Imaging of islet grafts

Purpose of review Islet transplantation is one of the most promising approaches to cure type 1 diabetes patients, but long-term results still have to be improved. Imaging of the islet graft is one of the monitoring tools that are currently being developed to detect loss of islet graft mass/function before functional impairment. Recent findings New techniques of imaging have been developed to detect islet damage early enough to prevent graft loss. Bioluminescence imaging is an interesting tool but is limited for clinical use. PET with in-situ and ex-vivo islet labeling is limited by the specificity of the markers, Promising new probes, however, such as DTBZ, which binds specifically to VMAT2 (specific for the brain and islets), are under scrutiny. MRI after ex-vivo labeling with contrast agents such as iron nanoparticles or gadolinium allows follow up of the islet in animal models and in the human. All these methods need improvement in terms of islet quantification, correlation of images with functional outcome, and P-cell specificity of the probes. Summary Novel approaches to better track islet graft rejection and to prevent islet function loss over time are presented and discussed in this paper.