Functional magnetic resonance imaging of the pediatric swallow: Imaging the cortex and the brainstem

Objective: To design and implement a functional magnetic resonance imaging (fMRI) protocol to investigate the cortical and brainstem patterns of activ ity in children with regard to the act of swallowing. Study Design: Pilot s tudy to assess the clinical feasibility of the project. Methods. Using a 3T Bruker Biospec 30/60 MRI scanner, images were obtained using the Behavior Interleaved Gradient/Blood Oxygen Level Dependent (BIG-BOLD) image acquisit ion method. Initially, regions of interest (ROI) were developed to identify the mean time from the onset of a swallow to maximum cortical blood flow i n the motor cortex. Using this data to design the BIG-BOLD acquisition meth od followed by postprocessing of the data, images from two volunteer adults and four volunteer children were obtained. Results: The average time from the onset of a swallow to maximum cortical blood now was 6 to 8 seconds. Re gions of cortical activity include pre- and post-central gyrus (Brodmann's areas 3 and 4), superior motor cortex (B.A. 24), insula, inferior frontal c ortex (B.A. 44 and 45), Heschl gyrus (B.A. 41 and 42), putamen, globus pall idus, and the superior temporal gyrus (B.A. 38), Of particular note is the first mapping of the functional activity of swallowing at the level of the brainstem; activity was seen in the region of the nucleus ambiguous. Conclu sions: fMRI provides a novel means of studying the central processes of bot h normal swallowing and its various pathologic forms in children. Further u nderstanding of how a child coordinates a swallow and how this coordination can be altered at the level of the brainstem and cortex may aid in the dev elopment of novel rehabilitative strategies.