k-space and q-space: Combining ultra-high spatial and angular resolution in diffusion imaging using ZOOPPA at 7 T
k-space and q-space: Combining ultra-high spatial and angular resolution in diffusion imaging using ZOOPPA at 7 T
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DOI：
10.1016/j.neuroimage.2011.12.081
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发表时间：
2012-04-02
期刊：
影响因子：
5.7
通讯作者：
Turner, Robert
中科院分区：
文献类型：
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作者：
Heidemann, Robin M.;Anwander, Alfred;Turner, Robert
对于使用更高的空间分辨率（采样k-空间）还是更高的角度分辨率（采样q-空间角度）是改善活体中基于弥散MRI（dMRI）的纤维束成像结果的更好方法，目前仍存在争议。在这两种情况下，限制因素是信噪比（SNR），由于有限的采集时间。在不牺牲SNR或角分辨率的情况下增加空间分辨率的一种可能方式是移动到更高的磁场强度。尽管如此，dMRI并不是超高场强（7 T）的首选应用。这是因为单次激发回波平面成像（EPI）已成为人体体内dMRI的首选方法。EPI面临与在高场强下使用高分辨率相关的若干挑战，例如失真和图像模糊。这些问题很容易损害预期的SNR增益与场强。在目前的研究中，我们介绍了一个适应EPI序列结合ZOOmed成像和部分并行采集（ZOOPPA）的组合。我们证明，该方法可以产生高质量的扩散加权图像与高空间和角分辨率在7 T。我们提供的例子，在体内人体dMRI的各向同性分辨率为1毫米和800 μ m。这些数据集特别适合于解析复杂和微妙的纤维结构，包括白色物质中的纤维交叉、皮质中的各向异性和进入皮质的纤维。(c)2012 Elsevier Inc. All rights reserved.
There is ongoing debate whether using a higher spatial resolution (sampling k-space) or a higher angular resolution (sampling q-space angles) is the better way to improve diffusion MRI (dMRI) based tractography results in living humans. In both cases, the limiting factor is the signal-to-noise ratio (SNR), due to the restricted acquisition time. One possible way to increase the spatial resolution without sacrificing either SNR or angular resolution is to move to a higher magnetic field strength. Nevertheless, dMRI has not been the preferred application for ultra-high field strength (7 T). This is because single-shot echo-planar imaging (EPI) has been the method of choice for human in vivo dMRI. EPI faces several challenges related to the use of a high resolution at high field strength, for example, distortions and image blurring. These problems can easily compromise the expected SNR gain with field strength. In the current study, we introduce an adapted EPI sequence in conjunction with a combination of ZOOmed imaging and Partially Parallel Acquisition (ZOOPPA). We demonstrate that the method can produce high quality diffusion-weighted images with high spatial and angular resolution at 7 T. We provide examples of in vivo human dMRI with isotropic resolutions of 1 mm and 800 mu m. These data sets are particularly suitable for resolving complex and subtle fiber architectures, including fiber crossings in the white matter, anisotropy in the cortex and fibers entering the cortex. (c) 2012 Elsevier Inc. All rights reserved.