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

背景：炎症与包括中风在内的多种人类疾病有关，提高炎症成像能力将有助于疾病诊断和多种疾病的预后。准确测量人类炎症的一种潜在方法是在人体中使用氟化造影剂的19 F MRI;由于19 F不是内源性存在的，因此它可以在没有任何背景干扰的情况下测量炎症过程。由于缺乏临床批准的氟化造影剂和19 F MRI的低信噪比（SNR），19 F MRI尚未在人类中应用。我们在当地开发的全氟化碳乳剂目前正在进行临床试验，我们建议通过开发一种新型的19 F/1H RF线圈设计并利用7 T的增加SNR来解决SNR挑战。超高场MRI扫描仪提高了SNR，最先进的高场7 T MRI扫描仪正在格拉斯哥安装（2017年初投入使用）。然而，目前还没有用于7 T人脑19 F MRI的专用RF硬件解决方案。目的和目标：我们提出开发一种混合1H/19 F MRI RF线圈;这是一种新颖的设计，可以提高传统使用的双调谐方法的SNR和效率。它由一个独特的8通道收发器阵列组成，用于1H成像，可切换到19 F频率，以用作19 F发射线圈。在紧密贴合的头盔上的24通道接收阵列用于接收19 F信号并使SNR最大化。由于双频操作，受试者不需要重新定位到不同的线圈上进行图像配准和B 0匀场。除了最佳SNR外，该硬件解决方案还将缩短设置时间并提高患者舒适度。优势和应用：我们的射频解决方案将解决当前多核成像硬件的局限性，并将在7 T下实现人脑的1H/19 F MRI。炎症过程直接或间接地参与各种人类疾病。提出的解决方案将允许将19 F成像转化为临床，同时也为炎症和代谢机制的基础研究提供了新的工具。

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.