1. Department of Medicine, The Johns Hopkins University, 600 North Wolfe Street, MD 21287, Baltimore, USA
2. Division of Cardiology, Department of Medicine, Albert Einstein College of Medicine, 1300 Morris Park Ave, Bronx, NY 10461, New York, USA
3. Department of Radiology, The Johns Hopkins University, 600 North Wolfe Street, MD 21287, Blalock 524, Baltimore, USA
4. National Heart, Lung, and Blood Institute, 31 Center St, MD 20892, Bethesda, USA
5. Department of Epidemiology, University of Washington, 1959 NE Pacific Street, Health Sciences Building, WA 98195, Seattle, USA
6. National Institutes of Health, Radiology and Imaging Sciences, 10 Center St, MD 20892, Bethesda, USA