1. Department of Radiology, Jichi Medical University, School of Medicine, Japan
2. Department of Pediatric Radiology, Jichi Children's Medical Center Tochigi, Japan
3. Department of Diagnostic Radiology, Tokyo Medical and Dental University, Japan
4. Department of Radiology, Graduate School of Medicine, The University of Tokyo, Japan
5. Division of Cardiovascular Medicine, Department of Medicine, Jichi Medical University, School of Medicine, Japan