[1] Stellenbosch Univ, Dept Otorhinolaryngol, Cape Town, South Africa
[2] Tygerberg Hosp, Cape Town, South Africa
[3] Stellenbosch Univ, Fac Med & Hlth Sci, Dept Paediat & Child Hlth, Cape Town, South Africa
[4] Childrens Hosp Philadelphia, Dept Paediat Radiol, Philadelphia, PA USA
[5] Univ Penn, Perelman Sch Med, Dept Radiol, Philadelphia, PA USA