Brain and Mind Centre, The University of Sydney.
Sydney Neuroimaging Analysis Centre.
Curr Opin Neurol. 2019 Jun;32(3):338-345. doi: 10.1097/WCO.0000000000000698.
Focal white matter lesions are the defining pathological and imaging hallmark of the multiple sclerosis. Until recently, elucidation of the pathophysiology of lesion formation, progression and repair has relied on point neuropathological observations. Here, we review current and emerging concepts of the MRI-defined multiple sclerosis lesion phenotype, advanced longitudinal imaging techniques that permit in-vivo exploration of dynamic microstructural change within lesions and emerging MRI measures of lesion repair.
Novel MRI techniques have elucidated dynamic features of the active multiple sclerosis lesion, defined imaging surrogates for chronic active lesions and revealed progressive microstructural change within chronic inactive lesions. Lesion-related anterograde, retrograde and trans-synaptic neurodegenerative mechanisms are being unravelled in vivo through MRI. An array of myelin-imaging techniques have emerged and in some cases have already been integrated into Phase 2 remyelination trials.
MRI has shed new light on dynamic processes that occur over the lifespan of the multiple sclerosis lesion, and reaffirms the critical role of focal pathology as a determinant of disease progression. The development of robust, longitudinal biomarkers of lesion microstructure, such as advanced diffusion imaging, will be especially important as the era of neurorepair trials in multiple sclerosis dawns.
局灶性脑白质病变是多发性硬化症的定义性病理和影像学标志。直到最近，病变形成、进展和修复的病理生理学的阐明还依赖于点状神经病理学观察。在这里，我们回顾了目前和新兴的 MRI 定义的多发性硬化症病变表型概念、允许在体内探索病变内动态微观结构变化的先进纵向成像技术以及新兴的 MRI 病变修复测量方法。
新的 MRI 技术阐明了活动期多发性硬化症病变的动态特征，定义了慢性活动性病变的影像学替代物，并揭示了慢性非活动性病变内进行性微观结构变化。通过 MRI 正在体内揭示病变相关的顺行、逆行和跨突触神经退行性机制。一系列髓鞘成像技术已经出现，在某些情况下已经整合到 2 期髓鞘修复试验中。
MRI 为多发性硬化症病变的整个生命周期中发生的动态过程提供了新的认识，并再次证实了局灶性病变作为疾病进展决定因素的关键作用。随着多发性硬化症神经修复试验时代的到来，开发稳健的、纵向的病变微观结构生物标志物，如高级扩散成像，将尤为重要。
