1. Department of Gastrointestinal Surgery, First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan 650032, P.R. China
2. Department of Ultrasound, First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan 650032, P.R. China
3. Department of Gastroenterology, First Affiliated Hospital of Kunming Medical University, Kunming, Yunnan 650032, P.R. China