Performance of a 200-MHz cryogenic RF probe designed for MRI and MRS of the murine brain
Performance of a 200-MHz cryogenic RF probe designed for MRI and MRS of the murine brain
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DOI：
10.1002/mrm.21629
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发表时间：
2008-06-01
影响因子：
3.3
通讯作者：
Rudin, Markus
中科院分区：
文献类型：
--
作者：
Ratering, David;Baltes, Christof;Rudin, Markus
描述了一种由铜制成、专为小鼠大脑研究而设计的低温 200 MHz 射频发射/接收探针 (CryoProbe)。该探头的工作温度为 30K，其性能与相同尺寸的自制表面线圈和鼠标头体积谐振器进行了比较，两者均在室温 (RT) 下工作。由于对于小体积的被询问组织（< 5 mL），样本噪声和接收器的热噪声具有可比性，因此可以通过冷却接收器系统（例如使用冷氦气）来实现相当大的噪声降低。使用传统 MRI 序列（自旋和梯度回波）和单体素 MR 波谱，在体模和活体鼠脑研究中评估了温度降低对信噪比 (SNR) 的影响。观察到 CryoProbe 的灵敏度持续增加。与 MRI 和 MRS 实验的 RT 表面线圈相比，体模实验的 SNR 增加 >= 2 倍，体内实验的 SNR 增加 1.8 至 1.9 倍。这些结果与冷却至 30K 的圆形表面线圈探头的估计 SNR 增益非常一致。使用低温探头是提高小动物 MRI/MRS 灵敏度的经济上有吸引力的选择。
A cryogenic 200-MHz RF transmit/receive probe (CryoProbe) made of copper and designed for murine brain studies is described. The probe operates at 30K and its performance was compared to a home-made surface coil of equal dimensions and a mouse head volume resonator, both operating at room temperature (RT). Since for small volumes of tissue interrogated (< 5 mL) sample noise and thermal noise of the receiver are of comparable magnitude, considerable noise reduction can be achieved by cooling of the receiver system, e.g., using cold helium gas. The effect of temperature lowering on the signal-to-noise ratio (SNR) was assessed in phantom and in vivo murine brain studies using conventional MRI sequences (spin and gradient echo) and single voxel MR spectroscopy. Consistent sensitivity increases were observed for the CryoProbe. SNR increases by a factor >= 2 for the phantom experiments and by factors of 1.8 to 1.9 for in vivo experiments when compared to the RT surface coil for both MRI and MRS experiments. These results are in good agreement with estimated SNR gains for a circular surface coil probe cooled to 30K. The use of a cryogenic probe represents an economically attractive option to enhance the sensitivity in small animal MRI/MRS.