1. Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan.
2. Department of Electronic Science and Engineering, Nanjing University, Nanjing, China.
3. Department of Radiology, University of Michigan, Ann Arbor, Michigan.
4. Department of Ultrasound, The Second Affiliated Hospital of Army Medical University, Chongqing, China.
5. Department of Applied Physics Program, University of Michigan, Ann Arbor, Michigan.