Improved BOLD detection in the medial temporal region using parallel imaging and voxel volume reduction
Improved BOLD detection in the medial temporal region using parallel imaging and voxel volume reduction
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DOI：
10.1016/j.neuroimage.2005.08.042
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发表时间：
2006-02-15
期刊：
影响因子：
5.7
通讯作者：
Bodurka, J
中科院分区：
文献类型：
--
作者：
Bellgowan, PSF;Bandettini, PA;Bodurka, J
使用梯度回波EPI，由于宏观非共振效应引起的信号丢失可以阻止血氧水平依赖（BOLD）信号变化检测。前内侧颞叶（MTL）位于这些磁化率梯度附近，因此GE-EPI显示出相当大的信号丢失。减小图像体素的体积减少了与可测量性相关的信号丢失。然而，这伴随着信号-音调噪声比（SNR）的禁止性降低。为了用较小的体素补偿SNR损失，我们使用了多通道MRI接收器，该接收器具有在3 T下仅接收的16元件表面线圈阵列。我们证明，通过使用高分辨率图像，再加上从阵列线圈的图像SNR的增益，减少磁化率伪影，提高了时间信噪比（TSNR），提高了对比度噪声比（CNR）。此外，2圈与4 mm厚轴向图像的比较（两者具有相同的平面内分辨率）表明，较薄的切片增强了整个颞叶腹内侧区域的TSNR和CNR，其中MTL最前部区域的改善最大。当相邻的2 mm切片组合以匹配整体体素体积时，观察到进一步的改善。这些结果表明，BOLD研究的前MTL功能可以通过减少体素的大小，但只有在结合使用16通道头部线圈系统获得的SNR增强。爱思唯尔公司出版
Using gradient-echo EPI, signal dropout due to macroscopic off resonance effects can prevent blood-oxygenation-level-dependent (BOLD) signal change detection. The anterior medial temporal lobe (MTL) is located near these susceptibility gradients and therefore shows considerable signal dropout with GE-EPI. Reducing the volume of the image voxel reduces susceptibility-related signal dropout. However, this is accompanied by a prohibitive reduction in signal-tonoise ratio (SNR). To compensate for SNR loss with smaller voxels, we used a multi-channel MRI receiver with an array of receive-only 16-element surface coils at 3 T. We demonstrate that the reduction of susceptibility artifacts, through use of high resolution images, coupled with the gains in image SNR from the array coil improves the temporal signal-to-noise ratio (TSNR) and enhances the contrast-to-noise ratio (CNR). Furthermore, a comparison of 2 turn with 4-mm-thick axial images both with the same in-plane resolution showed that thinner slices enhanced TSNR and CNR throughout the ventral-medial regions of the temporal lobes, with the greatest improvement in the most anterior regions of the MTL. Further improvements were seen when adjacent 2 mm slices were combined to match overall voxel volume. These results demonstrate that BOLD investigation of anterior MTL function can be enhanced by decreasing voxel size but only in combination with the SNR gained by using the 16-channel head coil system. Published by Elsevier Inc.