阿尔茨海默病18F-FDG PET显像诊断的研究☆

目的探讨阿尔茨海默病(AD)脑葡萄糖代谢及其18F-脱氧葡萄糖正电子发射计算机断层扫描(18F-FDGPET)显像的影像学特征和PET诊断标准.方法静脉注射18F-FDG后行脑断层显像,检查13例AD、13例非AD痴呆及13例正常人.获得纹状体、丘脑、黑质、顶叶、颞叶、额叶、枕叶、海马单位面积放射性计数与小脑计数的比值(Rcl/cb),进行半定量分析,并与MR进行对照.结果AD患者PET异常率为100%,MR异常者占10/13.PET显像特征①对称性双侧颞顶叶及海马伴额叶或枕叶代谢减低占9例(9/13);②双侧颞叶对称性代谢减低伴海马或额叶代谢下降占3例(3/13);③双顶叶对称性代谢降低1例(1/13).12例(12/13)非AD痴呆表现为不对称、多发性代谢降低,降低区位于黑质、纹状体、丘脑及脑皮质区,MR异常率为11/13.结论在除外脑内结构特异性损害基础上,PET发现对称性双颞顶叶、海马或颞叶、顶叶,伴或不伴枕叶、额叶代谢下降,可诊断AD.PET对AD早期诊断及鉴别诊断具有临床意义.     

阿尔茨海默病~(18)F-FDG PET显像诊断的研究

目的 探讨阿尔茨海默病（AD）脑葡萄糖代谢及其18F-脱氧葡萄糖正电子发射计算机断层扫描（18F-FDG PET）显像的影像学特征和PET诊断标准。方法 静脉注射18F-FDG后行脑断层显像,检查13例 AD、13例非AD痴呆及13例正常人。获得纹状体、丘脑、黑质、顶叶、颞叶、额叶、枕叶、海马单位面积放射性计数与小脑计数的比值（Rcl/cb）,进行半定量分析,并与MR进行对照。结果AD患者PET异常率为100％,MR异常者占10/13。PET显像特征:①对称性双侧颞顶叶及海马伴额叶或枕叶代谢减低占9例（9/13）;②双侧颞叶对称性代谢减低伴海马或额叶代谢下降占3例（3/13）;③双顶叶对称性代谢降低1例（1/13）。12例（12/13）非AD痴呆表现为不对称、多发性代谢降低,降低区位于黑质、纹状体、丘脑及脑皮质区,MR异常率为11/13。结论 在除外脑内结构特异性损害基础上,PET发现对称性双颞顶叶、海马或颞叶、顶叶,伴或不伴枕叶、额叶代谢下降,可诊断AD。PET对AD早期诊断及鉴别诊断具有临床意义。     

~(11)C-PIBPET和~(18)F-FDGPET显像诊断阿尔茨海默病与遗忘型轻度认知损害的临床价值

目的应用11C-PIB PET和18F-FDG PET显像研究阿尔茨海默病和遗忘型轻度认知损害患者β-淀粉样蛋白(Aβ)沉积与葡萄糖代谢之间的关系,联合载脂蛋白E(ApoE)基因型进一步探讨遗忘型轻度认知损害与阿尔茨海默病的相关性。方法利用PET显像对阿尔茨海默病(14例)、遗忘型轻度认知损害(10例)和正常对照者(5例)脑组织Aβ沉积和葡萄糖代谢变化进行分析,采用聚合酶链反应-限制性片段长度多态性方法对ApoE基因型进行分析。结果阿尔茨海默病组患者11C-PIB标准化摄取比值在下顶叶、颞叶外侧、额叶、后扣带回皮质和楔前叶、枕叶和纹状体均高于正常对照组(P0.05);遗忘型轻度认知损害组患者脑组织11C-PIB结合水平呈双峰形。11C-PIB+aMCI亚组与阿尔茨海默病组、11C-PIB-aMCI亚组与正常对照组之间11C-PIB标准化摄取比值差异均无统计学意义(P0.05)。18F-FDG PET显像显示,3/5例11C-PIB+aMCI亚组患者双侧顶叶、颞叶和楔前叶代谢减低,其中2例ApoEε4等位基因携带者随访期间进展至阿尔茨海默病;3/5例11C-PIB-aMCI亚组患者双侧额叶和前扣带回代谢减低。结论11C-PIB PET显像是筛查具有阿尔茨海默病病理特点的遗忘型轻度认知损害患者的有效工具。具有阿尔茨海默病病理特征的遗忘型轻度认知损害患者可伴有顶叶、颞叶外侧皮质和楔前叶代谢减低,其中ApoEε4等位基因携带者更易进展至阿尔茨海默病痴呆。     

