Necropsy studies performed in New York and California over the past 20 years have shown that fetlock joint fractures represent nearly 50% of all equine fatalities. The overarching goal of this research is to identify diagnostic imaging patterns from advanced modalities (MRI, photon-counting CT) correlated with pathology that has confirmed associations to break down. Specifically, the study will use the NAEOTOM Alpha CT (the world’s first photon-counting CT at a veterinary college) and high-field 3T MRI to further define early bone pathology in racehorses that suffer fatal fractures of the fetlock joint, with comparison to the contralateral uninjured limb and comparison to necropsy findings. This work will be performed at Cornell University in Ithaca, NY. Imaging findings will be correlated to gross and histological findings, and additional analysis of joint tissues or synovial fluid can be performed. We anticipate a minimum of 30 horses per year (60 limbs) for the 3-year study period (180 limbs in total) for MRI and photon-counting CT analysis.