TRD4 - Ultrahigh Field Engineering and Safety

项目摘要/摘要 TRD4的总体目标是开发支持对方所需的创新工程解决方案 在这个P41中心，TRDS和各种协作和服务项目。最重要的问题之一是 需要解决的问题，特别是在开发新的超高场磁共振技术时，是为了确保 总体而言，MR相关技术的安全性。我们论证了准确预测温度的可行性。 由于10.5T天线阵列的能量沉积，麻醉动物的数量增加，并将在此基础上扩展 通过研究体内绝对温度变化，研究和探索发射阵列的真实安全极限。我们 还提出了一种将红外摄像机集成到线圈外壳中来监测表面温度的新方法。 对于更大的MR社区来说，另一个重要的技术障碍是如何解决安全问题 以及与金属植入物和脑深部刺激器导联相关的成像伪影。磁共振成像在诊断中的应用 在植入导线的情况下测量组织结构和功能对于研究也是至关重要的 旨在了解神经调节的机制和评价神经调节的影响。然而，大多数个人 这种金属植入物不能接受磁共振成像，因为严重的射频诱导图像伪影和 组织加热。因此，新的MRI策略可以最大限度地减少伪影和组织的先验发生 供暖是非常需要的。我们建议开发并行射频传输策略，扩展到 以前开发的用于预测和/或减少植入物周围热量的方法。 在超高频(7T和10.5T)下可获得更高的信噪比，与新开发的优化射频相结合 线圈设计，提供了实现前所未有的高分辨率大脑图像的潜力。然而，由于 图像分辨率提高，采集过程中头部运动导致伪影和模糊的问题 变得更加充实。为了解决这个问题，改进的运动检测和校正方法是 这是必要的。我们建议开发新的传感器硬件并翻译现有的外部软件 改进运动检测和校正的发展。这些传感器提供的数据还可以 用于其他目的，如安全监控。 最后，我们计划扩展我们广泛的超高频技术专业知识，并提出优化的发射阵列 以及接收用于结合质子和多核成像应用的头部和身体的阵列组合。 将超高介电常数材料(UHDC)与多核线圈结合使用已被证明 潜在地降低了射频功率需求，同时提高了信噪比并降低了SAR。这个 最佳介电常数取决于感兴趣的谐振频率，而谐振频率取决于场强和 原子核正在调查中。X核10.5T工作频率的增加预计将允许 使用具有在超线性信噪比增加之外的信噪比附加增益的潜力的低损耗介质 由于场强的原因。

PROJECT SUMMARY/ ABSTRACT The overall objective of TRD4 is to develop innovative engineering solutions required to support the other TRDs and various collaborative and service projects in this P41 Center. One of the most important issues that needs to be addressed, particularly while developing new ultra-high field MR technologies, is to ensure the overall MR related safety of the technology. We demonstrated the feasibility of accurately predicting temperature increase in anesthetized animals due to power deposition from antenna arrays at 10.5 T and will expand on this work and explore true safety limits of transmit arrays by investigating in-vivo absolute temperature change. We also propose a novel approach to monitor surface temperatures with IR cameras integrated into coil housings. Another significant technological barrier for the larger MR community is how to address the safety issues and imaging artifacts associated with metallic implants and deep brain stimulator leads. The use of MRI for measuring tissue structure and function in the presence of implanted leads is also critically important for research aimed at understanding the mechanisms and evaluating the impact of neuromodulation. Yet, most individuals with such metallic implants cannot undergo MR imaging because of severe, RF-induced image artifacts and tissue heating. Therefore, novel MRI strategies that minimize a priori the occurrence of artifacts and tissue heating are desperately needed. We propose to develop parallel RF transmission strategies expanding on the previous methods that were developed to predict and/or reduce heating around implants. The increased SNR available at UHF (7 T and 10.5 T), in combination with newly developed optimized RF coil designs, offers the potential of achieving unprecedented high-resolution images of the brain. However, as image resolution increases, the problem of head motion during acquisition causing artifacts and blurring becomes more substantial. To address this problem, improved motion detection and correction approaches are necessary. We propose to develop novel sensor hardware and to translate existing external software developments for improved motion detection and correction. The data provided by these sensors can also be used for other purposes such as safety monitoring. Finally, we plan to expand on our extensive UHF technology expertise and propose optimized transmit arrays and receive array combinations for head and body that combine proton and multinuclear imaging applications. Using ultrahigh dielectric constant materials (uHDC) in conjunction with multinuclear coils has been shown to potentially decrease RF power requirements while simultaneously increasing SNR and reducing SAR. The optimal permittivity is dependent on the resonant frequency of interest, which depends on the field strength and nucleus under investigation. The increase in the 10.5T operating frequencies for X-nuclei is expected to allow use of lower loss dielectrics with the potential of additional gains in SNR beyond the supralinear SNR increase due to the field strength.