1. Department of Biomedical Engineering; Fourth Military Medical University; Xi'an Shaanxi P.R. China
2. Department of Radiology; Tangdu Hospital, Fourth Military Medical University; Xi'an Shaanxi P.R. China
3. Department of Neurosurgery; Tangdu Hospital, Fourth Military Medical University; Xi'an Shaanxi P.R. China
4. Departments of Radiology, Computer Science and Biomedical Engineering; State University of New York; Stony Brook New York USA