Abstract Rodent animal models, including genetically engineered animals, surgical models, and naturally occurring disease models, remain the cornerstone of preclinical research, and are routinely used to study the mechanisms and pathogenesis of human disease and develop new therapies. High resolution ultrasound imaging is an essential phenotyping tool to be able to study internal animal anatomy and physiology non- invasively across the animal’s lifespan, during disease pathogenesis, and before or after preclinical testing of treatments. This SIG application requests funds to purchase a Visualsonics Vevo3100 Ultrasound Imaging System. This new imaging system will be essential to the operations of the Physiology Phenotyping Core, which has almost two decades of experience in providing ultrasound imaging to NIH funded investigators across the University of Michigan Campus. The new Vevo3100 will replace an aging Vevo 2100 that has reached its end of supported lifespan and routinely requires costly repairs. The Vevo3100 utilizes very high frequency linear array MX-series transducers that provide the highest resolution 2D and 3D imaging of small animal heart structure and function available, and also allow for quantitative, functional imaging of blood vessels and tumor volumes in animals as small as mouse embryos and up to large rats and rabbits. EKG and respiration gating and EKV Software provide unparalleled cine loop image reconstruction during the cardiac cycle at up to 10,000 frames per second, and enables a novel 4D Imaging Mode (3D + time) to capture 3D imaging of the heart during the cardiac cycle at near MRI levels of resolution but at a fraction of the time and cost. In addition, the VevoVasc imaging analysis and high-resolution color Doppler imaging provides a capability of analyzing consequences of vascular disease including aneurysms, atherosclerosis and the physiological effects of thrombosis. Importantly, the Vevo3100 will be incorporated into a robust, fully functional animal phenotyping core with expert ultrasound technical staff, an efficient recharge mechanism, standing animal protocols, procedural space, and laboratory animal support to ease access to novice or expert users across the university. The core also provides users access to surgical models of cardiovascular disease, telemetry recording, blood pressure, drug delivery and other phenotyping modalities which provide a pipeline for preclinical studies from disease models to experimental outcomes. For example, when combined with the blood pressure telemetry services available in the Physiology Phenotyping Core, VevoVasc allows for real-time non-invasive analysis of vascular wall mechanics. Overall, the Vevo3100 will allow the Physiology Phenotyping Core to provide new state of the art modes of functional ultrasound imaging to NIH funded users, and by replacing aging end-of-life equipment will allow the core to continue to provide ultrasound services to users into the next decad...