Institute of Medicine, Research Centre Jülich, 52425 Jülich, Germany.
Magn Reson Imaging. 2010 Apr;28(3):329-40. doi: 10.1016/j.mri.2009.11.006. Epub 2010 Feb 1.
We present high-resolution in vivo anatomical scans with 3D whole-brain coverage and an isotropic resolution of 0.6 mm, obtained at a clinical field of 1.5 T. The data are acquired in 10 independent scans over two sessions using a 3D magnetization-prepared, gradient echo sequence, modified to output phase images in addition to magnitude images. The independent scans are coregistered to correct for head motion, prior to performing complex averaging. The resolution of the final, averaged image, is found to be equal to the nominal one. The separation between the distribution of gray-scale values characterizing the gray and white matter, respectively, is substantially improved over single-scan images. Complex and magnitude averaging are compared and found to deliver similar results for regions with a high initial signal-to-noise ratio (SNR) within the brain. However, complex averaging is strongly recommended for quantitative applications or for studies where regions of low initial SNR are important. To summarize, a method for high-resolution in vivo anatomical imaging at a clinical field strength is demonstrated and is recommended for brain mapping. The method can also be applied at higher fields with a reduced acquisition time.
我们展示了在临床 1.5T 场强下获得的具有 3D 全脑覆盖和 0.6 毫米各向同性分辨率的高分辨率活体解剖扫描。该数据是在两个会话中使用 3D 磁化准备、梯度回波序列采集的 10 个独立扫描获得的，该序列经过修改，除了幅度图像外还输出相位图像。在进行复杂平均之前，将独立扫描配准以校正头部运动。最终平均图像的分辨率被发现等于标称分辨率。与单扫描图像相比，分别表征灰质和白质的灰度值分布之间的分离度得到了显著提高。对大脑内具有高初始信噪比 (SNR) 的区域进行了复杂平均和幅度平均的比较，发现两者产生了类似的结果。然而，强烈推荐复杂平均用于定量应用或对初始 SNR 较低的区域很重要的研究。总之，展示了一种在临床场强下进行高分辨率活体解剖成像的方法，并推荐用于脑图谱。该方法也可以在具有缩短采集时间的更高场强下应用。
