Real‐time MRI of speaking at a resolution of 33 ms: Undersampled radial FLASH with nonlinear inverse reconstruction

@article{Niebergall2013RealtimeMO,
  title={Real‐time MRI of speaking at a resolution of 33 ms: Undersampled radial FLASH with nonlinear inverse reconstruction},
  author={Aaron Niebergall and Shuo Zhang and Esther Kunay and G{\"o}tz Keydana and Michael Job and Martin Uecker and Jens Frahm},
  journal={Magnetic Resonance in Medicine},
  year={2013},
  volume={69}
}
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. [...] Key Method 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…Expand
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References

SHOWING 1-10 OF 31 REFERENCES
Real‐time MRI at a resolution of 20 ms
TLDR
A unique method for real‐time MRI that reduces image acquisition times to only 20 ms is described, approaching the ultimate limit of MRI technology, and yields high image quality in terms of spatial resolution, signal‐to‐noise ratio and the absence of artifacts. Expand
Nonlinear inverse reconstruction for real‐time MRI of the human heart using undersampled radial FLASH
TLDR
An extension of the nonlinear inverse algorithm to non‐Cartesian k‐space encodings, its implementation on a graphicalprocessing unit to reduce reconstruction times, and the use of a convolution‐based iteration, which considerably simplifies the graphical processing unit implementation compared to a gridding technique are introduced. Expand
Real-time cardiovascular magnetic resonance at high temporal resolution: radial FLASH with nonlinear inverse reconstruction
TLDR
A new approach providing true real-time CMR with image acquisition times as short as 20 to 30 ms or rates of 30 to 50 frames per second is described, which combines a strongly undersampled radial FLASH CMR sequence with image reconstruction by regularized nonlinear inversion. Expand
An approach to real-time magnetic resonance imaging for speech production.
TLDR
This study uses spiral k-space acquisitions with a low flip-angle gradient echo pulse sequence on a conventional GE Signa 1.5-T CV/i scanner to examine the dynamics of vocal-tract shaping during fluent speech using MRI. Expand
Flexible retrospective selection of temporal resolution in real‐time speech MRI using a golden‐ratio spiral view order
TLDR
A first application of golden‐ratio spiral temporal view order to real‐time speech MRI is demonstrated and its performance by comparison with conventional bit‐reversed temporal view orders is investigated. Expand
Real‐time phase‐contrast MRI of cardiovascular blood flow using undersampled radial fast low‐angle shot and nonlinear inverse reconstruction
TLDR
A new method for real‐time phase‐contrast MRI that combines flow‐encoding gradients with highly undersampled radial fast low‐angle shot acquisitions and phase‐sensitive image reconstructions by regularized nonlinear inversion is presented. Expand
Accelerated three‐dimensional upper airway MRI using compressed sensing
TLDR
This study provides a first application of compressed sensing to high‐resolution 3D upper airway MRI using spatial finite difference as the sparsifying transform, and to experimentally determine the benefit of applying constraints on image phase. Expand
Image reconstruction by regularized nonlinear inversion—Joint estimation of coil sensitivities and image content
TLDR
A respective algorithm based on a Newton‐type method with appropriate regularization terms is demonstrated to improve the performance of autocalibrating parallel MRI—mainly due to a better estimation of the coil sensitivity profiles. Expand
Faster dynamic imaging of speech with field inhomogeneity corrected spiral fast low angle shot (FLASH) at 3 T
To evaluate the impact of magnetic field inhomogeneity correction on achievable imaging speeds for magnetic resonance imaging (MRI) of articulating oropharyngeal structures during speech and toExpand
[MRT sequences as a database for a visual articulatory model].
TLDR
The articulatory model developed here was based on static MRI data of sustained sounds and showed a strong influence of the vocalic context on the articulatory target-positions of all consonants. Expand
...
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3
4
...