Abstract：
We aim to assess a straightforward technique to enhance spectral quality in the brain, particularly in the cerebellum, during 7 T MRI scans. This is achieved through a wireless RF array insert designed to mitigate signal dropouts caused by the limited transmit field efficiency in the inferior part of the brain. We recently developed a wireless RF array to improve MRI and 1H-MRS at 7 T by augmenting signal via inductive coupling between the wireless RF array and the MRI coil. In vivo experiments on a Siemens 7 T whole-body human scanner with a Nova 1Tx/32Rx head coil quantified the impact of the dorsal cervical array in improving signal in the posterior fossa, including the cerebellum, where the transmit efficiency of the coil is inherently low. The 1H-MRS experimental protocol consisted of paired acquisition of data sets, both with and without the RF array, using the semi-LASER and SASSI sequences. The overall results indicate that the localized 1H-MRS is improved significantly in the presence of the array. Comparison of in vivo 1H-MRS plots in the presence versus absence of the array demonstrated an average SNR enhancement of a factor of 2.2. LCModel analysis reported reduced Cramér-Rao lower bounds, indicating more confident fits. This wireless RF array can significantly increase detection sensitivity. It may reduce the RF transmission power and data acquisition time for 1H-MRS and MRI applications, specifically at 7 T, where 1H-MRS requires a high-power RF pulse. The array could provide a cost-effective and efficient solution to improve detection sensitivity for human 1H-MRS and MRI in the regions with lower transmit efficiency.
摘要：
我们的目标是评估一种简单的技术来提高大脑的光谱质量，尤其是小脑,在7TMRI扫描期间。这是通过无线RF阵列插入来实现的,该无线RF阵列插入被设计为减轻由大脑下部的有限的发射场效率引起的信号丢失。我们最近开发了一种无线RF阵列，通过无线RF阵列和MRI线圈之间的电感耦合来增强信号，从而改善7T的MRI和1H-MRS。在带有Nova1Tx/32Rx头线圈的西门子7T全身人体扫描仪上进行的体内实验，量化了背颈椎阵列在改善后颅窝信号方面的影响，包括小脑,其中线圈的传输效率固有地很低。1H-MRS实验协议包括成对采集数据集，有和没有射频阵列，使用半激光和SASSI序列。总体结果表明,在阵列的存在下,局部1H-MRS显著改善。在存在与不存在阵列的情况下的体内1H-MRS图的比较表明平均SNR增强为2.2倍。LCPmodel分析报告Cramér-Rao下界减少，表明更自信的适合。该无线RF阵列可以显著提高检测灵敏度。它可以减少1H-MRS和MRI应用的RF发射功率和数据采集时间，特别是在7T时，其中1H-MRS需要高功率RF脉冲。该阵列可以提供一种成本有效且有效的解决方案，以提高传输效率较低的区域中人类1H-MRS和MRI的检测灵敏度。
