Characterization of upper airway obstruction using cine MRI in children with residual obstructive sleep apnea after adenotonsillectomy

Objectives/Background: Tonsillectomy and adenoidectomy (T&A) lead to resolution of obstructive sleep apnea (OSA) in most children. However, OSA persists in about 25–40% of children. Cinematic magnetic resonance imaging (cine MRI) can aid the management of persistent OSA by localizing airway obstruction. We describe our experience in implementing and optimizing a cine MRI protocol by using a 3 Tesla MRI scanner, and the use of dexmedetomidine for sedation to improve reproducibility, safety, and diagnostic accuracy. Patients/Methods: Patients aged 3–18 years who underwent cine MRI for the evaluation of persistent OSA after T&A and failed positive airway pressure (PAP) therapy were included. Clinical data and the apnea-hyponea index were compared with quantitative and qualitative estimates of airway obstruction from imaging sequences. Results: A total of 36 children were included with a mean age of 9.6 ± 4.6 (SD) years with 40% over 12 years of age. Two-thirds of them were boys. Seventeen out of 36 children (47%) had Down syndrome. Single site and multilevel obstruction were identified in 21 of 36 patients (58%) and in 12 of 36 patients (33%), respectively. All cine MRIs were performed without complications. Multiple regression analysis demonstrated that a combination of the minimum airway diameter and body mass index z-score best predicted OSA severity (P = 0.002). Conclusions: Cine MRI is a sensitive, safe, and noninvasive modality for visualizing upper airway obstruction in children with persistent OSA after T&A. Accurate identification of obstruction can assist in surgical planning in children who fail PAP therapy.