1 Neuroprotection Research Laboratories, Departments of Radiology and Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
2 College of Pharmacy, Seoul National University, Seoul, Korea.
3 Athinoula Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
4 Cerebrovascular Research Institute, XuanWu Hospital, Capital Medical University, Beijing, China.
5 Neuroprotection Research Laboratories, Departments of Radiology and Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA. lo@helix.mgh.harvard.edu.