Integrated Next-generation RF Transmit, Receive and B0 shimming coil system for brain and spinal cord MRI at 7 Tesla

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Project Summary/Abstract This proposal is to develop a pre-shimmed parallel transmit array, an optimized receive array, and an RF/ΔB0 array to correct the severe B1 inhomogeneity, maximize the signal-to-noise ratio (SNR), and correct B0 inhomogeneity in simultaneous human brain and spinal cord MR imaging 7 Tesla (T). Simultaneous functional imaging of the brain and spinal cord can provide valuable insight into interactions and processing pathways between these organs in normal and abnormal states of spinal cord injury, chronic pain, and motor disease. It is emerging as a new tool to study the central nervous system and is necessary to enable new investigations of task-based and resting-state sensory/motor processing throughout the cerebrum and spinal cord and shed new light on the nature of resting-state networks within the cerebellum and spinal cord. 7T MRI offers new opportunities to visualize structures of interest with high spatial resolution and enhanced conspicuity and to detect brain function and networks with greater sensitivity. However, at high fields, B1 and B0 inhomogeneities, and the lack of optimized receive coils for some specific applications are major challenges that limit imaging performance. Existed designs are aimed at either brain-only or spinal-cord-only applications, and none have solved all the challenges mentioned above. Moreover, the performance of these designs is limited by the small number of transmit channels available from scanner vendors, and a lack of optimization for actual imaging applications. The first goal of this project is to build a pre-shimmed transmit array which compresses 48 basic coils into 8-“virtual” coils with RF pulse jointly optimized weights, to maximize the transmit performance of standard 8-transmit-channel 7 Tesla scanners. The second goal of this project is to build a close-fitting massive- element receive array with optimum coil geometry/layout/size, to provide high SNR and excellent parallel imaging performance in both the whole brain and the spinal cord. The third goal of this project is to build routing-optimized low-profile RF/ΔB0 array to correct B0 inhomogeneity with less hardware complications. The optimization algorithms, electromagnetic simulation models, and electric/mechanical designs of the final pre-shimmed transmit array, high dense receive array and the routing-optimized ΔB0 arrays, will be distributed for open access. These transmit, receive, and ΔB0 arrays do not depend on the vendors’ platform and can be easily transferred to other 7T sites, with benefits for the entire community.