Measurement of pharyngeal volume by digitized magnetic resonance imaging. Effect of nasal continuous positive airway pressure.

Pharyngeal size is thought to play an important role in the pathogenesis of snoring and obstructive sleep apnea. It has been hypothesized that nasal continuous positive airway pressure (CPAP) works by enlarging pharyngeal size and splinting the airway open. In this study, we selected 12 heavy snorers and abolished their snoring with nasal CPAP in our sleep laboratory. Using magnetic resonance imaging and a computer program utilizing a digitizing pad, we measured these awake subjects' pharyngeal volumes without and with the nasal CPAP apparatus on at the level used to abolish their snoring. We found an average 27.7% increase in pharyngeal volume with nasal CPAP. We have visually shown an increase in pharyngeal size with the use of nasal CPAP in a cohort of heavy snorers.