To develop an efficient distortion- and blurring-free multi-shot EPI technique for time-resolved multiple-contrast and/or quantitative imaging.EPI is a commonly used sequence but suffers from geometric distortions blurring. Here, we introduce new termed echo planar imaging (EPTI), which has the ability to rapidly acquire multi-contrast data set. The EPTI approach performs encoding in ky -t space uses highly accelerated spatio-temporal CAIPI sampling trajectory take advantage of signal...

Abstract We present a whole-brain in vivo diffusion MRI (dMRI) dataset acquired at 760 μm isotropic resolution and sampled 1260 q-space points across 9 two-hour sessions on single healthy participant. The creation of this benchmark is possible through the synergistic use advanced acquisition hardware software including high-gradient-strength Connectom scanner, custom-built 64-channel phased-array coil, personalized motion-robust head stabilizer, recently developed SNR-efficient dMRI method,...

Multi-parametric quantitative MRI has shown great potential to improve the sensitivity and specificity of clinical diagnosis enhance our understanding complex brain processes, but suffers from long scan time especially at high spatial resolution. To address this longstanding challenge, we introduce a novel approach, termed 3D Echo Planar Time-resolved Imaging (3D-EPTI), which significantly increases acceleration capacity sampling, provides acquisition efficiency for multi-parametric MRI....

Purpose To improve image quality and accelerate the acquisition of 3D MR fingerprinting (MRF). Methods Building on multi‐axis spiral‐projection MRF technique, a subspace reconstruction with locally low‐rank constraint modified spatiotemporal encoding scheme called tiny golden‐angle shuffling were implemented for rapid whole‐brain high‐resolution quantitative mapping. Reconstruction parameters such as regularization parameter rank tuned using retrospective in vivo data simulated examinations....

Abstract Purpose To overcome the major challenges in dMRI acquisition, including low SNR, distortion/blurring, and motion vulnerability. Methods A novel Romer-EPTI technique is developed to provide distortion-free with significant SNR gain, high motion-robustness, sharp spatial resolution, simultaneous multi-TE imaging. It introduces a ROtating-view Motion-robust supEr-Resolution (Romer) combined distortion/blurring-free EPTI encoding. Romer enhances by multi-thick-slice acquisition...

To develop a method for fast distortion- and blurring-free imaging.EPI with point-spread-function (PSF) mapping can achieve imaging at cost of long acquisition time. In this study, an acquisition/reconstruction technique, termed "tilted-CAIPI," is proposed to >20× acceleration PSF-EPI. The systematically optimized the k-space sampling trajectory B0 -inhomogeneity-informed reconstruction, exploit inherent signal correlation in PSF-EPI take full advantage coil sensitivity....

Purpose: To develop new encoding and reconstruction techniques for fast multi-contrast quantitative imaging. Methods: The recently proposed Echo Planar Time-resolved Imaging (EPTI) technique can achieve distortion- blurring-free In this work, a subspace framework is developed to improve the accuracy of EPTI at high accelerations. number unknowns in significantly reduced by modeling temporal signal evolutions using low-rank subspace. As part approach, B0-update algorithm shot-to-shot B0...

Myelin water imaging techniques based on multi-compartment relaxometry have been developed as an important tool to measure myelin concentration in vivo, but are limited by the long scan time of multi-contrast multi-echo acquisition. In this work, a fast technique, termed variable flip angle Echo Planar Time-Resolved Imaging (vFA-EPTI), is acquire and multi-flip-angle gradient-echo data with significantly reduced acquisition time, providing rich information for analysis (GRE-MWI). The...

To develop an efficient MR technique for ultra-high resolution diffusion MRI (dMRI) in the presence of motion.gSlider is SNR-efficient high-resolution dMRI acquisition technique. However, subject motion inevitable during a prolonged scan high spatial resolution, leading to potential image artifacts and blurring. In this study, integrated termed Motion Corrected gSlider (MC-gSlider) proposed obtain high-quality, large in-plane through-plane motion. A motion-aware reconstruction with spatially...

To develop an efficient acquisition technique for distortion-free diffusion MRI and diffusion-relaxometry.A new accelerated echo-train shifted echo-planar time-resolved imaging (ACE-EPTI) is developed to achieve high-SNR, diffusion, diffusion-relaxometry imaging. ACE-EPTI uses a newly designed variable density spatiotemporal encoding with self-navigators phase correction, that allows submillimeter in-plane resolution using only 3-shot. Moreover, echo-train-shifted minimal TE, together...

Cerebrospinal fluid (CSF) flow is a key component of the brain's waste clearance system. However, our understanding CSF in human brain, particularly within brain-wide subarachnoid space (SAS), limited due to lack non-invasive tools for measuring slow flow. Here, we propose flowmetry technique using phase-contrast MRI combined with slow-flow-sensitized acquisition. It achieves high sensitivity (e.g., 100 um/s), and enables quantitative measurement velocity direction whole-brain coverage,...

To develop a novel diffusion imaging reconstruction framework based on iterative self-consistent parallel (SPIRiT) for multishot interleaved echo planar (iEPI), with computation acceleration by virtual coil compression.As general approach autocalibrating imaging, SPIRiT improves the performance of traditional generalized partially acquisitions (GRAPPA) methods in that formulation self-consistency is better conditioned, suggesting to be candidate k-space-based reconstruction. In this study,...

