Yoshida Tsukasa, Shirata Kensei, Urikura Atsushi, Ito Michitoshi, Nakaya Yoshihiro
Department of Imaging Diagnostics, Shizuoka Cancer Center, 1007 Shimonagakubo, Nagaizumi, Sunto, Shizuoka, 411-8777, Japan,
Radiol Phys Technol. 2015 Jul;8(2):305-11. doi: 10.1007/s12194-015-0321-6. Epub 2015 May 26.
The signal-to-noise ratio (SNR) and parallel imaging (PI) performance of two commercial phased-array coils (PACs) were examined in magnetic resonance imaging (MRI) of the brain. All measurements were performed on a 3.0 T MRI instrument. The SNR and PI performance were evaluated with 32-channel and 15-channel PACs. A gradient echo sequence was used for obtaining images of a phantom. SNR and geometry factor (g-factor) maps were calculated from two images with identical parameters. Horizontal and vertical profiles were taken through the SNR maps in the axial plane. The average g-factor was measured in a circular region of interest in the g-factor maps for the axial plane. The SNR map of the 32-channel coil showed a higher SNR than that of the 15-channel coil at the phantom's posterior and lateral surfaces. The SNR profiles for the 32-channel coil also showed a 1.3-fold increase at the phantom's center. The average g-factor of the 32-channel coil was lower than that of the 15-channel coil at the same acceleration factor. These results indicate that the 32-channel coil can provide a higher spatial resolution and/or a faster imaging speed. Horizontal and vertical profiles are useful for evaluation of the performance of commercially available PACs.
在脑部磁共振成像（MRI）中，对两款商用相控阵线圈（PAC）的信噪比（SNR）和平行成像（PI）性能进行了检测。所有测量均在一台3.0 T MRI仪器上进行。使用32通道和15通道的PAC评估SNR和PI性能。采用梯度回波序列获取模体图像。根据具有相同参数的两幅图像计算SNR和几何因子（g因子）图。在轴向平面上通过SNR图获取水平和垂直剖面。在轴向平面g因子图的圆形感兴趣区域测量平均g因子。在模体的后表面和侧面，32通道线圈的SNR图显示出比15通道线圈更高的SNR。32通道线圈的SNR剖面在模体中心也显示出1.3倍的增加。在相同加速因子下，32通道线圈的平均g因子低于15通道线圈。这些结果表明，32通道线圈可提供更高的空间分辨率和/或更快的成像速度。水平和垂直剖面对于评估商用PAC的性能很有用。
