Improved imaging of lingual articulation using real‐time multislice MRI

Purpose: To develop a real‐time imaging technique that allows for simultaneous visualization of vocal tract shaping in multiple scan planes, and provides dynamic visualization of complex articulatory features. Materials and Methods: Simultaneous imaging of multiple slices was implemented using a custom real‐time imaging platform. Midsagittal, coronal, and axial scan planes of the human upper airway were prescribed and imaged in real‐time using a fast spiral gradient‐echo pulse sequence. Two native speakers of English produced voiceless and voiced fricatives /f/‐/v/, /θ/‐/ð/, /s/‐/z/, /∫/‐ in symmetrical maximally contrastive vocalic contexts /a_a/, /i_i/, and /u_u/. Vocal tract videos were synchronized with noise‐cancelled audio recordings, facilitating the selection of frames associated with production of English fricatives. Results: Coronal slices intersecting the postalveolar region of the vocal tract revealed tongue grooving to be most pronounced during fricative production in back vowel contexts, and more pronounced for sibilants /s/‐/z/ than for /∫/‐. The axial slice best revealed differences in dorsal and pharyngeal articulation; voiced fricatives were observed to be produced with a larger cross‐sectional area in the pharyngeal airway. Partial saturation of spins provided accurate location of imaging planes with respect to each other. Conclusion: Real‐time MRI of multiple intersecting slices can provide valuable spatial and temporal information about vocal tract shaping, including details not observable from a single slice. J. Magn. Reson. Imaging 2012;35:943–948. © 2011 Wiley Periodicals, Inc.