1. Department of Radiology, Myongji Hospital, Seonam University College of Medicine, Goyang 10475, Korea.
2. Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul 06351, Korea.
3. Philips Healthcare Korea, Philips, Seoul 04342, Korea.
4. Biostatistics and Clinical Epidemiology Center, Samsung Medical Center, Seoul 06351, Korea.