Q-ball reconstruction of multimodal fiber orientations using the spherical harmonic basis
Q-ball reconstruction of multimodal fiber orientations using the spherical harmonic basis
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DOI：
10.1002/mrm.20931
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发表时间：
2006-07-01
影响因子：
3.3
通讯作者：
Vigneron, Daniel B.
中科院分区：
文献类型：
--
作者：
Hess, Christopher P.;Mukherjee, Pratik;Vigneron, Daniel B.
当高斯扩散模型有效时，扩散张量成像（DTI）可准确描绘白色物质通路。然而，当弥散呈现更复杂的分布时，DTI会产生错误的结果，就像大脑中纤维束交叉时的情况一样。高角分辨率扩散成像（HARDI）通过更全面地表征体素内扩散的角度依赖性克服了DTI的这一限制。在已经提出的各种HARDI方法中，ODF具有线性、模型独立和相对容易实现等优点。在这项工作中，重建的q球取向分布函数（ODF）的球谐基函数，产生一个有用的特性的频域表示的解析解。谐波基础对于典型的b值是简约的，这使得ODF能够从相对少量的噪声测量合成，从而从总成像时间的角度来看使该技术更接近临床可行性。所提出的方法进行评估，使用Monte Carlo计算机模拟，并与传统的q球重建使用球形径向基函数。还提供了成年志愿者的3T全脑HARDI的体内结果以验证基本的数学理论。
Diffusion tensor imaging (DTI) accurately delineates white matter pathways when the Gaussian model of diffusion is valid. However, DTI yields erroneous results when diffusion takes on a more complex distribution, as is the case in the brain when fiber tracts cross. High angular resolution diffusion imaging (HARDI) overcomes this limitation of DTI by more fully characterizing the angular dependence of intravoxel diffusion. Among the various HARDI methods that have been proposed, ODF offers advantages such as linearity, model independence, and relatively easy implementation. In this work, reconstruction of the q-ball orientation distribution function (ODF) is reformulated in terms of spherical harmonic basis functions, yielding an analytic solution with useful properties of a frequency domain representation. The harmonic basis is parsimonious for typical b-values, which enables the ODF to be synthesized from a relatively small number of noisy measurements and thus brings the technique closer to clinical feasibility from the standpoint of total imaging time. The proposed method is assessed using Monte Carlo computer simulations and compared with conventional q-ball reconstruction using spherical RBFs. In vivo results from 3T whole-brain HARDI of adult volunteers are also provided to verify the underlying mathematical theory.