MRI结构成像及先进技术多参数计算机辅助诊断鉴别阿尔茨海默病与额颞型痴呆

正摘要目的探讨动脉自旋标记(ASL)和扩散张量成像(DTI)能否在MRI结构成像之外增加计算机辅助诊断对阿尔茨海默病(AD)、额颞叶痴呆(FTD)和对照组的鉴别价值。     

AD型与非AD型变性痴呆大脑葡萄糖代谢的SPM分析

目的 探讨阿尔茨海默病(AD)型与非AD型变性痴呆患者的大脑葡萄糖代谢特征.方法 对23例AD患者、24例非AD型变性痴呆[包括9例帕金森病痴呆(PDD)、7例额颞痴呆(FTD)及8例路易体痴呆(DLB)]患者及40名健康对照者进行静息状态下的18F-脱氧葡萄糖(FDG)PET脑显像.结果 采用统计参数图(SPM)法进行基于体素水平分析.结果 (1)AD组:AD患者大脑葡萄糖代谢较对照组减低的脑区包括双侧颞-顶联合皮质区、额叶、楔前叶及后扣带回等部位.(2)非AD型变性痴呆组:FTD组大脑葡萄糖代谢较对照组减低的脑区包括双侧额叶、顶叶、岛叶、扣带回及左侧楔前叶、右侧皮质下结构等部位,以双侧额叶及皮质下结构为著;PDD组大脑葡萄糖代谢较对照组减低的脑区包括双侧额叶、颞-顶联合皮质区及皮质下结构,如基底节、丘脑等部位;DLB组大脑葡萄糖代谢较对照组减低的脑区包括双侧枕叶、楔前叶、额叶、顶叶及左侧前扣带回、右侧颞叶及皮质下结构如基底节、丘脑等部位,以双侧颞-顶-枕叶联合皮质区为著.结论 AD型与非AD型变性痴呆的大脑葡萄糖代谢特征不同,18F-FDG PET脑显像可为临床诊断及鉴别诊断神经变性痴呆提供依据.     

阿尔茨海默病等痴呆疾病的脑功能影像学研究

痴呆类疾病可分为阿尔茨海默病(AD)、皮克病、多发性梗死性痴呆(MID)等类型,它们各具不同的临床特点。神经心理学检查对痴呆的诊断及鉴别诊断起一定作用。AD等痴呆疾病的神经影像学发展越来越迅速,其中18F-FDG PET脑功能显像技术可以早期发现AD患者大脑皮层顶、颞叶等区域葡萄糖代谢率降低,并且左、右半球不对称。18F-FDG PET方法还可以鉴别诊断AD与其他痴呆类疾病。     

阿尔茨海默病、额颞叶性痴呆与路易体痴呆的独特血流灌注方式

正摘要目的采用假性连续动脉自旋标记(PCASL)MRI定量测量法对兴趣区(ROI)脑血流(CBF)进行基于体素的分析,比较其在额颞叶性痴呆(FTD)、路易体痴呆(DLB)、阿尔     

应用MR动脉自旋标记技术早期鉴别诊断早老性阿尔茨海默病与额颞叶痴呆

正摘要目的研究MR动脉自旋标记技术(ASL)对于两种最为常见的早老性痴呆,即阿尔茨海默病(AD)和额颞叶痴呆(FTD)的早期诊断、早期鉴别,并对年龄相关性脑灌注异常与病理性脑灌注异常进行鉴别。方法 AD组13例,FTD组19例,老年对照组25例,年轻对照组22例,均行3.0 T MR3D-ASL扫描。部分容积效应校正后,测量整个幕上皮质的10个灰质区的脑灰质体积(GM)、脑血流量(CBF)。对病人组     

阿尔茨海默病及额颞叶痴呆的脑灌注与葡萄糖代谢:同一枚硬币的两面?

<正>摘要目的阿尔茨海默病(AD)及额颞叶痴呆(FTD)可用[18F]-2-脱氧-2-氟-D-葡萄糖(FDG)-PET进行鉴别。因为脑血流量(CBF)与葡萄糖代谢相关,本研究目的是观察AD     

阿尔茨海默病等痴呆疾病的脑功能影像学研究

痴呆类疾病可分为阿尔茨海默病（AD）、皮克病、多发性梗死性痴呆（MID）等类型。它们各具不同的临床特点,神经心理学检查对痴呆的诊断及鉴别诊断起一定作用。AD等痴呆疾病的神经影像学发展越来越迅速,其中^18F-FDGPET脑功能显像技术可以早期发现AD患者大脑皮层顶,颞叶等区域葡萄糖代谢率降低,并且左,右半球不对称。^18F-FDGPET方法还可以鉴别诊断AD与其他痴呆类疾病。     

