J David SpenceJ. David Spence, MD, one of the world's leading experts in stroke prevention, is Professor of Neurology and Clinical Pharmacology at the University of Western Ontario and Director of the Stroke Prevention and Atherosclerosis Research Centre at the Roarts Research Institute. He pioneered ultrasound measurement of carotid plaque, and was one of the researchers on the team that discovered the dangerous drug interactions with grapefruit. Read More Read Less