[1] Nippon Vet & Life Sci Univ, Fac Vet Sci, Lab Vet Radiol, Musashino, Tokyo, Japan
[2] Nippon Vet & Life Sci Univ, Res Ctr Anim Life Sci, Musashino, Tokyo, Japan
[3] Nippon Vet & Life Sci Univ, Vet Med Teaching Hosp, Musashino, Tokyo, Japan
[4] Univ Tokyo, Grad Sch Agr & Life Sci, Lab Vet Pathol, Bunkyo Ku, Tokyo, Japan