Leucoaraiosis (LA), also referred to as white matter hyperintensities (WMHs), are usually seen as patchy or confluent hyperintense areas on T2-weighted or fluid-attenuated inversion recovery MRI in the elderly. It is often asymptomatic in its early stages, yet its persistent evolution to more advanced stages may lead to substantial neurological dysfunction including dementia, stroke and death. Despite its clinical significance, the pathogenic mechanisms underlying LA development are uncertain. In patients with LA, the pathophysiological changes in white matter (WM) are suggested to be continuous from WMHs to its neighbourhood ‘normal-appearing white matter (NAWM)’ on conventional MRI sequences. Multimodal imaging studies revealed that the so-called ‘NAWM’ was actually abnormal with regard to underlying haemodynamic and microstructural changes. On the basis of positron emission tomography CT, xenon-CT, perfusion MRI, etc, the cerebral blood flow of NAWM was found to be significantly reduced in patients with LA, compared with healthy controls. Meanwhile, the integrity of microstructures and blood–brain barrier in NAWM was also demonstrated to be impaired with diffusion tensor imaging and dynamic contrast-enhanced MRI studies, respectively. In addition,the integrity of NAWM correlated much stronger with cognitive performance than did WMHs load. It is reasonable to assume that the subtle injury of NAWM would be more reversible than WMHs themselves. Therefore, multimodal imaging modalities could be appropriately applied to future interventional studies targeting at early pathophysiological changes of NAWM. In this paper, we summarise current knowledge about NAWM of LA mainly acquired from multimodal imaging studies in vivo, and attempt to give options for future work.
This is an Open Access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Statistics from Altmetric.com
If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.