Collaborative Research: IDBR: TYPE A: Unconventional Antenna Probes for Ultra-High-Resolution Magnetic Resonance Imaging

磁共振成像(MRI)设备具有更高的空间分辨率和更短的扫描时间，迫切需要用于研究从单细胞到人类的各种生物系统。高场磁共振扫描仪的主要优势是它们有潜力提供更好的解剖和时间分辨率。在过去的十年里，临床扫描仪的磁场从1.5特斯拉(T)增加到3T，革命性地使用功能磁共振来绘制大脑活动图。更高的图像分辨率也可能消除对体内注射化学造影剂的需要，并允许更早地发现疾病。最近，用于人体解剖学研究的9.4T磁共振扫描仪已经被开发出来。预计动物和植物成像将在7T到20T核磁共振扫描仪中进行更多的进步。细胞成像将有可能达到微米级的分辨率，用11.7T和更高的场扫描仪实现。然而，常规线圈探头的性能在高场磁共振系统所需的更高频率下退化，因此，需要新的高频磁共振探头。这项研究将通过开发用于高场磁共振扫描仪的非传统天线探头来取代标准射频线圈，来解决高分辨率磁共振成像的基本电磁挑战。该项目的结果将增强高场磁共振的能力，并对正在进行的动物行为研究产生立竿见影的影响。生物人类学、渔业和生物学的研究人员将受益于扫描时间更短、分辨率更高的新工具。这项工作还将为人类和临床MRI开辟新的天线探测器的道路。来自电气和计算机工程系(密歇根理工大学)、材料研究所((宾夕法尼亚州立大学)和哈克磁共振中心(宾夕法尼亚州立大学)的小组将探索一种集成天线和MRI技术的新方法，并提出使用梯度折射率超材料小型化的新型贴片天线探测器，作为天线与MRI环境兼容性的解决方案。由于贴片和馈电系统之间的优化耦合，新型天线探头将为高MRI频率提供低损耗、高Q因子和强信号等优势，这将使20T磁共振扫描仪中的图像体积分辨率比目前的线圈提高10倍。该项目包括天线探头的计算电磁建模、设计和优化；设计复合介质基板和制造天线系统；以及在天线设施和核磁共振扫描仪中对模体和生物样本进行测试。这些探头将直接在生物学研究中进行测试：斑马鱼的大脑发育将作为其他系统的模型进行初步探索。新型天线的尺寸灵活性将提供定制的统一射频场，并允许分析包括老鼠和单细胞在内的各种样品。通过宾夕法尼亚州立大学的核磁共振中心、好时医学中心和由工业公司组成的NSF支持的介电研究中心，可以广泛和立即地传播项目成果。

Magnetic Resonance Imaging (MRI) facilities with enhanced spatial resolution and reduced scan time are in urgent demand for investigating a comprehensive range of biological systems from single cells to humans. The main advantage of high-field MRI scanners is their potential to provide improved anatomic and temporal resolution. Over the past decade, the magnetic field of clinical scanners has increased from 1.5 Tesla (T) to 3 T, revolutionizing functional MRI to map the brain activity. Higher image resolution may also eliminate the need for chemical contrast agents injected in the body and allow for earlier detection of disease. Recently, 9.4 T MRI scanners have been explored for the human anatomy studies. Additional advancements are anticipated for animal and plant imaging, which will be carried out in 7 T to 20 T MRI scanners. Cell imaging will be possible for the micron scale resolutions that are achieved with 11.7 T and higher field scanners. The performance of conventional coil probes, however, degrades at the higher frequencies required by high-field MRI systems, therefore, new high-frequency MRI probes are needed. This research will address fundamental electromagnetic challenges of high-resolution MRI by developing unconventional antenna probes for high-field MRI scanners to replace standard radio frequency coils. The results of the project will enhance the capabilities of high-field MRI and have an immediate impact on ongoing studies in animal behavior. Researchers of biological anthropology, fisheries and biology will benefit from new tools with shorter scan times and higher resolution. This work will also open the paths for new antenna probes for human and clinical MRI.This collaborative effort between the groups from the Electrical and Computer Engineering Department (Michigan Tech University), the Materials Research Institute ((Penn State University), and the Huck Magnetic Resonance Center (Penn State University) will explore a new approach to integrating antenna and MRI technologies, and propose novel patch antenna probes miniaturized by using gradient index metamaterials as a solution for antenna compatibility with MRI environment. Novel antenna probes will provide such advantages for high MRI frequencies as low loss, high Q factor and strong signal due to optimized coupling between patch and feeding systems that will increase image volume resolution by a factor of 10 over that of the present-day coils in a 20 T MRI scanner. The project includes computational electromagnetic modeling, design, and optimization of antenna probes; engineering composite dielectric substrates and fabricating antenna systems; and testing probes at the antenna facilities and in MRI scanners on phantoms and biological samples. The probes will be directly tested in biological research: the brain development of zebrafish will be initially explored as a model for other systems. The size flexibility of novel antennas will provide for customized volumes of uniform radio frequency field and allow for analyzing diverse samples including mice and single cells. There are outstanding opportunities for the broad and immediate dissemination of the project results through the Penn State's Center for MRI, which is a shared-use facility for all departments including anthropology and bioengineering, the Hershey Medical Center, and the NSF supported Center for Dielectric Studies comprised of industrial companies.