A5070103909- Advanced MRI Techniques and Applications
- Advanced Neuroimaging Techniques and Applications
- Functional Brain Connectivity Studies
- Atomic and Subatomic Physics Research
- Medical Imaging Techniques and Applications
- MRI in cancer diagnosis
- Blind Source Separation Techniques
- Neurological disorders and treatments
- Neuroscience and Neural Engineering
- Advanced X-ray and CT Imaging
- Fetal and Pediatric Neurological Disorders
- EEG and Brain-Computer Interfaces
- Advanced X-ray Imaging Techniques
- Advanced Memory and Neural Computing
- Photoacoustic and Ultrasonic Imaging
- Neural dynamics and brain function
- Radiation Dose and Imaging
- NMR spectroscopy and applications
- Optical Imaging and Spectroscopy Techniques
- CCD and CMOS Imaging Sensors
- Neural Networks and Reservoir Computing
- Thyroid and Parathyroid Surgery
- Fluid Dynamics and Turbulent Flows
- Elasticity and Material Modeling
- Intraoperative Neuromonitoring and Anesthetic Effects
Mayo Clinic in Arizona
2017-2025
Mayo Clinic
2016-2024
WinnMed
2016-2024
Mayo Clinic in Florida
2019
Otto-von-Guericke University Magdeburg
2011-2017
Gachon University
2007-2011
Charles R. Drew University of Medicine and Science
2011
High-resolution diffusion MRI can provide the ability to resolve small brain structures, enabling investigations of detailed white matter architecture. A major challenge for in vivo high-resolution is low signal-to-noise ratio. In this work, we combine two highly compatible methods, ultra-high field and three-dimensional multi-slab acquisition improve SNR MRI. As each kz plane encoded using a single-shot echo planar readout, scan speeds proposed technique are similar commonly used...
Functional imaging with sub-millimeter spatial resolution is a basic requirement for assessing functional MRI (fMRI) responses across different cortical depths and used extensively in the emerging field of laminar fMRI. Such studies seek to investigate detailed organization brain may develop new powerful tool human neuroscience. However, several have shown that measurement fMRI can be biased by image acquisition data processing strategies. In this work, measurements three gradient-echo EPI...
Stimulation-evoked signals are starting to be used as biomarkers indicate the state and health of brain networks. The human limbic network, often targeted for stimulation therapy, is involved in emotion memory processing. Previous anatomic, neurophysiological, functional studies suggest distinct subsystems within network (Rolls, 2015). Studies using intracranial electrical stimulation, however, have emphasized similarities evoked waveforms across network. We test whether these...
In echo-planar imaging (EPI), such as commonly used for functional MRI (fMRI) and diffusion-tensor (DTI), compressed distortion is a more difficult challenge than local stretching spatial information can be lost in strongly areas. addition, the effects are severe at ultra-high field (UHF) 7T due to increased inhomogeneity. To resolve this problem, two EPIs with opposite phase-encoding (PE) polarity were acquired combined after correction. For correction, point spread function (PSF) mapping...
Abstract Objective . Conventional computed tomography (CT) imaging does not provide quantitative information on local thermal changes during percutaneous ablative therapy of cancerous and benign tumors, aside from few qualitative, visual cues. In this study, we have investigated in CT signal across a wide range temperatures two physical phases for different tissue mimicking materials, each. Approach A series experiments were conducted using an anthropomorphic phantom filled with water-based...
Electrical stimulation is increasingly used to modulate brain networks for clinical purposes. The basic unit of neurostimulation, a single electrical pulse, can travel through white matter influence connected neuronal populations. However, the mechanisms by which it influences populations not well understood: may excite, inhibit, or add noise population activity. In this study, we investigated how pulses processing images in well-controlled visual paradigm. two human subjects implanted with...
Despite its wide use, echo-planar imaging (EPI) suffers from geometric distortions due to off-resonance effects, i.e., strong magnetic field inhomogeneity and susceptibility. This article reports a novel method for correcting the observed in EPI acquired at ultra-high-field such as 7 T. Point spread function (PSF) mapping methods have been proposed EPI. The PSF shift map can be derived either along nondistorted or distorted coordinates. Along coordinates more information about compressed...
Background Distortion‐free, high‐resolution diffusion imaging using DIADEM (Distortion‐free Imaging: A Double Encoding Method), proposed recently, has great potential for clinical applications. However, it can suffer from prolonged scan times and its reliability quantitative not been evaluated. Purpose To investigate the feasibility of DIADEM‐based on a novel compact 3T (C3T) by evaluating measurements utilizing both high‐performance gradients (80 mT/m, 700 T/m/s) sequence optimization with...
