A5039007799- Advanced MRI Techniques and Applications
- Atomic and Subatomic Physics Research
- Advanced NMR Techniques and Applications
- Medical Imaging Techniques and Applications
- NMR spectroscopy and applications
- Advanced Neuroimaging Techniques and Applications
- MRI in cancer diagnosis
- Photoacoustic and Ultrasonic Imaging
- Cardiac Imaging and Diagnostics
- Seismic Imaging and Inversion Techniques
- Functional Brain Connectivity Studies
- Ultrasound Imaging and Elastography
- Characterization and Applications of Magnetic Nanoparticles
- Sparse and Compressive Sensing Techniques
- Advanced X-ray Imaging Techniques
- Advanced X-ray and CT Imaging
- Advanced Vision and Imaging
- Electron Spin Resonance Studies
- Spectroscopy Techniques in Biomedical and Chemical Research
- Peripheral Artery Disease Management
- Photonic and Optical Devices
- Cardiovascular Function and Risk Factors
- Advanced Optical Sensing Technologies
- Ultrasound and Hyperthermia Applications
- Advanced Biosensing Techniques and Applications
Yale University
2012-2024
National University of San Juan
2024
University Radiology
2019
Resonance Research (United States)
2010
Princeton University
2004-2009
Duke University
2005-2009
Low-field magnetic resonance imaging (MRI) has recently experienced a renaissance that is largely attributable to the numerous technological advancements made in MRI, including optimized pulse sequences, parallel receive and compressed sensing, improved calibrations reconstruction algorithms, adoption of machine learning for image postprocessing. This new attention on low-field MRI originates from lack accessibility traditional need affordable imaging. provides viable option due its reliance...
Abstract Recent improvements in parallel imaging have been driven by the use of greater numbers independent surface coils placed so as to minimize aliasing along phase‐encode direction(s). However, gains from increasing number diminish coil coupling problems begin dominate and ratio acceleration gain expense for multiple receiver chains becomes prohibitive. In this work, we redesign spatial‐encoding strategy order efficiency, achieving a gradient encoding scheme that is complementary spatial...
Conventional magnetic resonance methods that provide interior temperature profiles, which find use in clinical applications such as hyperthermic therapy, can develop inaccuracies caused by the inherently inhomogeneous field within tissues or probe dynamics, and work poorly important fatty tissues. We present a method is suitable for imaging wide range of environments. It uses sharp resonances intermolecular zero-quantum coherences, this case flipping up water spin while down nearby fat spin....
Clinical magnetic resonance spectroscopy is typically limited by inhomogeneities which destroy spectral resolution, but intermolecular zero quantum coherences (iZQCs) are insensitive to such inhomogeneities. iZQC resolution in vivo, however, has been hampered physiological fluctuations over the time scale of two-dimensional acquisition. A faster sequence will allow us average away these fluctuations, and thus we present a new approach ultrafast spectroscopy. This communication reports...
Abstract To increase image acquisition efficiency, we develop alternative gradient encoding strategies designed to provide spatial complementary the provided by multiple receiver coil elements in parallel acquisitions. Intuitively, is achieved when magnetic field gradients are encode information where ambiguous, for example, along sensitivity isocontours. Specifically, method generates a basis set null space of sensitivities with singular value decomposition and calculates fields from...
Abstract Recently, spatial encoding with nonlinear magnetic fields has drawn attention for its potential to achieve faster gradient switching within safety limits, tailored resolution in regions of interest, and improved parallel imaging using that complement the sensitivity profiles radio frequency receive arrays. Proposed methods can broadly be divided into those use phase (Cartesian‐trajectory PatLoc COGNAC) acquire projections (O‐Space, Null space imaging, radial PatLoc, 4D‐RIO)....
Nonlinear spatial encoding magnetic fields (SEMs) have been studied to reconstruct images from a minimum number of echoes. Previous work has also explored single shot trajectories in nonlinear SEMs. However, the search continues for optimal schemes that apply SEMs improve efficiency and image quality.
