遗忘型轻度认知功能损害患者大脑皮质结构磁共振成像的改变

目的 运用MRI及FMRIB software library(FSL)和Freesurfer软件包分析技术,研究遗忘型轻度认知功能损害(amnestic mild cognitive impairment,aMCI)患者全脑皮质结构改变情况.方法 对20例aMCI患者和20名年龄、性别、文化程度相匹配的健康志愿者,应用SEMENTS trio3.0 T MRI仪,采用高分辨扫描技术获取大脑精细结构立体像,然后应用FSL软件和Freesurfer软件包进行数据分析和后处理,计算出全脑不同部位皮质密度和厚度,比较aMCI组与健康对照组皮质结构特征的区别.结果 与健康对照组相比,aMCI组的左侧额叶、顶叶、颞叶皮质密度显著降低,右侧丘脑、颞叶及左侧岛叶皮质密度轻度降低;aMCI组左侧前扣带回[(2.19±0.24)mm]、顶下小叶[(2.27±0.15)mm],双侧海马旁回[(2.03±0.15)、(2.04±0.17)mm]、额上回[(2.42±0.34)、(2.40±0.28)mm]、额中回[(2.31±0.31)、(2.33±0.29)mm]、颞极[(3.41±0.68)、(3.30±0.56)mm]、颞横回[(2.04±0.12)、(2.01±0.11)mm]、中央前回[(2.20±0.11)、(2.31±0.19)mm]、中央后回[(1.88±0.11)、(1.82±0.09)mm]、缘上回[(2.53±0.33)、(2.55±0.23)mm]的皮质厚度显著降低(t=2.13～3.75,P＜0.05),其余部位无明显改变(t=0.09～1.88,P＞0.05).结论 aMCI患者大脑多个部位存在皮质结构改变,皮质厚度的变薄早于密度的降低.     

基于体素的MRI形态学测量对遗忘型轻度认知障碍和轻度阿尔茨海默病脑灰质萎缩的研究

目的：利用磁共振3DT1WI成像研究遗忘型轻度认知障碍（aMCI）、轻度阿尔茨海默病（AD）患者相对于正常老年人灰质体积改变的特点。方法：采用3．0T磁共振,对33例aMCI患者（aMCI组）、32例轻度AD患者（轻度AD组）及31名正常老年人（对照组）进行3DT1WI扫描,利用基于SPM5的DARTEL工具箱对扫描获得的结构图像进行预处理,再对aMCI组、轻度AD组和对照组的全脑灰质体积进行基于体素的统计学比较。结果：与对照组比较,aMCI组左侧海马、海马旁回、舌回、颞上回,双侧岛叶和颞中回等结构的灰质体积萎缩,其差异有显著统计学意义（P〈0．01,FDR corrected,K〉50体素）。轻度AD组的双侧海马、海马旁回及杏仁核、双侧丘脑、双侧颞顶叶皮质等结构灰质体积萎缩,额叶和枕叶皮质也出现灰质萎缩,其差异也有统计学意义（P〈0．05,FDR corrected,K≥50体素）。结论：基于体素的MRI形态学测量能够客观揭示AD早期阶段的脑灰质萎缩改变,对左侧海马萎缩的识别有助于AD的早期诊断。     

