Center For Neurosciences, Vrije Universiteit Brussel, Brussels, Belgium.
, Ke.2.13; Pleinlaan 2, 1050, Elsene, Belgium.
Sci Rep. 2021 Apr 1;11(1):7376. doi: 10.1038/s41598-021-86792-0.
Graph-theoretical analysis is a novel tool to understand the organisation of the brain.We assessed whether altered graph theoretical parameters, as observed in multiple sclerosis (MS), reflect pathology-induced restructuring of the brain's functioning or result from a reduced signal quality in functional MRI (fMRI). In a cohort of 49 people with MS and a matched group of 25 healthy subjects (HS), we performed a cognitive evaluation and acquired fMRI. From the fMRI measurement, Pearson correlation-based networks were calculated and graph theoretical parameters reflecting global and local brain organisation were obtained. Additionally, we assessed metrics of scanning quality (signal to noise ratio (SNR)) and fMRI signal quality (temporal SNR and contrast to noise ratio (CNR)). In accordance with the literature, we found that the network parameters were altered in MS compared to HS. However, no significant link was found with cognition. Scanning quality (SNR) did not differ between both cohorts. In contrast, measures of fMRI signal quality were significantly different and explained the observed differences in GTA parameters. Our results suggest that differences in network parameters between MS and HS in fMRI do not reflect a functional reorganisation of the brain, but rather occur due to reduced fMRI signal quality.
图论分析是一种理解大脑组织的新工具。我们评估了多发性硬化症（MS）中观察到的改变的图论参数是否反映了病理引起的大脑功能重构，或者是否是由于功能磁共振成像（fMRI）中的信号质量降低所致。在一个由 49 名 MS 患者和 25 名匹配的健康受试者（HS）组成的队列中，我们进行了认知评估并获取了 fMRI。从 fMRI 测量中，我们计算了基于 Pearson 相关性的网络，并获得了反映全局和局部大脑组织的图论参数。此外，我们评估了扫描质量（信噪比（SNR））和 fMRI 信号质量（时间 SNR 和对比噪声比（CNR））的指标。与文献一致，我们发现与 HS 相比，MS 中的网络参数发生了改变。然而，与认知没有发现显著的联系。两个队列之间的扫描质量（SNR）没有差异。相比之下，fMRI 信号质量的测量值差异显著，解释了 GTA 参数的观察到的差异。我们的结果表明，fMRI 中 MS 和 HS 之间的网络参数差异不是大脑功能重组的反映，而是由于 fMRI 信号质量降低而产生的。
