Center for Environmental Measurement and Analysis, National Institutes for Environmental Studies, Tsukuba, Ibaraki, Japan.
Magn Reson Med Sci. 2012;11(3):193-6. doi: 10.2463/mrms.11.193.
We demonstrated that the radiofrequency (RF) reception field is proportional to B₁⁻* straightforwardly in magnetic resonance (MR) imaging experiments at 4.7 T. We compared maps of the reception field and the B₁⁻ of a saline phantom in magnitude and phase. First, we measured the image using an adiabatic spin echo (ASE) sequence with homogeneous excitation. That image corresponds to a map of the reception field. Next, we rotated the RF coil with the sample 180° around the vertical axis to measure the map of the transmission field that corresponded to B₁⁻ in the original configuration. The magnitude of the distribution fields of the reception field and B₁⁻ maps was almost identical. Examining the phases of the ASE images in the original and inverted configurations, we observed almost the same distribution in both phase maps, which indicated the proportionality of the reception field to B₁⁻*.
我们在 4.7T 的磁共振成像实验中证明，射频（RF）接收场与 B₁⁻*成正比。我们比较了盐溶液模型的接收场和 B₁⁻的幅度和相位图。首先，我们使用各向同性激发的绝热自旋回波（ASE）序列测量图像。该图像对应于接收场的图谱。接下来，我们绕垂直轴将 RF 线圈与样品旋转 180°，以测量与原始配置中 B₁⁻对应的传输场图谱。接收场和 B₁⁻图谱的分布场幅度几乎相同。检查原始和倒置配置中 ASE 图像的相位，我们观察到两个相位图谱中的分布几乎相同，这表明接收场与 B₁⁻*成正比。