脑网络模块化分析用于阿尔茨海默病、路易体痴呆和帕金森病性痴呆脑葡萄糖代谢特点研究

目的本研究探究脑功能成像的脑网络模块化分析在阿尔茨海默病(AD),路易体痴呆(DLB),帕金森病性痴呆(PDD)脑网络模块参数特点和异同点,寻找疾病相关特异性脑葡萄糖代谢网络模块参数。方法回顾性分析复旦大学附属华山医院AD、DLB、PDD组和正常对照组的静息状态18F-FDG PET显像,采用网络模块化分析分别获得4组受试者的脑葡萄糖代谢网络模块化参数,并应用种子点相关分析得到葡萄糖代谢网络连接改变的脑区,比较4组受试者脑代谢网络连接的异同点。结果在稀疏阈值15%时,正常对照组和AD组的网络由4个模块组成,PDD组由6个模块组成,DLB组由10个模块组成。以右侧丘脑为种子点,AD组的颞叶和皮质下脑区连接增强,枕叶和左侧额叶连接减弱。PDD组的额叶、皮质下脑区连接增强,枕叶、颞叶、左侧顶叶的连接减弱。DLB组的左侧额叶和皮质下脑区连接增强,右侧枕叶和顶叶连接减弱。结论 3种不同类型痴呆患者的脑葡萄糖代谢网络具有不同的模块化特性,提示发病机制的差异,为进一步探究其神经机制提供新思路。     

DTI评价轻度认知障碍及轻中度阿尔茨海默病脑白质微细结构损害的研究

目的应用磁共振弥散张量成像(DTI)技术研究轻度认知障碍(MCI)及轻中度阿尔茨海默病(AD)患者脑白质微细结构的改变。方法对MCI患者、轻中度AD患者各12例及健康老年人12名(对照组)行常规MRI及DTI检查,测量其胼胝体压部、额叶、顶叶、颞叶、枕叶、内囊前肢及内囊后肢白质区部分各向异性分数(FA)和平均弥散率(MD)。将3组的FA、MD值进行比较,并与MMSE评分、单词回忆及单词再认评分进行相关性分析。结果 (1)MCI患者顶叶白质FA值为0.489±0.079,与对照组(0.558±0.079)相比下降(P0.05)。(2)AD患者额叶、顶叶及颞叶FA值分别为0.405±0.072、0.454±0.069和0.363±0.056,与对照组(分别为0.499±0.081、0.558±0.079和0.440±0.061)比较差异均有统计学意义(P0.05)。AD患者胼胝体压部、额叶及顶叶MD值分别为0.978±0.082、0.920±0.054和0.81 7±0.045,均高于对照组(分别为0.801±0.093、0.820±0.084、0.712±0.096)(P0.05)。AD、MCI两组内囊前、后肢及枕叶FA及MD值分别与健康对照组比较均无统计学差异(P0.05)。(3)3组顶叶、颞叶FA值与MMSE、单词回忆及单词再认评分均有相关性(分别r=0.869、-0.621、-0.759,均P0.01;r=0.446、-0.486、-0.361,均P0.05),胼胝体压部FA值与单词再认评分有相关性(r=-0.343,P0.05);3组胼胝体压部及顶叶MD值与MMSE、单词回忆及单词再认评分均有相关性(分别r=-0.612、0.547、0.586,均P0.01;r=-0.576、0.499、0.519,均P0.01),内囊前肢MD值与MMSE评分相关(r=-0.340,P0.05)。结论 MCI及轻中度AD患者存在脑白质选择性微细结构损害,且该损害出现在与高级皮层功能相关的脑区,而与初级功能相关的区域未见明显受损。     

