1. Department of Internal Medicine 2, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan
2. Department of Emergency Medicine, Hamamatsu University School of Medicine, Hamamatsu 431-3192, Japan
3. Hamamatsu Medical Imaging Center, Hamamatsu Medical Photonics Foundation, Hamamatsu 434-0041, Japan
4. Department of Internal Medicine, Kuma Hospital, Kobe 650-0011, Japan