Imagerie des récepteurs du GLP-1 dans l’exploration des sécrétions inappropriées d’insuline

Abstract

Endogenous hyperinsulinemic hypoglycemia is a rare disorder (incidence 2–4/Mio/year). In adult patients, the differential diagnosis includes benign and malignant insulinoma, insulinoma in the context of MEN-1 and nesidioblastosis whereby benign insulinoma is the most frequent diagnosis. The preoperative localization of benign insulinomas is challenging using conventional imaging procedures since these lesions are small (0.5–2 cm). GLP-1R imaging (SPECT/CT and PET/CT) using 111 In-DOTA-exendin-4 and a 68 Ga-DOTA-exendin-4, respectively and is an emerging technique targeting the GLP-1R expressed in very high density on insulinomas. All patients included in the prospective studies had a confirmed endogenous hyperinsulinemic hypoglycemia with neurogylcopenic symptoms. GLP-1R imaging using SPECT/CT ( n = 30) showed a sensitivity of 95% in detecting insulinomas (gold standard: histology), whereas conventional imaging exhibited a sensitivity of 47%. The follow-up study that compared GLP-1R SPECT/CT with PET/CT technique (ongoing study) confirmed the high sensitivity of this imaging procedure with an advantage for the PET/CT technique. Patients with NEM-1 develop multicentric pancreatic islet tumors, the most common functional ones being gastrinomas and insulinomas. Surgery is the only treatment option. However, the surgical intervention should be limited as surgery cannot cure patients with MEN-1. It is therefore, mandatory to correctly localize tumor lesions. The experience with 6 patients suggests that adding GLP-1R imaging to conventional imaging is a helpful tool in differentiating insulinomas from other pancreatic islet lesions. Adding GLP-1R imaging to conventional imaging is a very useful technique in preoperatively localizing benign insulinomas and insulinomas in the context of MEN-1.