Real-time MRI of speaking at a resolution of 33 ms: Undersampled radial FLASH with nonlinear inverse reconstruction
Article first published online: 12 APR 2012
Copyright © 2012 Wiley Periodicals, Inc.
Magnetic Resonance in Medicine
Volume 69, Issue 2, pages 477–485, February 2013
How to Cite
Niebergall, A., Zhang, S., Kunay, E., Keydana, G., Job, M., Uecker, M. and Frahm, J. (2013), Real-time MRI of speaking at a resolution of 33 ms: Undersampled radial FLASH with nonlinear inverse reconstruction. Magn Reson Med, 69: 477–485. doi: 10.1002/mrm.24276
- Issue published online: 24 JAN 2013
- Article first published online: 12 APR 2012
- Manuscript Accepted: 9 MAR 2012
- Manuscript Revised: 14 FEB 2012
- Manuscript Received: 22 DEC 2011
- real-time MRI;
- tongue dynamics;
- speech production;
Dynamic MRI studies of the upper airway during speaking, singing or swallowing are complicated by the need for high temporal resolution and the presence of air-tissue interfaces that may give rise to image artifacts such as signal void and geometric distortions. This work exploits a recently developed real-time MRI technique to address these challenges for monitoring speech production at 3 T. The method combines a short-echo time radial FLASH MRI sequence (pulse repetition time/echo time = 2.22/1.44 ms; flip angle 5°) with pronounced undersampling (15 radial spokes per image) and image reconstruction by regularized nonlinear inversion. The resulting serial images at 1.5 mm in-plane resolution and 33.3 ms acquisition time are free of motion or susceptibility artifacts. This application focuses on a dynamic visualization of the main articulators during natural speech production (Standard Modern German). Respective real-time MRI movies at 30 frames per second clearly demonstrate the spatiotemporal coordination of lips, tongue, velum, and larynx for generating vowels, consonants, and coarticulations. The quantitative results for individual phonetic events are in agreement with previous non-MRI findings. Magn Reson Med, 2013. © 2012 Wiley Periodicals, Inc.