应用18F-DOPA PET显像诊断路易小体性痴呆

目的评价测定纹状体突触前多巴胺代谢水平对路易小体性痴呆(DLB)诊断、鉴别诊断的价值.方法研究对象分为3组7例DLB患者,10例老年性痴呆(AD)患者及9例年龄相匹配的正常对照者.用18F-fluorodopa(DOPA)PET显像测定受检者纹状体突触前多巴胺的摄取(即脑内18F-DOPA放射性水平, 以流入速率常数Ki表示),然后对3组Ki值进行比较.结果①DLB组Ki值(壳核0.006 4±0.001 7,尾状核0.005 1±0.001 9)明显低于AD组(分别为0.011 9±0.002 1及0.009 2±0.001 4)及对照组(分别为0.013 1±0.002 8及0.012 2±0.003 5),差异均有显著性(P均<0.01);而AD组与对照组间的Ki值差异无显著性(P>0.05).②DLB的尾状核Ki值(正常值的42%)降低较壳核(正常值的49%)更为明显.③以Ki=0.006 2作为临界点(正常尾状核-2s),DLB与AD鉴别的灵敏度和特异性分别为86%和100%.结论用18F-DOPA PET显像检测多巴胺代谢功能有助于DLB的早期诊断和鉴别诊断.     

基于皮质萎缩自动识别对阿尔茨海默病和行为异常型额颞叶痴呆的个体化诊断

正摘要目的探讨用一种基于图像的分类器来个体化区分阿尔茨海默病(AD)和行为异常型额颞叶痴呆(bv FTD)的诊断准确性,这种分类器是用多个成像系统获得标准的T1加权结构图来计算灰质(GM)密度图并有独立的训练数据和预测数据。材料与方法该研究经当地机构伦理委员会批准。     

磁共振波谱定量分析脑内代谢产物鉴别诊断早老痴呆和血管性痴呆

目的:探讨1HMRS鉴别早老痴呆(AD)和血管性痴呆(VD)。材料和方法:61名被试者,AD组20例,VD组20例,健康对照组(HC)21例,均用GESigna1.5T超导磁共振扫描仪,采用PRESS序列对兴趣区内脑代谢产物浓度采集并计算比值;并行统计学处理。结果:AD和VD患者的额叶NAA浓度及NAA/Cr、NAA/MI的比值较HC组明显降低;AD患者颞叶和海马区MI浓度明显高于VD和HC组;而AD患者海马区的NAA浓度以及NAA/Cr和NAA/MI的比值降低。结论:AD组海马区的NAA浓度和NAA/Cr明显降低而MI浓度和MI/Cr明显升高,与VD之间具有鉴别诊断意义。     

Multicenter standardized 18F-FDG PET diagnosis of mild cognitive impairment, Alzheimer's disease, and other dementias.

This multicenter study examined (18)F-FDG PET measures in the differential diagnosis of Alzheimer's disease (AD), frontotemporal dementia (FTD), and dementia with Lewy bodies (DLB) from normal aging and from each other and the relation of disease-specific patterns to mild cognitive impairment (MCI). METHODS: We examined the (18)F-FDG PET scans of 548 subjects, including 110 healthy elderly individuals ("normals" or NLs), 114 MCI, 199 AD, 98 FTD, and 27 DLB patients, collected at 7 participating centers. Individual PET scans were Z scored using automated voxel-based comparison with generation of disease-specific patterns of cortical and hippocampal (18)F-FDG uptake that were then applied to characterize MCI. RESULTS: Standardized disease-specific PET patterns were developed that correctly classified 95% AD, 92% DLB, 94% FTD, and 94% NL. MCI patients showed primarily posterior cingulate cortex and hippocampal hypometabolism (81%), whereas neocortical abnormalities varied according to neuropsychological profiles. An AD PET pattern was observed in 79% MCI with deficits in multiple cognitive domains and 31% amnesic MCI. (18)F-FDG PET heterogeneity in MCI with nonmemory deficits ranged from absent hypometabolism to FTD and DLB PET patterns. CONCLUSION: Standardized automated analysis of (18)F-FDG PET scans may provide an objective and sensitive support to the clinical diagnosis in early dementia.     

