1. Department of Ultrasound, Yan’an Hospital Affiliated to Kunming Medical University, Kunming, Yunnan, P.R. China
2. Department of Ultrasound, Anning First People’s Hospital, Kunming City, Yunnan, P.R. China
3. Department of Ultrasound, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, P.R. China