不同类型痴呆脑代谢改变图型:~(18)F-FDG PET显像

目的探讨不同类型痴呆患者基于像素水平的脑代谢图型特点。方法对最终临床诊断为阿尔茨海默病(20例)、额颞叶痴呆(20例)、路易体痴呆(10例)、进行性核上性麻痹(7例)、原发性进行性失语(3例)、皮质基底节变性(1例)和多系统萎缩(1例)等认知功能障碍患者的18F-FDG PET显像资料进行回顾分析,描述各种神经变性疾病脑代谢降低区域和程度。结果 SPM分析表明,各种神经变性疾病引起的痴呆18F-FDG PET显像均表现为皮质代谢降低,但其代谢图型变化明显不同:阿尔茨海默病组以双侧颞顶叶和额叶皮质代谢降低为主,基本感觉运动皮质、枕叶、基底节和丘脑活性保留;额颞叶痴呆组额叶和颞叶皮质不对称性代谢降低,伴部分顶叶皮质和基底节、丘脑等皮质下核团不同程度代谢降低;路易体痴呆组枕叶、视皮质和双侧颞上回前部代谢降低;进行性核上性麻痹组双侧前额叶背外侧、颞叶前外侧、中脑和双侧尾状核代谢降低;原发性进行性失语组左侧额叶Broca区、左侧颞叶皮质(除左侧颞上回后部)和右侧颞叶内侧皮质代谢降低;皮质基底节变性组双侧中央沟周围额顶叶皮质(右侧显著)、右侧基底节代谢降低;多系统萎缩组双侧小脑背外侧皮质和左侧壳核代谢降低。结论神经变性疾病所致痴呆在18F-FDG PET显像中表现出各自特征性脑代谢降低图型,18F-FDG PET显像有可能成为痴呆鉴别诊断的一种辅助手段。     

2型糖尿病合并轻度认知损害的正电子发射计算机断层扫描研究

目的 探讨2型糖尿病(DM)合并轻度认知损害( MCI)患者脑葡萄糖代谢特点.方法 应用18-氟代脱氧葡萄糖(18F-FDG)正电子发射计算机断层扫描(PET),对7例单纯DM患者(DM组)、6例DM合并MCI患者(DM+ MCI组)及10名正常对照者(对照组)脑葡萄糖代谢进行检测；采用简易精神状态检查量表(MMSE)、画钟试验(CDT)及临床痴呆评定量表(CDR)测定患者认知功能.结果 (1)认知功能:DM+ MCI组的MMSE得分[(24.67±0.82)分]显著低于对照组[(29.20± 0.79)分]及DM组(29.14±1.21)分](P均＜0.01),CDR得分[(0.58±0.20)分]显著高于对照组[(0.10±0.21)分]及DM组[(0.14±0.24)分](P均＜0.01),CDT得分与对照组及DM组间差异无统计学意义.(2)18F-FDG PET检查:与对照组比较,DM组左顶叶平均标准化摄取值(SUV)半定量比值降低(1.03 ±0.07比1.16 ±0.09,P＜0.05),DM+ MCI组左额叶(1.02±0.16比1.15 ±0.08)、右额叶(0.90±0.07比1.10±0.06)、扣带回(0.92 ±0.06比1.17±0.08)、左顶叶(0.94±0.12比1.16±0.09)、右顶叶(0.93 ±0.10比1.11 ±0.06)、左颞顶后叶(0.96±0.11比1.17 ±0.01)、右颞顶后叶(0.90±0.09比1.15 ±0.06)的SUV半定量比值均降低(P＜0.01)；与DM组比较,DM+ MCI组左额叶(1.02±0.16比1.15 ±0.11)、右额叶(0.90±0.07比1.06±0.18)、扣带回(0.92 ±0.06比1.16± 0.08)、右顶叶(0.93±0.10比1.10±0.12)、左颞顶后叶(0.96±0.11比1.14 ±0.14)、右颞顶后叶(0.90±0.09比1.18±0.17)的SUV半定量比值降低(P＜0.01或P＜0.05).结论 2型糖尿病合并MCI患者的双侧额叶、扣带回、顶叶、颞顶后叶等多个脑区葡萄糖代谢均降低.     

