Dan Zhang1,2, Shixue Xu1, Yulong Tian1,3, Xingshun Qi1. 1. SVT Interest Group, Department of Gastroenterology, General Hospital of Northern Theater Command (Formerly General Hospital of Shenyang Military Area), Shenyang, China. 2. Department of General Surgery, General Hospital of Northern Theater Command (Formerly General Hospital of Shenyang Military Area), Shenyang, China. 3. Department of Interventional Radiology, First Affiliated Hospital of China Medical University, Shenyang, China.