Value of analyzing deep gray matter and occipital lobe perfusion to differentiate dementia with Lewy bodies from Alzheimer’s disease

Objective  Dementia with Lewy bodies (DLB) is generally characterized by a decrease in regional cerebral blood flow (rCBF) in the occipital lobe. However, not all patients with DLB have this feature. We explored characteristics of rCBF pattern changes to improve the identification of DLB, in addition to occipital hypoperfusion. Methods  The study population comprised 30 patients with probable DLB and 49 patients with probable Alzheimer’s disease (AD) who underwent single-photon emission computed tomography. The data were analyzed using Neurological Statistical Image Analysis Software (NEUROSTAT). We established a template of the region of interest (ROI) presenting the parietal lobe, posterior cingulate, striatum, thalamus, and occipital lobe on the standard brain atlas. We then compared the mean Z scores in each ROI between DLB and AD. Moreover, we investigated the value of analyzing relative rCBF changes in both the deep gray matter and occipital lobe in differentiating DLB from AD. Results  The DLB group showed a significant relative rCBF increase in the bilateral striatum and thalamus, and a significant relative rCBF decrease in the bilateral occipital lobe when compared with the AD group. Receiver-operating characteristic analysis revealed that determining the hyperperfusion in the thalamus together with the hypoperfusion in the occipital lobe enabled a more accurate differentiation between DLB and AD than studying individual areas. Conclusions  Studying the relative increase of rCBF in the deep gray matter, and the relative decrease of that in the occipital lobe achieved a high differentiation between DLB and AD. This suggests that determining both an increase and a decrease in rCBF pattern may be important in differentiating between the two diseases.     

Computer-assisted diagnostic system for neurodegenerative dementia using brain SPECT and 3D-SSP

Purpose  To develop a computer-assisted automated diagnostic system to distinguish among Alzheimer disease (AD), dementia with Lewy bodies (DLB), and other degenerative disorders in patients with mild dementia. Methods  Single photon emission computed tomography (SPECT) images with injection of N-Isopropyl-p-[¹²³I]iodoamphetamine (IMP) were obtained from patients with mild degenerative dementia. First, datasets from 20 patients mild AD, 15 patients with dementia with DLB, and 17 healthy controls were used to develop an automated diagnosing system based on three-dimensional stereotactic surface projections (3D-SSP). AD- and DLB-specific regional templates were created using 3D-SSP, and critical Z scores in the templates were established. Datasets from 50 AD patients, 8 DLB patients, and 10 patients with non-AD/DLB type degenerative dementia (5 with frontotemporal dementia and 5 with progressive supranuclear palsy) were then used to test the diagnostic accuracy of the optimized automated system in comparison to the diagnostic interpretation of conventional IMP-SPECT images. These comparisons were performed to differentiate AD and DLB from non-AD/DLB and to distinguish AD from DLB. A receiver operating characteristic (ROC) analysis was performed. Results  The area under the ROC curve (Az) and the accuracy of the automated diagnosis system were 0.89 and 82%, respectively, for AD/DLB vs. non-AD/DLB patients, and 0.70 and 65%, respectively, for AD vs. DLB patients. The mean Az and the accuracy of the visual inspection were 0.84 and 77%, respectively, for AD/DLB vs. non-AD/DLB patients, and 0.70 and 65%, respectively, for AD vs. DLB patients. The mean Az and the accuracy of the combination of visual inspection and this system were 0.96 and 91%, respectively, for AD/DLB vs. non-AD/DLB patients, and 0.70 and 66%, respectively, for AD vs. DLB patients. Conclusion  The system developed in the present study achieved as good discrimination of AD, DLB, and other degenerative disorders in patients with mild dementia as the commonly performed visual inspection of conventional SPECT images. A combination of visual inspection and this system is helpful in the differential diagnosis of patients with mild dementia.     

99Tcm-HMPAO SPECT in suspected dementia

To evaluate the usefulness of 99Tcm-hexamethylpropyleneamine oxime (HMPAO) single photon emission computed tomography (SPECT) in suspected dementia we studied 160 consecutively imaged elderly patients from our hospital's memory disorder clinic. The diagnosis was based on clinical data, laboratory tests, neuropsychological examination, computed tomography (CT) and EEG. The patients were divided into six diagnostic categories: Alzheimer's disease (AD), multi-infarct dementia (MID), frontal lobe-type dementia (FTD), vascular encephalopathy not fulfilling the criteria of dementia, specific organic conditions, and psychiatric disorders. SPECT images were assessed without knowing the clinical diagnosis, and divided into AD pattern, FTD pattern, MID pattern, abnormal but unclassifiable, and normal. Twenty-three of 36 patients with clinical AD, 25/33 patients with clinical MID, and 2/5 patients with clinical TFD had compatible SPECT patterns. SPECT distinguished AD from MID in the majority (80%) of cases. In patients with depression or anxiety SPECT was abnormal in 16/21 cases, suggesting that SPECT may give early clues to the presence of an underlying organic disease in such elderly patients. Thus, SPECT with 99Tcm-HMPAO seems to be useful in the diagnosis of suspected dementia.     

