Experimental considerations for fast kurtosis imaging.
Experimental considerations for fast kurtosis imaging.
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DOI：
10.1002/mrm.26055
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发表时间：
2016-11
影响因子：
3.3
通讯作者：
Jespersen SN
中科院分区：
文献类型：
--
作者：
Hansen B;Lund TE;Sangill R;Stubbe E;Finsterbusch J;Jespersen SN
峰度成像的临床应用受到长时间采集和后处理的阻碍。最近，通过简单的后处理，可以从13个不同的DWI采集（1-3-9方案）中估计平均峰度张量W和平均扩散率（D）。在这里，我们分析了噪声和非理想扩散编码的影响，并提出了一种新的校正策略。我们还提出了一个1-9-9协议，增加了实验缺陷和最小的额外扫描时间的鲁棒性。这种细化不影响计算时间，也提供了一个快速估计分数各向异性（FA）。在大鼠和人脑中获得1-3-9/1-9-9数据，并将来自人脑的D β、FA、W β的估计值与来自广泛DKI数据集的传统估计值进行比较。仿真被用来评估噪声和扩散编码偏离该方案的影响，以及校正策略的性能。根据模拟和数据确定最佳b值。D-1和W-2的准确度和精密度与非线性最小二乘估计相当，并且通过1-9-9方案得到改善。补偿策略极大地改善了非理想数据中的参数估计。该框架提供了一个强大的和紧凑的方法来估计几个扩散度量。该协议很容易实现。
The clinical use of kurtosis imaging is impeded by long acquisitions and post-processing. Recently, estimation of mean kurtosis tensor W̅ and mean diffusivity (D̅) was made possible from 13 distinct DWI acquisitions (the 1-3-9 protocol) with simple post-processing. Here, we analyze the effects of noise and nonideal diffusion encoding, and propose a new correction strategy. We also present a 1-9-9 protocol with increased robustness to experimental imperfections and minimal additional scan time. This refinement does not affect computation time and also provides a fast estimate of fractional anisotropy (FA). 1-3-9/1-9-9 data are acquired in rat and human brains, and estimates of D̅, FA, W̅ from human brains are compared to traditional estimates from an extensive DKI data set. Simulations are used to evaluate the influence of noise and diffusion encodings deviating from the scheme, and the performance of the correction strategy. Optimal b-values are determined from simulations and data. Accuracy and precision in D̅ and W̅ are comparable to nonlinear least squares estimation, and is improved with the 1-9-9 protocol. The compensation strategy vastly improves parameter estimation in non-ideal data. The framework offers a robust and compact method for estimating several diffusion metrics. The protocol is easily implemented.