Fractional Order Anisotropy at 9.4 T
Fractional Order Anisotropy at 9.4 T
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9.4 T 下的分数阶各向异性
DOI：
10.1166/jmihi.2019.2661
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发表时间：
2019-06
影响因子：
--
通讯作者：
Zhong Kai
中科院分区：
文献类型：
--
作者：
Wen Qingqing;Zhang Xiaoming;Tong Haiyang;Yang Hongyi;Zhong Kai
分数阶微积分（FC）模型在Bloch-Torrey方程中引入分数阶微分算子。以往对FC模型的研究没有考虑扩散各向异性。研究了分数阶微积分（FC）扩散模型参数的各向异性性质，研究了扩散系数D、异质性指数β和空间参数μ。在9.4 T下，使用小鼠脑、心脏和肾脏的组织样品在体外进行扩散加权成像实验，分别沿着三个主轴施加扩散梯度（b值范围：0-3500 s/mm 2）。此外，在小鼠脑实验中还使用了几个扩散时间（12-33 ms）。结果表明，在所有研究的样品中，β的各向异性比D和μ的各向异性小得多，表明β与D和β相比与扩散方向没有强相关性。此外，扩散时间对灰质中β的各向异性影响不大，而D和μ的各向异性随扩散时间的增加而发生显著变化。由于β的方向不敏感性，从单向扩散加权成像获得的参数β图可以提供可靠的组织异质性信息。
The fractional order calculus (FC) model applied fractional order differential operators in the Bloch-Torrey equation. Previous studies on the FC model didn't consider the diffusion anisotropy. In this study, the anisotropy property of parameters in fractional order calculus (FC) diffusion model, i.e., the diffusion coefficient D, the heterogeneity index β and the spatial parameter μ were investigated. The diffusion-weighted imaging experiments were performed in vitro at 9.4 T using tissue samples of mice brains, hearts and kidneys with the diffusion gradient applied along the three principle axes separately (b-value range: 0–3500 s/mm2). In addition, several diffusion times (12–33 ms) were also used in mice brain experiments. The results showed that the anisotropy of β was much smaller compared to that of D and μ in all the samples studied, indicating that β was not strongly correlated to the diffusional directions compared to D and β. In addition, the diffusion time had little influence on the anisotropy of β in gray matter, while the anisotropy of D and μ changed significantly with increased diffusion time. Due to the direction-insensitive of β, parameter β maps obtained from single-direction diffusion-weighted imaging can give reliable tissue heterogeneity information.