1. Department of Radiology, Chonnam National University Hospital, Gwangju 61469, Korea.
2. Department of Radiology, Chonnam National University Medical School, Gwangju 61469, Korea.
3. Center for Aging and Geriatrics, Chonnam National University Medical School, Gwangju 61469, Korea.
4. Department of Gastroenterology, Chonnam National University Medical School, Gwangju 61469, Korea.