[1] Osaka Univ, Grad Sch Med, Dept Radiol, Suita, Osaka 5650825, Japan
[2] Univ British Columbia, Dept Radiol, Vancouver, BC V5Z 1M9, Canada
[3] Vancouver Hosp & Hlth Sci Ctr, Vancouver, BC V5Z 1M9, Canada
[4] Osaka Univ, Grad Sch Med, Dept Med Phys, Osaka, Japan
[5] Kumamoto Univ, Sch Med, Dept Internal Med 1, Kumamoto 860, Japan
[6] Tosei Gen Hosp, Dept Resp Med, Aichi, Japan
[7] Kurume Univ, Sch Med, Dept Radiol, Fukuoka, Japan