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  • 1
    In: Magnetic Resonance in Medicine, Wiley, Vol. 91, No. 3 ( 2024-03), p. 987-1001
    Abstract: This study aims to develop a high‐efficiency and high‐resolution 3D imaging approach for simultaneous mapping of multiple key tissue parameters for routine brain imaging, including T 1 , T 2 , proton density (PD), ADC, and fractional anisotropy (FA). The proposed method is intended for pushing routine clinical brain imaging from weighted imaging to quantitative imaging and can also be particularly useful for diffusion‐relaxometry studies, which typically suffer from lengthy acquisition time. Methods To address challenges associated with diffusion weighting, such as shot‐to‐shot phase variation and low SNR, we integrated several innovative data acquisition and reconstruction techniques. Specifically, we used M1‐compensated diffusion gradients, cardiac gating, and navigators to mitigate phase variations caused by cardiac motion. We also introduced a data‐driven pre‐pulse gradient to cancel out eddy currents induced by diffusion gradients. Additionally, to enhance image quality within a limited acquisition time, we proposed a data‐sharing joint reconstruction approach coupled with a corresponding sequence design. Results The phantom and in vivo studies indicated that the T 1 and T 2 values measured by the proposed method are consistent with a conventional MR fingerprinting sequence and the diffusion results (including diffusivity, ADC, and FA) are consistent with the spin‐echo EPI DWI sequence. Conclusion The proposed method can achieve whole‐brain T 1 , T 2 , diffusivity, ADC, and FA maps at 1‐mm isotropic resolution within 10 min, providing a powerful tool for investigating the microstructural properties of brain tissue, with potential applications in clinical and research settings.
    Type of Medium: Online Resource
    ISSN: 0740-3194 , 1522-2594
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2024
    detail.hit.zdb_id: 1493786-4
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  • 2
    In: Magnetic Resonance in Medicine, Wiley, Vol. 91, No. 5 ( 2024-05), p. 2028-2043
    Abstract: To develop a framework that jointly estimates rigid motion and polarizing magnetic field (B 0 ) perturbations () for brain MRI using a single navigator of a few milliseconds in duration, and to additionally allow for navigator acquisition at arbitrary timings within any type of sequence to obtain high‐temporal resolution estimates. Theory and Methods Methods exist that match navigator data to a low‐resolution single‐contrast image (scout) to estimate either motion or . In this work, called QUEEN (QUantitatively Enhanced parameter Estimation from Navigators), we propose combined motion and estimation from a fast, tailored trajectory with arbitrary‐contrast navigator data. To this end, the concept of a quantitative scout (Q‐Scout) acquisition is proposed from which contrast‐matched scout data is predicted for each navigator. Finally, navigator trajectories, contrast‐matched scout, and are integrated into a motion‐informed parallel‐imaging framework. Results Simulations and in vivo experiments show the need to model to obtain accurate motion parameters estimated in the presence of strong . Simulations confirm that tailored navigator trajectories are needed to robustly estimate both motion and . Furthermore, experiments show that a contrast‐matched scout is needed for parameter estimation from multicontrast navigator data. A retrospective, in vivo reconstruction experiment shows improved image quality when using the proposed Q‐Scout and QUEEN estimation. Conclusions We developed a framework to jointly estimate rigid motion parameters and from navigators. Combing a contrast‐matched scout with the proposed trajectory allows for navigator deployment in almost any sequence and/or timing, which allows for higher temporal‐resolution motion and estimates.
    Type of Medium: Online Resource
    ISSN: 0740-3194 , 1522-2594
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2024
    detail.hit.zdb_id: 1493786-4
    Location Call Number Limitation Availability
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  • 3
    Online Resource
    Online Resource
    Wiley ; 2020
    In:  Magnetic Resonance in Medicine Vol. 83, No. 3 ( 2020-03), p. 892-905
    In: Magnetic Resonance in Medicine, Wiley, Vol. 83, No. 3 ( 2020-03), p. 892-905
    Abstract: To demonstrate that vessel selectivity in dynamic arterial spin labeling angiography can be achieved without any scan‐time penalty or noticeable loss of image quality compared with conventional arterial spin labeling angiography. Methods Simulations on a numerical phantom were used to assess whether the increased sparsity of vessel‐encoded angiograms compared with non‐vessel‐encoded angiograms alone can improve reconstruction results in a compressed‐sensing framework. Further simulations were performed to study whether the difference in relative sparsity between nonselective and vessel‐selective dynamic angiograms was sufficient to achieve similar image quality at matched scan times in the presence of noise. Finally, data were acquired from 5 healthy volunteers to validate the technique in vivo. All data, both simulated and in vivo, were sampled in 2D using a golden‐angle radial trajectory and reconstructed by enforcing image domain sparsity and temporal smoothness on the angiograms in a parallel imaging and compressed‐sensing framework. Results Relative sparsity was established as a primary factor governing the reconstruction fidelity. Using the proposed reconstruction scheme, differences between vessel‐selective and nonselective angiography were negligible compared with the dominant factor of total scan time in both simulations and in vivo experiments at acceleration factors up to R = 34. The reconstruction quality was not heavily dependent on hand‐tuning the parameters of the reconstruction. Conclusion The increase in relative sparsity of vessel‐selective angiograms compared with nonselective angiograms can be leveraged to achieve higher acceleration without loss of image quality, resulting in the acquisition of vessel‐selective information at no scan‐time cost.
    Type of Medium: Online Resource
    ISSN: 0740-3194 , 1522-2594
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2020
    detail.hit.zdb_id: 1493786-4
    Location Call Number Limitation Availability
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  • 4
    Online Resource
    Online Resource
    Wiley ; 2023
    In:  Magnetic Resonance in Medicine Vol. 89, No. 4 ( 2023-04), p. 1323-1341
    In: Magnetic Resonance in Medicine, Wiley, Vol. 89, No. 4 ( 2023-04), p. 1323-1341
    Abstract: Click here for author‐reader discussions
    Type of Medium: Online Resource
    ISSN: 0740-3194 , 1522-2594
    URL: Issue
    Language: English
    Publisher: Wiley
    Publication Date: 2023
    detail.hit.zdb_id: 1493786-4
    Location Call Number Limitation Availability
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