1. Center for Biomedical Engineering, University of Science and Technology of China, Hefei, Anhui 230027, China
2. Laboratory of Digital Medical Imaging, Medical Imaging Center, The First Affiliated Hospital, Anhui University of Chinese Medicine, Hefei, Anhui 230031, China
3. Anhui Computer Application Institute of Traditional Chinese Medicine, Hefei, Anhui 230038, China
4. Department of Radiology, University of Washington School of Medicine, Seattle, WA 98108, USA