1. Department of Pathology, Brain Korea 21 Project for Medical Science, Institute of Gastroenterology, Yonsei University College of Medicine, Seoul, Korea.
2. Department of Surgery, Brain Korea 21 Project for Medical Science, Institute of Gastroenterology, Yonsei University College of Medicine, Seoul, Korea.
3. Department of Radiology, Brain Korea 21 Project for Medical Science, Institute of Gastroenterology, Yonsei University College of Medicine, Seoul, Korea.