IEEE Trans Biomed Eng. 2021 Jan;68(1):109-118. doi: 10.1109/TBME.2020.2997770. Epub 2020 Dec 21.
Most MRI scanners are equipped to receive signals from H array coils but few support multi-channel reception for other nuclei. Using receive arrays can provide significant SNR benefits, usually exploited to enable accelerated imaging, but the extension of these arrays to non-H nuclei has received less attention because of the relative lack of broadband array receivers. Non-H nuclei often have low sensitivity and stand to benefit greatly from the increase in SNR that arrays can provide. This paper presents a cost-effective approach for adapting standard H multi-channel array receivers for use with other nuclei - in this case, C.
A frequency translation system has been developed that uses active mixers residing at the magnet bore to convert the received signal from a non-H array to the H frequency for reception by the host system receiver.
This system has been demonstrated at 4.7T and 7T while preserving SNR and isolation. H decoupling, particularly important for C detection, can be straightforwardly accommodated.
Frequency translation can convert H-only multi-channel receivers for use with other nuclei while maintaining SNR and channel isolation while still enabling H decoupling.
This work allows existing multi-channel MRI receivers to be adapted to receive signals from nuclei other than H, allowing for the use of receive arrays for in vivo multi-nuclear NMR.
大多数 MRI 扫描仪都配备了接收 H 数组线圈信号的功能，但很少支持其他核的多通道接收。使用接收阵列可以提供显著的信噪比增益，通常用于实现加速成像，但由于宽带阵列接收器相对较少，这些阵列扩展到非 H 核的应用较少。非 H 核通常灵敏度较低，从阵列提供的 SNR 增加中获益良多。本文提出了一种经济有效的方法，可将标准的 H 多通道阵列接收器用于其他核，在本例中为 C。
开发了一种频率转换系统，该系统使用位于磁体孔内的有源混频器将非 H 阵列接收到的信号转换为 H 频率，以便主机系统接收器接收。
该系统已在 4.7T 和 7T 下进行了演示，同时保持了 SNR 和隔离度。H 去耦，特别是对 C 检测非常重要，可以直接适应。
频率转换可以将仅用于 H 的多通道接收器转换为接收其他核的信号，同时保持 SNR 和通道隔离，同时仍然能够实现 H 去耦。
这项工作允许现有的多通道 MRI 接收器接收除 H 以外的核的信号，从而能够在体内多核 NMR 中使用接收阵列。
