1. Department of Radiology, Nagoya City University Graduate School of Medical Sciences, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya 467-8601, Japan
2. Department of Radiology, Nagoya Daini Red Cross Hospital, Nagoya 466-8650, Japan
3. Department of Pediatrics, Nagoya Daini Red Cross Hospital, Nagoya 466-8650, Japan
4. Department of Radiology, Hokuto Hospital, Obihiro, Hokkaido, 080-0833, Japan
5. Department of Radiation Oncology, Aizawa Comprehensive Cancer Center, Matsumoto, Nagano, 390-8510, Japan