[⁶⁸Ga]Ga-FAPI Versus [¹⁸F]FDG PET/CT in Signet Ring Cell Carcinoma with Linitis Plastica: Diagnostic Performance and...

Area of Science:

• Oncology
• Radiology
• Molecular Imaging

Background:

• Gastric carcinoma, particularly linitis plastica, presents diagnostic challenges.
• Fibroblast activation protein (FAP) is highly expressed in cancer-associated fibroblasts, offering potential for targeted imaging.
• Standard imaging like [18F]FDG PET/CT may show limited utility in certain gastric cancer subtypes.

Purpose of the Study:

• To evaluate the diagnostic performance of fibroblast activation protein inhibitor ([68Ga]Ga-FAPI-04) PET/CT in signet ring cell gastric adenocarcinoma with linitis plastica morphology.
• To compare [68Ga]Ga-FAPI-04 PET/CT findings with [18F]FDG PET/CT in these challenging cases.

Main Methods:

• Case report of 2 patients with signet ring cell gastric adenocarcinoma and linitis plastica.
• Utilized [68Ga]Ga-FAPI-04 PET/CT and [18F]FDG PET/CT for imaging.
• Assessed tumor uptake and tumor-to-background contrast.

Main Results:

• Both cases showed minimal uptake on [18F]FDG PET/CT.
• Intense uptake was observed on [68Ga]Ga-FAPI-04 PET/CT in both cases.
• Fibroblast activation protein inhibitor imaging demonstrated high tumor-to-background contrast.

Conclusions:

• [68Ga]Ga-FAPI-04 PET/CT exhibits superior diagnostic performance for linitis plastica gastric cancer compared to [18F]FDG PET/CT.
• Fibroblast activation protein inhibitor imaging is a promising tool for challenging gastric cancer diagnoses.
• Targeting fibroblast activation protein improves visualization of specific gastric cancer subtypes.