There are several aspects of autoimmune/inflammatory diseases that are poorly understood and are currently difficult to assess experimentally in vivo or clinically. These include identification of the causal and earliest players inciting autoimmune disease, understanding systems biology in intact host environments, the ability to determine treatment efficacy early on and to tailor treatments for optimized use in a given patient. Many of these processes have been elusive to demonstrate in an in vivo setting. The overall goal of this Project is to develop and optimize novel imaging approaches that can ultimately be used to objectively monitor different autoimmune diseases, in particular rheumatoid arthritis and diabetes both experimentally and clinically. The imaging strategies utilized in this Project are based on previously developed novel techniques that allow serial and functional assessment during initiation of inflammation, treatment and relapse. For example, we have shown that target-specific MR imaging of activated endothelium is feasible, that we can track different immune cells in vivo by MR nuclear and bioluminescence imaging, that beta-cell mass can be quantitated, and importantly that a host of degradative enzymes can now be visualized in vivo using near-infrared fluorescence imaging. The primary goal of this project is to further develop and validate the new techniques particularly for 1) microvascular imaging, 2) cellular tracking and 3) protease imaging. A high degree of interaction with the other three Projects will assure the application of these techniques experimentally (Projects 2 and 3) and clinically (Project 4).