[1] Red Cross Soc Azumino Hosp, Dept Emergency Med, 5685 Toyoshina, Azumino, Nagano 3998292, Japan
[2] Jichi Med Univ, Dept Clin Lab Med, Shimotsuke, Tochigi, Japan
[3] GE Healthcare, Ultrasound Div, Hino, Tokyo, Japan
[4] Natl Def Med Coll, Dept Internal Med 2, Tokorozawa, Saitama, Japan