Validation of diffusion spectrum magnetic resonance imaging with manganese-enhanced rat optic tracts and ex vivo phantoms
Validation of diffusion spectrum magnetic resonance imaging with manganese-enhanced rat optic tracts and ex vivo phantoms
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DOI：
10.1016/s1053-8119(03)00154-x
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发表时间：
2003-07-01
期刊：
影响因子：
5.7
通讯作者：
Tseng, WYI
中科院分区：
文献类型：
--
作者：
Lin, CP;Wedeen, VJ;Tseng, WYI
扩散光谱成像（DSI）已被证明可以通过映射水分子在每个体素上扩散的概率密度函数来分辨交叉轴突纤维。然而，DSI在确定单个光纤取向方面的准确性和有限梯度脉冲宽度下傅里叶关系的有效性尚未得到评估。我们分别建立了离体和体内模型来评估梯度脉冲宽度相对较短和较长时DSI的误差。离体模型是一个由充满水的平行毛细血管片组成的幻影。薄片相互堆叠，毛细血管呈45度或90度交叉。高分辨率t2加权图像（T2W1）可作为交叉毛细血管方向的参考。在体内模型中，将锰离子注入大鼠视神经束。在t1加权图像（T1WI）上增强视神经束，作为视神经束定位的参考。DSI与T2WI对比，弥散谱主取向与90度、45度幻像的偏离角分别为1.19°+/- 4.82°和-0.71°+/- 4.91°。DSI与大鼠视神经束T1WI比较，弥散谱初级取向与视神经束的偏差角为-0.41°+/- 6.18°。此外，在大鼠脑中使用短和长梯度脉冲进行两组DSI序列。这两个序列之间的主取向偏差约为10度。综上所述，DSI可以准确地分辨出交叉光纤的方向。有限梯度脉冲宽度对初级定向的影响并不重要。(C) 2003 Elsevier Science（美国）版权所有。
Diffusion spectrum imaging (DSI) has been demonstrated to resolve crossing axonal fibers by mapping the probability density function of water molecules diffusion at each voxel. However, the accuracy of DSI in defining individual fiber orientation and the validity of Fourier relation under finite gradient pulse widths are not assessed yet. We developed an ex vivo and an in vivo model to evaluate the error of DSI with gradient pulse widths being relatively short and long, respectively. The ex vivo model was a phantom comprising sheets of parallel capillaries filled with water. Sheets were stacked on each other with capillaries crossed at 45degrees or 90degrees. High-resolution T2-weighted images (T2W1) of the phantom served as a reference for the orientation of intersecting capillaries. In the in vivo model, manganese ions were infused into rats' optic tracts. The optic tracts were enhanced on T1-weighted images (T1WI) and served as a reference for the tract orientation. By comparing DSI with T2WI, the deviation angles between the primary orientation of diffusion spectrum and the 90degrees and 45degrees phantoms were 1.19degrees +/- 4.82degrees and -0.71degrees +/- 4.91degrees, respectively. By comparing DSI with the T1WI of rat optic tracts, the deviation angle between primary orientation of diffusion spectrum and optic tracts was -0.41degrees +/- 6.18degrees. In addition, two sequences of DSI using short and long gradient pulses were performed in a rat brain. The bias of the primary orientation between these two sequences was approximately 10degrees. In conclusion, DSI can resolve crossing fiber orientation accurately. The effect of finite gradient pulse widths on the primary orientation is not critical. (C) 2003 Elsevier Science (USA). All rights reserved.