PROJECT SUMMARY/ABSTRACT The mission of the Metabolic Imaging Core (MIC) and its three Sub-Cores (Advanced Body Composition, Positron Emission Tomography [PET], and Functional Neuroimaging) is to support nutrition and obesity research from NORC-H members, by providing access to advanced non-invasive imaging technologies. Since the last funding period, the MIC has enabled highly sophisticated assessments of body composition, tissue physiology and brain function that accelerated translational research in human obesity and nutrition. The NORC-H Metabolic Imaging Core coordinates and centralizes research imaging needs of NORC-H members and encourages use of advanced metabolic imaging techniques, also providing support in research design and consultation. The Advanced Body Composition Sub-Core provides services in multi-organ MRI/MR spectroscopy, CT imaging and high-throughput image analysis used in a variety of body composition assessments. The PET Sub-Core includes services of PET/CT, PET/MRI, and development of physiologic and functional radiotracers. The Functional Neuroimaging Sub-Core provides services in fMRI and structural brain imaging. The NORC-H combines the expertise of long-standing MGH imaging Cores, and over the last funding cycle the MIC was rated very highly by NORC-H members and exceptionally productive, performing over 2,000 imaging services for members, including consultation and technical support, showing sustained demand serving over 37 researchers, including 34 NORC-H members. The MIC also has expanded its imaging services and technological innovations, making them available to NORC-H investigators. The aims of the current renewal application are to: 1) Provide a variety of advanced imaging services, paired with consultation, to support studies in need of imaging-based endpoints, with continued innovation in imaging technologies, provision of new services, and expansion of user base, 2) Provide standalone imaging analysis services, including quantitative interpretation of imaging data and high-throughput body composition analyses of large datasets using deep learning algorithms developed in- house during the current funding cycle, 3) Harmonize imaging protocols used for brain, liver, muscle, and visceral fat MR studies across multiple NORCs, targeting high repeatability of MR-based measurements across Centers.