磁共振成像阴性颞叶癫痫的临床特点分析

目的探讨磁共振成像(MRI)阴性颞叶癫痫(nonlesional temporal lobe epilepsy,TLE-NL)患者的临床特征、记忆水平和影像学特点。方法纳入2012年9月1日至2017年8月31日在浙江大学医学院附属第二医院确诊的44例单侧TLE-NL患者和53例同期就诊单侧颞叶癫痫伴海马硬化(temporal lobe epilepsy with hippocampal sclerosis,TLE-HS)患者,对TLE-NL和TLE-HS的临床特点进行对比。同时纳入20名健康志愿者作为正常对照组。采用韦氏记忆量表评估患者和对照组记忆功能,并通过高分辨率MRI定量分析海马体积及形态,评估TLE-NL和TLE-HS患者记忆水平和海马体积的改变。结果TLE-NL患者比TLE-HS患者发病年龄更晚[(24.3±12.6)岁与(15.8±10.3)岁;t=3.684,P<0.01],癫痫病程更短[4.00(2.00,8.75)年与14.00(7.50,22.00)年;Z=-4.675,P<0.01],热性惊厥史比例[4.5%(2/44)与62.3%(33/53);χ2=32.270,P<0.01)和药物难治性比例更低[47.7%(21/44)与84.9%(45/53);χ2=15.282,P<0.01)。TLE-NL患者在性别比例、癫痫家族史、致痫灶侧别、先兆发生率、症状学类型及发作频率上与TLE-HS患者类似。TLE-NL患者与正常对照组相比无明显记忆损害(记忆商数:105.2±17.4与103.8±16.2;P=1.000),而TLE-HS患者与正常对照组相比存在明显记忆损害(记忆商数:84.5±20.3与103.8±16.2;P<0.01)。TLE-NL患者海马体积和形态与正常对照组相比无明显改变,而TLE-HS患者存在明显致痫灶同侧海马萎缩[(2953±481)mm3与(4431±505)mm3;P<0.01),形态分析结果提示萎缩以海马头及海马体部明显。结论TLE-NL是一类有别于TLE-HS的颞叶癫痫综合征,具有发病年龄晚、病程短、热性惊厥史少、药物难治性癫痫发生率较低、无明显记忆损害及海马萎缩的临床特点。     

女性抑郁状态患者海马形态体积的变化

目的 探讨女性抑郁患者的双侧海马及其各部形态体积变化的特点.方法 采用3.0 T磁共振,分别测量女性抑郁患者(30例,抑郁组)及对照组(30名)的海马及其各部体积和层数.结果 (1)抑郁组左侧海马头平均层面积(121±33)mm2,小于对照组的(148±32)mm2;层数(14.9±3.2)层,多于对照组的(12.3±3.1)层;P均<0.01;抑郁组左右侧尾部层数[(5.9±2.6)层,(6.4±1.8)层]少于对照组[(7.7±2.5)层,(7.8±2.3)层],P<0.05.(2)抑郁组左右侧海马体积[(3164±218)mm3,(3202±202)mm3]、于对照组[(3324±334)mm3,(3338±301)mm3],P<0.05,海马左右侧尾体积[(384±120)mm3,(414±101)mm3]亦小于对照组[(498±134)mm3,(501±121)mm3],P<0.01.结论 左侧海马头部形态改变和两侧海马尾体积缩小及其形态改变可能是女性抑郁患者的特征之一.     

轻度认知损害海马萎缩的磁共振研究

目的　探讨轻度认知损害 (MCI)海马体积变化的特点。方法　对 16例健康老年人 (对照组 )、 15例MCI和 17例 Alzheimer病 (AD)患者行核磁共振 (MRI)、简易智力状态检查 (MMSE) ,经标准化处理和年龄性别修正后比较海马体积变化及其与 MMSE评分的相关性。结果　 MCI组 (6 0 79± 187mm3)、AD组 (5 12 4± 185 mm3)较对照组 (70 6 2± 2 0 4 mm3)的海马体积显著减少 ,萎缩程度分别为 14 % (P<0 .0 1)、2 7% (P<0 .0 0 1) ;AD组的海马体积较 MCI组显著萎缩 (P<0 .0 1) ,3组人群合并后 ,全体研究对象的海马体积与 MMSE评分呈显著正相关 (r=0 .8,P<0 .0 0 1) ,对照组 (r=0 .2 5 ,P>0 .0 5 )和 MCI组 (r=0 .33,P>0 .0 5 )不存在相关性。结论　海马体积萎缩有助于 MCI的诊断 ,可进一步监测其变化以判断转归     

