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

背景：炎症与包括中风在内的各种人类疾病有关，提高对炎症的成像能力将有助于疾病诊断和多种疾病的预后。一种准确测量人体炎症的潜在方法是在人体中使用含氟造影剂的19F MRI；由于19F不是内源性存在的，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19F MRI的低信噪比(SNR)，19F MRI还没有在人类中得到应用。我们本地开发的全氟化碳乳剂目前正在进行临床试验，我们建议通过开发新的19F/1H射频线圈设计并利用7T的更高信噪比来应对SNR挑战。超高场核磁共振扫描仪提高了信噪比，格拉斯哥正在安装最先进的高场7T核磁共振扫描仪(2017年初投入使用)。然而，目前还没有用于7T人脑19F MRI的专用射频硬件解决方案。目的和目的：我们提出开发一种混合型1H/19F磁共振射频线圈，这是一种新的设计，可以比传统使用的双调谐方法提高信噪比和效率。它由一个独特的用于1H成像的8通道收发器阵列组成，该阵列可切换到19F频率，以用作19F发射线圈。紧贴头盔上的24通道接收阵列用于接收19F信号并最大化信噪比。由于采用了双频操作，被摄体无需重新定位到不同的线圈上，即可实现图像配准和B0垫片。除了最佳信噪比外，该硬件解决方案还将减少设置时间并改善患者舒适度。优点和应用：我们的射频解决方案将解决目前多核成像硬件的限制，并将在7T时实现人脑的1H/19F磁共振成像。炎症过程直接或间接地参与了各种人类疾病。建议的解决方案将允许将19F成像应用于临床，同时也为炎症和新陈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.