Combined assessment of obstructive sleep apnea syndrome with dynamic MRT and parallel EEG registration - Initial results

RATIONALE AND OBJECTIVES. To detect obstructive pharyngeal changes in sleeping patients with obstructive sleep apnea syndrome by dynamic MRI and concurrent EEG monitoring during true apneic episodes. METHODS. Five volunteers and eight patients with clinically diagnosed obstructive sleep apnea were polysomnographically monitored inside the scanner before, during, and after sleep discontinuation. After sleep interruption, the Mueller maneuver was performed to compare induced pharyngeal collapse with real collapse during sleep. RESULTS. In all patients, on-line EEG registration was achieved in the static magnetic field. Sleep was proved in four of the eight patients who showed typical EEG findings. A complete pharyngeal collapse was shown in two of the four sleeping patients. The other patients predominately showed local epi- and oropharyngeal obstructions in the apneic state. Compared with the apneic episodes, the Mueller maneuver did not reveal the same extent of pharyngeal narrowing, nor a complete collapse. CONCLUSIONS. Polysomnographically monitored MRI can directly assess findings induced by the pathophysiology of sleep apnea and shows promise for use in sleep investigation and therapy planning and monitoring.