首发抑郁症海马体积及影响因素研究

目的 探讨首发抑郁症患者海马体积的特点.方法 应用磁共振成像(MRI)检测17例未用药首发抑郁症患者和19名正常对照的海马体积.结果 患者组双侧海马绝对体积(AHV)以及AHV/颅内脑体积(ICV)与对照组之间的差异均无统计学意义(P>0.05),左侧海马的AHV/ICV(1.380±0.162)低于右侧(1.462±0.105)和对照组左侧(1.478±0.133),但差异无统计学意义(P分别为0.055和0.051).未见年龄、病程和汉密尔顿抑郁量表评分与海马体积相关(P>0.05).结论 未发现首发抑郁症患者海马体积异常.     

多发性硬化患者MRI扩散张量成像脑白质束示踪的三维仿真定量研究

目的 研究多发性硬化(MS)患者脑白质束示踪的三维仿真影像表现,评价其定量结果与残疾状态扩展评分(EDSS)的相关性. 方法 对28例MS患者(MS组)和28名健康自愿者(对照组)通过MRI扩散张量成像扫描进行脑白质束示踪,测量示踪纤维数和示踪纤维密度,并应用配对t检验比较两组间差异;对MS组脱髓鞘斑块、正常表现脑白质和对照组感兴趣区的ADC值和FA值进行方差分析,使用线性回归模型计算MS组脑白质束示踪的定量结果与EDSS评分的相关性. 结果 在MS组脑白质束示踪三维仿真图像中可直接观察到脑白质束的受损和减少.MS组的示踪纤维数(2220±100)和示踪纤维密度(0.75±0.04)明显低予对照组(2750±70、0.93±0.02),差异有统计学意义(P＜0.05).MS组脱髓鞘斑块、正常表现脑白质和对照组感兴趣区的ADC值依次下降,分别为(1.23 ±0.13)× 10-3 mm2/s、(0.76±0.09)× 10-3 mm2/s、(0.63 ±0.10)×10-3 mm2/s; FA值依次升高,分别为0.24±0.04、0.42±0.07、0.48±0.06,差异均有统计学意义(P＜0.05).MS组示踪纤维数和示踪纤维密度都与EDSS评分呈负相关关系(r=-0.782,P=0.000;r=-0.771,P=0.000). 结论 通过MRI扩散张量成像扫描进行脑白质束示踪可以发现MS患者脑白质束的受损情况,其较常规MRI能提供更多的空间信息.     

老年轻度认知障碍患者海马萎缩的MRI定量测定

目的:探讨老年人轻度认知障碍(MCI)患者海马体积的变化及其与简易智力状态检查(MMSE)的相关性。方法:对15例MCI和16例健康老年人(对照组)行核磁共振(MRI)及MMSE检查,经标准化处理和年龄性别修正后比较海马体积变化及其与MMSE评分的相关性。结果:MCI组(6079±187mm~3)、较对照组(7062±204mm~3)的海马体积显著减少(P<0.01),萎缩程度14％。海马体积与MMSE评分相关性检测MCI组(r=0.33)、对照组(r=0.25),相关性均不明显(P>0.05);两组人群合并后,全体研究对象的海马体积与MMSE评分呈显著正相关(r=0.069,P<0.001)。结论:海马萎缩的MRI定量测定有助于MCI的诊断;海马体积萎缩是老年人认知功能下降的关联因素。     

