68Ga-NODAGA-Exendin-4 PET/CT 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 glucagonlike peptide 1 receptor on pancreatic β-cells. In this study, we compared the performance of ¹⁸F-DOPA PET/CT, the current standard imaging method for CHI, and PET/CT with the new tracer ⁶⁸Ga-NODAGA-exendin-4 in the preoperative detection of focal CHI. Methods: Nineteen CHI patients underwent both ¹⁸F-DOPA PET/CT and ⁶⁸Ga-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_max Image quality was rated by pediatric surgeons in a questionnaire. Results: Fourteen of 19 patients having focal lesions underwent surgery. On the basis of clinical readings, the sensitivity of ⁶⁸Ga-NODAGA-exendin-4 PET/CT (100%; 95% CI, 77%-100%) was higher than that of ¹⁸F-DOPA PET/CT (71%; 95% CI, 42%-92%). Interobserver agreement between readings was higher for ⁶⁸Ga-NODAGA-exendin-4 than for ¹⁸F-DOPA PET/CT (Fleiss κ = 0.91 vs. 0.56). ⁶⁸Ga-NODAGA-exendin-4 PET/CT provided significantly (P = 0.021) higher target-to-nontarget ratios (2.02 ± 0.65) than did ¹⁸F-DOPA PET/CT (1.40 ± 0.40). On a 5-point scale, pediatric surgeons rated ⁶⁸Ga-NODAGA-exendin-4 PET/CT as superior to ¹⁸F-DOPA PET/CT. Conclusion: For the detection of focal CHI, ⁶⁸Ga-NODAGA-exendin-4 PET/CT has higher clinical sensitivity and better interobserver correlation than ¹⁸F-DOPA PET/CT. Better contrast and image quality make ⁶⁸Ga-NODAGA-exendin-4 PET/CT superior to ¹⁸F-DOPA PET/CT in surgeons' intraoperative quest for lesion localization.

Keywords: 18F-DOPA PET/CT; 68Ga-NODAGA-exendin-4 PET/CT; congenital hyperinsulinism; diagnostic imaging; focal CHI.