1. From the Departments of Medicine (E.M.L., S.Y., Q.Y., S.S., A.M.-C., J.B., K.K.T.) and Radiology (C.I.D.), McMaster University, Hamilton, Ontario, Canada; The University of Alberta Hospitals, Edmonton, Alberta, Canada (V.D., K.K.T.); the Canadian Cardiovascular Collaboration (E.M.L., S.Y., V.D., C.I.D., Q.Y., S.S., A.M.-C., J.B., K.K.T.); and the Bowman Gray School of Medicine, Department of Neurology, Winston-Salem, NC (W.A.R.).