TRD4 - Ultrahigh Field Engineering and Safety

项目总结/摘要 TRD 4的总体目标是开发创新的工程解决方案， TRD和各种合作和服务项目在这个P41中心。最重要的问题之一， 需要解决的问题，特别是在开发新的超高场MR技术时，是确保 技术的总体MR相关安全性。我们证明了准确预测温度的可行性 在10.5 T下，由于天线阵列的功率沉积，麻醉动物增加，并将对此进行扩展 通过研究体内绝对温度变化，研究和探索发射阵列的真正安全极限。我们 还提出了一种新的方法来监测表面温度与红外摄像机集成到线圈外壳。 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深部脑刺激器引线相关的成像伪影。MRI的使用 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并评估其影响。然而，大多数人 由于严重的RF诱发的图像伪影， 组织加热。因此，最小化伪影和组织的先验发生的新型MRI策略 暖气是迫切需要的。我们建议开发并行RF传输策略， 先前开发的用于预测和/或减少植入物周围发热的方法。 在UHF（7 T和10.5 T）下提供更高的SNR，结合新开发的优化RF 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。但随着 图像分辨率增加，采集期间头部运动的问题导致伪影和模糊 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被 必要我们建议开发新的传感器硬件和翻译现有的外部软件 改进的运动检测和校正的发展。这些传感器提供的数据也可以 用于其他目的，如安全监测。 最后，我们计划扩展我们广泛的UHF技术专业知识，并提出优化的发射阵列 以及用于头部和身体的接收阵列组合，其组合了联合收割机质子和多核成像应用。 使用介电常数小于100的材料（uHDC）结合多核线圈已经被证明， 潜在地降低RF功率要求，同时增加SNR并降低SAR。的 最佳介电常数取决于感兴趣的谐振频率，该谐振频率取决于场强， 正在调查的核。X核10.5T工作频率的增加预计将允许 使用较低损耗的SNR，在超线性SNR增加之外可能有额外的SNR增益 因为磁场强度。

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.