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Article ; Online: Multi sequence average templates for aging and neurodegenerative disease populations

Mahsa Dadar / Richard Camicioli / Simon Duchesne

Scientific Data, Vol 9, Iss 1, Pp 1-

2022 Volume 13

Abstract: Measurement(s) Human Brain Technology Type(s) Magnetic resonance imaging Sample Characteristic - Organism Homo Sapiens Sample Characteristic - Location ... ...

Abstract	Measurement(s) Human Brain Technology Type(s) Magnetic resonance imaging Sample Characteristic - Organism Homo Sapiens Sample Characteristic - Location Canada
Keywords	Science ; Q
Language	English
Publishing date	2022-05-01T00:00:00Z
Publisher	Nature Portfolio
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Predicting cognitive decline in a low-dimensional representation of brain morphology

Rémi Lamontagne-Caron / Patrick Desrosiers / Olivier Potvin / Nicolas Doyon / Simon Duchesne

Scientific Reports, Vol 13, Iss 1, Pp 1-

2023 Volume 18

Abstract: Abstract Identifying early signs of neurodegeneration due to Alzheimer’s disease (AD) is a necessary first step towards preventing cognitive decline. Individual cortical thickness measures, available after processing anatomical magnetic resonance imaging ...

Abstract	Abstract Identifying early signs of neurodegeneration due to Alzheimer’s disease (AD) is a necessary first step towards preventing cognitive decline. Individual cortical thickness measures, available after processing anatomical magnetic resonance imaging (MRI), are sensitive markers of neurodegeneration. However, normal aging cortical decline and high inter-individual variability complicate the comparison and statistical determination of the impact of AD-related neurodegeneration on trajectories. In this paper, we computed trajectories in a 2D representation of a 62-dimensional manifold of individual cortical thickness measures. To compute this representation, we used a novel, nonlinear dimension reduction algorithm called Uniform Manifold Approximation and Projection (UMAP). We trained two embeddings, one on cortical thickness measurements of 6237 cognitively healthy participants aged 18–100 years old and the other on 233 mild cognitively impaired (MCI) and AD participants from the longitudinal database, the Alzheimer’s Disease Neuroimaging Initiative database (ADNI). Each participant had multiple visits ( $$n \ge 2$$ n ≥ 2 ), one year apart. The first embedding’s principal axis was shown to be positively associated ( $$r = 0.65$$ r = 0.65 ) with participants’ age. Data from ADNI is projected into these 2D spaces. After clustering the data, average trajectories between clusters were shown to be significantly different between MCI and AD subjects. Moreover, some clusters and trajectories between clusters were more prone to host AD subjects. This study was able to differentiate AD and MCI subjects based on their trajectory in a 2D space with an AUC of 0.80 with 10-fold cross-validation.
Keywords	Medicine ; R ; Science ; Q
Subject code	150
Language	English
Publishing date	2023-10-01T00:00:00Z
Publisher	Nature Portfolio
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Bias-adjustment in neuroimaging-based brain age frameworks

Iman Beheshti / Scott Nugent / Olivier Potvin / Simon Duchesne

NeuroImage: Clinical, Vol 24, Iss , Pp - (2019)

A robust scheme

2019

Abstract: The level of prediction error in the brain age estimation frameworks is associated with the authenticity of statistical inference on the basis of regression models. In this paper, we present an efficacious and plain bias-adjustment scheme using ... ...

Abstract	The level of prediction error in the brain age estimation frameworks is associated with the authenticity of statistical inference on the basis of regression models. In this paper, we present an efficacious and plain bias-adjustment scheme using chronological age as a covariate through the training set for downgrading the prediction bias in a Brain-age estimation framework. We applied proposed bias-adjustment scheme coupled by a machine learning-based brain age framework on a large set of metabolic brain features acquired from 675 cognitively unimpaired adults through fluorodeoxyglucose positron emission tomography data as the training set to build a robust Brain-age estimation framework. Then, we tested the reliability of proposed bias-adjustment scheme on 75 cognitively unimpaired adults, 561 mild cognitive impairment patients as well as 362 Alzheimer's disease patients as independent test sets. Using the proposed method, we gained a strong R2 of 0.81 between the chronological age and brain estimated age, as well as an excellent mean absolute error of 2.66 years on 75 cognitively unimpaired adults as an independent set; whereas an R2 of 0.24 and a mean absolute error of 4.71 years was achieved without bias-adjustment. The simulation results demonstrated that the proposed bias-adjustment scheme has a strong capability to diminish prediction error in brain age estimation frameworks for clinical settings. Keywords: Brain age, Estimation, Pet, Bias-adjustment, Brain metabolism
Keywords	Computer applications to medicine. Medical informatics ; R858-859.7 ; Neurology. Diseases of the nervous system ; RC346-429
Subject code	616
Language	English
Publishing date	2019-01-01T00:00:00Z
Publisher	Elsevier
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Cognitive and motor correlates of grey and white matter pathology in Parkinson’s disease

