Minimal number of gradient directions for robust measurement of spherical mean diffusion weighted signal.
Minimal number of gradient directions for robust measurement of spherical mean diffusion weighted signal.
复制标题
DOI：
10.1016/j.mri.2018.08.020
复制
发表时间：
2018-12
影响因子：
2.5
通讯作者：
Chugani HT
中科院分区：
文献类型：
--
作者：
Li H;Chow HM;Chugani DC;Chugani HT
确定球面平均扩散加权信号稳健测量的最小梯度方向数 (Nmin) ()。采用计算机模拟将测量的球平均信号的相对标准偏差 (RSD) 描述为梯度方向数 (N) 的函数。研究了扩散加权 b 值和信噪比 (SNR) 的影响。对多壳高角分辨率人类连接组计划扩散数据进行了分析，以支持模拟结果。 RSD随着N的增加而减小，RSD≤5%所需的最小N数称为Nmin。在高 SNR 下，Nmin 随着 b 值的增加而增加，以实现足够的采样。模拟表明 Nmin 与 b 值线性相关。在低 SNR 下，Nmin 随着 b 值的增加而增加，以降低噪声。 RSD 可以估计为 ，其中 σ = 1/SNR 是噪声水平。实验结果与模拟结果吻合良好。可以使用梯度方向的子集来精确测量球平均信号。由于 Nmin 受 b 值和 SNR 的影响，因此我们建议使用 10×b/b1 (b1 = 1 ms/μm2) 均匀分布的梯度方向进行典型的人体扩散研究，SNR ~ 20 以获得稳健的球面平均信号测量。
Determination of the minimum number of gradient directions (Nmin) for robust measurement of spherical mean diffusion weighted signal (). Computer simulations were employed to characterize the relative standard deviation (RSD) of the measured spherical mean signal as a function of the number of gradient directions (N). The effects of diffusion weighting b-value and signal-to-noise ratio (SNR) were investigated. Multi-shell high angular resolution Human Connectome Project diffusion data were analyzed to support the simulation results. RSD decreases with increasing N, and the minimum number of N needed for RSD ≤ 5% is referred to as Nmin. At high SNRs, Nmin increases with increasing b-value to achieve sufficient sampling. Simulations showed that Nmin is linearly dependent on the b-value. At low SNRs, Nmin increases with increasing b-value to reduce the noise. RSD can be estimated as , where σ = 1/SNR is the noise level. The experimental results were in good agreement with the simulation results. The spherical mean signal can be measured accurately with a subset of gradient directions. As Nmin is affected by b-value and SNR, we recommend using 10×b/b1 (b1 = 1 ms/μm2) uniformly distributed gradient directions for typical human diffusion studies with SNR ~ 20 for robust spherical mean signal measurement.
登录
查看更多内容
影响因子：
5.7
作者：
Sotiropoulos, Stamatios N.;Jbabdi, Saad;Xu, Junqian;Andersson, Jesper L.;Moeller, Steen;Auerbach, Edward J.;Glasser, Matthew F.;Hernandez, Moises;Sapiro, Guillermo;Jenkinson, Mark;Feinberg, David A.;Yacoub, Essa;Lenglet, Christophe;Van Essen, David C.;Ugurbil, Kamil;Behrens, Timothy E. J.
通讯作者：
Behrens, Timothy E. J.
影响因子：
5.7
作者：
Calamante, Fernando;Smith, Robert E.;Connelly, Alan
通讯作者：
Connelly, Alan
影响因子：
5.7
作者：
Novikov DS;Veraart J;Jelescu IO;Fieremans E
通讯作者：
Fieremans E
影响因子：
3.3
作者：
Anderson, AW
通讯作者：
Anderson, AW
影响因子：
2.5
作者：
McKinnon ET;Jensen JH;Glenn GR;Helpern JA
通讯作者：
Helpern JA