From the Dementia Research Theme, The Florey Institute of Neuroscience and Mental Health, Melbourne, Australia (N.E., M.S.K., W.K., E.W., A.B.).
Melbourne School of Psychological Sciences, University of Melbourne, Australia (N.E., A.B.).
Stroke. 2020 May;51(5):1507-1513. doi: 10.1161/STROKEAHA.119.028143. Epub 2020 Apr 16.
Background and Purpose- We examined if ischemic stroke is associated with white matter degeneration predominantly confined to the ipsi-lesional tracts or with widespread bilateral axonal loss independent of lesion laterality. Methods- We applied a novel fixel-based analysis, sensitive to fiber tract-specific differences within a voxel, to assess axonal loss in stroke (N=104, 32 women) compared to control participants (N=40, 15 women) across the whole brain. We studied microstructural differences in fiber density and macrostructural (morphological) changes in fiber cross-section. Results- In participants with stroke, we observed significantly lower fiber density and cross-section in areas adjacent, or connected, to the lesions (eg, ipsi-lesional corticospinal tract). In addition, the changes extended beyond directly connected tracts, independent of the lesion laterality (eg, corpus callosum, bilateral inferior fronto-occipital fasciculus, right superior longitudinal fasciculus). Conclusions- We conclude that ischemic stroke is associated with extensive neurodegeneration that significantly affects white matter integrity across the whole brain. These findings expand our understanding of the mechanisms of brain volume loss and delayed cognitive decline in stroke.
背景与目的- 我们研究了缺血性卒中是否与主要局限于病灶对侧的白质退变有关，还是与病灶侧无关的广泛双侧轴突丢失有关。方法- 我们应用了一种新的基于固定元分析的方法，该方法对每个体素内的纤维束特异性差异敏感，以评估卒中患者（N=104，32 名女性）与对照组参与者（N=40，15 名女性）整个大脑中的轴突丢失情况。我们研究了纤维密度的微观结构差异和纤维横截面积的宏观结构（形态）变化。结果- 在卒中患者中，我们观察到病灶相邻或相连区域（例如病灶对侧皮质脊髓束）的纤维密度和横截面积明显降低。此外，这些变化不仅局限于直接连接的纤维束，而且与病灶侧无关（例如胼胝体、双侧额枕下束、右侧上纵束）。结论- 我们的结论是，缺血性卒中与广泛的神经退行性变有关，这显著影响了整个大脑的白质完整性。这些发现扩展了我们对卒中后脑容量损失和认知延迟机制的理解。
