1 Department of Radiology, Kangdong Seong-Sim Hospital, Hallym University College of Medicine, Seoul, Korea.
2 Department of Radiology and the Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Korea.
3 Department of Radiology and the Research Institute of Radiology, University of Ulsan College of Medicine, Asan Medical Center, Korea. Electronic address: edwardchoi83@gmail.com.