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

Abstract

Background and context: Glucagon-like peptide-1 receptor (GLP-1 R) based imaging has shown higher sensitivity for insulinoma localization as compared to other anatomic/functional imaging. Methodology: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.Main outcome measures: 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.Results: 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. Conclusion: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.

68Ga‐DOTATATE PET/CT imaging in endogenous hyperinsulinemic hypoglycemia: A tertiary endocrine centre experience

“…5 Though the superiority of GLP-1 R-based imaging has been shown in recent studies, availability of this tracer remains limited to few centres across the world. 9,14,15 showing 25.8% and 54.5% sensitivities, respectively. 7,9 In the present study with a larger sample size (n = 36), we have shown 67.6% sensitivity of 68 Ga-DOTATATE PET/CT for insulinoma localization.…”

PET with Different Radiopharmaceuticals in Neuroendocrine Neoplasms: An Umbrella Review of Published Meta-Analyses

“…Overall, 26 meta-analyses containing information on the diagnostic performance of PET with different radiopharmaceuticals in patients with NETs and NECs were included (Table 1) [10,11,[13][14][15][16]18,19,[21][22][23][24][25][28][29][30][31][32][33][34][35][36][37][38][39][40]. These evidence-based manuscripts provided quantitative data about the diagnostic performance of PET and related hybrid modalities (PET/CT and PET/MRI) using different radiopharmaceuticals in patients with suspected NETs [31], thoracic and/or gastroenteropancreatic NETs [10,14,15,18,23,[28][29][30]34,40], small cell lung cancer (SCLC) [24], metastatic NETs with unknown primary (CUP-NETs) [13,25], paraganglioma (PGL) [16,19,29,35], neuroblastoma (NB)…”

“…Several meta-analyses evaluated the diagnostic performance of PET or PET/CT with different radiopharmaceuticals in patients with thoracic and/or gastroenteropancreatic NETs [10,14,15,18,23,[28][29][30]34,40].…”

“…Some meta-analyses were focused on specific locations of thoracic and gastroenteropancreatic NETs [10,18,28,30].…”

“…In the specific subgroup of insulinomas, radiolabelled exendin-4 imaging showed excellent results, superior to other PET modalities. The meta-analysis of Shah et al reported high pooled sensitivity (94%) and specificity (83%) of 68 Ga-exendin-4 PET/CT for insulinoma localization; these values were significantly higher compared to radiolabeled exendin-4 single-photon emission computed tomography (SPECT)/CT [30]. Recently, Piccardo et al compared the diagnostic performance of 68 Ga-SSA and 18 F-FDOPA PET/CT in the group of patients with intestinal NETs through a head-to-head meta-analytic approach.…”