Oladosu Olayinka, Liu Wei-Qiao, Brown Lenora, Pike Bruce G, Metz Luanne M, Zhang Yunyan
Department of Neuroscience, Faculty of Graduate Studies, University of Calgary, Calgary, AB, Canada.
Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada.
Front Hum Neurosci. 2022 Aug 12;16:944908. doi: 10.3389/fnhum.2022.944908. eCollection 2022.
Disease development in multiple sclerosis (MS) causes dramatic structural changes, but the exact changing patterns are unclear. Our objective is to investigate the differences in brain structure locally and spatially between relapsing-remitting MS (RRMS) and its advanced form, secondary progressive MS (SPMS), through advanced analysis of diffusion magnetic resonance imaging (MRI) and image texture.
A total of 20 patients with RRMS and nine patients with SPMS from two datasets underwent 3T anatomical and diffusion tensor imaging (DTI). The DTI was harmonized, augmented, and then modeled, which generated six voxel- and sub-voxel-scale measures. Texture analysis focused on T2 and FLAIR MRI, which produced two phase-based measures, namely, phase congruency and weighted mean phase. Data analysis was 3-fold, i.e., histogram analysis of whole-brain normal appearing white matter (NAWM); region of interest (ROI) analysis of NAWM and lesions within three critical white matter tracts, namely, corpus callosum, corticospinal tract, and optic radiation; and along-tract statistics. Furthermore, by calculating the z-score of core-rim pathology within lesions based on diffusion measures, we developed a novel method to define chronic active lesions and compared them between cohorts.
Histogram features from diffusion and all but one texture measure differentiated between RRMS and SPMS. Within-tract ROI analysis detected cohort differences in both NAWM and lesions of the corpus callosum body in three measures of neurite orientation and anisotropy. Along-tract statistics detected cohort differences from multiple measures, particularly lesion extent, which increased significantly in SPMS in posterior corpus callosum and optic radiations. The number of chronic active lesions were also significantly higher (by 5-20% over z-scores 0.5 and 1.0) in SPMS than RRMS based on diffusion anisotropy, neurite content, and diameter.
Advanced diffusion MRI and texture analysis may be promising approaches for thorough understanding of brain structural changes from RRMS to SPMS, thereby providing new insight into disease development mechanisms in MS.
多发性硬化症（MS）的疾病发展会导致显著的结构变化，但确切的变化模式尚不清楚。我们的目的是通过对扩散磁共振成像（MRI）和图像纹理进行高级分析，研究复发缓解型多发性硬化症（RRMS）与其晚期形式继发进展型多发性硬化症（SPMS）在局部和空间上脑结构的差异。
来自两个数据集的20例RRMS患者和9例SPMS患者接受了3T解剖和扩散张量成像（DTI）。对DTI进行了协调、增强，然后建模，生成了六个体素和亚体素尺度的测量值。纹理分析聚焦于T2和FLAIR MRI，产生了两个基于相位的测量值，即相位一致性和加权平均相位。数据分析分三步进行，即对全脑正常表现的白质（NAWM）进行直方图分析；对NAWM以及胼胝体、皮质脊髓束和视辐射这三条关键白质束内的病变进行感兴趣区域（ROI）分析；以及沿束统计。此外，通过基于扩散测量计算病变内核心-边缘病理的z分数，我们开发了一种定义慢性活动性病变的新方法，并在不同队列之间进行比较。
扩散直方图特征以及除一项外的所有纹理测量值在RRMS和SPMS之间存在差异。束内ROI分析在胼胝体体部的NAWM和病变的神经突方向和各向异性的三项测量中检测到队列差异。沿束统计从多项测量中检测到队列差异，特别是病变范围，在SPMS中胼胝体后部和视辐射的病变范围显著增加。基于扩散各向异性、神经突含量和直径，SPMS中的慢性活动性病变数量也显著高于RRMS（比z分数0.5和1.0时高5%-20%）。
先进的扩散MRI和纹理分析可能是全面了解从RRMS到SPMS脑结构变化的有前景的方法，从而为MS疾病发展机制提供新的见解。
