Simultaneous dynamic and functional MRI scanning (SimulScan) of natural swallows.

In studies of swallowing, dynamic and functional MRI are increasingly used to observe motor oropharyngeal behaviors and identify associated brain regions. However, monitoring of motor performance during a functional examination requires disruptive monitoring sensors, visual or auditory cued tasks, and strict subject compliance to stimuli. In this work, a simultaneous acquisition (SimulScan) was developed to provide dynamic images to monitor oropharyngeal motions during swallowing (1 mid-sagittal slice at 14.5 frames per second) simultaneous with functional MRI (24 oblique-axial slices with a TR of 1.6512 s). Data were acquired while three healthy adult subjects passively viewed a movie during three 15-min scans with the purpose of covertly studying uncued natural swallows. Dynamic MR images were used to determine timing of swallow onsets for subsequent functional analysis. Resulting functional maps show significant areas of activation that agree with previous functional magnetic resonance imaging studies of cued water swallows, except for regions associated with processing the task stimulus. SimulScan may prove a useful tool in developing new techniques for studying swallowing and associated neuromuscular disorders.