A5093702322- Advanced MRI Techniques and Applications
- Atomic and Subatomic Physics Research
- Advanced NMR Techniques and Applications
- Biomedical and Engineering Education
- Medical Imaging Techniques and Applications
- Copper Interconnects and Reliability
- Superconducting Materials and Applications
- Particle accelerators and beam dynamics
- Semiconductor materials and devices
- Scientific Measurement and Uncertainty Evaluation
- Electric Motor Design and Analysis
- Advanced Sensor Technologies Research
- Electromagnetic Compatibility and Noise Suppression
- Advanced Optical Sensing Technologies
- Sparse and Compressive Sensing Techniques
- Biomedical Text Mining and Ontologies
Yale University
2024
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...
Eliminating conventional pulsed B
Motivation: To break the accessibility barrier of high-field MRI, we demonstrate that hardware and software systems necessary for an affordable MRI system, can be designed constructed within a week using open-source tools conventional 3D printing approaches. Goal(s): illustrate realization ultra low field system fully operational open source toolsApproach: Over course week, researchers across USA have assembled to build main magnet, homogenization, gradient, radio-frequency (RF), needed...
Abstract Neuroimaging has achieved considerable success in elucidating the neurophysiological underpinnings of various brain functions 1 . Tools such as standardized cognitive tests and symptom inventories have played a crucial role informing neuroimaging studies, helping to uncover underlying systems associated with these measures. Substantial strides been taken developing models, connectome-based predictive modeling (CPM), that establish connections between external measures human...
Motivation: Point-of-care MRI systems need electromagnetic interference (EMI) cancellation with limited passive shielding to improve cost and portability. Existing methods require external hardware or training, which increases costs design complexity. Goal(s): This novel solution targeting narrowband EMI is hardware-free, training-free, introduces no white-noise can be used in conjunction other methods. Approach: Exploiting the sparsity, L1-regularized compressed sensing extract from a...
Motivation: High production costs limit the accessibility of MRI. To break this and cost barrier, we demonstrate that affordable gradients can be designed built in less than two weeks using open-source software conventional 3D printing. Goal(s): develop X, Y, Z for an ultra low-field Halbach Approach: We used to design gradients. The casing was printed, coils were manually wound. fields measured field-mapping probe. Results: constructed generated magnetic with great correspondence simulated...
Motivation: By adjusting individual coil currents, a loop array can generate uniform B0 field and it offers the flexibility to control gradient direction making suitable for compact MRI systems. Goal(s): The goal is show that produces and/or magnetic fields. Approach: current values of loops were determined by ptimization achieve either strength, whose orientation be rotated, or linear gradientResults: A method calculating required has been presented, simulations validate its effectiveness....
Motivation: Spatial resolution in an open low-field MRI that uses surface RF coils for B1-encoding can be improved by repositioning the within FOV each TR. However, this approach is limited space constraints left-right dimension. Linear gradients, especially movable ones optimized a slab, effectively supplement encoding direction. Goal(s): To improve spatial direction of MRI. Approach: A linear gradient on B0 slice volume moved anterior-posterior dependent readout location. Results: Movable...
Motivation: The field cycling (FC) scanner introduces an extra degree of freedom for adjusting the B0 strength during both polarization and readout. However, ideal readout Larmor frequency remains unexplored. Goal(s): To investigate optimal non-uniform (NuBo) regarding SNR, T2*, T2 dephasing. Approach: Controlled experiments at two frequencies, 1MHz 2MHz, were conducted. Echo trains these frequencies acquired. Results: Results show that a lower could benefit from longer echo train, but with...
We introduced a new RF coil made with Moebius cable and shield bowl that can be tuned relatively low capacitance has good isolation between the coils at field. B1 amplitude, coils, SNR of NMR signal proposed were compared reference (made copper wire without an shield). Both bench measurements MR experiments have demonstrated this performs well as part field array.
The cost and complexity of MR scanners can be significantly reduced by eliminating conventional linear gradient coils, instead using RF coils for spatial encoding. Here we have developed a novel multi-echo phase encoding pulse sequence that exploits the Bloch-Siegert shift nonlinear in nonuniform, field-cycling, low-field system. Phantoms varying sizes were successfully imaged this sequence, demonstrating technique used to perform gradient-free imaging an inhomogeneous B0-field at low-field.
Model-based deep learning reconstruction with a nonlinear encoding matrix poses unique challenges to GPU memory, due the densely connected computational graph nodes in physics model part. In this work, SVD compression is demonstrated as necessary for such networks, and it applied highly case of Bloch-Siegert from low-field MR scanner. The redundancy across all dimensions exploited compression. With compressed matrix, model-based network feasible implement. It outperforms traditional at...
We developed a stop-motion imaging technique in which 3x3 radiofrequency coil that transmits Bloch-Siegert encodings is placed different position within the field-of-view for each MR signal acquisition. This study performed using non-linear gradient-free low-field MRI system. High spatial resolution achieved through imaging. show done with total of 200 (20 positions and 10 per position) outperformed stationary (1 position).