1. Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul 138-736, Korea.
2. Department of Radiology & Imaging, Queen Elizabeth Hospital, Kowloon, Hong Kong.
3. Department of Microbiology, Bio-Medical Institute Technology, Asan Medical Center, University of Ulsan College of Medicine, Seoul 138-736, Korea.
4. Department of Colorectal Surgery, Asan Medical Center, University of Ulsan College of Medicine, Seoul 138-736, Korea.