Purpose To develop a novel framework for rapid, intrinsic head motion measurement in MRI using FID navigators (FIDnavs) from multichannel coil array. Methods FIDnavs encode substantial rigid‐body information; however, current implementations require patient‐specific training with external tracking data to extract quantitative positional changes. In this work, forward model of FIDnav signals was calibrated simulated movement reference image within the spatial sensitivities. A module inserted...

To measure spatiotemporal B0 field changes in real time using FID navigators (FIDnavs) and to demonstrate the efficacy of retrospectively correcting high-resolution T2* -weighted images a novel FIDnav framework.A forward model complex signals was generated by simulating effect underlying inhomogeneity coefficients, with spatial encoding provided multi-channel reference image. Experiments were performed at 3T assess accuracy estimates from FIDnavs acquired 64-channel head coil under different...

To develop a method for slice-wise dynamic distortion correction EPI using rapid spatiotemporal B0 field measurements from FID navigators (FIDnavs) and to evaluate the efficacy of this new approach relative an established data-driven technique.A low-resolution reference image was used create forward model FIDnav signal changes enable estimation inhomogeneity variations up second order measured FIDnavs. Five volunteers were scanned at 3 T 64-channel coil with FID-navigated EPI. The accuracy...

To evaluate the utility of oxygen challenge and report on temporal changes in blood oxygenation level-dependent (BOLD) contrast normal liver, hepatocellular carcinoma (HCC) background fibrosis.

Purpose To investigate the feasibility of using an electromagnetic (EM) tracker to estimate rigid body head motion parameters, and these measurements retrospectively reduce artifacts. Theory Methods A clinically used MPRAGE sequence was modified measure EM tracking system once per repetition time. retrospective k‐space based correction algorithm that corrects for phase ramps (translation in image domain) rotation 3D (rotation developed, parameters recorded tracker. The accuracy purpose...

To investigate the effects of radiofrequency transmit field (B1(+)) correction on (a) measured T1 relaxation times normal breast tissue and malignant lesions (b) pharmacokinetically derived parameters at 3 T.

ABSTRACT BACKGROUND AND PURPOSE Geometric distortions resulting from large pose changes reduce the accuracy of motion measurements and interfere with ability to generate artifact‐free information. Our goal is develop an algorithm pulse sequence enable motion‐compensated, geometric distortion compensated diffusion‐weighted MRI, evaluate its efficacy in correcting for field inhomogeneity position changes, induced by frequent head motions. METHODS Dual echo planar imaging (EPI) a blip‐reversed...

Abstract Background and Purpose Super‐resolutionreconstruction (SRR) can be used to reconstruct 3‐dimensional (3D) high‐resolution (HR) volume from several 2‐dimensional (2D) low‐resolution (LR) stacks of MRI slices. The purpose is compare lengthy 2D T2‐weighted HR image acquisition neonatal subjects with 3D SRR LR in terms quality for clinical morphometric assessments. Methods brain images were acquired isotropic volumes by using algorithm. Quality assessments done an experienced pediatric...

Motivation: To correct breathing-induced field fluctuations and ensuing artifacts on T2*-weighted MRI of the cervical cord to improve T2* mapping. Goal(s): characterize B0 changes caused by respiration within retrospectively compensate for those spatiotemporal using a FID navigator-based correction technique. Approach: coefficients up second order were measured navigators multi-channel low-resolution reference image. Retrospective was performed during an iterative image reconstruction....

To implement a method for real-time field control using rapid FID navigator (FIDnav) measurements and evaluate the efficacy of proposed approach mitigating dynamic perturbations improving T2*$$ {\mathrm{T}}_2^{\ast } $$ -weighted image quality.FIDnavs were embedded in gradient echo sequence subject-specific linear calibration model was generated on scanner to facilitate shim updates response measured FIDnav signals. confirm accuracy FID-navigated updates, phantom volunteer scans performed...

