1 a Department of Radiology and Research Institute of Radiology , University of Ulsan College of Medicine, Asan Medical Center , Seoul , Republic of Korea.
2 b Department of Radiology , GangNeung Asan Hospital , Gangneung-si Gangwon-do , Republic of Korea.
3 c Department of Radiology , Human Medical Imaging and Intervention Center , Seocho-gu Seoul , Republic of Korea.