About the Authors

Zhen Wang

Contributed equally to this work with: Zhen Wang, Li-jun Yuan

Affiliation Department of Ultrasound Diagnostics, Tangdu Hospital, Fourth Military Medical University, Xi’an, China

Li-jun Yuan

Contributed equally to this work with: Zhen Wang, Li-jun Yuan

Affiliation Department of Ultrasound Diagnostics, Tangdu Hospital, Fourth Military Medical University, Xi’an, China

Tie-sheng Cao

caots4335@yahoo.cn

Affiliation Department of Ultrasound Diagnostics, Tangdu Hospital, Fourth Military Medical University, Xi’an, China

Yong Yang

Affiliation Department of Ultrasound Diagnostics, Tangdu Hospital, Fourth Military Medical University, Xi’an, China

Yun-you Duan

Affiliation Department of Ultrasound Diagnostics, Tangdu Hospital, Fourth Military Medical University, Xi’an, China

Chang-yang Xing

Affiliation Department of Ultrasound Diagnostics, Tangdu Hospital, Fourth Military Medical University, Xi’an, China

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

Researched literature: ZW LY. Calibrated the manometer of the pressure measurement device used in this study: ZW TC. Edited and revised manuscript critically for important intellectual content: ZW LY YY YD CX. Conceived and designed the experiments: ZW LY TC. Performed the experiments: ZW LY YY YD CX. Analyzed the data: ZW LY YD TC. Contributed reagents/materials/analysis tools: ZW LY YY YD CX. Wrote the paper: ZW LY TC.