Abstract Purpose To develop a self‐navigated motion compensation strategy for 3D radial MRI that can compensate continuous head by measuring rigid body parameters with high temporal resolution from the central k‐space acquisition point (self‐encoded FID navigator) in each spoke. Methods A forward model was created low‐resolution calibration data to simulate effect of relative between coil sensitivity profiles and underlying object on self‐encoded navigator signal. Trajectory deviations were...

Purpose To evaluate blood oxygenation level‐dependent (BOLD) contrast changes in healthy breast parenchyma and carcinoma during administration of vasoactive gas stimuli. Materials Methods Magnetic resonance imaging (MRI) was performed at 3T 19 premenopausal female volunteers using a single‐shot fast spin echo sequence to acquire dynamic T 2 ‐weighted images. 2% ( n = 9) 5% 10) carbogen mixtures were interleaved with either medical air or oxygen 2‐minute blocks, for four complete cycles. A...

Multi-shot EPI can be a promising technique to improve the resolution limits of single shot EPI. However, its application has been so far limited in abdominal MRI, as phase errors between shots due unavoidable breathing motion creates artifacts images. Here, we tested Variable-Flip-Angle Fast Low-angle Excitation Echo planar Technique (VFA-FLEET) pulse sequence and showed that it used create high-resolution motion-robust images with high geometric fidelity without breath holding.

3D EPI is a clinically promising alternative for susceptibility weighted imaging due to multi-shot acceleration. However, achieving submillimeter resolution with challenging as shot-to-shot B0 variations result in artifactual images that limit detection of small veins which can be decisive the central vein sign multiple sclerosis. FID navigators have been shown estimate phase drifts sequences. We demonstrate FID-navigated acquisitions enable correction phase-induced distortions and achieve...

Radial acquisitions are inherently motion-robust and facilitate self-navigation, however the frequency of motion updates from navigator images is limited. Pilot tone (PT) enables continuous sensing, but estimation quantitative parameters requires a subject-specific calibration. In this work, we propose (i) using PT detection to guide navigator-based 3D radial acquisition (ii) these measurements calibrate model in order provide high temporal resolution tracking. This hybrid approach...

High-resolution, 3D structural scans are susceptible to patient motion as they take several minutes or more acquire. Radial MRI acquisitions emerging a motion-robust alternative Cartesian trajectories. Most approaches involve co-registration of navigator images once the acquisition is complete. However, time needed for images, coupled with long reconstruction times required high-resolution NUFFT, challenge integration motion-compensated non-Cartesian imaging into clinical protocols. In this...

Visit any magnetic resonance imaging (MRI) facility, and all will agree that patient motion is an ongoing matter. This holds particularly true for pediatric facilities performing functional MRI (fMRI) exams. During fMRI exams, artifacts are subtle contribute to data corruption which not discovered until the analyzed. To enable technologist intervene when occurs, a real-time monitoring system “Slice Localization Integrated Monitoring” (SLIMM) was established detect reduce amount of scan time...

Abdominal MRI scans often require breath-holding to prevent image quality degradation, which can be challenging for patients. XD-GRASP enables generation of motion-robust images free-breathing abdominal by binning the data into respiratory phases. In this study, we compared three navigation techniques, namely k-space center, free induction decay navigators (FIDnavs) and pilot tone (PT), reconstruction. FIDnavs PT have advantages over center since they are insensitive gradient delays,...

Motivation: Motion-induced artifacts in pediatric MRI lead to frequent need for rescan, which increases examination time, costs and patient's discomfort. Goal(s): To develop validate a deep learning-based method automated assessment of diagnostic image quality, overcoming limitations existing motion measurement techniques. Approach: FID navigators embedded into MPRAGE sequence can provide valuable information without prolonging scan time. We train neural network on these signals accurately...

Motivation: 2D high-resolution late gadolinium enhancement (LGE) imaging can benefit from shorter scan times. Current acceleration techniques lead large signal-to-noise (SNR) penalties, reducing diagnostic quality while longer breath-holds increases time and makes the susceptible to artifacts. Goal(s): To assess feasibility of a rapid LGE using Resolution Enhancement Generative Adversarial Inline Neural Network (REGAIN). Approach: Images were acquired with 3.3 5.7-fold accelerations,...