Abstract Purpose To develop EPTI, a multi-shot distortion-free multi-echo imaging technique, into single-shot acquisition to achieve improved robustness motion and physiological noise, increased temporal resolution, high SNR efficiency for dynamic applications. Methods A new spatiotemporal encoding was developed EPTI by enhancing correlation in k-t space. The proposed improves reconstruction conditioning sampling efficiency, with additional optimization under various accelerations optimized...

To develop a new approach to correct for physiological and macroscopic motion in multishot, interleaved echo-planar diffusion imaging.This work built on the previous SPIRiT (iterative self-consistent parallel imaging reconstruction) based reconstruction correction multishot diffusion-weighted account motion. In-plane rotation, translation correction, data rejection, weighted combination are integrated SPIRiT-based ghosting artifacts, blurring, altered b-matrix, residual artifacts caused by...

Abstract Purpose To develop a single‐shot SNR‐efficient distortion‐free multi‐echo imaging technique for dynamic applications. Methods Echo planar time‐resolved (EPTI) was first introduced as multi‐shot imaging. This work aims to EPTI (ss‐EPTI) achieve improved robustness motion/physiological noise, increased temporal resolution, and higher SNR efficiency. A new spatiotemporal encoding that enables reduced phase‐encoding blips minimized echo spacing under the regime developed, which improves...

To overcome the major challenges in diffusion MRI (dMRI) acquisition, including limited SNR, distortion/blurring, and susceptibility to motion artifacts. A novel Romer-EPTI technique is developed achieve SNR-efficient acquisition while providing distortion-free imaging, minimal spatial blurring, high robustness, simultaneous multi-TE imaging. It introduces a ROtating-view Motion-robust supEr-Resolution (Romer) combined with distortion/blurring-free Echo Planar Time-resolved Imaging (EPTI)...

Multishot interleaved echo-planar imaging (iEPI) can achieve higher image resolution than single-shot EPI for diffusion tensor (DTI), but its application is limited by the prolonged acquisition time. To reduce time, a novel model-based reconstruction simultaneous multislice (SMS) and parallel (PI) accelerated iEPI DTI proposed.DTI datasets acquired with SMS PI acceleration be regarded as 3D k-space data, which undersampled along both slice phase encoding directions. Instead of individual...

Purpose To develop a motion estimation and correction method for motion‐robust three‐dimensional (3D) quantitative imaging with 3D‐echo‐planar time‐resolved imaging. Theory Methods The technique was designed additional four‐dimensional navigator acquisition ( x‐y‐z ‐echoes) to achieve fast of the human brain. four‐dimensional‐navigator is inserted into relaxation‐recovery deadtime sequence in every pulse TR (∼2 s) avoid extra scan time, provide continuous tracking 3D head B 0 ‐inhomogeneity...

Purpose To study the effects of 2D navigator distortion and noise level on interleaved EPI (iEPI) DWI reconstruction, using either image‐ or k‐space‐based method. Methods The acquisition was adjusted by reducing its echo spacing in readout direction undersampling phase encoding direction. A POCS‐based reconstruction image‐space sampling function (IRIS) algorithm (POCSIRIS) developed to reduce impact distortion. POCSIRIS then compared with original IRIS a SPIRiT‐based k‐space algorithm, under...

Purpose To develop a motion‐robust extension to the recently developed echo‐planar time‐resolved imaging (EPTI) approach, referred as PROPELLER EPTI with dynamic encoding (PEPTIDE), by incorporating rotations into rapid, multishot acquisition enable shot‐to‐shot motion correction. Methods Echo‐planar is EPI‐based approach that allows extremely rapid of distortion‐free and blurring‐free multicontrast quantitative mapping. By combining k‐space sampling strategy repeatedly sample low‐resolution...

Spin-echo (SE) BOLD fMRI has high microvascular specificity, and thus provides a more reliable means to localize neural activity compared conventional gradient-echo fMRI. However, the most common SE acquisition method, SE-EPI, is known suffer from T2′ contrast contamination with undesirable draining vein bias. To address this, in this study, we extended recently developed distortion/blurring-free multi-shot EPI technique, Echo-Planar Time-resolved Imaging (EPTI), cortical-depth dependent...

To improve time-resolved reconstructions by training auto-encoders to learn compact representations of Bloch-simulated signal evolution and inserting the decoder into forward model.

Purpose Effective removal of chemical‐shift artifacts in echo‐planar imaging (EPI) is a challenging problem especially with severe field inhomogeneity. This study aims to develop reliable water/fat separation technique for point spread function (PSF) encoded EPI (PSF‐EPI) by using its intrinsic multiple echo‐shifted images. Theory and Methods PSF encoding can achieve distortion‐free be highly accelerated the tilted‐CAIPI technique. In this study, existing intermediate images different time...

Echo-planar time resolved imaging (EPTI) is an effective approach for acquiring high-quality distortion-free images with a multi-shot EPI (ms-EPI) readout. As traditional ms-EPI acquisitions, inter-shot phase variations present main challenge when incorporating EPTI into diffusion-prepared pulse sequence. The aim of this study to develop self-navigated Cartesian EPTI-based (scEPTI) acquisition together magnitude and constrained reconstruction diffusion imaging. A sequence designed. different...

The subspace method has been widely used for multi-echo/contrast MRI reconstruction, assuming the temporal MR signal evolution can be compactly represented using a few linear coefficients. Recently, methods based on artificial neural networks (trained with large datasets) enabled nonlinear representations of or spatio-temporal signals and demonstrated improved performance. This work proposes novel zero-shot generative prior nonlinearly generated deep without external training data. proposed...