Purpose To describe a model‐based reconstruction strategy for single‐shot echo planar imaging (EPI) that intrinsically accounts k‐space nonuniformity, Nyquist ghosting, and geometric distortions during rather than before or after image reconstruction. Methods Ramp sampling inhomogeneous B0 field‐induced distortion cause the EPI samples to lie on non‐Cartesian grid, thus requiring nonuniform fast Fourier transform. Additionally, 2D ghost phase correction without need extra navigator...
To accurately correct diffusion-encoding direction-dependent eddy-current-induced geometric distortions in diffusion-weighted echo-planar imaging (DW-EPI) and to minimize the calibration time at 7 Tesla (T).A point spread function (PSF) mapping based eddy-current method is newly presented determine even including nonlinear effects within readout acquisition window. evaluate temporal stability of maps, was performed four times 3 months. Furthermore, spatial variations measured maps versus...
One of the major concerns associated with high-performance gradients is peripheral nerve stimulation (PNS) subject during MRI exams. Since installation, more than 680 volunteer subjects (patients and controls) have been scanned on a compact 3 T system gradients, capable 80 mT m-1 gradient amplitude 700 s-1 slew rate simultaneously. Despite PNS due to smaller physical dimensions coils, minimal or no sensation was reported most pulse sequences. The exception by only five 252 (about 2%)...
A novel distortion-free multi-shot diffusion-weighted-imaging (DWI), termed DIADEM (Distortion-free Imaging: Double Encoding Method), was compared with commercially available state-of-the-art DWI techniques for clinical brain imaging. High-resolution is feasible within clinically acceptable acquisition times using the technique, and demonstrated better performance than current techniques.
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 used. Equipped with high-performance gradients, the compact 3T MRI system (C3T) enables a three-echo whole-brain ME-EPI protocol smaller than 2.5 mm isotropic voxel and shorter 1 s repetition time, as required in landmark fMRI studies. The performance was comprehensively evaluated...
Purpose To investigate the feasibility of substantially reducing acoustic noise while performing diffusion tensor imaging (DTI) on a compact 3T (C3T) MRI scanner equipped with 42‐cm inner‐diameter asymmetric gradient. Methods A‐weighted measurements were made using 10 mT/m‐amplitude sinusoidal waveforms, corresponding to echo‐planar (EPI) echo spacing 0.25 5.0 ms, conventional, whole‐body and C3T. Acoustic DTI trapezoidal EPI waveforms then at peak gradient performance C3T (80 mT/m...
Harmaline-induced tremor is one of the most commonly utilized disease models for essential (ET). However, underlying neural networks involved in harmaline-induced and degree to which these are a representative model pathophysiologic mechanism ET incompletely understood. In this study, we evaluated functional brain network effects induced by systemic injection harmaline using pharmacological magnetic resonance imaging (ph-fMRI) swine model. With administration, observed significant activation...
Purpose To demonstrate the feasibility of pseudo‐continuous arterial‐spin–labeled (pCASL) imaging with 3D fast‐spin‐echo stack‐of‐spirals on a compact 3T scanner (C3T), to perform trajectory correction for eddy‐current–induced deviations in spiral readout pCASL imaging, and assess effect perfusion‐related images high‐performance gradients (80 mT/m, 700T/m/s) C3T. Methods track artifacts Archimedean readout, was performed 5 different peak gradient slew rate ( S max ) values ranging from 70...
Improved gradient performance in an MRI system reduces distortion echo planar imaging (EPI), which has been a key method for functional studies. A lightweight, low-cryogen compact 3T scanner (C3T) is capable of achieving 80 mT m-1 amplitude with 700 T s-1 slew rate, comparison conventional whole-body (WB3T, 50 200 s-1). We investigated benefits the high-performance gradients high-spatial-resolution (1.5 mm isotropic) study. Reduced spacing EPI pulse sequence inherently leads to less severe...
Purpose Asymmetric gradient coils introduce zeroth‐ and first‐order concomitant field terms, in addition to higher‐order terms common both asymmetric symmetric gradients. Salient compensation strategies is the accurate calibration of spatial offset parameters for coils. A method that allows one‐time described. Theory Methods modified phase contrast pulse sequence with single‐sided bipolar flow encoding proposed calibrate offsets asymmetric, transverse By fitting measured different...