Respiratory dynamics in phonation and breathing-A real-time MRI study.

The respiratory system is a central part of voice production, but for phonation neither the underlying functional relations between diaphragm (DPH) and rib cage (RC), nor differences to normal breathing are yet understood. This study aims to compare respiratory dynamics in phonation and breathing via dynamic MRI of the lung. Images of the breathing apparatus of 6 professional singers were captured in a 1.5T MRI system in supine position during vital capacity breathing and maximal long sustained phonation at 3 different pitches and loudness conditions. In a dynamic series of cross-sectional images of the lung, distances between characteristic anatomical landmarks were measured. During exhalation in normal breathing the diaphragm and rib cage moved synchronously to reduce lung volume, but during phonation different functional units could be identified, which support phonation by facilitating the control of subglottic pressure.