GLP-1 Receptor Agonists: An Emerging Pitfall in FDG PET/CT Interpretation
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Abstract
Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) are increasingly used for type 2 diabetes and obesity, but recent reports indicate they can alter FDG biodistribution on PET/CT, creating potential pitfalls in oncologic imaging. Atypical uptake may occur in skeletal muscle, brown adipose tissue, and the gastrointestinal tract, mimicking inflammatory or malignant processes. These pharmacologically induced patterns can lead to diagnostic uncertainty, unnecessary investigations, and inappropriate management decisions. Recognizing the mechanisms — delayed gastric emptying, brown fat activation, and altered insulin-sensitive tissue uptake — is critical for accurate image interpretation. Integrating medicine-related information in daily PET/CT planning and being aware of GLP-1 RA use throughout the process of image processing could potentially help decrease diagnosis-related uncertainty. Imaging professionals and nuclear treatment experts need to be mindful of these possible implications in an effort to decode oncological images in individuals receiving GLP-1 therapy with care.
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Copyright (c) 2026 Nizam R, et al.
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1) Li P, Varghese JS, Shah MK, Galindo RJ, Pasquel FJ, Ali MK, et al. Prescribing trends of glucagon-like peptide-1 receptor agonists for type 2 diabetes or obesity. JAMA Netw Open. 2025 Oct 31;8(10):e2540890. Available from: https://doi.org/10.1001/jamanetworkopen.2025.40890
2) Minamimoto R, Kato K, Naganawa S. Clinical scenarios of unusual FDG uptake in muscle. Jpn J Radiol. 2024; 43:177–185. Available from: https://doi.org/10.1007/s11604-024-01672-7
3) Harrison DB, Phillips AL, Tansey JB, Clarke TJ, Wood CB, Nedzi L, et al. Brown adipose tissue mimicking head and neck cancer on PET scan in a patient on a GLP-1 agonist. Laryngoscope. 2025 Feb;135(2):741-743. Available from: https://doi.org/10.1002/lary.31815
4) Drucker DJ. Mechanisms of action and therapeutic application of glucagon-like peptide-1. Cell Metab. 2018; 27:740–756. Available from: https://doi.org/10.1016/j.cmet.2018.03.001
5) Oldan JD, Landman PG, Schroeder JA, Khandani AH , Solnes LB, Lee CB, et al. FDG PET in a patient on a GLP-1 agonist/insulin secretagogue. Clin Nucl Med. 2024; 49: e436–e438. Available from: https://doi.org/10.1097/rlu.0000000000005318
6) Vangu MDT, Momodu JI. F-18 FDG PET/CT imaging in normal variants, pitfalls, and artifacts in the abdomen and pelvis. Front Nucl Med. 2022; 1:826109. Available from: https://doi.org/10.3389/fnume.2021.826109
7) Hiramoto B, McCarty TR, Lodhia NA, Jenkins A, Elnaiem A, Muftah M, et al. Quantified metrics of gastric emptying delay by glucagon-like peptide-1 agonists: a systematic review and meta-analysis with insights for periprocedural management. Am J Gastroenterol. 2024;119(6):1126-1140. Available from: https://doi.org/10.14309/ajg.0000000000002820
8) Szabari M, Ali F, Calais J, Czernin J, Salavati A. FDG PET scan in the era of novel glucagon-like peptide-1 receptor agonists (GLP-1RAs): do we need to modify the scan protocol or patient preparation? J Nucl Med 66(Suppl 1): 2025; 251413. Available from: https://jnm.snmjournals.org/content/66/supplement_1/251413
9) Boellaard R, Herrmann K, Barrington SF, Cranston I, Mottaghy FM, Hoekstra CJ, et al. [18F]FDG PET/CT: EANM procedure guidelines for tumour imaging: version 3.0. The EANM Journal. 2025 Sep 24;1:100006. Available from: https://doi.org/10.1016/j.eanmj.2025.100006
10) Tsuchida H, Morita Y, Nogami M, Ogawa W. Metformin action in the gut―insight provided by [18F]FDG PET imaging. Diabetology International 2021 Sep 23;13(1):35–40. Available from: https://doi.org/10.1007/s13340-021-00545-y