1. Department of Cardiology, Hokkaido Cardiovascular Hospital , 1-30, Minami-27, Nishi-13, Chuo-ku, Sapporo 064-8622 , Japan
2. Department of Cardiology, Hokkaido Cardiovascular Hospital , 1-30, Minami-27, Nishi-13, Chuo-ku Sapporo 064-8622 , Japan
3. Department of Radiology, Jichi Medical University Saitama Medical Center , 1-847 Amanuma-cho, Omiya-ku, Saitama 330-8503 , Japan