1. From the Section of Vascular Medicine, University Department of Medicine, Department of Radiology, Ninewells Hospital and Medical School, Dundee, Scotland (J.J.F.B., J.W.S., G.K., M.M., R.R., C.M.); and the Department of Clinical Statistics, Scotia Pharmaceuticals Ltd, Woodbridge Meadows, Guildford, England (P.M.).