[1] Sichuan Univ, West China Hosp, Dept Radiol, 37 Guoxue Xiang, Chengdu 610041, Peoples R China
[2] Zunyi Med Univ, Dept Radiol, Affiliated Hosp, Zunyi 563000, Guizhou, Peoples R China
[3] Sichuan Univ, Key Lab Birth Defects & Related Dis Women & Child, West China Univ Hosp 2, Dept Radiol,Minist Educ, Chengdu 610041, Peoples R China