To date, there have been no published reports of normal variations in tracheal dimensions for pediatric patients undergoing MRIs. While there are reports of normals in CT studies, the reported dimensions were for average areas and lengths over the entire length of the trachea and not for normal variation in the dimensions at various sites in the trachea. Moreover, CT measurements are likely not entirely applicable to MRI measurements. Since cardiac MRI has become the procedure of choice to document the presence of vascular rings as well as the significance of any ring that is found, there is a need for normal values to be generated. This would in turn permit physicians to determine in cases of documented vascular rings the severity of the tracheal stenosis/deformity if found.