Dual-time-point 68Ga-FAPI PET/CT in gastrointestinal malignancies: head-to-head comparison with 18 F-FDG for lesion detection and patient-level assessment.

Authors

Hasan Pala, Murat Tuncel, Suayib Yalcin, Erdem Karabulut, Nezih Akkapulu, Timucin Erol, Omer Ugur

Published in

Annals of nuclear medicine. Jun 25, 2026. Epub Jun 25, 2026.

Abstract

To compare the diagnostic performance of 18 F-Fluorodeoxyglucose (FDG) and 68Ga-fibroblast activation protein inhibitor (FAPI) positron emission tomography/computed tomography (PET/CT) in gastrointestinal malignancies, with particular emphasis on lesion detection, peritoneal disease assessment, and the potential added value of dual-time-point FAPI imaging.
Thirty-eight patients with histologically confirmed gastrointestinal cancers who underwent both FDG and FAPI PET/CT within a 4-week interval were retrospectively analyzed. FAPI PET/CT images were acquired at 10 and 60 min after tracer injection. Patient-level analyses (staging/restaging accuracy, impact on management) and lesion-based analyses (detection rate, characterization, maximum standardized uptake value [SUVmax] dynamics, lesion size) were evaluated against follow-up data as the reference standard.
FAPI PET/CT demonstrated superior agreement with the reference standard compared with FDG PET/CT for staging and restaging (κ = 0.91 vs. 0.32). On lesion-based analysis, FAPI showed markedly higher detection rate for malignant lesions (86% vs. 34%) and fewer indeterminate findings. Median peritoneal carcinomatosis index score and the number of detected malignant lesions per patient were significantly higher with FAPI PET/CT (p < 0.001). Dual-time-point FAPI imaging revealed a significant increase in SUVmax from early to later time points in malignant lesions, whereas benign lesions showed no significant change. Larger lesions (> 10 mm) demonstrated more pronounced delayed uptake, and greater early-to-delayed SUVmax increases were independently associated with malignancy, suggesting a potential role for dynamic uptake patterns in lesion characterization.
Dual-time-point 68Ga-FAPI PET/CT demonstrated superior lesion detectability compared with FDG PET/CT in gastrointestinal malignancies and may help reduce diagnostic uncertainty. These findings suggest that dual-time-point FAPI imaging may provide incremental value for lesion characterization and support its complementary role in oncologic imaging.

PMID:
42348133
Bibliographic data and abstract were imported from PubMed on 25 Jun 2026.

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