Mahsa Dadar / Myrlene Gee / Ashfaq Shuaib / Simon Duchesne / Richard Camicioli

NeuroImage: Clinical, Vol 27, Iss , Pp 102353- (2020)

2020

Abstract: Introduction: Previous studies have found associations between grey matter atrophy and white matter hyperintensities (WMH) of vascular origin with cognitive and motor deficits in Parkinson’s disease (PD). Here we investigate these relationships in a ... ...

Abstract	Introduction: Previous studies have found associations between grey matter atrophy and white matter hyperintensities (WMH) of vascular origin with cognitive and motor deficits in Parkinson’s disease (PD). Here we investigate these relationships in a sample of PD patients and age-matched healthy controls. Methods: Data included 50 PD patients and 45 age-matched controls with T1-weighted and FLAIR scans at baseline, 18-months, and 36-months follow-up. Deformation-based morphometry was used to measure grey matter atrophy. SNIPE (Scoring by Nonlocal Image Patch Estimator) was used to measure Alzheimer’s disease-like textural patterns in the hippocampi. WMHs were segmented using T1-weighted and FLAIR images. The relationship between MRI features and clinical scores was assessed using mixed-effects models. The motor subscore of the Unified Parkinson's Disease Rating Scale (UPDRSIII), number of steps in a walking trial, and Dementia Rating Scale (DRS) were used respectively as measures of motor function, gait, and cognition. Results: Substantia nigra atrophy was significantly associated with motor deficits, with a greater impact in PDs (p < 0.05). Hippocampal SNIPE scores were associated with cognitve decline in both PD and controls (p < 0.01). WMH burden was significantly associated with cognitive decline and increased motor deficits in the PD group, and gait deficits in both PD and controls (p < 0.03). Conclusion: While substantia nigra atrophy and WMH burden were significantly associated with additional motor deficits, WMH burden and hippocampal atrophy were associated with cognitive deficits in PD patients. These results suggest an additive contribution of both grey and white matter damage to the motor and cognitive deficits in PD.
Keywords	Parkinson’s disease ; White matter hyperintensities ; Grey matter atrophy ; Deformation based morphometry ; Scoring by Nonlocal Image Patch Estimator ; Computer applications to medicine. Medical informatics ; R858-859.7 ; Neurology. Diseases of the nervous system ; RC346-429
Subject code	616
Language	English
Publishing date	2020-01-01T00:00:00Z
Publisher	Elsevier
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Neural correlates of resilience to the effects of hippocampal atrophy on memory

Sylvie Belleville / Samira Mellah / Simon Cloutier / Thien Thanh Dang-Vu / Simon Duchesne / Samantha Maltezos / Natalie Phillips / Carol Hudon

NeuroImage: Clinical, Vol 29, Iss , Pp 102526- (2021)

2021

Abstract: Introduction: Cognitive reserve can be defined as a property of the brain that enables an individual to sustain cognitive performance in spite of age-related neural changes. This study uses brain imaging to identify which cognitive reserve mechanisms ... ...

Abstract	Introduction: Cognitive reserve can be defined as a property of the brain that enables an individual to sustain cognitive performance in spite of age-related neural changes. This study uses brain imaging to identify which cognitive reserve mechanisms protect against the detrimental effect of hippocampal atrophy on associative memory. Methods: The study included 108 older adults from the Quebec Consortium for the early identification of Alzheimer’s disease. They received a magnetic resonance imaging examination to measure memory-related activations and hippocampal volume. Participants also completed a reserve-proxy questionnaire, and received a comprehensive clinical assessment. Results: Higher scores on the reserve questionnaire were associated with more activation in the right inferior temporal and left occipital fusiform gyri. The activation of the right temporal gyrus moderated the relationship between the volume of the hippocampus and face-name memory. A smaller volume was associated with weaker memory in participants with lower activation, but not in those with greater activation. Discussion: Recruitment of the temporal lobe protects against the detrimental effect of hippocampal atrophy on associative memory and contributes to cognitive reserve.
Keywords	Cognitive reserve ; Aging ; Subjective cognitive decline ; Mild cognitive impairment ; Hippocampal atrophy ; Associative memory ; Computer applications to medicine. Medical informatics ; R858-859.7 ; Neurology. Diseases of the nervous system ; RC346-429
Subject code	150
Language	English
Publishing date	2021-01-01T00:00:00Z
Publisher	Elsevier
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: FreeSurfer subcortical normative data