颞叶癫(癎)后认知功能障碍与海马萎缩的相关性

目的 比较颞叶癫(癎)患者与健康者认知障碍、海马萎缩的差异,探讨颞叶癫(癎)患者认知障碍与海马萎缩的相关性.方法 随机选取颞叶癫(癎)患者49例和健康对照者20名,神经心理量表评价其认知状态并测量双侧海马体积.结果 与健康者相比,颞叶癫(癎)患者的记忆商(83.2±21.0)和智商(91.0±12.3)显著下降(t=-3.365,-4.291,P=0.001,0.000),双侧海马显著萎缩(P=0.000),不对称指数显著增高(t=3.975,P=0.000),差异有统计学意义.颞叶癫(癎)患者记忆力与癫(癎)病程显著负相关(r=-0.339,P=0-017),左右两侧海马萎缩程度与认知指数均显著负相关(左侧:r=-0.297,P=0.038;右侧:r=-0.305,P=0.033),不对称指数与认知指数显著负相关(r=-0.441,P=0.002).结论 颞叶癫(癎)患者双侧海马的萎缩程度越高、对称性越差,认知损伤也就越显著.海马体积测量可以作为颞叶癫(癎)患者智力下降的评价因子.     

轻度认知障碍老年人情节记忆功能的磁共振成像研究

目的 运用核磁共振(MRI)技术探讨轻度认知障碍(MCI)老人与健康老人脑结构和功能的异同.方法 对14例MCI老人(MCI组)和15名健康老人(正常对照组)进行神经心理学检查,并应用基于体素的形态测量方法 ,测定两组的灰质体积,并用事件相关功能MRI技术,测定两组在执行情节记忆提取任务时相关脑区的功能变化.结果 (1)神经心理学:MCI组听觉词语记忆测试[(2.1±1.7)分]和画钟试验[(7.8±1.2)分]成绩差于正常对照组[分别为(9.2±1.3)分和(9.2±0.8)分;P＜0.05].(2)结构影像:MCI组的灰质体积小于正常对照组,主要位于情节记忆相关脑区(P＜0.001).(3)功能影像:MCI组与正常对照组任务正确率和反应时间的差别无统计学意义;MCI组激活降低的脑区主要是海马旁回,而增强激活的脑区主要是前额叶前侧、背外侧、右侧颞上回、右侧颞下回、枕叶皮层(P＜0.005).结论 MCI组内侧颞叶记忆系统结构萎缩、功能下降,在任务难度适当的情节记忆提取任务中,MCI组动员额外脑区激活,以代偿颞叶内侧记忆系统的损害.     

Hippocampal shape analysis in Alzheimer's disease and frontotemporal lobar degeneration subtypes

Hippocampal pathology is central to Alzheimer's disease (AD) and other forms of dementia such as frontotemporal lobar degeneration (FTLD). Autopsy studies have shown that certain hippocampal subfields are more vulnerable than others to AD and FTLD pathology, in particular the subiculum and cornu ammonis 1 (CA1). We conducted shape analysis of hippocampi segmented from structural T1 MRI images on clinically diagnosed dementia patients and controls. The subjects included 19 AD and 35 FTLD patients [13 frontotemporal dementia (FTD), 13 semantic dementia (SD), and 9 progressive nonfluent aphasia (PNFA)] and 21 controls. Compared to controls, SD displayed severe atrophy of the whole left hippocampus. PNFA and FTD also displayed atrophy on the left side, restricted to the hippocampal head in FTD. Finally, AD displayed most atrophy in left hippocampal body with relative sparing of the hippocampal head. Consistent with neuropathological studies, most atrophic deformation was found in CA1 and subiculum areas in FTLD and AD.     

Automated volumetry and regional thickness analysis of hippocampal subfields and medial temporal cortical structures in mild cognitive impairment

