Multi-compartmental diffusion characterization of the human cervical spinal cord in vivo using the spherical mean technique.
Multi-compartmental diffusion characterization of the human cervical spinal cord in vivo using the spherical mean technique.
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DOI：
10.1002/nbm.3894
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发表时间：
2018-04
影响因子：
2.9
通讯作者：
Smith SA
中科院分区：
文献类型：
--
作者：
By S;Xu J;Box BA;Bagnato FR;Smith SA
目的：评价球面平均技术(SMT)在健康对照组脊髓中的可行性和重复性，并评价其在3特斯拉强度下改善多发性硬化症(MS)患者脊髓特征的能力。对8例对照组和6例复发缓解期MS患者的颈髓进行SMT检查。SMT提供了一个完美的框架来模拟表观轴突体积分数Vax、固有扩散系数Dax和轴外横向扩散系数Dex_perp(估计为Vax和Dax的函数)，而不会混淆与扩散MRI建模中的复杂纤维取向分布有关的问题。在一个月内用两次不同的扫描评估SMT的重复性，并比较健康队列和MS队列中SMT衍生的指数。并对采集方案对SMT的影响进行了评估。SMT的VAX、DAX和Dex_perp测量均显示出较高的重复性。病变部位和正常白质的Vax降低(p<；0.05)，并有降低Dax和增加Dex_perp的趋势。重要的是，将采集量减少两倍，就可以获得与SMT类似的高精度。SMT提供了一种快速、可重复、准确的方法来改善颈髓的定性，并可能对MS患者具有临床潜力。球面平均技术是一种多间隔扩散模型，提供了轴突体积分数(Vax)、固有扩散系数(DAX)和轴突外横向扩散系数(Dex_Perp)的测量。所有测量结果在健康对照组的脊髓中都有很高的重复性。MS患者脊髓内Vax减少，Dax减少，Dex_perp增加。此外，尽管扫描时间显著减少，SMT仍然很健壮，能够在一半的扫描时间内提供准确的组织参数估计。
To evaluate the feasibility and reproducibility of the spherical mean technique (SMT), a multi-compartmental diffusion model, in the spinal cord of healthy controls and to assess its ability in improving spinal cord characterization in multiple sclerosis (MS) patients at 3 Tesla. SMT was applied in the cervical spinal cord of 8 controls and 6 relapsing-remitting MS patients. SMT provides an elegant framework to model the apparent axonal volume fraction vax, intrinsic diffusivity Dax, and extra-axonal transverse diffusivity Dex_perp (which is estimated as a function of vax and Dax) without confounds related to complex fiber orientation distribution that reside in diffusion MRI modeling. SMT’s reproducibility was assessed with two different scans within a month and SMT-derived indices in healthy and MS cohorts were compared. The influence of acquisition scheme on SMT was also evaluated. SMT’s vax, Dax, and Dex_perp measurements all showed high reproducibility. A decrease in vax was observed at the site of lesions and normal appearing white matter (p<0.05), and trends towards a decreased Dax and increased Dex_perp were seen. Importantly, a two-fold reduction in acquisition yielded similarly high accuracy with SMT. SMT provides a fast, reproducible, and accurate method to improve characterization of the cervical spinal cord, and may have clinical potential for MS patients. Spherical mean technique, a multi-compartmental diffusion model, provides measures of axonal volume fractions (vax), intrinsic diffusivity (Dax) and transverse extra-axonal diffusivity (Dex_perp). All measurements yield high reproducibility in the spinal cord of healthy controls. In the spinal cord of MS patients, a decreased vax, decreased Dax, and increased Dex_perp are observed. Furthermore, SMT is robust despite significant decreases in scan time, capable of providing accurate estimation of tissue parameters in half the scan time.
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影响因子：
2.2
作者：
Assaf, Y;Cohen, Y
通讯作者：
Cohen, Y
影响因子：
5.7
作者：
Avants BB;Tustison NJ;Song G;Cook PA;Klein A;Gee JC
通讯作者：
Gee JC
影响因子：
3.3
作者：
Haselgrove, JC;Moore, JR
通讯作者：
Moore, JR
影响因子：
5.7
作者：
Kaden E;Kelm ND;Carson RP;Does MD;Alexander DC
通讯作者：
Alexander DC
DOI：
10.1016/j.nicl.2017.05.010
发表时间：
2017
期刊：
NeuroImage. Clinical
影响因子：
--
作者：
By S;Xu J;Box BA;Bagnato FR;Smith SA
通讯作者：
Smith SA