1. Department of Radiology, Research Institute of Radiological Science, Yonsei University College of Medicine, 50-1 Yonsei-Ro, Seodaemun-Gu, Seoul 03722, Korea.
2. Department of Radiology, National Health Insurance Service Ilsan Hospital, Goyang, Korea.
3. Department of Internal Medicine, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea.