Ga-NODAGA-Exendin-4 PET/CT Improves the Detection of Focal Congenital Hyperinsulinism.

Surgery with curative intent can be offered to congenital hyperinsulinism (CHI) patients, provided that the lesion is focal. Radiolabeled exendin-4 specifically binds the glucagonlike peptide 1 receptor on pancreatic β-cells. In this study, we compared the performance of F-DOPA PET/CT, the current standard imaging method for CHI, and PET/CT with the new tracer Ga-NODAGA-exendin-4 in the preoperative detection of focal CHI. Nineteen CHI patients underwent both F-DOPA PET/CT and Ga-NODAGA-exendin-4 PET/CT before surgery. The images were evaluated in 3 settings: a standard clinical reading, a masked expert reading, and a joint reading. The target (lesion)-to-nontarget (normal pancreas) ratio was determined using SUV Image quality was rated by pediatric surgeons in a questionnaire. Fourteen of 19 patients having focal lesions underwent surgery. On the basis of clinical readings, the sensitivity of Ga-NODAGA-exendin-4 PET/CT (100%; 95% CI, 77%-100%) was higher than that of F-DOPA PET/CT (71%; 95% CI, 42%-92%). Interobserver agreement between readings was higher for Ga-NODAGA-exendin-4 than for F-DOPA PET/CT (Fleiss κ = 0.91 vs. 0.56). Ga-NODAGA-exendin-4 PET/CT provided significantly ( = 0.021) higher target-to-nontarget ratios (2.02 ± 0.65) than did F-DOPA PET/CT (1.40 ± 0.40). On a 5-point scale, pediatric surgeons rated Ga-NODAGA-exendin-4 PET/CT as superior to F-DOPA PET/CT. For the detection of focal CHI, Ga-NODAGA-exendin-4 PET/CT has higher clinical sensitivity and better interobserver correlation than F-DOPA PET/CT. Better contrast and image quality make Ga-NODAGA-exendin-4 PET/CT superior to F-DOPA PET/CT in surgeons' intraoperative quest for lesion localization.