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View article: What If Each Voxel Were Measured With a Different Diffusion Protocol?
What If Each Voxel Were Measured With a Different Diffusion Protocol? Open
Purpose Expansion of diffusion MRI (dMRI) both into the realm of strong gradients and into accessible imaging with portable low‐field devices brings about the challenge of gradient nonlinearities. Spatial variations of the diffusion gradie…
View article: Engineering clinical translation of OGSE diffusion MRI
Engineering clinical translation of OGSE diffusion MRI Open
Oscillating gradient spin echo (OGSE) diffusion MRI (dMRI) can probe the diffusive dynamics on short time scales ≲10 ms, which translates into the sensitivity to tissue microstructure at the short length scales m. OGSE‐based tissue microst…
View article: Feasibility of brain intra-axonal microstructure imaging with ultrahigh B-encoding using MAGNUS ultra-high-performance gradients
Feasibility of brain intra-axonal microstructure imaging with ultrahigh B-encoding using MAGNUS ultra-high-performance gradients Open
The MAGNUS high-performance MRI gradient platform delivers Gmax = 200–300 mT/m, and SRmax = 500–750 T/m/s using standard clinical 3.0T system power electronics. This enables the exploration of an expanded diffusion parameter space (b~7–≥30…
View article: Modeling and measurement of lead tip heating and resonant length for implanted, insulated wires
Modeling and measurement of lead tip heating and resonant length for implanted, insulated wires Open
Purpose To study implant lead tip heating because of the RF power deposition by developing mathematical models and comparing them with measurements acquired at 1.5 T and 3 T, especially to predict resonant length. Theory and Methods A simp…
View article: Autoencoder-based Feature Extraction and Classification for fMRI-based Deep Brain Stimulation Parameter Optimization for Parkinson’s Disease Treatment: Towards a Rapid Semi-automated Stimulation Optimization
Autoencoder-based Feature Extraction and Classification for fMRI-based Deep Brain Stimulation Parameter Optimization for Parkinson’s Disease Treatment: Towards a Rapid Semi-automated Stimulation Optimization Open
Optimized deep brain stimulation (DBS) is fast becoming a therapy of choice for the treatment of Parkinson’s disease (PD). However, the post-operative optimization (patient clinical benefits are maximized and adverse effects are minimized)…
View article: Deep Learning and fMRI-Based Pipeline for Optimization of Deep Brain Stimulation During Parkinson’s Disease Treatment: Toward Rapid Semi-Automated Stimulation Optimization
Deep Learning and fMRI-Based Pipeline for Optimization of Deep Brain Stimulation During Parkinson’s Disease Treatment: Toward Rapid Semi-Automated Stimulation Optimization Open
The proposed AE-MLP models yielded promising results for fMRI-based DBS parameter classification and prediction, potentially facilitating rapid semi-automated DBS parameter optimization. Clinical and Translational Impact Statement-A deep l…
View article: Human prostate <scp>MRI</scp> at ultrahigh‐performance gradient: A feasibility study
Human prostate <span>MRI</span> at ultrahigh‐performance gradient: A feasibility study Open
Purpose To demonstrate the technical feasibility and the value of ultrahigh‐performance gradient in imaging the prostate in a 3T MRI system. Methods In this local institutional review board–approved study, prostate MRI was performed on 4 h…
View article: Frequency-dependent diffusion kurtosis imaging in the human brain using an oscillating gradient spin echo sequence and a high-performance head-only gradient
Frequency-dependent diffusion kurtosis imaging in the human brain using an oscillating gradient spin echo sequence and a high-performance head-only gradient Open
Measuring the time/frequency dependence of diffusion MRI is a promising approach to distinguish between the effects of different tissue microenvironments, such as membrane restriction, tissue heterogeneity, and compartmental water exchange…
View article: Revealing tumor microstructure with oscillating diffusion encoding <scp>MRI</scp> in pre‐surgical and post‐treatment glioma patients
Revealing tumor microstructure with oscillating diffusion encoding <span>MRI</span> in pre‐surgical and post‐treatment glioma patients Open
Purpose We hypothesized that the time‐dependent diffusivity at short diffusion times, as measured by oscillating gradient spin echo (OGSE) diffusion MRI, can characterize tissue microstructures in glioma patients. Theory and Methods Five a…
View article: Improved Resting-State Functional MRI Using Multi-Echo Echo-Planar Imaging on a Compact 3T MRI Scanner with High-Performance Gradients
Improved Resting-State Functional MRI Using Multi-Echo Echo-Planar Imaging on a Compact 3T MRI Scanner with High-Performance Gradients Open
In blood-oxygen-level-dependent (BOLD)-based resting-state functional (RS-fMRI) studies, usage of multi-echo echo-planar-imaging (ME-EPI) is limited due to unacceptable late echo times when high spatial resolution is used. Equipped with hi…
View article: Diffusion MRI with free gradient waveforms on a high-performance gradient system: Probing restriction and exchange in the human brain
Diffusion MRI with free gradient waveforms on a high-performance gradient system: Probing restriction and exchange in the human brain Open
The dependence of the diffusion MRI signal on the diffusion time carries signatures of restricted diffusion and exchange. Here we seek to highlight these signatures in the human brain by performing experiments using free gradient waveforms…
