows). This was visualized as a diffuse [⁶⁸Ga]Ga-FAPI pattern with no obvious CT changes (Fig. 1e), supporting the pattern for stent-induced pancreatitis. A recent prospective study reported a diffuse [⁶⁸Ga]Ga-FAPI uptake pattern around biliary stent sites in 56% of evaluated patients using [⁶⁸Ga]Ga-FAPI PET/CT [1]. This pattern was linked to stent-induced inflammation following the recent stent introduction. However, this study did not showcase a representative imaging instance and did not express contributing factors, such as the gauge of the stent, type of stent, and timing interval of sustained uptake, which determine the optimal time for imaging patients with hepatobiliary malignancies with [⁶⁸Ga]Ga-FAPI PET/CT scans after stenting, especially with the increased popularity and adoption of [⁶⁸Ga]Ga-FAPI PET/CT currently.

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