Robust determination of the fibre orientation distribution in diffusion MRI: Non-negativity constrained super-resolved spherical deconvolution
Robust determination of the fibre orientation distribution in diffusion MRI: Non-negativity constrained super-resolved spherical deconvolution
复制标题
DOI：
10.1016/j.neuroimage.2007.02.016
复制
发表时间：
2007-05-01
期刊：
影响因子：
5.7
通讯作者：
Connelly, Alan
中科院分区：
文献类型：
--
作者：
Tournier, J-Donald;Calamante, Fernando;Connelly, Alan
弥散加权（DW） MR图像包含有关脑白质纤维方向的信息，这些信息有可能用于利用神经束成像技术在体内研究人类大脑连接。目前，扩散张量模型被广泛用于从DW-MRI数据中提取纤维方向，但在包含多个纤维方向的区域中失败。球面反褶积技术最近被提出来解决这一限制。它通过假设从任何纤维束测量到的DW信号被一个单一的响应函数充分描述，提供了对纤维取向分布（FOD）的估计。然而，反褶积是病态的，容易受到噪声污染。这往往会在FOD中引入人为的负区域，这显然在物理上是不可能的。在本研究中，提出了对这些负区域的约束，以改善球面反褶积的条件。这种方法被证明可以提供对噪声具有鲁棒性的FOD估计，同时保持角分辨率。该方法还允许使用超分辨率，由此估计的FOD参数比实际测量的要多，从而提高了结果的角分辨率。该方法提供了更明确的纤维取向估计，并且可以分辨出比以前更小的角度分离的取向。这样就可以设计出能够通过交叉纤维区域可靠跟踪的轨迹图算法。(c) 2007爱思唯尔公司版权所有。
Diffusion-weighted (DW) MR images contain information about the orientation of brain white matter fibres that potentially can be used to study human brain connectivity in vivo using tractography techniques. Currently, the diffusion tensor model is widely used to extract fibre directions from DW-MRI data, but fails in regions containing multiple fibre orientations. The spherical deconvolution technique has recently been proposed to address this limitation. It provides an estimate of the fibre orientation distribution (FOD) by assuming the DW signal measured from any fibre bundle is adequately described by a single response function. However, the deconvolution is ill-conditioned and susceptible to noise contamination. This tends to introduce artefactual negative regions in the FOD, which are clearly physically impossible. In this study, the introduction of a constraint on such negative regions is proposed to improve the conditioning of the spherical deconvolution. This approach is shown to provide FOD estimates that are robust to noise whilst preserving angular resolution. The approach also permits the use of super-resolution, whereby more FOD parameters are estimated than were actually measured, improving the angular resolution of the results. The method provides much better defined fibre orientation estimates, and allows orientations to be resolved that are separated by smaller angles than previously possible. This should allow tractography algorithms to be designed that are able to track reliably through crossing fibre regions. (c) 2007 Elsevier Inc. All rights reserved.