We evaluate a fully automatic technique for labeling hippocampal subfields and cortical subregions in the medial temporal lobe in in vivo 3 Tesla MRI. The method performs segmentation on a T2‐weighted MRI scan with 0.4 × 0.4 × 2.0 mm³ resolution, partial brain coverage, and oblique orientation. Hippocampal subfields, entorhinal cortex, and perirhinal cortex are labeled using a pipeline that combines multi‐atlas label fusion and learning‐based error correction. In contrast to earlier work on automatic subfield segmentation in T2‐weighted MRI [Yushkevich et al., 2010], our approach requires no manual initialization, labels hippocampal subfields over a greater anterior‐posterior extent, and labels the perirhinal cortex, which is further subdivided into Brodmann areas 35 and 36. The accuracy of the automatic segmentation relative to manual segmentation is measured using cross‐validation in 29 subjects from a study of amnestic mild cognitive impairment (aMCI) and is highest for the dentate gyrus (Dice coefficient is 0.823), CA1 (0.803), perirhinal cortex (0.797), and entorhinal cortex (0.786) labels. A larger cohort of 83 subjects is used to examine the effects of aMCI in the hippocampal region using both subfield volume and regional subfield thickness maps. Most significant differences between aMCI and healthy aging are observed bilaterally in the CA1 subfield and in the left Brodmann area 35. Thickness analysis results are consistent with volumetry, but provide additional regional specificity and suggest nonuniformity in the effects of aMCI on hippocampal subfields and MTL cortical subregions. Hum Brain Mapp, 36:258–287, 2015. © 2014 Wiley Periodicals, Inc .     

Selective perforant-pathway atrophy in Huntington disease: MRI analysis of hippocampal subfields

Introduction

While individuals with Huntington disease (HD) show memory impairment that indicates hippocampal dysfunction, the available literature does not consistently identify structural evidence for involvement of the whole hippocampus but rather suggests that hippocampal atrophy may be confined to certain hippocampal subregions.

Methods

We processed T1-weighted MRI from IMAGE-HD study using FreeSurfer 7.0 and compared the volumes of the hippocampal subfields among 36 early motor symptomatic (symp-HD), 40 pre-symptomatic (pre-HD), and 36 healthy control individuals across three timepoints over 36 months.

Results

Mixed-model analyses revealed significantly lower subfield volumes in symp-HD, compared with pre-HD and control groups, in the subicular regions of the perforant-pathway: presubiculum, subiculum, dentate gyrus, tail, and right molecular layer. These adjoining subfields aggregated into a single principal component, which demonstrated an accelerated rate of atrophy in the symp-HD. Volumes between pre-HD and controls did not show any significant difference. In the combined HD groups, CAG repeat length and disease burden score were associated with presubiculum, molecular layer, tail, and perforant-pathway subfield volumes. Hippocampal left tail and perforant-pathway subfields were associated with motor onset in the pre-HD group.

Conclusions

Hippocampal subfields atrophy in early symptomatic HD affects key regions of the perforant-pathway, which may implicate the distinctive memory impairment at this stage of illness. Their volumetric associations with genetic and clinical markers suggest the selective susceptibility of these subfields to mutant Huntingtin and disease progression.     

Hippocampal atrophy and ventricular enlargement in normal aging, mild cognitive impairment (MCI), and Alzheimer Disease

Alzheimer disease (AD) is the most common type of dementia worldwide. Hippocampal atrophy and ventricular enlargement have been associated with AD but also with normal aging. We analyzed 1.5-T brain magnetic resonance imaging data from 46 cognitively normal elderly individuals (NC), 33 mild cognitive impairment and 43 AD patients. Hippocampal and ventricular analyses were conducted with 2 novel semiautomated segmentation approaches followed by the radial distance mapping technique. Multiple linear regression was used to assess the effects of age and diagnosis on hippocampal and ventricular volumes and radial distance. In addition, 3-dimensional map correction for multiple comparisons was made with permutation testing. As expected, most significant hippocampal atrophy and ventricular enlargement were seen in the AD versus NC comparison. Mild cognitive impairment patients showed intermediate levels of hippocampal atrophy and ventricular enlargement. Significant effects of age on hippocampal volume and radial distance were seen in the pooled sample and in the NC and AD groups considered separately. Age-associated differences were detected in all hippocampal subfields and in the frontal and body/occipital horn portions of the lateral ventricles. Aging affects both the hippocampus and lateral ventricles independent of AD pathology, and should be included as covariate in all structural, hippocampal, and ventricular analyses when possible.     

