Effects of signal-to-noise ratio on the accuracy and reproducibility, of diffusion tensor imaging-derived fractional anisotropy, mean diffusivity, and principal eigenvector measurements at 1.5T
Effects of signal-to-noise ratio on the accuracy and reproducibility, of diffusion tensor imaging-derived fractional anisotropy, mean diffusivity, and principal eigenvector measurements at 1.5T
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DOI：
10.1002/jmri.21053
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发表时间：
2007-09-01
影响因子：
4.4
通讯作者：
Mori, Susumu
中科院分区：
文献类型：
--
作者：
Farrell, Jonathan A. D.;Landman, Bennett A.;Mori, Susumu
目的：为了开发一个实验协议，以计算的精度和准确性的分数各向异性（FA），平均扩散率（MD），和方向的主特征向量（PEV）作为一个函数的信号-噪声比（SNR）在vivo.Materials和方法：一个健康的男性志愿者进行扫描，在三个独立的扫描会话，共产生45个扩散张量成像（DTI）扫描。为了提供作为SNR函数的FA、MD和PEV，将来自扫描会话的顺序扫描分组为不相交的集合。的准确性和精度的DTI派生的对比度的分析是在两个体素和区域的利益（ROI）为基础的martens.Results：FA的向上的偏见和MD没有显着的偏见，目前作为SNR下降，确认从模拟为基础的研究结果。值得注意的是，虽然PEV的精度在低SNR下变得更差，但没有观察到PEV方向的偏差。总体而言，准确和精确的定量FA值在GM需要更多的SNR比量化的白色物质（WM）FA valuesConclusion：这项研究提供了指导FA，MD和PEV的量化和手段，调查最小的可检测的差异内和跨扫描会话作为SNR的函数。
Purpose: To develop an experimental protocol to calculate the precision and accuracy of fractional anisotropy (FA), mean diffusivity (MD), and the orientation of the principal eigenvector (PEV) as a function of the signal-to-noise ratio (SNR) in vivo.Materials and Methods: A healthy male volunteer was scanned in three separate scanning sessions, yielding a total of 45 diffusion tensor imaging (DTI) scans. To provide FA, MD, and PEV as a function of SNR, sequential scans from a scan session were grouped into nonintersecting sets. Analysis of the accuracy and precision of the DTI-derived contrasts was done in both a voxel-wise and region of interest (ROI)-based manner.Results: An upward bias of FA and no significant bias in MD were present as SNR decreased, confirming results from simulation-based studies. Notably, while the precision of the PEV became worse at low SNR, no bias in the PEV orientation was observed. Overall, an accurate and precise quantification of FA values in GM requires substantially more SNR than the quantification of white matter (WM) FA valuesConclusion: This study provides guidance for FA, MD, and PEV quantification and a means to investigate the minimal detectable differences within and across scan sessions as a function of SNR.