Type 1 diabetes results from the autoimmune destruction of the insulin-producing beta cells of the islets of Langerhans of the pancreas. Initially, diabetes is usually clinically silent with immune cells invading the pancreatic islets, a process termed insulitis, which eventually leads to loss of beta cells in the islets. If enough beta cells are destroyed, the body can not make enough insulin to maintain blood sugars in the normal range and clinical diabetes develops. The purpose of this study is to assess the ability of magnetic resonance imaging with ferumoxytol to detect changes in the pancreas associated with the insulitis of type 1 diabetes.

This study is designed to monitor changes associated with the development of autoimmune diabetes. A magnetic resonance imaging (MRI) based technique will be used to noninvasively measure changes within the pancreas associated with the development of autoimmune diabetes. The iron-containing drug ferumoxytol will be used as an intravenous MRI contrast agent for this study.

Individuals will be asked to participate one time, for 1-year, or over a 2-year period. During the development phase of the study, each imaging series will consist of 3 or more MRI scans. At the initial imaging visit a pre-ferumoxytol scan will be done, followed by ferumoxytol injection, and then an immediate post-injection scan. The subsequent scans will be concluded within 96 hours of ferumoxytol injection (typically at 48 hours). Those who participate for 1-year will have repeat imaging at approximate times 0, 6 months, and 12 months. Those who participate for 2-years will have repeat imaging at approximate times 0, 3, 6, 12, 18, and 24 months after enrollment.

Measurements of autoimmunity and metabolic parameters (collected as part of collaborating diabetes clinical studies) will be used in the data analysis for the longitudinal portion of the study. Stimulated C-peptide will be measured as a marker of endogenous insulin production capacity and beta-cell mass.

Inclusion Criteria:

• Participation in a collaborating diabetes clinical trial
• Able to understand written consent document and HIPAA authorization prior to initiation of study related procedures and are willing to participate

Exclusion Criteria:

• Known allergy to ferumoxytol or iron
• Individuals who are pregnant or lactating
• Iron saturation above the upper limit of normal
• Individuals with a counter-indication to MRI, such as the presence of metallic prostheses or implanted metal device (e.g., infusion pump, defibrillator)
• Individuals with known clinical conditions that may lead to iron overload including hemochromatosis, cirrhosis, or sickle cell disease

Study participants will be selected from those already participating in diabetes clinical trials.