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

Niebergall, Aaron; Zhang, Shuo; Kunay, Esther; Keydana, Götz; Job, Michael; Uecker, Martin; Frahm, Jens

doi:10.1002/mrm.24673

Cited by 43 publications

(55 citation statements)

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“…Examples of human studies include examinations of cardiac function using T1 contrast at 3.0 T [8,13] as well as SSFP contrast at 1.5 T [14], cardiovascular blood flow [22,23], swallowing [24], and speaking [21]. Due to the absence of an in vivo gold standard, all present evaluations are based on a specialpurpose motion phantom built to rotate positive (or negative) objects at defined angular velocity.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

On the Temporal Fidelity of Nonlinear Inverse Reconstructions for Real- Time MRI – The Motion Challenge

Frahm¹,

Schätz²,

Untenberger³

et al. 2014

TOMIJ

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Abstract:Purpose: To evaluate the temporal accuracy of a self-consistent nonlinear inverse reconstruction method (NLINV) for real-time MRI using highly undersampled radial gradient-echo sequences and to present an open source framework for the motion assessment of real-time MRI methods.Methods: Serial image reconstructions by NLINV combine a joint estimation of individual frames and corresponding coil sensitivities with temporal regularization to a preceding frame. The temporal fidelity of the method was determined with a phantom consisting of water-filled tubes rotating at defined angular velocity. The conditions tested correspond to realtime cardiac MRI using SSFP contrast at 1.5 T (40 ms resolution) and T1 contrast at 3.0 T (33 ms and 18 ms resolution). In addition, the performance of a post-processing temporal median filter was evaluated.Results: NLINV reconstructions without temporal filtering yield accurate estimations as long as the speed of a small moving object corresponds to a spatial displacement during the acquisition of a single frame which is smaller than the object itself. Faster movements may lead to geometric distortions. For small objects moving at high velocity, a median filter may severely compromise the spatiotemporal accuracy.Conclusion: NLINV reconstructions offer excellent temporal fidelity as long as the image acquisition time is short enough to adequately sample ("freeze") the object movement. Temporal filtering should be applied with caution. The motion framework emerges as a valuable tool for the evaluation of real-time MRI methods.

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Section: Discussionmentioning

confidence: 99%

“…The two chosen ranges of velocities, i.e. up to 10 cm s -1 and 30 cm s -1 , extend to the fastest movements of the myocardial wall during postsystolic expansion and of the tongue tip during rapid speaking [21], respectively. Fig.…”

Section: Motion Phantommentioning

confidence: 99%

On the Temporal Fidelity of Nonlinear Inverse Reconstructions for Real- Time MRI – The Motion Challenge

Frahm¹,

Schätz²,

Untenberger³

et al. 2014

TOMIJ

Self Cite

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“…[16][17][18][19] The quest for improving the possible spatial and temporal resolution, and identifying effective trade offs for given application needs, is ongoing. However, with current imaging and audio acquisition capabilities, it is possible to collect large amounts of speech production data than ever before such as demonstrated by the current database.…”

Section: Discussionmentioning

confidence: 99%

Real-time magnetic resonance imaging and electromagnetic articulography database for speech production research (TC)

Narayanan

Toutios

Ramanarayanan

et al. 2014

The Journal of the Acoustical Society of America

145

117

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USC-TIMIT is an extensive database of multimodal speech production data, developed to complement existing resources available to the speech research community and with the intention of being continuously refined and augmented. The database currently includes real-time magnetic resonance imaging data from five male and five female speakers of American English. Electromagnetic articulography data have also been presently collected from four of these speakers. The two modalities were recorded in two independent sessions while the subjects produced the same 460 sentence corpus used previously in the MOCHA-TIMIT database. In both cases the audio signal was recorded and synchronized with the articulatory data. The database and companion software are freely available to the research community.

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“…Respective applications range from cardiac MRI without ECG synchronization and during free breathing (2) to real-time studies of blood flow (3), swallowing (4), dysphagia (5), esophageal functions (6), dynamics of the temporomandibular joint (7), respiration-induced flow of the cerebrospinal fluid (8,9) as well as movements of the articulators during normal speech (10) or brass playing of patients with embouchure dystonia (11). In a technical sense, the method is based on highly undersampled radial gradient-echo sequences in combination with iterative image reconstruction by nonlinear inversion (NLINV) and temporal regularization (1).…”

Section: Introductionmentioning

confidence: 99%

Towards MRI temperature mapping in real time—the proton resonance frequency method with undersampled radial MRI and nonlinear inverse reconstruction

Zhang

Michaelis

Frahm

2017

Quant. Imaging Med. Surg.

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IntroductionRecent developments in MRI provide a new method for real-time imaging (1) which offers so far unsurpassed diagnostic capabilities in a large variety of clinical fields. Respective applications range from cardiac MRI without ECG synchronization and during free breathing (2) to real-time studies of blood flow (3), swallowing (4), dysphagia (5), esophageal functions (6), dynamics of the temporomandibular joint (7), respiration-induced flow of the cerebrospinal fluid (8,9) as well as movements of the articulators during normal speech (10) or brass playing of patients with embouchure dystonia (11). In a technical sense, the method is based on highly undersampled radial gradient-echo sequences in combination with iterative image reconstruction by nonlinear inversion (NLINV) and temporal regularization (1). These new possibilities are expected to vastly broaden the range of clinical MRI and, in particular, to stimulate renewed interest in "interventional MRI", i.e., the use of real-time MRI for monitoring and guiding minimally invasive procedures.In this sense, true "real-time" MRI not only refers to high-speed data acquisitions, but includes (I) online Original ArticleTowards MRI temperature mapping in real time-the proton resonance frequency method with undersampled radial MRI and nonlinear inverse reconstruction

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

Cited by 43 publications

References 0 publications

On the Temporal Fidelity of Nonlinear Inverse Reconstructions for Real- Time MRI – The Motion Challenge

On the Temporal Fidelity of Nonlinear Inverse Reconstructions for Real- Time MRI – The Motion Challenge

Real-time magnetic resonance imaging and electromagnetic articulography database for speech production research (TC)

Towards MRI temperature mapping in real time—the proton resonance frequency method with undersampled radial MRI and nonlinear inverse reconstruction

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