Differential [18F]FAPI-42 and [18F]FDG uptake patterns distinguish desmoid tumours from GISTs on PET/CT imaging
摘要
Intra-abdominal desmoid tumours (IADT) can closely mimic gastrointestinal stromal tumours (GISTs), particularly in recurrence and metastases. However, differentiating these two diseases using radiological methods remains challenging. This study aimed to investigate the value of [18F]FAPI-42 PET/CT in differentiating IADT and GISTs compared to [18F]FDG PET/CT.
MethodsThis study retrospectively included a total of 24 patients (12 patients with IADT and 12 patients with recurrent/metastatic GISTs) who underwent two separate PET/CT scans using [18F]FAPI-42 and [18F]FDG, respectively. The differences in tumour SUVmax on [18F]FAPI-42 PET/CT (SUVmax-FAPI) and [18F]FDG PET/CT (SUVmax-FDG) and the ratio of tumour SUVmax on FAPI PET/CT to SUVmax on FDG PET/CT [SUVmax ratio (FAPI/FDG)] were compared between IADT and GISTs. Receiver operating characteristic (ROC) curve analyses were performed to evaluate the diagnostic performance of these parameters in differentiating IADTs from GISTs. Immunohistochemistry was used to verify FAP expression in all IADT lesions and GISTs lesions.
ResultsThe SUVmax of IADTs on [18F]FAPI-42 PET/CT was significantly higher than that of GISTs [8.8 (7.2, 10.6) vs. 3.9 (2.8, 7.6),
The distinct uptake characteristics of [18F]FAPI-42 and [18F]FDG observed in IADTs and GISTs provide preliminary evidence that these two tracers may offer complementary diagnostic information when evaluating desmoid tumours that mimic recurrent or metastatic GISTs.