68Ga-NODAGA-exendin-4 PET improves the detection of focal congenital hyperinsulinism

Abstract

Surgery with curative intent can be offered to Congenital Hyperinsulinism (CHI) patients, provided that the lesion is focal. Radiolabeled Exendin-4 specifically binds the glucagon-like peptide 1 receptor (GLP-1R) on pancreatic beta cells. In this study we compared the performance of [¹⁸F]F-DOPA positron emission tomography/computed tomography (DOPA PET) and PET/CT with the new tracer [⁶⁸Ga]Ga-NODAGA-exendin-4 (Exendin PET) in the preoperative detection of focal CHI. <b>Methods:</b> Nineteen CHI patients underwent both DOPA PET and Exendin PET prior to surgery. The images were evaluated in three settings a) standard clinical reading b) blinded expert reading and c) joined reading. Target (lesion) / non target (normal pancreas) ratio were determined using maximum standard uptake value (SUV_max). Image quality was rated by pediatric surgeons in a questionnaire. <b>Results:</b> Fourteen/nineteen patients having focal lesions underwent surgery. Based on clinical readings, the sensitivity of Exendin PET (100% (CI 77-100%)) was higher than that of DOPA PET (71% (CI 42-92%)). Interobserver agreement between readings was higher for Exendin than for DOPA PET (Fleiss' kappa 0.91 vs. 0.56). Exendin PET provided significantly (<i>P</i> = 0.021) higher target / non target ratios (2.02 ± 0.65 ) than DOPA PET (1.40 ± 0.40). On a five point scale, Pediatric surgeons rated Exendin PET superior to DOPA PET. <b>Conclusion:</b> Exendin PET has higher clinical sensitivity and better interobserver correlation for the detection of focal CHI than DOPA PET. Better contrast and image quality makes Exendin PET superior to DOPA PET in surgeons' intra-operative quest for lesion localization.