Alotaibi Abdulmajeed, Podlasek Anna, AlTokhis Amjad, Aldhebaib Ali, Dineen Rob A, Constantinescu Cris S
Department of Radiological Sciences, School of Applied Medical Sciences, King Saud bin Abdul-Aziz University for Health Sciences, Riyadh 14611, Saudi Arabia.
Division of Clinical Neuroscience, School of Medicine, Nottingham University Hospitals NHS Trust, University of Nottingham, Nottingham NG7 2UH, UK.
Brain Sci. 2021 Aug 29;11(9):1151. doi: 10.3390/brainsci11091151.
Multiple sclerosis (MS) is characterised by widespread damage of the central nervous system that includes alterations in normal-appearing white matter (NAWM) and demyelinating white matter (WM) lesions. Neurite orientation dispersion and density imaging (NODDI) has been proposed to provide a precise characterisation of WM microstructures. NODDI maps can be calculated for the Neurite Density Index (NDI) and Orientation Dispersion Index (ODI), which estimate orientation dispersion and neurite density. Although NODDI has not been widely applied in MS, this technique is promising in investigating the complexity of MS pathology, as it is more specific than diffusion tensor imaging (DTI) in capturing microstructural alterations. We conducted a meta-analysis of studies using NODDI metrics to assess brain microstructural changes and neuroaxonal pathology in WM lesions and NAWM in patients with MS. Three reviewers conducted a literature search of four electronic databases. We performed a random-effect meta-analysis and the extent of between-study heterogeneity was assessed with the I2 statistic. Funnel plots and Egger's tests were used to assess publication bias. We identified seven studies analysing 374 participants (202 MS and 172 controls). The NDI in WM lesions and NAWM were significantly reduced compared to healthy WM and the standardised mean difference of each was -3.08 (95%CI -4.22 to (-1.95), ≤ 0.00001, I2 = 88%) and -0.70 (95%CI -0.99 to (-0.40), ≤ 0.00001, I2 = 35%), respectively. There was no statistically significant difference of the ODI in MS WM lesions and NAWM compared to healthy controls. This systematic review and meta-analysis confirmed that the NDI is significantly reduced in MS lesions and NAWM than in WM from healthy participants, corresponding to reduced intracellular signal fraction, which may reflect underlying damage or loss of neurites.
多发性硬化症（MS）的特征是中枢神经系统广泛受损，包括正常外观白质（NAWM）和脱髓鞘白质（WM）病变的改变。神经突方向离散度和密度成像（NODDI）已被提出用于精确表征WM微观结构。可以计算神经突密度指数（NDI）和方向离散度指数（ODI）的NODDI图，它们分别估计方向离散度和神经突密度。尽管NODDI尚未在MS中广泛应用，但该技术在研究MS病理学的复杂性方面很有前景，因为它在捕捉微观结构改变方面比扩散张量成像（DTI）更具特异性。我们对使用NODDI指标评估MS患者WM病变和NAWM中脑微观结构变化和神经轴突病理学的研究进行了荟萃分析。三位评审员对四个电子数据库进行了文献检索。我们进行了随机效应荟萃分析，并使用I2统计量评估研究间异质性的程度。漏斗图和Egger检验用于评估发表偏倚。我们确定了七项分析374名参与者（202名MS患者和172名对照）的研究。与健康WM相比，WM病变和NAWM中的NDI显著降低，各自的标准化平均差分别为-3.08（95%CI -4.22至（-1.95），≤0.00001，I2 = 88%）和-0.70（95%CI -0.99至（-0.40），≤0.00001，I2 = 35%）。与健康对照相比，MS的WM病变和NAWM中的ODI无统计学显著差异。这项系统评价和荟萃分析证实，与健康参与者的WM相比，MS病变和NAWM中的NDI显著降低，这与细胞内信号分数降低相对应，这可能反映了神经突的潜在损伤或丢失。
