 Approximately one million individuals are afflicted with autoimmune Type 1 diabetes mellitus T1DM in the United States. This disease results from the autoimmune destruction of the insulin-producing beta-cells of the islets of Langerhans of the pancreas. Initially, diabetes is usually clinically occult with localized pancreatic inflammation characterized by a lymphocytic infiltration of the pancreatic islets, termed insulitis, which leads to beta-cell specific destruction of the islets. This is often followed by the clinically overt phase that ensues when the bulk of beta cells have been destroyed and the pancreas is no longer able to produce sufficient insulin to maintain glycemic control. The purpose of this study is to assess the ability of magnetic resonance imaging with ferumoxtran-10, a functional molecular imaging agent consisting of iron oxide nanoparticles, to detect changes in the pancreas associated with the insulitis of T1DM. 