1. School of Biological Science and Medical Engineering, Southeast University, Nanjing 201196, P. R. China
2. Mathematical Sciences Department, Worcester Polytechnic Institute, Worcester, MA 01609, USA
3. Department of Mechanical Engineering, University of Washington, Seattle, WA 98195, USA
4. Division of Vascular Surgery, University of Washington, Seattle, WA 98195, USA
5. Biomedical Engineering Department, Worcester Polytechnic Institute, Worcester, MA 01609, USA
6. Department of Radiology, University of Washington, Seattle, WA 98195, USA