1. Department of Gastrointestinal Surgery, The Second Affiliated Hospital of Dalian Medical University, Dalian, Liaoning 116023, P.R. China
2. Department of Ultrasound, The Second Affiliated Hospital of Dalian Medical University, Dalian, Liaoning 116023, P.R. China
3. Department of Clinical Laboratory, The Second Affiliated Hospital of Dalian Medical University, Dalian, Liaoning 116023, P.R. China