Simultaneous multi‐slice MRI using cartesian and radial FLASH and regularized nonlinear inversion: SMS‐NLINV

Rosenzweig, Sebastian; Holme, H. Christian M.; Voit, Dirk; Frahm, Jens; Uecker, Martin

doi:10.1002/mrm.26878

Cited by 26 publications

(44 citation statements)

References 64 publications

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“…The combination of in-plane and SMS accelerations is thus highly desirable, but currently ill conditioned. Regularized parallel imaging methods could potentially alleviate this problem by enforcing some prior information in the spatial domain (6)(7)(8)(9)(10). Although undersampling factors above 10 have been reported in structural or fMRI, high acceleration is considerably more challenging in dMRI.…”

Section: Introductionmentioning

confidence: 99%

Diffusion Acceleration with Gaussian process Estimated Reconstruction (DAGER)

Koopmans

Andersson

et al. 2018

Preprint

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Total word count = Approx. 7500Running title: Diffusion Acceleration with DAGER Abstract Purpose: Image acceleration provides multiple benefits to diffusion MRI (dMRI), with in-plane acceleration reducing distortion and slice-wise acceleration increasing the number of directions that can be acquired in a given scan time. However, as acceleration factors increase, the reconstruction problem becomes ill-conditioned, particularly when using both in-plane acceleration and simultaneous multi-slice (SMS) imaging. In this work, we develop a novel reconstruction method for in-vivo MRI acquisition that provides acceleration beyond what conventional techniques can achieve. Theory and Methods:We propose to constrain the reconstruction in the spatial (k) domain by incorporating information from the angular (q) domain. This approach exploits smoothness of the signal in q-space using Gaussian processes, as has previously been exploited in postreconstruction analysis. We demonstrate in-plane acceleration exceeding the theoretical parallel imaging limits, and SMS combined with in-plane acceleration at a total factor of 12. This reconstruction is cast within a Bayesian framework that incorporates estimation of smoothness hyper-parameters, with no need for manual tuning.Results: Simulations and in vivo results demonstrate superior performance of the proposed method compared with conventional parallel imaging methods. These improvements are achieved without loss of spatial or angular resolution and require only a minor modification to standard pulse sequences. Conclusion:The proposed method provides improvements over existing methods for diffusion acceleration, particularly for high SMS acceleration with in-plane undersampling.

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Section: Introductionmentioning

confidence: 99%

Diffusion Acceleration with Gaussian process Estimated Reconstruction (DAGER)

Koopmans

Andersson

et al. 2018

Preprint

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“…Rotating the radial spokes along the through‐plane direction also in a GA‐ordered fashion has been shown to suppress streaking artifacts caused by undersampling . Simultaneous multislice imaging technique is another way to accelerate acquisition speed. In lieu of a KWIC filter, phase‐sensitive parallel imaging, compressed sensing, and other reconstruction techniques for undersampled data can be employed to reduce temporal footprint .…”

Section: Discussionmentioning

confidence: 99%

A variable flip angle golden‐angle‐ordered 3D stack‐of‐radial MRI technique for simultaneous proton resonant frequency shift and T₁‐based thermometry

Zhang

Armstrong

et al. 2019

Magnetic Resonance in Med

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Purpose To develop and evaluate a variable‐flip‐angle golden‐angle‐ordered 3D stack‐of‐radial MRI technique for simultaneous proton resonance frequency shift (PRF) and T1‐based thermometry in aqueous and adipose tissues, respectively. Methods The proposed technique acquires multiecho radial k‐space data in segments with alternating flip angles to measure 3D temperature maps dynamically on the basis of PRF and T1. A sliding‐window k‐space weighted image contrast filter is used to increase temporal resolution. PRF is measured in aqueous tissues and T1 in adipose tissues using fat/water masks. The accuracy for T1 quantification was evaluated in a reference T1/T2 phantom. In vivo nonheating experiments were conducted in healthy subjects to evaluate the stability of PRF and T1 in the brain, prostate, and breast. The proposed technique was used to monitor high‐intensity focused ultrasound (HIFU) ablation in ex vivo porcine fat/muscle tissues and compared to temperature probe readings. Results The proposed technique achieved 3D coverage with 1.1‐mm to 1.3‐mm in‐plane resolution and 2‐s to 5‐s temporal resolution. During 20 to 30 min of nonheating in vivo scans, the temporal coefficient of variation for T1 was <5% in the brain, prostate, and breast fatty tissues, while the standard deviation of relative PRF temperature change was within 3°C in aqueous tissues. During ex vivo HIFU ablation, the temperatures measured by PRF and T1 were consistent with temperature probe readings, with an absolute mean difference within 2°C. Conclusion The proposed technique achieves simultaneous PRF and T1‐based dynamic 3D MR temperature mapping in aqueous and adipose tissues. It may be used to improve MRI‐guided thermal procedures.