阿尔茨海默病的18F-FDG PET脑显像特征及意义

目的探讨轻、中、重度阿尔茨海默病(AD)患者的脑~(18)F-FDG正电子发射断层显像(PET/CT)特点。方法对10例AD患者和10例健康对照的脑~(18)F标记的脱氧葡萄糖正电子发射断层显像(~(18)F-FDG PET)进行视觉分析,测量感兴趣区的FDG标准化摄取值(SUV),并通过计算获得其与同侧小脑FDG的SUV的比值,比较组间是否有显著性差异。结果轻度AD患者的FDG摄取代谢降低区为后扣带回及楔前叶,且呈双侧不对称性,中度AD患者的颞叶、顶叶FDG代谢降低双侧对称且降低明显,重度AD患者全脑皮质代谢明显降低。结论 AD患者的~(18)F-FDG PET脑显像特征反映认知功能的损害程度,是临床诊断和评估AD的有力工具。     

阿尔茨海默病的脑血流灌注研究

目的探讨AD患者脑血流灌注的特征性变化。方法选择20例确诊AD患者和10例认知正常者,对所有入组对象行SPECT脑血流灌注显像检查,对所得图像进行视觉分析和半定量分析,比较两组对象各脑区血流灌注情况的差异,并比较AD患者左、右脑叶脑血流灌注的差异。结果 (1)视觉分析结果显示,AD组以颞叶或顶叶脑血流灌注减低为主,各占55%,其中双侧颞顶叶血流灌注减低者占15%,单侧颞顶叶血流灌注减低占20%。正常认知组SPECT影像学表现各异,额叶、颞叶、顶叶、枕叶、丘脑、基底节血流灌注减少情况均存在,各占10%。但无双侧颞顶叶血流灌注减少者,40%表现完全正常。(2)半定量分析结果显示,AD组在右额叶、双侧颞顶叶、右枕叶血流灌注显著低于正常认知组(P<0.05),以右侧颞叶血流灌注降低最明显,左右颞顶叶血流低灌注程度对比无显著性差异。结论 AD患者的SPECT特征性表现为双侧对称性颞顶叶血流低灌注,其中右侧颞叶血流灌注下降最严重。     

轻度认知损害和阿尔茨海默病的大脑灰质体积及其与记忆功能的关系

目的考察轻度认知损害(mild cognitive impairment,MCI)和阿尔茨海默病(Alzheimer’s disease,AD)的大脑灰质体积是否存在异常及其与记忆功能的关系。方法本研究共纳入56例轻度AD、14例MCI和16例正常对照,所有被试均进行了记忆功能测查和磁共振影像检查。影像数据分析采用患者基于体素的脑形态学分析(voxel-based morphometry,VBM)。结果 AD组和MCI组记忆测验评分下降,呈AD组相似文献   

轻度认知功能损害、阿尔茨海默病患者和健康对照者的枕区脑干听觉诱发电位的比较

背景轻度认知功能损害（mild cognitive impairment,MCI）患者枕叶异常的证据越来越多,这些患者也存在发展成阿尔茨海默病（Alzheimer s disease,AD）的高危险性。目的比较MCI患者、AD患者以及年龄匹配的健康对照者（normal control,NC）的枕区脑干听觉诱发电位特点。方法使用Nicolet Bravo脑诱发电位仪,用＂Click短声刺激,记录36例MCI、30例AD患者和45名健康对照者的脑干听觉诱发电位。比较脑干听觉诱发电位波III和波V的绝对潜伏期、绝对波幅的差异。结果 AD组的波III绝对潜伏期比MCI组、NC组的长[依次为5.12（0.36）ms、4.60（0.35）ms和4.71（0.35）ms;F=19.47,P〈0.001]。AD组的波III和波V的绝对波幅低于其他两组。MCI组的波V的绝对波幅低于健康对照组。结论枕区脑干听觉诱发电位有助于AD和MCI的诊断与鉴别诊断。     

