1. Department of Radiology, Massachusetts General Hospital, Harvard Medical School, 165 Cambridge St, Boston, MA 02114.
2. Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria.
3. Division of Cardiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA.
4. Cardiovascular Research Foundation, Columbia University Medical Center, New York, NY.
5. Institute of Diagnostic and Interventional Radiology, University Hospital, Zurich, Switzerland.
6. Department of Diagnostic and Interventional Radiology, Heidelberg University, Heidelberg, Germany.