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“…Stack‐of‐stars sampling schemes using complementary samples recently have been shown to outperform schemes with the same samples in each partition . In this work, the same samples in each partition were used to enable decoupling of the 3D problem by simple inverse Fourier transform along slice dimension.…”

Section: Discussionmentioning

confidence: 99%

“…Stack-of-stars sampling schemes using complementary samples recently have been shown to outperform schemes with the same samples in each partition. 50,51 In this work, the same samples in each partition were used to enable decoupling of the 3D problem by simple inverse Fourier transform along slice dimension. The main limitation of using complementary samples in the proposed approach is the increase in memory demand as the full 3D problem has to be solved as a whole in subspace including prior estimation of 3D coil…”

Section: Magnetic Resonance In Medicinementioning

confidence: 99%

Frequency‐modulated SSFP with radial sampling and subspace reconstruction: A time‐efficient alternative to phase‐cycled bSSFP

Roeloffs

Rosenzweig

Holme

et al. 2018

Magnetic Resonance in Med

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Purpose A novel subspace‐based reconstruction method for frequency‐modulated balanced steady‐state free precession (fmSSFP) MRI is presented. In this work, suitable data acquisition schemes, subspace sizes, and efficiencies for banding removal are investigated. Theory and Methods By combining a fmSSFP MRI sequence with a 3D stack‐of‐stars trajectory, scan efficiency is maximized as spectral information is obtained without intermediate preparation phases. A memory‐efficient reconstruction routine is implemented by introducing the low‐frequency Fourier transform as a subspace which allows for the formulation of a convex reconstruction problem. The removal of banding artifacts is investigated by comparing the proposed acquisition and reconstruction technique to phase‐cycled bSSFP MRI. Aliasing properties of different undersampling schemes are analyzed and water/fat separation is demonstrated by reweighting the reconstructed subspace coefficients to generate virtual spectral responses in a post‐processing step. Results A simple root‐of‐sum‐of‐squares combination of the reconstructed subspace coefficients yields high‐SNR images with the characteristic bSSFP contrast but without banding artifacts. Compared to Golden‐Angle trajectories, turn‐based sampling schemes were superior in minimizing aliasing across reconstructed subspace coefficients. Water/fat separated images of the human knee were obtained by reweighting subspace coefficients. Conclusions The novel subspace‐based fmSSFP MRI technique emerges as a time‐efficient alternative to phase‐cycled bSFFP. The method does not need intermediate preparation phases, offers high SNR and avoids banding artifacts. Reweighting of the reconstructed subspace coefficients allows for generating virtual spectral responses with applications to water/fat separation.

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Simultaneous multi‐slice MRI using cartesian and radial FLASH and regularized nonlinear inversion: SMS‐NLINV

Abstract: The extension of the NLINV algorithm for SMS data was implemented and successfully demonstrated in combination with a Cartesian and radial SMS-FLASH sequence. Magn Reson Med 79:2057-2066, 2018. © 2017 International Society for Magnetic Resonance in Medicine.

Cited by 26 publications

References 64 publications

Diffusion Acceleration with Gaussian process Estimated Reconstruction (DAGER)

Diffusion Acceleration with Gaussian process Estimated Reconstruction (DAGER)

A variable flip angle golden‐angle‐ordered 3D stack‐of‐radial MRI technique for simultaneous proton resonant frequency shift and T₁‐based thermometry

Frequency‐modulated SSFP with radial sampling and subspace reconstruction: A time‐efficient alternative to phase‐cycled bSSFP

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Simultaneous multi‐slice MRI using cartesian and radial FLASH and regularized nonlinear inversion: SMS‐NLINV

Abstract: The extension of the NLINV algorithm for SMS data was implemented and successfully demonstrated in combination with a Cartesian and radial SMS-FLASH sequence. Magn Reson Med 79:2057-2066, 2018. © 2017 International Society for Magnetic Resonance in Medicine.

Cited by 26 publications

References 64 publications

Diffusion Acceleration with Gaussian process Estimated Reconstruction (DAGER)

Diffusion Acceleration with Gaussian process Estimated Reconstruction (DAGER)

A variable flip angle golden‐angle‐ordered 3D stack‐of‐radial MRI technique for simultaneous proton resonant frequency shift and T1‐based thermometry

Frequency‐modulated SSFP with radial sampling and subspace reconstruction: A time‐efficient alternative to phase‐cycled bSSFP

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Resources

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A variable flip angle golden‐angle‐ordered 3D stack‐of‐radial MRI technique for simultaneous proton resonant frequency shift and T₁‐based thermometry