1. From the Department of Radiology, Kings College Hospital, London, United Kingdom (D.J.Q.); Departments of Medicine (J.W.E., J.I.W.) and Biochemistry and Biomedical Sciences (J.I.W.), McMaster University, Hamilton, Ontario, Canada; and Thrombosis and Atherosclerosis Research Institute, Hamilton, Ontario, Canada (J.W.E., J.I.W.).