Comparison of grey matter and metabolic reductions in frontotemporal dementia using FDG-PET and voxel-based morphometric MR studies

Purpose  The aim of this study was to investigate the regional differences between the morphologic and functional changes in the same patients with frontotemporal dementia (FTD) using statistical parametric mapping and voxel-based morphometry (VBM). Methods  Thirteen FTD patients (mean age, 64.9 years old; mean MMSE score, 17.7), 20 sex-matched Alzheimer’s disease (AD) patients (mean age, 65.0 years old; mean MMSE score, 17.5), and 20 normal volunteers (mean age, 65.2 years old; mean MMSE score, 29.0) underwent both [¹⁸F]FDG positron emission tomography and three-dimensional spoiled gradient echo MRI. Statistical parametric mapping was used to conduct a VBM analysis of the morphologic data, which were compared voxel by voxel with the results of a similar analysis of glucose metabolic data. Results  FTD patients showed decreased grey matter volume and decreased glucose metabolism in the frontal lobe and anterior temporal lobe. In addition, there was a clear asymmetry in grey matter volume in FTD patients by the VBM analysis while the glucose metabolic data showed little asymmetry. In AD patients, glucose metabolic reduction occurred in the bilateral posterior cingulate gyri and parietal lobules while grey matter density decreased the least in the same patients. Conclusion  In FTD, metabolic and morphologic changes occur in the bilateral frontal lobe and temporal lobe with a limited asymmetry whereas there was considerable discordance in the AD group.     

Imaging of the dopaminergic system in differential diagnosis of dementia

Neurodegenerative dementia is an increasingly common disorder with Alzheimer's disease (AD) and dementia with Lewy bodies (DLB) accounting for most cases. Due to the overlap in clinical symptoms, their differential diagnosis may be challenging. As clinical classification is not completely satisfying, there is a need to improve the diagnostic accuracy by complementary methods such as functional single-photon emission computed tomography (SPECT) and positron emission tomography (PET) imaging. The latter may be helpful to address one distinct biological difference between DLB and AD, the severe nigrostriatal degeneration which occurs in DLB, but not to any significant extent in AD. Based on this principle, autoradiographic studies targeting presynaptic dopaminergic functions have consistently demonstrated the ability to distinguish DLB from AD in postmortem series. At the same time, several single-site and one multicentre study have independently confirmed--no matter what technique was used (SPECT or PET) and which presynaptic function was addressed (dopamine turnover, dopamine transporter, vesicular monoamine transporter)--significantly compromised scan results in DLB subjects, whereas AD patients maintained almost normal findings. Even more important, in vivo findings of presynaptic dopaminergic imaging correlated well with neuropathological findings at autopsy, suggesting a remarkable sensitivity of 88% and a specificity of 100% for the imaging procedure to distinguish between DLB and AD. Taken together, imaging of presynaptic dopaminergic terminal functions with SPECT and PET has currently the greatest evidence base to support its use, and therefore, may be highly recommended to help in the discrimination between DLB and AD. Compared to presynaptic functions, corresponding data targeting postsynaptic dopamine receptors are comparatively rare, less conclusive and suggest a very limited role for this purpose. This review discusses the findings of studies specifically dealing with imaging of the dopaminergic system in the differential diagnosis of dementia.     

阿尔茨海默病与血管性痴呆的18 F-FDG PET脑显像

目的　观察18F 脱氧葡萄糖 (FDG)PET脑显像鉴别诊断阿尔茨海默病 (AD)与血管性痴呆 (VD)的价值。方法　分别对 10例AD、11例VD及 12例对照者进行18F FDGPET脑显像 ,采用统计参数图 (SPM)方法及感兴趣区 (ROI)方法进行分析 ,比较AD及VD的显像特点。结果　SPM图像显示 ,AD组患者两侧大脑皮层顶叶、颞叶、额叶及后扣带回等部位葡萄糖代谢明显降低 ,左、右不对称 ;而两侧皮层下基底节区等结构代谢不受影响。VD组患者代谢弥漫性降低 ,遍及大脑皮层及皮层下结构。ROI分析表明 ,AD组患者大脑皮层顶叶、颞叶、额叶放射性降低 ,差异有显著性 (P <0 0 5 ) ,皮层下神经核团等无明显变化。而VD组患者仅左侧额叶及右侧壳核放射性降低 ,差异有显著性 (P <0 0 5 )。结论　PET脑显像可有效诊断AD并鉴别诊断AD与VD。     

Distinct perfusion patterns in Alzheimer’s disease,frontotemporal dementia and dementia with Lewy bodies

Objectives

To compare pseudo-continuous arterial spin-labelled (PCASL) magnetic resonance imaging (MRI) measured quantitative cerebral blood flow (CBF) of patients with frontotemporal dementia (FTD), dementia with Lewy Bodies (DLB), Alzheimer’s disease (AD) and controls, in a region of interest (ROI) and voxel-wise fashion.