Olivier Potvin / Abderazzak Mouiha / Louis Dieumegarde / Simon Duchesne

Data in Brief, Vol 9, Iss C, Pp 732-

2016 Volume 736

Abstract: This article contains a spreadsheet computing estimates of the expected subcortical regional volumes of an individual based on its characteristics and the scanner characteristics, in addition to supplementary results related to the article “Normative ... ...

Abstract	This article contains a spreadsheet computing estimates of the expected subcortical regional volumes of an individual based on its characteristics and the scanner characteristics, in addition to supplementary results related to the article “Normative data for subcortical regional volumes over the lifetime of the adult human brain” (O. Potvin, A. Mouiha, L. Dieumegarde, S. Duchesne, 2016) [1] on normative data for subcortical volumes. Data used to produce normative values was obtained by anatomical magnetic resonance imaging from 2790 healthy individuals aged 18–94 years using 23 samples provided by 21 independent research groups. The segmentation was conducted using FreeSurfer. The spreadsheet includes formulas in order to compute for a new individual, significance test for volume abnormality, effect size and estimated percentage of the normative population with a smaller volume while taking into account age, sex, estimated intracranial volume (eTIV), and scanner characteristics. Detailed R-squares of each predictor for all formula are also reported as well as the difference of subcortical volumes segmented by FreeSurfer on two different computer hardware setups.
Keywords	Neuroimaging ; Age ; Sex ; Magnetic resonance ; Normality ; Normal aging ; Morphometry ; Computer applications to medicine. Medical informatics ; R858-859.7 ; Science (General) ; Q1-390
Subject code	310
Language	English
Publishing date	2016-12-01T00:00:00Z
Publisher	Elsevier
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Brain atrophy and patch-based grading in individuals from the CIMA-Q study

Christine Marcotte / Olivier Potvin / D. Louis Collins / Sylvie Rheault / Simon Duchesne

Scientific Reports, Vol 9, Iss 1, Pp 1-

a progressive continuum from subjective cognitive decline to AD

2019 Volume 10

Abstract: Abstract It has been proposed that individuals developing Alzheimer’s disease (AD) first experience a phase expressing subjective complaints of cognitive decline (SCD) without objective cognitive impairment. Using magnetic resonance imaging (MRI), our ... ...

Abstract	Abstract It has been proposed that individuals developing Alzheimer’s disease (AD) first experience a phase expressing subjective complaints of cognitive decline (SCD) without objective cognitive impairment. Using magnetic resonance imaging (MRI), our objective was to verify whether SNIPE probability grading, a new MRI analysis technique, would distinguish between clinical dementia stage of AD: Cognitively healthy controls without complaint (CH), SCD, mild cognitive impairment, and AD. SNIPE score in the hippocampus and entorhinal cortex was applied to anatomical T1-weighted MRI of 143 participants from the Consortium pour l’identification précoce de la maladie Alzheimer - Québec (CIMA-Q) study and compared to standard atrophy measures (volumes and cortical thicknesses). Compared to standard atrophy measures, SNIPE score appeared more sensitive to differentiate clinical AD since differences between groups reached a higher level of significance and larger effect sizes. However, no significant difference was observed between SCD and CH groups. Combining both types of measures did not improve between-group differences. Further studies using a combination of biomarkers beyond anatomical MRI might be needed to identify individuals with SCD who are on the beginning of the clinical continuum of AD.
Keywords	Medicine ; R ; Science ; Q
Subject code	610
Language	English
Publishing date	2019-09-01T00:00:00Z
Publisher	Nature Publishing Group
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Label Fusion Strategy Selection

Nicolas Robitaille / Simon Duchesne

International Journal of Biomedical Imaging, Vol

2012 Volume 2012

Abstract: Label fusion is used in medical image segmentation to combine several different labels of the same entity into a single discrete label, potentially more accurate, with respect to the exact, sought segmentation, than the best input element. Using ... ...

