1. Department of Radiology, Center for Evidence-Based Imaging, Brigham and Women's Hospital, Harvard Medical School, Boston, MA.
2. Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, 75 Francis St, Boston, MA 02115.
3. Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA.
4. Department of Anesthesiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA.
5. Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA.