The adaptation of MRI technology to use in rodents represents an unprecedented opportunity to revolutionize the design and monitoring of animal models of disease. High-field, small-animal MRI allows visualization deep into structures and permits this visualization to be carried out over extended periods of time with no damage to the animal. The Specific Aim of this proposal is to acquire funds to purchase a 4.7 Tesla (T) Magnetic Resonance Imaging (MRI) scanner for imaging small animals (primarily rodents). With the Wisconsin Molecular Imaging Center (WIMIC), the University of Wisconsin (UW) Comprehensive Cancer Center and the Departments of Radiology, and Medical Physics, the UW has become a leader in MRI technique development and application to a wide variety of disease states and organ systems. However, these studies have been limited to using clinical MRI scanners. The quality of the data has been limited by the clinical gradient and RF hardware and therefore studies have been restricted to lower resolution studies (>0.25mm). Acquisition of a high-field MRI scanner will allow researchers involved in numerous projects to explore in vivo anatomy and physiology with unprecedented resolution (100 mu/m in-plane). A unique aspect of the work at the UW is the close linkage between basic scientists and clinicians. The data generated with a 4.7T MRI scanner will markedly enhance current scientific efforts with the resolution required to explore disease models in both mice and rats. These data will be critical in guiding and interpreting human MRI studies. The new high-field MRI scanner will be housed in the UW Comprehensive Cancer Center located in the UW Hospital. This location is ideal because it will be readily accessible to the many Cancer Center users and it will also be next door to the micro-CT scanner. Because CT and MRI are complementary modalities, we foresee many opportunities for studies to be moved between the two scanners. A dedicated scientific advisory committee, made up of prominent MRI imaging researchers and principle investigators who use small animal models, will provide the administrative, scientific, and technical expertise. Among the broad research areas represented by potential users of the system are: cardiac, renal and muscle physiology, zoology, biomedical engineering, developmental biology, oncology, neuroscience, oncology, pathology, and stem cell research. The research programs of many of these users will be advanced significantly if a high field MRI system is available to them. The acquisition of the 4.7T scanner will complement the existing micro-imaging resources on campus including micro-PET and micro-CT scanners, and it will open new avenues of investigation for biological and physical scientists from across the UW-Madison campus.