Abstract	Label fusion is used in medical image segmentation to combine several different labels of the same entity into a single discrete label, potentially more accurate, with respect to the exact, sought segmentation, than the best input element. Using simulated data, we compared three existing label fusion techniques—STAPLE, Voting, and Shape-Based Averaging (SBA)—and observed that none could be considered superior depending on the dissimilarity between the input elements. We thus developed an empirical, hybrid technique called SVS, which selects the most appropriate technique to apply based on this dissimilarity. We evaluated the label fusion strategies on two- and three-dimensional simulated data and showed that SVS is superior to any of the three existing methods examined. On real data, we used SVS to perform fusions of 10 segmentations of the hippocampus and amygdala in 78 subjects from the ICBM dataset. SVS selected SBA in almost all cases, which was the most appropriate method overall.
Keywords	Medical physics. Medical radiology. Nuclear medicine ; R895-920 ; Medical technology ; R855-855.5
Language	English
Publishing date	2012-01-01T00:00:00Z
Publisher	Hindawi Limited
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Morphological Factor Estimation via High-Dimensional Reduction

Simon Duchesne / Abderazzak Mouiha

International Journal of Alzheimer's Disease, Vol

Prediction of MCI Conversion to Probable AD

2011 Volume 2011

Keywords	Geriatrics ; RC952-954.6 ; Special situations and conditions ; RC952-1245 ; Internal medicine ; RC31-1245 ; Medicine ; R ; DOAJ:Internal medicine ; DOAJ:Medicine (General) ; DOAJ:Health Sciences ; Neurosciences. Biological psychiatry. Neuropsychiatry ; RC321-571 ; DOAJ:Neurology
Language	English
Publishing date	2011-01-01T00:00:00Z
Publisher	Hindawi Publishing Corporation
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Selection of the optimal intensity normalization region for FDG-PET studies of normal aging and Alzheimer’s disease

Scott Nugent / Etienne Croteau / Olivier Potvin / Christian-Alexandre Castellano / Louis Dieumegarde / Stephen C. Cunnane / Simon Duchesne

Scientific Reports, Vol 10, Iss 1, Pp 1-

2020 Volume 8

Abstract: Abstract The primary method for measuring brain metabolism in humans is positron emission tomography (PET) imaging using the tracer 18F-fluorodeoxyglucose (FDG). Standardized uptake value ratios (SUVR) are commonly calculated from FDG-PET images to ... ...

Abstract	Abstract The primary method for measuring brain metabolism in humans is positron emission tomography (PET) imaging using the tracer 18F-fluorodeoxyglucose (FDG). Standardized uptake value ratios (SUVR) are commonly calculated from FDG-PET images to examine intra- and inter-subject effects. Various reference regions are used in the literature of FDG-PET studies of normal aging, making comparison between studies difficult. Our primary objective was to determine the optimal SUVR reference region in the context of healthy aging, using partial volume effect (PVE) and non-PVE corrected data. We calculated quantitative cerebral metabolic rates of glucose (CMRg) from PVE-corrected and non-corrected images from young and older adults. We also investigated regional atrophy using magnetic resonance (MR) images. FreeSurfer 6.0 atlases were used to explore possible reference regions of interest (ROI). Multiple regression was used to predict CMRg data, in each FreeSurfer ROI, with age and sex as predictors. Age had the least effect in predicting CMRg for PVE corrected data in the pons (r 2 = 2.83 × 10−3, p = 0.67). For non-PVE corrected data age also had the least effect in predicting CMRg in the pons (r 2 = 3.12 × 10−3, p = 0.67). We compared the effects of using the whole brain or the pons as a reference region in PVE corrected data in two regions susceptible to hypometabolism in Alzheimer’s disease, the posterior cingulate and precuneus. Using the whole brain as a reference region resulted in non-significant group differences in the posterior cingulate while there were significant differences between all three groups in the precuneus (all p < 0.004). When using the pons as a reference region there was significant differences between all groups for both the posterior cingulate and the precuneus (all p < 0.001). Therefore, the use of the pons as a reference region is more sensitive to hypometabism changes associated with Alzheimer’s disease than the whole brain.
Keywords	Medicine ; R ; Science ; Q
Language	English
Publishing date	2020-06-01T00:00:00Z
Publisher	Nature Portfolio
Document type	Article ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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