Magnetic resonance imaging of the upper airway in children with Down syndrome

As compared with control subjects, children with Down syndrome have differe nt size and shape relationships among tissues composing the upper airway, w hich may predispose them to obstructive sleep apnea (OSA). We hypothesized that Down syndrome children without OSA have similar subclinical difference s. We used magnetic resonance imaging to study the upper airway in 11 Down syndrome children without OSA (age, 3.2 +/- 1.4 yr) and in 14 control subje cts (age, 3.3 +/- 1.1 yr). Sequential T1- and T2-weighted spin-echo axial a nd sagittal images were obtained. We found a smaller airway volume in subje cts with Down syndrome (1.4 +/- 0.4 versus 2.3 +/- 0.8 cm(3) in controls, p < 0.005). Subjects with Down syndrome had a smaller mid- and lower face sk eleton. They had a shorter mental spine-clivus distance (5.7 +/- 0.6 versus 6.2 +/- 0.4 cm, p < 0.05), hard palate length (3.2 +/- 0.4 versus 3.7 +/- 0.2 cm, p < 0.005), and mandible volume (11.5 +/- 3.7 versus 16.9 +/- 2.9 c m(3), p < 0.0005). Adenoid and tonsil volume was significantly smaller in t he subjects with Down syndrome. However, the tongue, soft-palate, pterygoid , and parapharyngeal fat pads were similar to those of control subjects. Th is study shows that Down syndrome children without OSA do not have increase d adenoid or tonsillar volume; reduced upper airway size is caused by soft tissue crowding within a smaller mid- and lower face skeleton.