Global ETD Search
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Showing 1 to 12 of 12 for “"parallel transmit"”.
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NOVEL PARALLEL TRANSMIT SYSTEMS FOR MRI APPLICATIONS
In this work a new RF transmitter design is presented for MRI parallel transmissionapplications. Benchtop measurements and imaging experiments were performed withdifferent prototypes to prove system’s performance and potential advantages versus asystem based on conventional MRI RF hardware. The …
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Slice-selective parallel transmit magnetic resonance imaging at 7T
… produces signal dropouts and contrast losses. Parallel transmission (pTx) technology, employing multiple transmit channels to dynamically control RF pulses, is a promising solution to overcome these limitations. While pTx has shown maturity in 3D neuroimaging with universal pulses, its …
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Parallel transmit pulse sequence design for ultra-high field (7T) MRI
… solution to improve image homogeneity is parallel transmission (pTx). A pTx-enabled scanner has multiple independently-driven transmit channels, providing additional degrees of freedom for improved spatial and temporal control of the B+1 fields. This thesis aims to extend the methodology …
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Multiphoton Parallel Transmit MRI for Flip Angle Mitigation Without SAR Concerns
… elements in a process known as parallel transmit (pTx). While these multiple high-power, high-frequency transmit channels can solve the flip angle inhomogeneity problem, they are expensive and complicate the management of electromagnetic power dissipation in the body, known as …
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Local and global SAR constrained large tip angle 3D kT̳-points parallel transmit pulse design at 7 T
… to current imaging systems at high field is transmit magnetic field inhomogeneity, which degrades both SNR and contrast. This inhomogeneity can be mitigated through radio frequency (RF) pulse design with conventional single-channel RF systems, but at the cost of impractically long pulses. …
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Automatic design tool for robust radio frequency decoupling matrices in magnetic resonance imaging
… design of robust decoupling matrices for coupled transmit radio frequency arrays used in magnetic resonance imaging (MRI). In a coupled parallel transmit array, because of the coupling itself, the power delivered to a channel is typically partially re-distributed to other channels. This power must …
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Integral Equation-Based Inverse Scattering and Coil Optimization in Magnetic Resonance Imaging
… properties estimation (inverse scattering) and parallel transmit (pTx) coil array optimization. I also present novel regularization strategies that are ideally suited for inverse problems. I also discuss how we validated these approaches with numerical examples, and the efforts that we undertook …
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Multi-rate access schemes and successive interference cancellation for wireless multimedia MC-CDMA communications
… such as voice, video and higher rate data can be transmitted seanilessly through one MC-CDMA infrastructure. The performance of the multi-rate MC-CDMA is mainly limited by multiple access interference (MAI). For example, in the MFSL MC-CDMA systems, the interference is not only presented among …
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Algorithms for passive dynamical modeling and passive circuit realizations
… imaging (MRI) applications. In a coupled parallel transmit array, because of the coupling, the power delivered to a channel is partially distributed to other channels and is dissipated in the circulators. This dissipated power causes a significant reduction in the power efficiency of the …
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Ultra-high field (7T) magnetic resonance fingerprinting
… Chapter 10 describes my work to understand the parallel transmit framework on our new 7T Terra scanner, culminating in a successful human in vivo liver scan utilizing an 8-channel body transmit array coil. Overall, I have implemented key steps towards a viable 7T MRF sequence for human in vivo …
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Excitation and readout Designs for high field spectroscopic imaging
… in magnetic resonance imaging RF excitation with parallel transmission (pTx) and magnetic resonance spectroscopic imaging (MRSI). Recent work in parallel RF excitation in MRI has been demonstrated to offer dramatically improved flexibility for manipulation of magnetization preparation for imaging …
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A comparison of imaging modalities and decoding methods for detecting semantic information in the brain
Representation of semantic information enables us to engage with the world in a meaningful way – to comprehend and produce language, identify and use objects, and understand and participate in events that involve us. Our understanding of where in the brain semantic information is represented has …