Harmonic analysis of spherical sampling in diffusion MRI
Harmonic analysis of spherical sampling in diffusion MRI
复制标题
扩散 MRI 中球形采样的谐波分析
DOI：
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发表时间：
2011
期刊：
影响因子：
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通讯作者：
Y. Wiaux
中科院分区：
文献类型：
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作者：
Alessandro Daducci;J. McEwen;D. Ville;J. Thiran;Y. Wiaux
在过去的十年中，扩散MRI已成为一个强大的工具，非侵入性研究脑白质的完整性。最近，许多研究小组将注意力集中在多壳层球形采集上，目的是有效地映射具有较低数量的q空间样本的扩散信号，从而实现采集时间的关键减少。在这种情况下，通常研究的量之一是所谓的取向分布函数（ODF）。在这种情况下，球谐（SH）变换由于其能够有效和准确地执行卷积运算而获得了很大的普及，例如从q空间数据进行ODF计算所需的Funk-Radon变换。然而，如果q空间信号在任何探测的b值处用不合适的角分辨率来描述，则会不可避免地产生混叠（或插值）伪影。到目前为止，这方面已经解决了经验，据我们所知，没有研究已经解决了这个问题的定量方法。本工作的目的是从理论上研究扩散MRI中多壳层球形采样的效率，以便了解HYDI类方法，可能为进一步优化策略铺平道路。
In the last decade diffusion MRI has become a powerful tool to non-invasively study white-matter integrity in the brain. Recently many research groups have focused their attention on multi-shell spherical acquisitions with the aim of effectively mapping the diffusion signal with a lower number of q-space samples, hence enabling a crucial reduction of acquisition time. One of the quantities commonly studied in this context is the so-called orientation distribution function (ODF). In this setting, the spherical harmonic (SH) transform has gained a great deal of popularity thanks to its ability to perform convolution operations efficiently and accurately, such as the Funk-Radon transform notably required for ODF computation from q-space data. However, if the q-space signal is described with an unsuitable angular resolution at any b-value probed, aliasing (or interpolation) artifacts are unavoidably created. So far this aspect has been tackled empirically and, to our knowledge, no study has addressed this problem in a quantitative approach. The aim of the present work is to study more theoretically the efficiency of multi-shell spherical sampling in diffusion MRI, in order to gain understanding in HYDI-like approaches, possibly paving the way to further optimization strategies.