Department of Radiology, Integrated Brain Imaging Center, University of Washington Medical Center, Seattle, WA.
Department of Pathology, Stanford University, Stanford, CA.
J Neuroimaging. 2020 Nov;30(6):843-850. doi: 10.1111/jon.12778. Epub 2020 Sep 16.
Cerebrovascular disease is a common comorbidity in older adults, typically assessed in terms of white matter hyperintensities (WMHs) on MRI. While it is well known that WMHs exacerbate cognitive symptoms, the exact relation of WMHs with cognitive performance and other degenerative diseases is unknown. Furthermore, based on location, WMHs are often classified into periventricular and deep WMHs and are believed to have different pathological origins. Whether the two types of WMHs influence cognition differently is unclear. Using regression models, we assessed the independent association of these two types of WMHs with cognitive performance in two separate studies focused on distinct degenerative diseases, early Alzheimer's (mild cognitive impairment), and Parkinson's disease. We further tested if the two types of WMHs were differentially associated with reduced cortical cerebral blood flow (CBF) as measured by arterial spin labeling and increased mean diffusivity (MD, a marker of tissue injury) as measured by diffusion imaging. Our approach revealed that both deep and periventricular WMHs were associated with poor performance on tests of global cognition (Montreal cognitive Assessment, MoCA), task processing (Trail making test), and category fluency in the study of mild cognitive impairment. They were associated with poor performance in global cognition (MoCA) and category fluency in the Parkinson's disease study. Of note, more associations were detected between cognitive performance and deep WMHs than between cognitive performance and periventricular WMHs. Mechanistically, both deep and periventricular WMHs were associated with increased MD. Both deep and periventricular WMHs were also associated with reduced CBF in the gray matter.
脑血管疾病是老年人常见的合并症，通常通过 MRI 上的脑白质高信号（WMHs）来评估。虽然众所周知 WMHs 会加重认知症状，但 WMHs 与认知表现和其他退行性疾病的确切关系尚不清楚。此外，根据位置，WMHs 通常分为脑室周围和深部 WMHs，据信它们具有不同的病理起源。这两种类型的 WMHs 是否对认知有不同的影响尚不清楚。我们使用回归模型，在两项分别针对不同退行性疾病（早期阿尔茨海默病（轻度认知障碍）和帕金森病）的研究中，评估了这两种类型的 WMHs 与认知表现的独立关联。我们进一步测试了这两种类型的 WMHs 是否与动脉自旋标记测量的皮质脑血流（CBF）减少和扩散成像测量的平均扩散度（MD，组织损伤的标志物）增加有差异相关。我们的方法表明，深部和脑室周围的 WMHs 均与轻度认知障碍研究中整体认知（蒙特利尔认知评估，MoCA）、任务处理（Trail 制作测试）和类别流畅性测试的表现差有关。它们与帕金森病研究中的整体认知（MoCA）和类别流畅性差有关。值得注意的是，认知表现与深部 WMHs 之间的关联比认知表现与脑室周围 WMHs 之间的关联更多。从机制上讲，深部和脑室周围的 WMHs 均与 MD 增加有关。深部和脑室周围的 WMHs 也与灰质中的 CBF 减少有关。
