Functional MR with use of FLASH sequences in the evaluation of the phono-articulatory tract.

Abstract

The aims of this study are to determine visualization of normal phonation structures with the use of MR fast sequences and anatomical reference indices which can be used in evaluating upper resonator pathologies. A total of 12 normal subjects were studied, a 1 T system, a volumetric receiving head and neck coil and FLASH sequences for one sagittal and two coronal scans. Each subject was instructed to take a deep breath and then to produce the vowel sounds for the entire duration of the scan. The movement of the following anatomical structures were considered: lips, tongue, soft palate, pharynx and epiglottis. For each subject sagittal scans were used to measure the minimal palate tongue distance (p-t), the minimal anterio-posterior diameter of the mesopharynx (mp), and the epiglottis excursion angle (ep) with respect to the plane determined by the false vocal cords. Our results were compared with a diagrammed representation of tongue movements (vocal trapezium). This study underlines the validity of MR imaging techniques in the study of the phono-articulatory tract, because MR provided good detail of the phono-articulatory structures enabling an overall functional evaluation. MR would appear useful in evaluating defects in the velum and palate, in staging of oropharyngeal neoplasms and in surgical reconstructions of the tongue.