Comparing Hippocampal Atrophy in Alzheimer's Dementia and Dementia with Lewy Bodies

Background/Aims: Dementia with Lewy bodies (DLB) and Alzheimer's disease (AD) are the two most common neurodegenerative dementias. During the early stages, clinical distinction between them is often challenging. Our objective is to compare hippocampal atrophy patterns in mild AD and mild DLB. We hypothesized that DLB subjects have milder hippocampal atrophy relative to AD subjects. Methods: We analyzed the T1-weighted magnetic resonance imaging data from 113 subjects: 55 AD, 16 DLB and 42 cognitively normal elderly (normal controls, NC). Using the hippocampal radial distance technique and multiple linear regression, we analyzed the effect of clinical diagnosis on hippocampal radial distance, while adjusting for gender and age. Three-dimensional statistical maps were adjusted for multiple comparisons using permutation-based statistics with a threshold of p < 0.01. Results: Compared to NC, AD exhibited significantly greater atrophy in the cornu ammonis (CA)1, CA2-3 and subicular regions bilaterally while DLB showed left-predominant atrophy in the CA1 region and subiculum. Compared directly, AD and DLB did not reveal statistically significant differences. Conclusion: Hippocampal atrophy, while present in mildly impaired DLB subjects, is less severe than atrophy seen in mildly impaired AD subjects, when compared to NC. Both groups show predominant atrophy of the CA1 subfield and subiculum.     

Regional vulnerability of hippocampal subfields and memory deficits in Parkinson's disease

Neuropathological studies show the hippocampus is affected in Parkinson's disease (PD), with the second subfield of the cornu armonis (CA2) being the most involved. Our aims were to assess in vivo volumes of different hippocampal subfields in patients with PD with and without visual hallucinations using MRI and test their association with verbal learning and long‐term recall. A total of 18 nondemented PD patients, 18 nondemented PD patients with visual hallucinations and 18 neurologically unimpaired elderly controls matched by age and gender were enrolled in this study. We assessed the volumes of seven hippocampal subfields on MRI, including the cornu armonis (CA) sectors, subiculum, presubiculum, and the dentate gyrus (DG) using a novel technique that enables automated volumetry. The CA2‐3 and CA4‐DG subfields were significantly smaller in both groups of patients, while the subiculum was only reduced in PD patients with visual hallucinations, compared to controls. Significant correlations were found between learning performance and CA2‐3 as well as CA4‐DG volumes in the whole patient sample. These data show there is regional atrophy of specific hippocampal subfields in PD, which is more severe and further extends to the subiculum in patients with visual hallucinations. Our findings indicate that learning deficits are associated with volume loss in subfields that act as input regions in the hippocampal circuit, suggesting that degeneration in these regions could be responsible for cognitive dysfunction in PD. © 2013 Wiley Periodicals, Inc.     

Intrinsic connectivity of hippocampal subfields in normal elderly and mild cognitive impairment patients

Hippocampal connectivity has been widely described but connectivity specificities of hippocampal subfields and their changes in early AD are poorly known. The aim of this study was to highlight hippocampal subfield networks in healthy elderly (HE) and their changes in amnestic patients with mild cognitive impairment (aMCI). Thirty‐six HE and 27 aMCI patients underwent resting‐state functional MRI scans. Specific intrinsic connectivity of bilateral CA1, SUB (subiculum), and CA2/3/4/DG was identified in HE (using seeds derived from manually delineation on high‐resolution scans) and compared between HE and aMCI. Compared to the other subfields, CA1 was more strongly connected to the amygdala and occipital regions, CA2/3/4/DG to the left anterior cingulate cortex, temporal, and occipital regions, and SUB to the angular, precuneus, putamen, posterior cingulate, and frontal regions. aMCI patients showed reduced connectivity within the SUB network (with frontal and posterior cingulate regions). Our study highlighted for the first time three specific and distinct hippocampal subfield functional networks in HE, and their alterations in aMCI. These findings are important to understand AD specificities in both cognitive deficits and lesion topography, given the role of functional connectivity in these processes. Hum Brain Mapp 38:4922–4932, 2017. © 2017 Wiley Periodicals, Inc.     