Cognitive decline and amyloid accumulation in patients with mild cognitive impairment

Background/Aims: The relationship between baseline (11)C-Pittsburgh compound B ((11)C-PIB) uptake and cognitive decline during a 2-year follow-up was studied in 9 patients with mild cognitive impairment (MCI) who converted to Alzheimer's disease (AD) and 7 who remained with MCI. Methods: (11)C-PIB PET scan was conducted at baseline and cognitive assessment both at baseline and at follow-up. To obtain quantitative regional values of (11)C-PIB uptake, automated region of interest analysis was done using spatially normalized parametric ratio (region-to-cerebellar cortex) images. Results: At baseline, there were statistically significant differences in (11)C-PIB uptake, but not in cognitive test performances between the converters and nonconverters. Memory and executive function declined only in the converters during follow-up. In the converters, lower baseline frontal (11)C-PIB uptake was associated with faster decline in verbal learning. Higher baseline uptake in the caudate nucleus was related to faster decline in memory consolidation, and higher temporal uptake was associated with decline in executive function. Conclusion: Higher (11)C-PIB uptake in the caudate nucleus and temporal lobe was related to decline in memory and executive functions, whereas lower frontal uptake was related to decline in verbal learning. The results indicate that in prodromal AD, frontal amyloid accumulation reaches its maximum in the MCI stage, characterized by memory problems without full-blown dementia.     

A visual [18F]FDG-PET rating scale for the differential diagnosis of frontotemporal lobar degeneration

This study presents a visual rating scale for the assessment of cerebral [¹⁸F]fluoro-2-deoxy-d-glucose positron emission tomography (FDG-PET) scans to characterize typical findings in dementias associated with frontotemporal lobar degeneration (FTLD) and to differentiate individual patients with FTLD compared to Alzheimer’s disease (AD) and mild cognitive impairment (MCI). A total of 43 cerebral PET scans from patients with FTLD (n = 16, mean age 58.4 years), AD (n = 16, 59.9 years) and MCI (n = 11, 57.9 years) were analysed. Every PET data set was visually rated for seven brain regions on each hemisphere (frontal lobe, temporal lobe, parietal lobe, occipital lobe, basal ganglia, thalamus and cerebellum). The extent of the impairment in metabolism was classified as absent, mild, medium or strong. Using this four-stage visual rating scale, characteristic profiles of metabolic impairment in FTLD, AD, MCI and the FTLD-subgroup FTD (n = 9) could be demonstrated. Patients with FTLD showed a significantly lower metabolism in the left frontal lobe and in the left basal ganglia when compared to AD and to MCI. Complementary analyses using statistical parametric mapping (SPM2) supported the findings of the visual analysis. In detecting FTLD with visual rating, sensitivity/specificity was 81/94% compared to AD and 81/64% compared to MCI. Patients with FTD were correctly attributed to a diagnosis of FTLD with a sensitivity of 89%. This visual rating scale may facilitate the differential diagnosis of FTLD in clinical routine.     

