1. Department of Radiology, Beijing Friendship Hospital; Capital Medical University; Beijing China
2. Comparative Medical Center, Peking Union Medical College (PUMC) & Institute of Laboratory Animal Science; Chinese Academy of Medical Science (CAMS); Beijing China
3. Swiss Light Source, Paul Scherrer Institute; Villigen, 5232 Switzerland
4. Institute for Biomedical Engineering; University and ETH Zurich; Zurich, 8092 Switzerland