Department of Neurology, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, The Netherlands.
J Alzheimers Dis. 2014;38(1):211-21. doi: 10.3233/JAD-130542.
Cerebral microbleeds are a manifestation of small vessel disease and are common in patients with Alzheimer's disease (AD). However, their clinical significance in this condition is uncertain. We hypothesized that microbleeds contribute to disturbances of the cerebral network in AD and as such may affect cognition.
The goal of this study was to examine the relationship between microbleeds and brain networks in patients with amnestic mild cognitive impairment (aMCI) or early AD.
Sixty-seven patients (77.9 ± 7.5 years) with aMCI (n = 29) or early AD (n = 38) underwent cognitive testing and 3Tesla MRI. Microbleeds were rated visually. Diffusion tensor imaging and graph theoretical analysis were used to reconstruct brain networks and to quantify network efficiency for each patient. Network measures were compared between patients without and with ≥1 microbleeds and between patients without or with ≥3 microbleeds. In secondary analyses, cognitive functioning was compared between groups. Analyses were adjusted for age and gender, and additionally for other markers of small vessel disease and atrophy.
Network measures did not differ between patients with ≥1 microbleed (n = 26) and patients without microbleeds (n = 41). However, patients with ≥3 microbleeds (n = 11) showed significant white matter disruptions, longer path length, and less global efficiency than patients without microbleeds, independent of other markers of small vessel disease and atrophy. Cognitive functioning did not differ between patients without microbleeds and patients with ≥1 or ≥3 microbleeds.
Multiple microbleeds are related to structural network disruption in patients with early AD, but their direct impact on cognitive functioning appears to be limited.
脑微出血是小血管疾病的一种表现，在阿尔茨海默病（AD）患者中较为常见。然而，其在该疾病中的临床意义尚不确定。我们假设微出血导致 AD 患者的大脑网络紊乱，从而可能影响认知。
本研究旨在探讨遗忘型轻度认知障碍（aMCI）或早期 AD 患者的微出血与大脑网络之间的关系。
67 例患者（77.9±7.5 岁），其中 aMCI 患者 29 例，早期 AD 患者 38 例，均行认知测试和 3T MRI 检查。采用视觉评估微出血。采用弥散张量成像和图论分析重建脑网络，并量化每位患者的网络效率。比较无微出血和≥1 个微出血患者、无微出血和≥3 个微出血患者的网络指标。在次要分析中，比较各组间认知功能。分析调整了年龄和性别因素，并进一步调整了小血管疾病和萎缩的其他标志物。
≥1 个微出血患者（n=26）与无微出血患者（n=41）的网络指标无差异。然而，≥3 个微出血患者（n=11）的白质破坏更明显，路径长度更长，全局效率更低，与无微出血患者相比，与小血管疾病和萎缩的其他标志物无关。无微出血患者与≥1 个或≥3 个微出血患者的认知功能无差异。
多发性微出血与早期 AD 患者的结构网络破坏有关，但对认知功能的直接影响似乎有限。