轻度认知障碍和轻度Alzeimer病的海马体积MRI测量

目的研究轻度认知功能障碍（mildcognitiveimpairment,MCI）和轻度阿尔兹海默病（A1zheimerdisease,AD）患者的海马体积萎缩情况,评价利用影像学测定海马体积对MCI、AD的诊断价值。方法应用3．0T磁共振分别对20例MCI患者,20例轻度AD患者,20例认知功能正常的对照者的海马体积进行测量,所得数值用头颅体积进行标准化处理。采用计算机SPSS13．0统计学软件进行资料的统计学处理,比较三组之间体积的差异。结果对照组与MCI组,对照组与AD组的两侧海马体积均存在显著的统计学差异,轻度AD与MCI组两侧的海马体积无显著的统计学差异。结论认知功能障碍与海马体积具有一定的相关性,海马萎缩对早期认知障碍有一定的诊断意义。     

Differential associations of age with volume and microstructure of hippocampal subfields in healthy older adults

Hippocampal atrophy in advanced healthy aging has frequently been reported. However, the vulnerability of different hippocampal subfields to age‐related atrophy is still a source of debate. Moreover, the association of age with the microstructural integrity of subfields is largely unknown. In this study, we investigated the associations between age and volume as well as microstructural integrity of hippocampal subfields using a three‐dimensional (3D) surface mapping approach. Forty‐three healthy older adults spanning the age range from 60 to 85 years underwent T1‐weighted and diffusion‐tensor imaging. Analyses demonstrated an association of age with hippocampal volume predominantly in the most anterior part of the hippocampal head, mainly corresponding to the subiculum. In contrast, the association of age with hippocampal microstructural integrity was mainly confined to regions located in the hippocampal body and tail, corresponding to the subiculum and CA1. Results indicate that age‐related volumetric and microstructural alterations within hippocampal subfields provide complementary information and reflect different age‐related processes. Potential mechanisms underlying the differential associations of age with volume and microstructure of hippocampal subfields are discussed. Hum Brain Mapp 36:3819–3831, 2015. © 2015 Wiley Periodicals, Inc.     

Automated hippocampal subfield segmentation in amnestic mild cognitive impairments

Although a few automated hippocampal subfield segmentation methods have been developed, the effects of amnestic mild cognitive impairment (aMCI) on the hippocampal subfield volumes on magnetic resonance imaging (MRI) are not clear. The aim of this study was to investigate the hippocampal subfield volume changes and their relationships with various neuropsychological tests in aMCI using an automated hippocampal subfield segmentation technique. Forty-five subjects with aMCI and 49 group-matched healthy control subjects underwent 3-tesla MRI scanning, and hippocampal subfield volumes were measured and compared. Additionally, we explored the correlation pattern between hippocampal subfield volumes and the Korean version of the Consortium to Establish a Registry for Alzheimer's Disease (CERAD-K) neuropsychological test scores in aMCI subjects. Subjects with aMCI exhibited significant hippocampal volume reductions in the presubiculum, subiculum and cornu ammonis 2-3 areas compared with healthy subjects. In addition, we also found significant positive correlations between presubiculum and subicular area volumes and the CERAD-K verbal and visuospatial delayed recall scores in aMCI. This study was the first to explore the relationships between hippocampal subfield volumes and various types of cognitive performances in aMCI. These structural changes might be at the core of the underlying neurobiological mechanisms of hippocampal dysfunction in aMCI.