Eliminating conventional pulsed B
Intermolecular double quantum coherences (iDQCs), signals that result from simultaneous transitions of two or more separated spins, are known to produce images highly sensitive subvoxel structure, particularly local anisotropy. Here we demonstrate how iDQCs signal can be used efficiently detect the anisotropy created in breast tumor tissues and prostate by targeted (LHRH-conjugated) superparamagnetic nanoparticles (SPIONs), thereby distinguishing necrotic area surrounding tissue.
Purpose Nonlinear spatial encoding magnetic (SEM) field strategies such as O‐space imaging have previously reported dispersed artifacts during accelerated scans. Compressed sensing (CS) has shown a sparsity‐promoting convex program allows image reconstruction from reduced data set when using the appropriate sampling. The development of pseudo‐random center placement (CP) CS approach optimizes incoherence through SEM modulation to reconstruct an with error. Theory and Methods parameter...
Sequences that encode the spatial information of an object using nonlinear gradient fields are a new frontier in MRI, with potential to provide lower peripheral nerve stimulation, windowed view, tailored spatially-varying resolution, curved slices mirror physiological geometry, and, most importantly, very fast parallel imaging multichannel coils. The acceleration for images is generally explained by fact curvilinear isocontours better complement azimuthal encoding provided typical receiver...
Purpose Turbo spin echo (TSE) imaging reduces time by acquiring multiple echoes per repetition (TR), requiring fewer TRs. O‐space can also require TRs using a combination of nonlinear magnetic gradient fields and surface coil arrays. Although to date, has only been demonstrated for imaging, it is valuable combine these two techniques. However, collecting TR difficult because the different local k‐space trajectories variable T2‐weighting. Theory Methods A practical scheme benefits TSE highly...
Abstract Fast ROtary Nonlinear Spatial ACquisition (FRONSAC) was recently introduced as a new strategy that applies nonlinear gradients small perturbation to improve image quality in highly undersampled MRI. In addition experimentally showing the previously simulated improvement quality, this work introduces insight Cartesian-FRONSAC retains many desirable features of Cartesian imaging. preserves existing linear gradient waveforms sequence while adding oscillating waveforms. Experiments show...
This work examines the prototypical MR echo that would be expected for a voxel of spins evolving in strong nonlinear field, specifically focusing on quadratic z(2) - ½(x(2) + y(2) ) field. Dephasing under gradients is increasingly relevant given growing interest imaging, and here, we report several notable differences from linear case. Most notably, addition to signal loss, intravoxel dephasing creating wide asymmetric frequency distribution across can cause skewed phase evolution. After...
This work presents the early performance characteristics of an inside-out prostate nonlinear gradient (NLG). Diffusion-weighted imaging (DWI) could detect cancers non-invasively. However, it requires high b-values, which in turn require a pulse with long duration, increasing echo time. A longer time means lower SNR and contribution from short T2 components. NLG coil circumvents this issue by having amplitude within limited field view, applies to imaging.
This report introduces a new approach that enhances nonlinear solution magnetic resonance signals from intermolecular dipolar interactions. The resulting can theoretically be as large the full equilibrium magnetization. Simple, readily implemented pulse sequences using square-wave magnetization modulation simultaneously refocus all even order multiple quantum coherences, leading to substantial net signal enhancement, complex dynamics, and improved structural sensitivity under realistic conditions.
To study the additional value of FRONSAC encoding in 2D and 3D wave sequences, implementing a simple strategy to trajectory mapping for gradients.
Purpose To investigate algebraic reconstruction technique (ART) for parallel imaging of radial data, applied to accelerated cardiac cine. Methods A graphics processing unit (GPU)‐accelerated ART was implemented and simulations, point spread functions in 12 subjects imaged with cine acquisitions. Cine images were reconstructed at multiple undersampling levels (192 N r × p = 96 16). Images qualitatively quantitatively analyzed sharpness artifacts, compared filtered back‐projection, conjugate...