Exendin-4-based imaging in insulinoma localization: Systematic review and meta-analysis.

Ravikumar Shah, Robin Garg, Monil Majmundar, Nilendu Purandare, Gaurav Malhotra, Virendra Patil, Swati Ramteke-Jadhav, Anurag Lila, Nalini Shah, Tushar Bandgar

Clinical endocrinology 2021 Aug

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Glucagon-like peptide-1 receptor (GLP-1 R) based imaging has shown higher sensitivity for insulinoma localization as compared to other anatomic/functional imaging. We reviewed the published English literature for GLP-1 R targeted imaging in insulinoma in PubMed until August 2020 in accordance with PRISMA guidelines using the MeSH terms "((Exendin-4 PET/CT) OR (Exendin-4 SPECT/CT) OR (GLP-1 R imaging)) AND (Insulinoma)". An individual patient data-metanalysis (IPD-MA) was performed, and performance parameters were calculated for the histopathological diagnosis of insulinoma. True-positive (TP), false-positive (FP), false-negative (FN), true-negative (TN), sensitivity (Sn), specificity (Sp), positive predictive value (PPV) and negative predictive value (NPV) for insulinoma localization. A total of 179 cases (316 lesions) from 16 publications were included for IPD-MA. For insulinoma localization, exendin-4-PET/CT (Sn & PPV: 94%) performed better than exendin-4-SPECT/CT (Sn: 63%, PPV: 94%). The Sn was lower in malignant insulinoma cases whereas the Sp was higher in cases with MEN-1 syndrome. With exendin-4-based imaging, FP uptakes in Brunner's gland, normal pancreas, and other β-cell pathologies and FN results in pancreatic tail lesions and malignancy were seen in a few patients. TN results suggested the correct diagnosis of other endogenous hyperinsulinemic hypoglycaemia (EHH) subtypes. For insulinoma localization, exendin-4 PET/CT should be preferred over exendin-4 SPECT/CT because of higher sensitivity and specificity. FP uptakes in Brunner's gland, normal pancreas, and other β-cell pathologies and FN results in tail lesions, and malignant insulinomas are limitations. Higher specificity for insulinoma localization is particularly useful in patients with MEN-1 syndrome. © 2021 John Wiley & Sons Ltd.

Citation

Ravikumar Shah, Robin Garg, Monil Majmundar, Nilendu Purandare, Gaurav Malhotra, Virendra Patil, Swati Ramteke-Jadhav, Anurag Lila, Nalini Shah, Tushar Bandgar. Exendin-4-based imaging in insulinoma localization: Systematic review and meta-analysis. Clinical endocrinology. 2021 Aug;95(2):354-364