0000000000076271

AUTHOR

Alexander Hammers

0000-0001-9530-4848

showing 5 related works from this author

Choice of reference area in studies of Alzheimer's disease using positron emission tomography with fluorodeoxyglucose-F18

2007

At present, there is still no consensus on the choice of the reference area in positron emission tomography (PET) studies of Alzheimer's disease (AD). In this study, PET scans with fluorodeoxyglucose-F18 were carried out in the following groups of subjects: 47 patients with probable AD, 8 patients with mild cognitive impairment, and 15 age-similar healthy subjects. Scans normalized to the cerebral global mean (CGM), cerebellum (CBL), and the primary sensorimotor cortex (SMC). We evaluated the effect of the different count normalization procedures on the accuracy of (18)F-FDG PET to detect AD-specific metabolic abnormalities (voxel-based group comparison) and to differentiate between patient…

MaleNormalization (statistics)Pathologymedicine.medical_specialtyAdolescentNeuroscience (miscellaneous)Neuropsychological TestsStatistical parametric mappingGyrus CinguliSeverity of Illness IndexCentral nervous system diseaseAlzheimer DiseaseFluorodeoxyglucose F18CerebellumParietal LobemedicineHumansDementiaRadiology Nuclear Medicine and imagingAgedFluorodeoxyglucosemedicine.diagnostic_testbusiness.industryCognitive disorderMotor CortexSomatosensory Cortexmedicine.diseaseTemporal LobeFrontal LobePsychiatry and Mental healthPositron emission tomographyPositron-Emission TomographyFemaleRadiopharmaceuticalsAlzheimer's diseaseCognition DisordersNuclear medicinebusinessPsychologymedicine.drugPsychiatry Research: Neuroimaging
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A systematic comparison of kinetic modelling methods generating parametric maps for [11C]-(R)-PK11195

2006

[(11)C]-(R)-PK11195 is presently the most widely used radiotracer for the monitoring of microglia activity in the central nervous system (CNS). Microglia, the resident immune cells of the brain, play a critical role in acute and chronic diseases of the central nervous system and in host defence against neoplasia. The purpose of this investigation was to evaluate the reliability and sensitivity of five kinetic modelling methods for the formation of parametric maps from dynamic [(11)C]-(R)-PK11195 studies. The methods we tested were the simplified reference tissue model (SRTM), basis pursuit, a simple target-to-reference ratio, the Logan plot and a wavelet based Logan plot. For the reliabilit…

Correlation coefficientComputer scienceCognitive NeuroscienceBasis pursuitKinetic energySensitivity and SpecificityWaveletAlzheimer DiseaseModelling methodsComputer GraphicsImage Processing Computer-AssistedCluster AnalysisHumansPharmacokineticsCarbon RadioisotopesMathematical ComputingParametric statisticsBrain Mappingbusiness.industryBrainIsoquinolinesReceptors GABA-ALogan plotHuntington DiseaseNeurologyPositron-Emission TomographyMicrogliaNuclear medicinebusinessNeuroImage
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SPM-based count normalization provides excellent discrimination of mild Alzheimer's disease and amnestic mild cognitive impairment from healthy aging☆

2008

Statistical comparisons of [(18)F]FDG PET scans between healthy subjects and patients with Alzheimer's disease (AD) or amnestic mild cognitive impairment (aMCI) using Statistical Parametric Mapping (SPM) usually require normalization of regional tracer uptake via ROIs defined using additional software. Here, we validate a simple SPM-based method for count normalization. FDG PET scans of 21 mild, 15 very mild AD, 11 aMCI patients and 15 age-matched controls were analyzed. First, we obtained relative increases in the whole patient sample compared to controls (i.e. areas relatively preserved in patients) with proportional scaling to the cerebral global mean (CGM). Next, average absolute counts…

MaleNormalization (statistics)Agingmedicine.medical_specialtyPathologyCognitive NeuroscienceLogistic regressionStatistical parametric mappingNeuroimagingAlzheimer DiseaseFluorodeoxyglucose F18Internal medicineImage Interpretation Computer-AssistedmedicineHumansDementiaHealthy agingRadionuclide ImagingCognitive impairmentAgedRetrospective StudiesBrain Mappingmedicine.diagnostic_testBrainmedicine.diseaseNeurologyPositron emission tomographyCardiologyFemaleCognition DisordersPsychologyAlgorithmsNeuroImage
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Increased hippocampal head diffusivity predicts impaired episodic memory performance in early Alzheimer's disease

2010

Recent neuroanatomical and functional neuroimaging studies indicate that the anterior part of the hippocampus, rather than the whole structure, may be specifically involved in episodic memory. In the present work, we examined whether anterior structural measurements are superior to other regional or global measurements in mapping functionally relevant degenerative alterations of the hippocampus in Alzheimer's disease (AD). Twenty patients with early AD (MMSE 25.7+/-1.7) and 18 healthy controls were studied using magnetic resonance and diffusion-tensor imaging. Using a regions-of-interest analysis, we obtained volumetric and diffusivity measures of the hippocampal head and body-tail-section …

MaleCognitive NeuroscienceHippocampusExperimental and Cognitive PsychologyHippocampal formationHippocampusBehavioral NeuroscienceAlzheimer DiseasePredictive Value of TestsFunctional neuroimagingmedicineHumansDementiaAge of OnsetEpisodic memoryAgedMemory Disordersmedicine.diagnostic_testPerforant PathwayMagnetic resonance imagingmedicine.diseaseMagnetic Resonance ImagingMental RecallFemaleAtrophyPsychologyNeuroscienceDiffusion MRINeuropsychologia
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Supervised reference region extraction for the quantification of [11C]-(R)-PK11195 brain studies

2006

Neurologybusiness.industryCognitive NeuroscienceExtraction (chemistry)MedicinePattern recognitionArtificial intelligenceReference RegionbusinessNeuroImage
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