A 128-channel receive array for cortical brain imaging at 7 T.
A 128-channel receive array for cortical brain imaging at 7 T.
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用于 7°T 皮质脑成像的 128 通道接收阵列。
DOI：
10.1002/mrm.29798
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发表时间：
2023
影响因子：
3.3
通讯作者：
Wald,LawrenceL
中科院分区：
文献类型：
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作者：
Gruber,Bernhard;Stockmann,JasonP;Mareyam,Azma;Keil,Boris;Bilgic,Berkin;Chang,Yulin;Kazemivalipour,Ehsan;Beckett,AlexanderJS;Vu,AnT;Feinberg,DavidA;Wald,LawrenceL
目的模拟、设计、构建和测试一个7 T的128通道纯接收脑成像阵列，该阵列采用高性能的头部梯度，用于高分辨率功能成像。方法线圈采用紧贴的头盔几何结构，填充128个环路元件和前置放大器，以适应内置梯度内直径为39 cm的空间。在体内测量了系统的信噪比(SNR)和并行成像性能(1/g)，并用电磁模型进行了仿真。分析1/G因素的直方图以评估表现的范围。结果以体噪声为主的环路构成128通道阵列是可行的，平均噪声相关系数为5.4%。测量表明，与32通道和通道阵列相比，通过更高的本征信噪比和g因子的改进，提高了灵敏度。对于非加速成像，128通道阵列在大脑中央的信噪比分别比32通道阵列和通道阵列高17.6%和9.3%，在包括皮质在内的大脑外围区域的信噪比分别高42%和18%。在R = 5加速成像中，大脑中心的这些增益分别为44.2%和24.3%，皮质的这些增益分别为86.7%和48.7%。随着通道数目的增加，1/g因子直方图的均值和分布都得到了改善，并且随着加速程度的增加，这两种影响变得更加明显。结论实验结果证实，将通道数目增加到128个通道有利于7T脑成像，无论是提高周围脑区的SNR还是加速成像都是有利的。
PurposeA 128‐channel receive‐only array for brain imaging at 7 T was simulated, designed, constructed, and tested within a high‐performance head gradient designed for high‐resolution functional imaging.MethodsThe coil used a tight‐fitting helmet geometry populated with 128 loop elements and preamplifiers to fit into a 39 cm diameter space inside a built‐in gradient. The signal‐to‐noise ratio (SNR) and parallel imaging performance (1/g) were measured in vivo and simulated using electromagnetic modeling. The histogram of 1/gfactors was analyzed to assess the range of performance. The array's performance was compared to the industry‐standard 32‐channel receive array and a 64‐channel research array.ResultsIt was possible to construct the 128‐channel array with body noise–dominated loops producing an average noise correlation of 5.4%. Measurements showed increased sensitivity compared with the 32‐channel and 64‐channel array through a combination of higher intrinsic SNR and g‐factor improvements. For unaccelerated imaging, the 128‐channel array showed SNR gains of 17.6% and 9.3% compared to the 32‐channel and 64‐channel array, respectively, at the center of the brain and 42% and 18% higher SNR in the peripheral brain regions including the cortex. For R = 5 accelerated imaging, these gains were 44.2% and 24.3% at the brain center and 86.7% and 48.7% in the cortex. The 1/g‐factor histograms show both an improved mean and a tighter distribution by increasing the channel count, with both effects becoming more pronounced at higher accelerations.ConclusionThe experimental results confirm that increasing the channel count to 128 channels is beneficial for 7T brain imaging, both for increasing SNR in peripheral brain regions and for accelerated imaging.