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@ARTICLE{Bartel:306359,
author = {T. Bartel$^*$ and K. M. Pabst$^*$ and C. Barg$^*$ and C. A.
Berliner$^*$ and R. Hamacher$^*$ and S. Bauer$^*$ and J.
Falkenhorst$^*$ and L. Kessler$^*$ and M. Nader$^*$ and F.
Barbato$^*$ and J. Siveke$^*$ and K. Herrmann$^*$ and W. P.
Fendler$^*$},
title = {[68{G}a]{G}a-{FAPI}-46 {PET}/{CT} of {P}atients with
{G}astrointestinal {S}tromal {T}umors in {C}omparison to
2-[18{F}]{FDG} {PET}/{CT} and {C}ontrast-{E}nhanced {CT}:
{R}esults from a {P}rospective {O}bservational {S}tudy.},
journal = {Journal of nuclear medicine},
volume = {nn},
issn = {0097-9058},
address = {New York, NY},
publisher = {Soc.},
reportid = {DKFZ-2025-02571},
pages = {nn},
year = {2025},
note = {epub},
abstract = {Gastrointestinal stromal tumors (GISTs) are the most common
mesenchymal neoplasms of the gastrointestinal tract.
Although contrast-enhanced CT (ceCT) and 2-[18F]FDG PET/CT
remain standard imaging modalities, both exhibit limitations
in detecting small peritoneal metastases and tumors with low
metabolic activity. 68Ga-labeled fibroblast activation
protein inhibitors (FAPIs) have shown promising results in
various malignancies; however, comparative data on GISTs are
limited. This study aimed to assess the diagnostic
performance of [68Ga]Ga-FAPI-46 PET/CT in comparison with
2-[18F]FDG PET/CT and ceCT, including evaluation of
interreader reproducibility and clinical impact. Methods:
This study retrospectively reviewed 25 patients with
histopathologically confirmed GISTs undergoing
[68Ga]Ga-FAPI-46 PET/CT as part of a prospective
observational study (NCT04571086). All patients (n = 25)
underwent additional clinical 2-[18F]FDG PET/CT; ceCT was
performed for 23 of 25 patients. Imaging was assessed per
patient and per region (primary tumor, lymph nodes, and
visceral and bone metastases), and a composite reference
standard that included histopathology, follow-up imaging,
and clinical data was applied. Interreader agreement,
stratified by experience level, was analyzed using Cohen κ
(κCohen). Referring physicians completed questionnaires
before and after imaging to determine clinical impact.
Results: In total, 28 validated regions (n = 20 patients)
were included in the diagnostic efficacy analysis. Per
region, ceCT and [68Ga]Ga-FAPI-46 PET/CT demonstrated
comparable sensitivity $(83\%$ vs. $81\%),$ followed by
2-[18F]FDG PET/CT $(65\%).$ [68Ga]Ga-FAPI-46 PET/CT
demonstrated the highest region-based positive predictive
value $(100\%).$ The liver tumor-to-background ratio was
significantly higher for [68Ga]Ga-FAPI-46 PET/CT than for
2-[18F]FDG PET/CT (median, 7.6 vs. 5.9; P = 0.034), whereas
overall tumor uptake showed no significant difference.
Changes in clinical management attributable to
[68Ga]Ga-FAPI-46 PET/CT were observed for 6 of 24 patients
$(25\%),$ including 1 major change. Interreader agreement
for [68Ga]Ga-FAPI-46 PET/CT varied with reader experience,
showing the highest concordance between high- and
intermediate-experience readers (κCohen = 0.87 per patient
and 0.47-1.00 across regions), whereas comparisons involving
less experienced readers yielded lower agreement (κCohen =
0.00-0.60). Conclusion: [68Ga]Ga-FAPI-46 PET/CT demonstrated
diagnostic sensitivity comparable to ceCT and superior to
2-[18F]FDG PET/CT for patients with GISTs. High diagnostic
performance, especially in hepatic and peritoneal
metastases, and relevant clinical impact support a role for
[68Ga]Ga-FAPI-46 PET/CT as complementary imaging modality.},
keywords = {2-[18F]FDG PET/CT (Other) / GIST (Other) / [68Ga]Ga-FAPI-46
PET/CT (Other) / detection efficacy (Other)},
cin = {ED01},
ddc = {610},
cid = {I:(DE-He78)ED01-20160331},
pnm = {899 - ohne Topic (POF4-899)},
pid = {G:(DE-HGF)POF4-899},
typ = {PUB:(DE-HGF)16},
pubmed = {pmid:41266252},
doi = {10.2967/jnumed.125.270850},
url = {https://inrepo02.dkfz.de/record/306359},
}