TY - JOUR T1 - <strong>Pitfalls in the Detection of Insulinomas with GLP-1R Imaging</strong> JF - Journal of Nuclear Medicine JO - J Nucl Med SP - 566 LP - 566 VL - 61 IS - supplement 1 AU - Kwadwo Antwi AU - Matthias Hepprich AU - Jean Claude Reubi AU - Melpomeni Fani AU - Melpomeni Fani AU - Christof Rottenburger AU - Guillaume Nicolas AU - Felix Kaul AU - Emanuel Christ AU - Damian Wild Y1 - 2020/05/01 UR - http://jnm.snmjournals.org/content/61/supplement_1/566.abstract N2 - 566Purpose: Physiological pancreatico-duodenal uptake of radiolabeled exendin-4 in Brunner’s glands of the proximal duodenum is the most common pitfall for false interpretation of glucagon-like peptide-1 receptor (GLP-1R) imaging. The aim of this study was to analyze the pancreatico-duodenal uptake in GLP-1R PET/CT and SPECT/CT images and to identify other potential reading pitfalls in patients with suspected insulinoma. Materials and Methods: A post hoc analysis of a larger prospective study, including 52 consecutive patients, was performed. All patients underwent one 68Ga-exendin-4 PET/CT and two 111In-exendin-4 SPECT/CT scans (4 and 72h p.i.) in a randomized crossover order. Three board-certified nuclear medicine physicians read all scans independently. They were unaware of other results. Reference standard was surgery with histopathological confirmation of an insulinoma and normalization of blood glucose levels after surgery. Detection of insulinomas and nesidioblastosis in regard to localization and size were evaluated. Results: Pitfall evaluation: there were no false-positive readings. However, there were a number of false-negative PET/CT and SPECT/CT readings: 1) due to Brunner’s glands in the pancreatico-duodenal region (0.6% and 9.0%), 2) due to ectopic insulinoma (0% and 2.6%), 3) due to small insulinoma (1.9% and 5.1%), 4) due to insulinoma overlap with kidneys (1.9% and 4.5%), and 5) due to nesidioblastosis (0.6% and 1.9%). Pitfalls were identified in all GLP-1R PET/CT and SPECT/CT scans. Conclusions: Peripancreatic uptake, small size of insulinoma, insulinoma overlap with kidneys and the presence of nesidioblastosis are potential pitfalls in GLP-1R imaging which can lead to false reading results. ER -