1. Department of Ultrasound
2. the Third People's Hospital of Chengdu City
3. the Affiliated Hospital of Southwest Jiaotong University
4. Chengdu 610031
5. P. R. China
6. Hainan General Hospital
7. Haikou
8. State Key Lab of High Performance Ceramics and Superfine Microstructure
9. Shanghai Institute of Ceramics
10. Chinese Academy of Sciences
11. Shanghai