18F-FDG PET/CT脑显像评价认知障碍患者中的脑小血管病变对皮层功能的影响

目的 探讨18氟代脱氧葡萄糖（18F-fluorodeoxyglucose,18F-FDG）正电子发射断层成像/计算机断层扫
描（positron emission tomography/computed tomography,PET/CT）脑显像评价认知障碍患者中的脑小血
管病变对皮层功能的影响。
方法 本研究为回顾性研究,纳入2009年1月～2010年12月北京协和医院PET中心行18F-FDG PET/CT
脑显像且颅脑磁共振成像（magnetic resonance imaging,MRI）提示存在小血管病变的认知障碍患者21例,
其中临床诊断血管性痴呆（vascular dementia,VaD）10例,阿尔茨海默病（Alzheimer’s disease,AD）或混
合型痴呆（mixed dementia,MD）11例。首先目测两组患者的18F-FDG PET/CT脑显像皮层及皮层下核团代
谢减低特点,并结合颅脑MRI判断病变血管对脑代谢的影响。使用NeuroQ软件和Scenium软件对18F-FDG
PET/CT脑图像在像素基础上进行定量分析比较两组患者的皮层代谢情况。
结果 通过目测和NeuroQ软件分析发现VaD组患者18F-FDG PET/CT脑显像图像特点为无规律,不对
称皮层或皮层下核团代谢减低,其中额叶皮层代谢减低范围最广,程度最重。结合颅脑MRI改变,考
虑皮层和皮层下核团代谢减低主要为小血管病变引起。AD或MD组患者脑代谢均呈现双侧颞顶叶代谢
减低,其中8例出现皮层代谢减低不对称表现,6例出现基底节丘脑不对称代谢减低表现,与典型AD
的表现不符,结合颅脑MRI表现,考虑为病变血管所致,小血管病变可能导致相应皮层代谢减低。通
过定量分析发现两组患者的SUV比值在左右顶叶、内外颞叶和枕叶差异具有显著性。
结论 18F-FDG PET/CT脑显像作为功能影像可以推断小血管病变与皮层及皮层下核团代谢的关系。     

Amnestic mild cognitive impairment in Parkinson's disease: A brain perfusion SPECT study

The purpose of this study was to investigate cortical dysfunction in Parkinson's disease (PD) patients with amnestic deficit (PD‐MCI). Perfusion single photon emission computed tomography was performed in 15 PD‐MCI patients and compared (statistical parametric mapping [SPM2]) with three groups, i.e., healthy subjects (CTR), cognitively intact PD patients (PD), and common amnestic MCI patients (aMCI). Age, depression, and UPDRS‐III scores were considered as confounding variables. PD‐MCI group (P < 0.05, false discovery rate–corrected for multiple comparisons) showed relative hypoperfusion in bilateral posterior parietal lobe and in right occipital lobe in comparison to CTR. As compared to aMCI, MCI‐PD demonstrated hypoperfusion in bilateral posterior parietal and occipital areas, mainly right cuneus and angular gyrus, and left precuneus and middle occipital gyrus. With a less conservative threshold (uncorrected P < 0.01), MCI‐PD showed hypoperfusion in a left parietal region, mainly including precuneus and inferior parietal lobule, and in a right temporal‐parietal‐occipital region, including middle occipital and superior temporal gyri, and cuneus‐precuneus, as compared to PD. aMCI versus PD‐MCI showed hypoperfusion in bilateral medial temporal lobe, anterior cingulate, and left orbitofrontal cortex. PD‐MCI patients with amnestic deficit showed cortical dysfunction in bilateral posterior parietal and occipital lobes, a pattern that can be especially recognized versus both controls and common aMCI patients, and to a lesser extent versus cognitively intact PD. The relevance of this pattern in predicting dementia should be evaluated in longitudinal studies. © 2008 Movement Disorder Society     

多模态影像学在不同阶段阿尔茨海默病中应用研究

目的 评估多模态影像学技术在不同阶段阿尔茨海默病患者中的应用价值.方法 募集2016年12月1日至2018年11月30日就诊于包头市中心医院神经内科受试者共56例,根据入组标准及排除标准,纳入轻度认知功能障碍期者(MCI组)18例、痴呆阶段阿尔茨海默病者(AD组)18例以及与上述病例相匹配健康志愿者(正常组)20例.所...     

Amyloid PET in mild cognitive impairment and Alzheimer’s disease with BF-227: comparison to FDG–PET

