Enhancing linguistic research through 2‐mm isotropic <scp>3D</scp> dynamic speech MRI optimized by sparse temporal sampling and low‐rank reconstruction

Magnetic Resonance in Medicine · 2022 · 21 citations

• Computer Science
• Artificial Intelligence
• Computer Science

PURPOSE: To enable a more comprehensive view of articulations during speech through near-isotropic 3D dynamic MRI with high spatiotemporal resolution and large vocal-tract coverage. METHODS: Using partial separability model-based low-rank reconstruction coupled with a sparse acquisition of both spatial and temporal models, we are able to achieve near-isotropic resolution 3D imaging with a high frame rate. The total acquisition time of the speech acquisition is shortened by introducing a sparse temporal sampling that interleaves one temporal navigator with four randomized phase and slice-encoded imaging samples. Memory and computation time are improved through compressing coils based on the region of interest for low-rank constrained reconstruction with an edge-preserving spatial penalty. RESULTS: spatial resolution, 64-mm through-plane coverage, and a 35.6-fps temporal resolution are achieved. Investigations and analysis on specific speech samples support novel insights into nonsymmetric tongue movement, velum raising, and coarticulation events with adequate visualization of rapid articulatory movements. CONCLUSION: Three-dimensional dynamic images of the vocal tract structures during speech with high spatiotemporal resolution and axial coverage is capable of enhancing linguistic research, enabling visualization of soft tissue motions that are not possible with other modalities.

Articulatory and acoustic correlates of pharyngealization and pharyngealization spread in Cairene Arabic: A real-time magnetic resonance imaging study

2021

• Acoustics
• Linguistics
• Medicine

Articulatory and acoustic correlates of pharyngealization andpharyngealization spread in Cairene Arabic

Studies in Arabic linguistics · 2021 · 1 citations

• Computer Science
• Speech recognition
• Linguistics

Abstract Pharyngealized speech sounds in Arabic are articulated with a secondary posterior constriction and a lowered tongue body. This articulatory configuration spreads to adjacent and neighboring segments and has the acoustic consequence of lowering F2 in affected vowels. This study demonstrates that real-time Magnetic Resonance Imaging (rtMRI) can be successfully used to examine the role of (1) vowel length and (2) direction of spread in the extent of the articulatory modifications that occur in the segments to which pharyngealization spreads. Parallel acoustic measurements are also acquired to examine and compare the extent of modifications in formant frequencies. Results from both articulatory and acoustic data demonstrate that the extent of pharyngealization spread significantly varies with respect to these two factors.

4D magnetic resonance imaging atlas construction using temporally aligned audio waveforms in speech

The Journal of the Acoustical Society of America · 2021 · 7 citations

• Computer Science
• Artificial Intelligence
• Computer Science

Magnetic resonance (MR) imaging is becoming an established tool in capturing articulatory and physiological motion of the structures and muscles throughout the vocal tract and enabling visual and quantitative assessment of real-time speech activities. Although motion capture speed has been regularly improved by the continual developments in high-speed MR technology, quantitative analysis of multi-subject group data remains challenging due to variations in speaking rate and imaging time among different subjects. In this paper, a workflow of post-processing methods that matches different MR image datasets within a study group is proposed. Each subject's recorded audio waveform during speech is used to extract temporal domain information and generate temporal alignment mappings from their matching pattern. The corresponding image data are resampled by deformable registration and interpolation of the deformation fields, achieving inter-subject temporal alignment between image sequences. A four-dimensional dynamic MR speech atlas is constructed using aligned volumes from four human subjects. Similarity tests between subject and target domains using the squared error, cross correlation, and mutual information measures all show an overall score increase after spatiotemporal alignment. The amount of image variability in atlas construction is reduced, indicating a quality increase in the multi-subject data for groupwise quantitative analysis.

Standard‐space atlas of the viscoelastic properties of the human brain

Human Brain Mapping · 2020 · 88 citations

• Computer Science
• Artificial Intelligence
• Computer Science

Standard anatomical atlases are common in neuroimaging because they facilitate data analyses and comparisons across subjects and studies. The purpose of this study was to develop a standardized human brain atlas based on the physical mechanical properties (i.e., tissue viscoelasticity) of brain tissue using magnetic resonance elastography (MRE). MRE is a phase contrast-based MRI method that quantifies tissue viscoelasticity noninvasively and in vivo thus providing a macroscopic representation of the microstructural constituents of soft biological tissue. The development of standardized brain MRE atlases are therefore beneficial for comparing neural tissue integrity across populations. Data from a large number of healthy, young adults from multiple studies collected using common MRE acquisition and analysis protocols were assembled (N = 134; 78F/ 56 M; 18-35 years). Nonlinear image registration methods were applied to normalize viscoelastic property maps (shear stiffness, μ, and damping ratio, ξ) to the MNI152 standard structural template within the spatial coordinates of the ICBM-152. We find that average MRE brain templates contain emerging and symmetrized anatomical detail. Leveraging the substantial amount of data assembled, we illustrate that subcortical gray matter structures, white matter tracts, and regions of the cerebral cortex exhibit differing mechanical characteristics. Moreover, we report sex differences in viscoelasticity for specific neuroanatomical structures, which has implications for understanding patterns of individual differences in health and disease. These atlases provide reference values for clinical investigations as well as novel biophysical signatures of neuroanatomy. The templates are made openly available (github.com/mechneurolab/mre134) to foster collaboration across research institutions and to support robust cross-center comparisons.

Hydrolyzed Fat Formula Increases Brain White Matter in Small for Gestational Age and Appropriate for Gestational Age Neonatal Piglets

Frontiers in Pediatrics · 2020 · 7 citations

• Medicine
• Obstetrics
• Pediatrics

HF enhanced brain development in the neonatal piglet measured by brain volume and WM volume in specific brain regions; however, more studies are needed to assess long-term outcomes.