Comparison of MRI fast SPGR single slice scan and continuous dynamic scan in patients with obstructive sleep apnea-hypopnea syndrome.

Objective: To evaluate the application value of MRI fast SPGR single slice scan in patients with obstructive sleep apnea-hypopnea syndrome when comparing the images between fast SPGR single slice scan and continuous dynamic scan.

Methods: Eighteen patients with obstructive sleep apnea-hypopnea syndrome were examined by fast SPGR single slice scan and continuous dynamic scan in turn. Fast SPGR single slice scans were conducted when the phases of apnea, inspiration and expiration appeared on the respiratory wave of the subjects. Fast SPGR continuous dynamic scans were conducted when the patients were awake and apneic. The scan planes were median sagittal plane and axial planes (the slice of middle part of palate, the slice of inferior part of palate, the slice of middle part of lingual root and the slice of 0.5cm beneath the free margin of epiglottis). The obstructed sites and the cross-sectional areas of upper airway were compared between the two scan methods.

Results: Seven cases showed complete obstruction at the narrowest sites of upper airway when apnea appeared; eleven cases showed marked decrease in cross-sectional areas at the narrowest sites compared with the areas when the patients were awake; two cases manifested multiple narrowness. The obstructed sites showed by the two scan methods were same. The difference of the cross-sectional areas of upper airway between the two scan methods was insignificant (P>0.05).

Conclusion: Fast SPGR single slice scan can accurately reflect the obstructed sites of upper airway when the breath breaks off and is the complementary method of continuous dynamic scan. Sometimes, single slice scan can replace continuous dynamic scan.