Institute of Cardiovascular and Medical Sciences, University of Glasgow, Queen Elizabeth University Hospital, 1345 Govan Road, Glasgow, G51 4TF, UK.
Adv Exp Med Biol. 2019;1205:25-53. doi: 10.1007/978-3-030-31904-5_3.
Structural magnetic resonance imaging (MRI) has been used to characterise the appearance of the brain in cerebral small vessel disease (SVD), ischaemic stroke, cognitive impairment, and dementia. SVD is a major cause of stroke and dementia; features of SVD include white matter hyperintensities (WMH) of presumed vascular origin, lacunes of presumed vascular origin, microbleeds, and perivascular spaces. Cognitive impairment and dementia have traditionally been stratified into subtypes of varying origin, e.g., vascular dementia versus dementia of the Alzheimer's type (Alzheimer's disease; AD). Vascular dementia is caused by reduced blood flow in the brain, often as a result of SVD, and AD is thought to have its genesis in the accumulation of tau and amyloid-beta leading to brain atrophy. But after early seminal studies in the 1990s found neurovascular disease features in around 30% of AD patients, it is becoming recognised that so-called "mixed pathologies" (of vascular and neurodegenerative origin) exist in many more patients diagnosed with stroke, only one type of dementia, or cognitive impairment. On the back of these discoveries, attempts have recently been made to quantify the full extent of degenerative and vascular disease in the brain in vivo on MRI. The hope being that these "global" methods may one day lead to better diagnoses of disease and provide more sensitive measurements to detect treatment effects in clinical trials. Indeed, the "Total MRI burden of cerebral small vessel disease", the "Brain Health Index" (BHI), and "MRI measure of degenerative and cerebrovascular pathology in Alzheimer disease" have all been shown to have stronger associations with clinical and cognitive phenotypes than individual brain MRI features. This chapter will review individual structural brain MRI features commonly seen in SVD, stroke, and dementia. The relationship between these features and differing clinical and cognitive phenotypes will be discussed along with developments in their measurement and quantification. The chapter will go on to review emerging methods for quantifying the collective burden of structural brain MRI findings and how these "whole picture" methods may lead to better diagnoses of neurovascular and neurodegenerative disorders.
结构磁共振成像（MRI）已被用于描述脑小血管病（SVD）、缺血性中风、认知障碍和痴呆患者的脑部表现。SVD 是中风和痴呆的主要原因；SVD 的特征包括可能由血管引起的脑白质高信号（WMH）、可能由血管引起的腔隙、微出血和血管周围间隙。认知障碍和痴呆传统上分为不同病因的亚型，例如血管性痴呆与阿尔茨海默病型痴呆（阿尔茨海默病；AD）。血管性痴呆是由于大脑血流减少引起的，通常是由于 SVD 引起的，而 AD 被认为是由于 tau 和淀粉样蛋白-β的积累导致脑萎缩。但在 20 世纪 90 年代的早期开创性研究发现，约 30%的 AD 患者存在神经血管疾病特征后，人们逐渐认识到，在许多被诊断为中风、只有一种痴呆或认知障碍的患者中存在所谓的“混合病变”（血管性和神经退行性病变起源）。基于这些发现，最近有人试图在 MRI 上定量测量大脑中退行性和血管性疾病的全部程度。希望这些“整体”方法有朝一日能够更好地诊断疾病，并提供更敏感的测量方法来检测临床试验中的治疗效果。事实上，“脑小血管病的总 MRI 负担”、“脑健康指数”（BHI）和“阿尔茨海默病中退行性和脑血管病理的 MRI 测量”都与临床和认知表型的相关性强于单个脑 MRI 特征。本章将回顾 SVD、中风和痴呆患者常见的结构性脑 MRI 特征。将讨论这些特征与不同的临床和认知表型之间的关系，以及它们的测量和量化的进展。接着，还将回顾用于量化结构性脑 MRI 发现的综合负担的新兴方法，以及这些“全貌”方法如何有助于更好地诊断神经血管和神经退行性疾病。
