Hybrid 1H/19F Magnetic Resonance Imaging at 7T

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Context:Inflammation is involved in various human diseases including stroke, and improved ability to image inflammation will aid disease diagnosis, and prognosis in a multitude of disorders. A potential method for accurately measuring inflammation in humans is 19F MRI using fluorinated contrast agents in humans; since 19F is not endogenously present it can measure inflammation processes without any background interference. 19F MRI has not found applications in humans because of the lack of a clinically approved fluorinated contrast agent and the low signal to noise ratio (SNR) of 19F MRI. Our locally developed perfluorocarbon emulsion is currently undergoing clinical trials, and we propose to address the SNR challenge by developing a novel 19F/1H RF coil design and exploiting the increased SNR of 7T. Ultra high field MRI scanners increase the SNR and a state-of-the-art high-field 7T MRI scanner is being installed in Glasgow (operational early 2017). However, dedicated RF hardware solutions for 19F MRI of the human brain at 7T are currently not available. Aims and objectives:We propose to develop a hybrid 1H/19F MRI RF coil; this is a novel design that can improve the SNR and efficiency over the conventionally used dual-tuned approach. It consists of a unique eight-channel transceiver array for 1H imaging that is switchable to the 19F frequency in order to be used as the 19F transmit coil. A 24-channel receive array on a close fitting helmet is used to receive the 19F signal and maximize the SNR. Because of dual-frequency operation, the subject does not need to be repositioned on to a different coil for image co-registration and B0 shimming. In addition to optimum SNR, this hardware solution will reduce the setup time and improve patient comfort. Benefits and applications:Our RF solution will address the current multi-nuclei imaging hardware limitation and will enable 1H/19F MRI of the human brain at 7T. The process of inflammation is involved, either directly or indirectly in various human diseases. The proposed solution will allow translation of 19F imaging into the clinic, while also providing a new tool for fundamental research into the mechanisms of inflammation and metabolism.