[Study of Cine-MRI for the soft palate in patients with obstructive sleep apnea hypopnea syndrome].

OBJECTIVE: To study dynamic change and pathophysiology of airway obstruction of the soft palate in patients with obstructive sleep apnea hypopnea syndrome (OSAHS) during wakefulness and natural sleep.

METHOD: Sixteen patients who were diagnosed as OSAHS by sleep questionnaires, medical examination and polysomnography were enrolled in this study in Shanghai Tenth People' Hospital from May to December during 2007. All patients were requested to keep awake prior to examination. Sequential midline sagittal images of the upper airway were obtained during awake and asleep state with Cine-MRI and been transmitted to portable computer. Morphologic change of the soft palate, the anterior-posterior pendulum angle of the soft palate, the anteroposterior diameter and the length of soft palate were measured. Statistical analysis was performed with paired t-test.

RESULT: During wakefulness: soft palate caused obstruction by floating backwards and widening anteroposterior diameter(distance between hard palate and uvula P > 0.05, included angle of hard palate and segmental vente of uvula P < 0.05, included angle of hard palate and segmental dorsum of uvula P < 0.01, difference of included angle P < 0.01). Main obstruction site was on retropalatal region. During natural sleep: soft palate caused obstruction by lengthening down and widening anteroposterior diameter (distance between hard palate and uvula P < 0.01), included angle of hard palate and segmental vente of uvula P > 0.05, included angle of hard palate and segmental dorsum of uvula P > 0.05, difference of included angle P < 0.01). Main obstruction site was on retroglottal region.

CONCLUSION: Morphologic change of soft palate in patients with OSAHS is multiple, and level of obstruction is deeper during natural sleep than during wakefulness. Main reason of airway obstruction is distinct during different state. The obstruction of upper airway of patients with OSAHS during wakefulness can't replace that during natural sleep.