Clinical endocrinology | 2021
68 Ga-DOTATATE PET/CT imaging in endogenous hyperinsulinemic hypoglycemia: A tertiary endocrine centre experience.
Abstract
OBJECTIVE\nLiterature regarding utility of 68 Ga-DOTATATE PET/CT in insulinoma localization across various subgroups [benign/malignant/multiple endocrine neoplasia-1 (MEN-1) syndrome associated] remains scarce. In this study, the performance of 68 Ga-DOTATATE PET/CT was compared with contrast-enhanced computed tomography (CECT) and 68 Ga-NODAGA-Exendin-4 PET/CT (whenever available) in an endogenous hyperinsulinemic hypoglycemia (EHH) cohort.\n\n\nDESIGN\nRetrospective audit.\n\n\nPATIENTS\nEHH patients [N\u2009=\u200936, lesions (n)\u2009=\u200949, final diagnosis: benign sporadic insulinoma (BSI) (N\u2009=\u200920), malignant insulinoma (N\u2009=\u20094, n\u2009=\u200914), MEN-1 syndrome associated insulinoma (N\u2009=\u20099, n\u2009=\u200915), Munchausen syndrome (N\u2009=\u20092) and drug-induced hypoglycemia (N\u2009=\u20091)] having both preoperative imaging modalities (CECT and 68 Ga-DOTATATE PET/CT).\n\n\nMEASUREMENTS\nPer-lesion sensitivity (Sn) and positive predictive value (PPV) for histopathological diagnosis of insulinoma.\n\n\nRESULTS\nSn and PPV of 68 Ga-DOTATATE PET/CT were 67.3% and 89.2%; 55% and 100%; 85.7% and 100%; and 66.7% and 77% for overall EHH, BSI, malignant, and MEN-1 syndrome associated insulinoma cohorts respectively. Despite having comparatively lower sensitivity in BSI cohort, 68 Ga-DOTATATE PET/CT localized a pancreatic tail lesion missed by other modalities. 68 Ga-DOTATATE PET/CT had comparatively higher sensitivity in malignant insulinoma than BSI cohort. 68 Ga-DOTATATE PET/CT also paved the way for successful response to 177 Lu-based peptide receptor radionuclide therapy (PRRT). In MEN-1 cases, lower PPV as compared with BSI was due to uptake in non-insulinoma pancreatic neuroendocrine tumours (Pan-NET).\n\n\nCONCLUSIONS\n68 Ga-DOTATATE PET/CT has supplemental role in selected cases of BSI with negative and/or discordant results with CECT and 68 Ga-NODAGA-Exendin-4 PET/CT. In malignant insulinoma, 68 Ga-DOTATATE-PET/CT has an additional theranostic potential. Interference due to uptake in non-insulinoma Pan-NET in MEN-1 syndrome may hinder insulinoma localization with 68 Ga-DOTATATE-PET/CT.