Zhang Yunyan, Jonkman Laura, Klauser Antoine, Barkhof Frederik, Yong V Wee, Metz Luanne M, Geurts Jeroen Jg
Department of Radiology, University of Calgary, Calgary, AB, Canada/ Department of Clinical Neurosciences, University of Calgary, Calgary, AB, Canada/ Hotchkiss Brain Institute, University of Calgary, Calgary, AB, Canada
Department of Anatomy & Neurosciences, VU University Medical Center, Amsterdam, The Netherlands.
Mult Scler. 2016 Oct;22(12):1569-1577. doi: 10.1177/1352458515624771. Epub 2016 Jan 11.
Lesions with different extents of myelin pathology are found at autopsy in multiple sclerosis (MS), but the differences are not discernible in magnetic resonance imaging (MRI).
To determine whether analysis of the local spectrum in MRI is sensitive to lesion differences in myelin integrity.
We imaged fresh brain slices from 21 MS patients using 1.5T scanners. White matter lesions were identified in T2-weighted MRI, matched to corresponding specimens, and then classified into five categories in histology: pre-active (intact myelin); active, chronic active, chronic inactive (complete demyelination); and remyelinated lesions. Voxel-based frequency spectrum was calculated using T2-weighted MRI to characterize lesion structure (image texture).
MRI texture heterogeneity resulting from all spectral scales was greater in completely demyelinated lesions than in myelin-preserved lesions (p = 0.02) and normal-appearing white matter (p < 0.01). Moreover, the spectral distribution pattern over low-frequency scales differentiated demyelinated lesions from remyelinated and pre-active lesions (p < 0.01), where different lesion types also showed distinct texture scales.
Using multi-scale spectral analysis, it may be possible for standard MRI to evaluate myelin integrity in MS lesions. This can be critical for monitoring disease activity and assessing remyelination therapies for MS patients.
在多发性硬化症（MS）尸检中发现有不同程度髓鞘病理改变的病变，但在磁共振成像（MRI）中这些差异难以辨别。
确定MRI中局部频谱分析是否对髓鞘完整性的病变差异敏感。
我们使用1.5T扫描仪对21例MS患者的新鲜脑切片进行成像。在T2加权MRI中识别白质病变，将其与相应标本匹配，然后在组织学上分为五类：预活动期（髓鞘完整）；活动期、慢性活动期、慢性非活动期（完全脱髓鞘）；以及再髓鞘化病变。使用T2加权MRI计算基于体素的频谱，以表征病变结构（图像纹理）。
完全脱髓鞘病变中所有频谱尺度导致的MRI纹理异质性大于髓鞘保留病变（p = 0.02）和外观正常的白质（p < 0.01）。此外，低频尺度上的频谱分布模式将脱髓鞘病变与再髓鞘化和预活动期病变区分开来（p < 0.01），不同病变类型也显示出不同的纹理尺度。
使用多尺度频谱分析，标准MRI有可能评估MS病变中的髓鞘完整性。这对于监测疾病活动和评估MS患者的再髓鞘化治疗可能至关重要。
