3D-MB-MUSE: A robust 3D multi-slab, multi-band and multi-shot reconstruction approach for ultrahigh resolution diffusion MRI

Purpose To propose a novel 3D k-space Fourier encoding and reconstruction framework for simultaneous multi-slab (SMSlab) acquisition and demonstrate its efficacy in high-resolution imaging. Methods First it is illustrated in theory how the inter-slab gap interferes with the formation of the SMSlab 3D k-space. Then joint RF and gradient encoding are applied to remove the inter-slab-gap interference and form a SMSlab 3D k-space. In vivo experiments are performed to validate the proposed theory. Acceleration in the proposed SMSlab 3D k-space is also evaluated. Results High-resolution (1.0 mm isotropic) images can be reconstructed using the proposed SMSlab 3D framework. CAIPI sampling and 2D GRAPPA reconstruction can also be applied in the SMSlab 3D k-space. Compared with conventional multi-slab acquisition, SMSlab exhibits better SNR maintainability (such as lower g-factors), especially at high acceleration factors. Conclusion It is demonstrated that the joint application of RF and gradient encoding enables SMSlab within a 3D Fourier encoding framework. Images with high isotropic resolution can be reconstructed and further acceleration is also applicable. The proposed SMSlab 3D k-space can be valuable for both high-resolution and high-efficiency diffusion and functional MRI.

Section: Discussionmentioning

confidence: 99%

A 3D k‐space Fourier encoding and reconstruction framework for simultaneous multi‐slab acquisition

Dai

et al. 2019

“…Improving SNR efficiency is critical for achieving high‐isotropic‐resolution DWI. Three‐dimensional multislab DWI has emerged as a promising strategy to enhance the SNR in such acquisitions . However, shot‐to‐shot phase variations and slab‐boundary artifacts are key challenges for efficient sampling of whole‐brain high‐resolution DWI with this technique, where a number of effective techniques have been developed to mitigate these issues .…”

Section: Introductionmentioning

confidence: 99%

“…Three-dimensional multislab DWI has emerged as a promising strategy to enhance the SNR in such acquisitions. [28][29][30][31][32] However, shot-to-shot phase variations and slab-boundary artifacts are key challenges for efficient sampling of whole-brain high-resolution DWI with this technique, 33 where a number of effective techniques have been developed to mitigate these issues. 30,33,34 Another promising approach for high-SNR-efficiency, high-resolution DWI is the Generalized SLIce Dithered Enhanced Resolution (gSlider) method, which is a simultaneous multislab (SMSb) acquisition technique with selfnavigated RF slab encoding, which has been demonstrated for motion-robust, high-resolution DWI.…”

Section: Introductionmentioning

confidence: 99%

High‐fidelity, high‐isotropic‐resolution diffusion imaging through gSlider acquisition with and T₁ corrections and integrated ΔB₀/Rx shim array

Liao

Stockmann

Tian

et al. 2019

Purpose B1+ and T1 corrections and dynamic multicoil shimming approaches were proposed to improve the fidelity of high‐isotropic‐resolution generalized slice‐dithered enhanced resolution (gSlider) diffusion imaging. Methods An extended reconstruction incorporating B1+ inhomogeneity and T1 recovery information was developed to mitigate slab‐boundary artifacts in short‐repetition time (TR) gSlider acquisitions. Slab‐by‐slab dynamic B0 shimming using a multicoil integrated ΔB0/Rx shim array and high in‐plane acceleration (Rinplane = 4) achieved with virtual‐coil GRAPPA were also incorporated into a 1‐mm isotropic resolution gSlider acquisition/reconstruction framework to achieve a significant reduction in geometric distortion compared to single‐shot echo planar imaging (EPI). Results The slab‐boundary artifacts were alleviated by the proposed B1+ and T1 corrections compared to the standard gSlider reconstruction pipeline for short‐TR acquisitions. Dynamic shimming provided >50% reduction in geometric distortion compared to conventional global second‐order shimming. One‐millimeter isotropic resolution diffusion data show that the typically problematic temporal and frontal lobes of the brain can be imaged with high geometric fidelity using dynamic shimming. Conclusions The proposed B1+ and T1 corrections and local‐field control substantially improved the fidelity of high‐isotropic‐resolution diffusion imaging, with reduced slab‐boundary artifacts and geometric distortion compared to conventional gSlider acquisition and reconstruction. This enabled high‐fidelity whole‐brain 1‐mm isotropic diffusion imaging with 64 diffusion directions in 20 min using a 3T clinical scanner.

“…Others (self‐navigated interleaved spiral, keyhole, periodically rotated overlapping parallel lines with enhanced reconstruction, readout segmentation of long variable echo trains) use different acquisition trajectories, which repeatedly cover certain regions of k‐space, to deduce from these redundancies the phase corrections that should be used to compensate the motions occurring between different shots. Using multireceive head coil, parallel imaging methods that can deduce complementary k‐space regions have also been used to solve motion artefacts, and led to impressive 3D DTI reconstructions …”

Section: Introductionmentioning

confidence: 99%

“…Using multireceive head coil, parallel imaging methods that can deduce complementary k-space regions have also been used to solve motion artefacts 12,13 , and led to impressive 3D DTI reconstructions. 14,15 Spatiotemporal encoding (SPEN) is a single-shot MRI technique that excites the spins and rasterizes the image profile in a spatially sequential manner, rather than acquiring equally-weighted k-domain signals from all spins simultaneously. [16][17][18][19][20][21][22][23] SPEN's resolution is largely defined at excitation rather than at acquisition, allowing one to use stronger phaseencoding acquisition gradients than in EPI.…”

Section: Introductionmentioning

confidence: 99%

A regularized reconstruction pipeline for high‐definition diffusion MRI in challenging regions incorporating a per‐shot image correction

Cousin

Liberman

Solomon

et al. 2019

Purpose Diffusion MRI is of interest for clinical research and diagnosis. Whereas high‐ resolution DWI/DTI is hard to achieve by single‐shot methods, interleaved acquisitions can deliver these if motion and/or folding artefacts are overcome. Thanks to its ability to provide zoomed, folding‐free images, spatially encoded MRI can fulfill these requirements. This is here coupled with a regularized reconstruction and parallel receive methods, to deliver a robust scheme for human DWI/DTI at mm and sub‐mm resolutions. Methods Each shot along the spatially encoded dimension was reconstructed separately to retrieve per‐shot phase maps. These shots, together with coil sensitivities, were combined with spatially encoded quadratic phase‐encoding matrices associated to each shot, into single global operators. Their originating images were then iteratively computed aided by l1 and l2 regularization methods. When needed, motion‐corrupted shots were discarded and replaced by redundant information arising from parallel imaging. Results Full‐brain DTI experiments at 1 mm and restricted brain DTIs with 0.75 mm nominal in‐plane resolutions were acquired and reconstructed successfully by the new scheme. These 3 Tesla spetiotemporally encoded results compared favorably with EPI counterparts based on segmented and selective excitation schemes provided with the scanner. Conclusion A new procedure for achieving high‐definition diffusion‐based MRI was developed and demonstrated.