1Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, United States, 2Harvard Medical School, Boston, MA, United States, 3Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Stockholm, Sweden, 4Department of Radiology, Karolinska University Hospital, Stockholm, Sweden, 5Department of Neurosciences, University of California, San Diego, CA, United States