We recently developed a novel PET tracer, ¹¹C-labeled 2-(2-[2-dimethylaminothiazol-5-yl]ethenyl)-6-(2-[fluoro]ethoxy)benzoxazole ([¹¹C]BF-227), and had success with in vivo detection of amyloid plaques in Alzheimer’s disease (AD) brains (Kudo et al. in J Nucl Med 8:553–561, 2007). We applied this tracer to subjects with mild cognitive impairment (MCI) and AD in order to elucidate the status of amyloid plaque deposition in MCI and compared the diagnostic performance of BF-227-PET with that of FDG–PET in AD cases. We studied 12 aged normal (AN) subjects, 15 MCIs and 15 ADs with PET using [¹¹C]BF-227. PET images were obtained after administration of BF-227 and the regional standardized uptake value (SUV) and the ratio of regional to cerebellar SUV were calculated as an index of BF-227 binding. AD patients showed increased uptake of [¹¹C]BF-227 in the neocortical areas and striatum as well as decreased glucose metabolism in temporoparietal, posterior cingulate and medial temporal areas. MCI subjects showed a significant increase in BF-227 uptake in the neocortical areas similar to AD, and the most significant difference of BF-227 retention was observed in the parietal lobe if its retentions for MCI were compared to those for AD and AN. On the other hand, glucose hypometabolism in MCI was confined to cingulate and medial temporal cortices. Neocortical BF-227 uptake negatively correlated with glucose metabolism. Receiver operating characteristic (ROC) analysis indicated higher specificity and sensitivity with BF-227-PET than those with FDG–PET for differential diagnosis between AD and normal control. We conclude that [¹¹C]BF-227-PET has a possibility to be a useful technology for early detection of AD pathology and also even in the MCI stage.     

Magnetic resonance imaging of the entorhinal cortex and hippocampus in mild cognitive impairment and Alzheimer's disease

OBJECTIVES: To explore volume changes of the entorhinal cortex (ERC) and hippocampus in mild cognitive impairment (MCI) and Alzheimer's disease (AD) compared with normal cognition (NC); to determine the powers of the ERC and the hippocampus for discrimination between these groups. METHODS: This study included 40 subjects with NC, 36 patients with MCI, and 29 patients with AD. Volumes of the ERC and hippocampus were manually measured based on coronal T1 weighted MR images. Global cerebral changes were assessed using semiautomatic image segmentation. RESULTS: Both ERC and hippocampal volumes were reduced in MCI (ERC 13%, hippocampus 11%, p<0.05) and AD (ERC 39%, hippocampus 27%, p<0.01) compared with NC. Furthermore, AD showed greater volume losses in the ERC than in the hippocampus (p<0.01). In addition, AD and MCI also had cortical grey matter loss (p< 0.01) and ventricular enlargement (p<0.01) when compared with NC. There was a significant correlation between ERC and hippocampal volumes in MCI and AD (both p<0.001), but not in NC. Using ERC and hippocampus together improved discrimination between AD and CN but did not improve discrimination between MCI and NC. The ERC was better than the hippocampus for distinguishing MCI from AD. In addition, loss of cortical grey matter significantly contributed to the hippocampus for discriminating MCI and AD from NC. CONCLUSIONS: Volume reductions in the ERC and hippocampus may be early signs of AD pathology that can be measured using MRI.     

New MRI markers for Alzheimer's disease: a meta-analysis of diffusion tensor imaging and a comparison with medial temporal lobe measurements

The aim of the present study is to evaluate the diagnostic value of diffusion tensor imaging (DTI) for early Alzheimer's disease (AD) in comparison to widely accepted medial temporal lobe (MTL) atrophy measurements. A systematic literature research was performed into DTI and MTL atrophy in AD and mild cognitive impairment (MCI). We included seventy-six studies on MTL atrophy including 8,122 subjects and fifty-five DTI studies including 2,791 subjects. Outcome measure was the effect size (ES) expressed as Hedges g. In volumetric studies, atrophy of the MTL significantly differentiated between AD and controls (ES 1.32-1.98) and MCI and controls (ES 0.61-1.46). In DTI-Fractional anisotropy (FA) studies, the total cingulum differentiated best between AD and controls (ES = 1.73) and the parahippocampal cingulum between MCI and controls (ES = 0.97). In DTI-Mean diffusivity (MD) studies, the hippocampus differentiated best between AD and controls (ES = -1.17) and between MCI and controls (ES = -1.00). We can conclude that in general, the ES of volumetric MTL atrophy measurements was equal or larger than that of DTI measurements. However, for the comparison between controls and MCI-patients, ES of hippocampal MD was larger than ES of hippocampal volume. Furthermore, it seems that MD values have somewhat more discriminative power than FA values with higher ES in the frontal, parietal, occipital and temporal lobe.