Methods

We analysed whole-brain 3D fast-spin-echo PCASL images of 20 FTD patients, 14 DLB patients, 48 AD patients and 50 controls from the Amsterdam Dementia Cohort. Regional CBF patterns were compared using analyses of variance for repeated measures. Permutation tests were used for voxel-wise comparisons. Analyses were performed using uncorrected and partial volume corrected (PVC) maps. All analyses were corrected for age and sex.

Results

There was an interaction between diagnosis and region (p?Conclusions Patients with AD, FTD and DLB display distinct patterns of quantitative regional CBF changes. 3D-PCASL may provide additional value in the workup of dementia patients.

Key points

? Patterns of regional CBF changes differ between AD, FTD and DLB patients ? CBF is lower throughout the brain in DLB than AD and FTD ? 3D-PCASL MRI is a potential non-invasive and easily accessible alternative to FDG-PET ? 3D-PCASL MRI may be of additional value in the workup of dementia     

Quantitative gait analysis in patients with dementia with Lewy bodies and Alzheimer's disease

Gait disorders in people with dementia have been documented in a number of studies. There is some preliminary evidence suggesting there may be a relationship between dementia type and gait abnormality. Quantitative gait analysis has not previously been reported for people diagnosed with dementia with Lewy bodies (DLB). Therefore, this study aimed to quantify gait patterns of people with DLB and compare them with those of people with Alzheimer's disease (AD) and control subjects. Two groups of 10 subjects divided according to a diagnosis of DLB and AD, and 10 control subjects underwent gait analysis using an electronic walkway. Participants were required to walk at self-selected slow, preferred and fast speeds. There were no differences between the DLB and AD patient groups for any of the measured gait variables. Velocity and stride length values were significantly reduced in both patient groups compared to the control group at all speeds and percentage of time spent in double limb support was significantly increased in both patient groups compared to the control group at all walking speeds. Significant correlations were found between gait speeds and gait outcome variables. Spatiotemporal gait characteristics of people with AD and DLB are similar, but significantly different from the normal population.     

Alzheimer's disease and frontotemporal dementia exhibit distinct atrophy-behavior correlates: a computer-assisted imaging study

Rationale and Objectives. The purpose of this study was to test the hypothesis that distinct patterns of gray matter atrophy are responsible for unique interruptions of the naming process in Alzheimer’s disease (AD) and frontotemporal dementia (FTD).

Materials and Methods. Voxel-based morphometry (VBM) was performed to characterize at the voxel level the neuroanatomic changes that occur in AD and FTD based on high-resolution T1-weighted three-dimensional (3D) spoiled-gradient echo images of patients (AD, N = 12; FTD, N = 29) and healthy control subjects (n = 12). The cortical atrophy measurements were correlated with performance on behavioral measures of naming and related processes to identify brain regions that may contribute to this language function.

Results. Both AD and FTD have significant naming difficulty, and this difficulty in naming correlates with a measure of lexical retrieval in both patient groups as well. However, only FTD patients showed a correlation with semantic memory. Areas of cortical atrophy common to AD and FTD were found in the anterior temporal, posterolateral temporal, and dorsolateral prefrontal regions of the left hemisphere. Correlation with naming in both AD and FTD was seen in the left anterior temporal cortex, suggesting that this area may play a role in the lexical retrieval component of naming. We also observed several unique areas of cortical atrophy in temporal and frontal cortices of these patients. Right anterior temporal and left posterolateral temporal regions of atrophy correlated with naming difficulty in FTD, suggesting that these areas may contribute to the semantic memory component of naming. Cortical areas correlating with naming that are not atrophic may represent regions that play an optional role in naming.

Conclusion. VBM provides an important first step in analyzing brain-behavior relations in vivo in patients with neurodegenerative diseases. More refined analyses of brain morphology via high-dimensional normalization methods that are capable of modeling local as well as global variability in neuroanatomical structure promise to be even more informative.