Dataset Information

Focal hemosiderin deposits and β-amyloid load in the ADNI cohort.

ABSTRACT:

Background

Prevalence and risk factors for focal hemosiderin deposits are important considerations when planning amyloid-modifying trials for treatment and prevention of Alzheimer's disease (AD).

Methods

Subjects were cognitively normal (n = 171), early-mild cognitive impairment (MCI) (n = 240), late-MCI (n = 111), and AD (n = 40) from the Alzheimer's Disease Neuroimaging Initiative (ADNI). Microhemorrhages and superficial siderosis were assessed at baseline and on all available MRIs at 3, 6, and 12 months. β-amyloid load was assessed with (18)F-florbetapir positron emission tomography.

Results

Prevalence of superficial siderosis was 1% and prevalence of microhemorrhages was 25% increasing with age (P < .001) and β-amyloid load (P < .001). Topographic densities of microhemorrhages were highest in the occipital lobes and lowest in the deep/infratentorial regions. A greater number of microhemorrhages at baseline was associated with a greater annualized rate of additional microhemorrhages by last follow-up (rank correlation = 0.49; P < .001).

Conclusions

Focal hemosiderin deposits are relatively common in the ADNI cohort and are associated with β-amyloid load.

SUBMITTER: Kantarci K

PROVIDER: S-EPMC3770782 | biostudies-literature | 2013 Oct

REPOSITORIES: biostudies-literature

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Publications

Focal hemosiderin deposits and β-amyloid load in the ADNI cohort.

Kantarci Kejal K Gunter Jeffrey L JL Tosakulwong Nirubol N Weigand Stephen D SD Senjem Matthew S MS Petersen Ronald C RC Aisen Paul S PS Jagust William J WJ Weiner Michael W MW Jack Clifford R CR

Alzheimer's & dementia : the journal of the Alzheimer's Association 20130130 5 Suppl

<h4>Background</h4>Prevalence and risk factors for focal hemosiderin deposits are important considerations when planning amyloid-modifying trials for treatment and prevention of Alzheimer's disease (AD).<h4>Methods</h4>Subjects were cognitively normal (n = 171), early-mild cognitive impairment (MCI) (n = 240), late-MCI (n = 111), and AD (n = 40) from the Alzheimer's Disease Neuroimaging Initiative (ADNI). Microhemorrhages and superficial siderosis were assessed at baseline and on all available M ...[more]

PMID: 23375568

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Project description:IntroductionThe Centiloid scale was developed to harmonise the quantification of β-amyloid (Aβ) PET images across tracers, scanners, and processing pipelines. However, several groups have reported differences across tracers and scanners even after centiloid conversion. In this study, we aim to evaluate the impact of different pre and post-processing harmonisation steps on the robustness of longitudinal Centiloid data across three large international cohort studies.MethodsAll Aβ PET data in AIBL (N = 3315), ADNI (N = 3442) and OASIS3 (N = 1398) were quantified using the MRI-based Centiloid standard SPM pipeline and the PET-only pipeline CapAIBL. SUVR were converted into Centiloids using each tracer's respective transform. Global Aβ burden from pre-defined target cortical regions in Centiloid units were quantified for both raw PET scans and PET scans smoothed to a uniform 8 mm full width half maximum (FWHM) effective smoothness. For Florbetapir, we assessed the performance of using both the standard Whole Cerebellum (WCb) and a composite white matter (WM)+WCb reference region. Additionally, our recently proposed quantification based on Non-negative Matrix Factorisation (NMF) was applied to all spatially and SUVR normalised images. Correlation with clinical severity measured by the Mini-Mental State Examination (MMSE) and effect size, as well as tracer agreement in 11C-PiB-18F-Florbetapir pairs and longitudinal consistency were evaluated.ResultsThe smoothing to a uniform resolution partially reduced longitudinal variability, but did not improve inter-tracer agreement, effect size or correlation with MMSE. Using a Composite reference region for 18F-Florbetapir improved inter-tracer agreement, effect size, correlation with MMSE, and longitudinal consistency. The best results were however obtained when using the NMF method which outperformed all other quantification approaches in all metrics used.ConclusionsFWHM smoothing has limited impact on longitudinal consistency or outliers. A Composite reference region including subcortical WM should be used for computing both cross-sectional and longitudinal Florbetapir Centiloid. NMF improves Centiloid quantification on all metrics examined.

Dataset Information

Focal hemosiderin deposits and β-amyloid load in the ADNI cohort.

Background

Methods

Results

Conclusions

Publications

Focal hemosiderin deposits and β-amyloid load in the ADNI cohort.

Similar Datasets

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