High field MRI (3T, 7T and above) offers many potential advantages to clinical and scientific studies, including increased sensitivity and improved image contrast creating the potential for improved characterization of biological function and anatomy in health and disease. Parallel transmission (pTx) uses multiple excitation coils driven by independent RF pulse waveforms to subdivide the transmit field into multiple spatial regions each controlled by a separate transmit channel. Increasing the number of spatially distinct transmit elements and using temporally distinct RF pulse waveforms creates spatial degrees of freedom that allow the spatial pattern of the array to be exploited in the excitation process. Previous pTx work by ourselves and others has concentrated on the potential to utilize this additional flexibility to move beyond the uniform slice-select excitation and reduced SAR levels compared to birdcage type excitation. In the current proposal, we propose a program of translational bioengineering development to widely impact 3T clinical imaging and facilitate the advance of 7T clinical imaging by developing and validating individualized medicine to MRI RF safety. We undertake the development of methods to model the electromagnetics of the individual patient while he or she is in the scanner to more accurately assess SAR and temperature safety metrics. This addresses a longstanding weakness in MRI safety whereby current state-of-the-art applies E&M calculations performed on a supine male body model to, for example, a pregnant patient lying on her side. We also extend our individualized fast calculations to other unique configurations, such as quickly identifying metal implants in a pre-scan and including them in the individuals SAR and Temperature modeling. Successful implementation of such methods potentially allow us to expand the quality of clinical imaging by providing more slices, higher flip angles, or shorter TR periods in a wide range of clinical protocols.
This bioengineering project seeks to develop translational technology to improve Magnetic Resonance Imaging (MRI) safety and efficacy. Its ultimate goal is to provide improve the MR images used for clinical diagnosis of disease and to increase the ability of MR as a scientific tool for studying anatomy and function within the living human body in health and disease.
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|Davids, Mathias; Guérin, Bastien; Malzacher, Matthias et al. (2017) Predicting Magnetostimulation Thresholds in the Peripheral Nervous System using Realistic Body Models. Sci Rep 7:5316|
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