[1] Brigham & Womens Hosp, Appl Imaging Sci Lab, Boston, MA 02115 USA
[2] Brigham & Womens Hosp, Thorac Imaging Sect, Boston, MA 02115 USA
[3] Univ Calif San Francisco, Dept Radiol, San Francisco, CA 94143 USA
[4] Brigham & Womens Hosp, Noninvas Cardiovasc Imaging Program, Boston, MA 02115 USA