View article: Peripheral Nerve Stimulation (PNS) Analysis of MRI Head Gradient Coils with Human Body Models
Peripheral Nerve Stimulation (PNS) Analysis of MRI Head Gradient Coils with Human Body Models Open
The main objective of this chapter is to provide a comprehensive and intuitive introduction to MRI gradient coil related PNS modeling with human body models. We will present the fundamental concepts and analytical processes behind gradient…
View article: Calibration of concomitant field offsets using phase contrast MRI for asymmetric gradient coils
Calibration of concomitant field offsets using phase contrast MRI for asymmetric gradient coils Open
Purpose Asymmetric gradient coils introduce zeroth‐ and first‐order concomitant field terms, in addition to higher‐order terms common to both asymmetric and symmetric gradients. Salient to compensation strategies is the accurate calibratio…
View article: Deep learning-based reconstruction of highly accelerated 3D MRI
Deep learning-based reconstruction of highly accelerated 3D MRI Open
Purpose: To accelerate brain 3D MRI scans by using a deep learning method for reconstructing images from highly-undersampled multi-coil k-space data Methods: DL-Speed, an unrolled optimization architecture with dense skip-layer connections…
View article: Heat Modulation of Intrinsic MR Contrasts for Tumor Characterization
Heat Modulation of Intrinsic MR Contrasts for Tumor Characterization Open
(1) Background: The longitudinal relaxation time (T1), transverse relaxation time (T2), water proton chemical shift (CS), and apparent diffusion coefficient (ADC) are MR quantities that change with temperature. In this work, we investigate…
View article: Improved Brain <scp>MR</scp> Imaging from a Compact, Lightweight 3T Scanner with <scp>High‐Performance</scp> Gradients
Improved Brain <span>MR</span> Imaging from a Compact, Lightweight 3T Scanner with <span>High‐Performance</span> Gradients Open
Background A low‐cryogen, compact 3T (C3T) MRI scanner with high‐performance gradients capable of simultaneously achieving 80 mT/m gradient amplitude and 700 T/m/second slew rate has been in use to study research patients since March 2016 …
View article: Oscillating diffusion‐encoding with a high gradient‐amplitude and high slew‐rate head‐only gradient for human brain imaging
Oscillating diffusion‐encoding with a high gradient‐amplitude and high slew‐rate head‐only gradient for human brain imaging Open
Purpose We investigate the importance of high gradient‐amplitude and high slew‐rate on oscillating gradient spin echo (OGSE) diffusion imaging for human brain imaging and evaluate human brain imaging with OGSE on the MAGNUS head‐gradient i…
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Issue Information Open
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View article: Peripheral nerve stimulation limits of a high amplitude and slew rate magnetic field gradient coil for neuroimaging
Peripheral nerve stimulation limits of a high amplitude and slew rate magnetic field gradient coil for neuroimaging Open
Purpose To establish peripheral nerve stimulation (PNS) thresholds for an ultra‐high performance magnetic field gradient subsystem (simultaneous 200‐mT/m gradient amplitude and 500‐T/m/s gradient slew rate; 1 MVA per axis [MAGNUS]) designe…
View article: A Deep Learning–Based Approach to Reduce Rescan and Recall Rates in Clinical MRI Examinations
A Deep Learning–Based Approach to Reduce Rescan and Recall Rates in Clinical MRI Examinations Open
Fast, automated deep learning-based image-quality rating can decrease rescan and recall rates, while rendering them technologist-independent. It was estimated that decreasing rescans and recalls from the technologists' values to the values…
View article: A block matching based approach with multiple simultaneous templates for the real‐time 2D ultrasound tracking of liver vessels
A block matching based approach with multiple simultaneous templates for the real‐time 2D ultrasound tracking of liver vessels Open
Purpose The implementation of motion management techniques in radiation therapy can aid in mitigating uncertainties and reducing margins. For motion management to be effective, it is necessary to track key structures both accurately and at…
View article: A magnetic resonance compatible E4D ultrasound probe for motion management of radiation therapy
A magnetic resonance compatible E4D ultrasound probe for motion management of radiation therapy Open
We developed a magnetic resonance compatible real-time, three-dimensional imaging ultrasound probe for motion management of radiation therapy for liver cancer. The probe contains an 18,000-element, 46.8 mm × 21.5 mm matrix array constructe…
View article: <scp>B</scp><sub>0</sub> concomitant field compensation for <scp>MRI</scp> systems employing asymmetric transverse gradient coils
<span>B</span><sub>0</sub> concomitant field compensation for <span>MRI</span> systems employing asymmetric transverse gradient coils Open
Purpose Imaging gradients result in the generation of concomitant fields, or Maxwell fields, which are of increasing importance at higher gradient amplitudes. These time‐varying fields cause additional phase accumulation, which must be com…
View article: High slew‐rate head‐only gradient for improving distortion in echo planar imaging: Preliminary experience
High slew‐rate head‐only gradient for improving distortion in echo planar imaging: Preliminary experience Open
Purpose To investigate the effects on echo planar imaging (EPI) distortion of using high gradient slew rates (SR) of up to 700 T/m/s for in vivo human brain imaging, with a dedicated, head‐only gradient coil. Materials and Methods Simulati…