Department of Neurology, Donders Institute for Brain, Cognition and Behaviour, Centre for Neuroscience, Radboud University Nijmegen Medical Centre, 6500 HB Nijmegen, The Netherlands.
Hum Brain Mapp. 2012 Mar;33(3):542-51. doi: 10.1002/hbm.21231. Epub 2011 Mar 9.
Cerebral small vessel disease (SVD) and hippocampal atrophy are related to verbal memory failures and may ultimately result in Alzheimer's disease. However, verbal memory failures are often present before structural changes on conventional MRI appear. Changes in microstructural integrity of the hippocampus, which cannot be detected with conventional MRI, may be the underlying pathological substrate. With diffusion tensor imaging (DTI), we investigated the relation between the microstructural integrity of the hippocampus and verbal memory performance in 503 nondemented elderly with SVD.
The Radboud University Nijmegen Diffusion tensor and Magnetic resonance imaging Cohort study is a prospective cohort study among 503 nondemented elderly with cerebral SVD aged between 50 and 85 years. All participants underwent T1 MPRAGE, fluid-attenuated inversion recovery, DTI scanning and the Rey Auditory Verbal Learning Test. After manual segmentation of the hippocampi, we calculated the mean diffusivity (MD) and fractional anisotropy in both hippocampi. The relation between memory performance and hippocampal DTI parameters was adjusted for age, sex, education, depressive symptoms, hippocampal, and white-matter lesions volume and lacunar infarcts.
We found inverse relations between hippocampal MD and verbal memory performance (β = -0.22; P < 0.001), immediate recall (β = -0.22; P < 0.001), delayed recall (β = -0.20; P < 0.001), and forgetting rate (β = -0.13; P = 0.025), most pronounced in participants with a normal hippocampal volume.
Microstructural integrity of the hippocampus assessed by DTI is related to verbal memory performance in elderly with SVD, also in participants with an intact appearing hippocampus. Changes in hippocampal microstructure may be an early marker of underlying neurodegenerative disease, before macrostructural (i.e., volumetric) changes occur.
脑小血管病（SVD）和海马萎缩与言语记忆失败有关，最终可能导致阿尔茨海默病。然而，在常规 MRI 出现结构变化之前，言语记忆失败往往已经存在。海马的微观结构完整性的变化，常规 MRI 无法检测到，可能是潜在的病理基础。通过弥散张量成像（DTI），我们研究了 503 例无痴呆 SVD 老年患者海马微观结构完整性与言语记忆表现之间的关系。
Radboud 大学尼梅亨弥散张量和磁共振成像队列研究是一项针对 503 例 50-85 岁无痴呆脑 SVD 老年患者的前瞻性队列研究。所有参与者均接受 T1 MPRAGE、液体衰减反转恢复、DTI 扫描和 Rey 听觉言语学习测试。在手动分割海马后，我们计算了双侧海马的平均弥散度（MD）和各向异性分数。记忆表现与海马 DTI 参数之间的关系，经过年龄、性别、教育、抑郁症状、海马和白质病变体积以及腔隙性梗死的调整。
我们发现海马 MD 与言语记忆表现（β=-0.22；P<0.001）、即刻回忆（β=-0.22；P<0.001）、延迟回忆（β=-0.20；P<0.001）和遗忘率（β=-0.13；P=0.025）呈负相关，在海马体积正常的参与者中最为明显。
DTI 评估的海马微观结构完整性与 SVD 老年患者的言语记忆表现有关，即使在海马外观完整的参与者中也是如此。海马微观结构的变化可能是潜在神经退行性疾病的早期标志物，在出现宏观结构（即体积）变化之前。
