A5000345576- Intracerebral and Subarachnoid Hemorrhage Research
- Advanced Neuroimaging Techniques and Applications
- Dementia and Cognitive Impairment Research
- Advanced MRI Techniques and Applications
- Cerebrovascular and Carotid Artery Diseases
- Alzheimer's disease research and treatments
- Acute Ischemic Stroke Management
- Functional Brain Connectivity Studies
- MRI in cancer diagnosis
- Neurological Disease Mechanisms and Treatments
- Cerebrovascular and genetic disorders
- Traumatic Brain Injury and Neurovascular Disturbances
- Cardiovascular and exercise physiology
- Advanced Optical Imaging Technologies
- Brain Tumor Detection and Classification
- Anesthesia and Neurotoxicity Research
- Cerebrospinal fluid and hydrocephalus
- Parkinson's Disease Mechanisms and Treatments
- Electromagnetic Fields and Biological Effects
- Cardiovascular Health and Disease Prevention
- Photorefractive and Nonlinear Optics
- Muscle activation and electromyography studies
- Magnetic and Electromagnetic Effects
- Ocular and Laser Science Research
- Medical Imaging Techniques and Applications
University of Calgary
2016-2025
Foothills Medical Centre
2013-2024
Alberta Health Services
2013-2024
Centre for Mental Health
2022
Women and Children’s Health Research Institute
2022
University of Alberta
2022
St. Francis Xavier University
2022
Population Health Research Institute
2014-2021
Hamilton Health Sciences
2014-2021
Ontario Brain Institute
2021
Background and Purpose— We investigated the sensitivity reliability of MRI susceptibility-weighted imaging (SWI) compared with routine T2*-weighted gradient-recalled echo (GRE) for cerebral microbleed (CMB) detection. Methods— used data from a prospective study amyloid angiopathy (n=9; mean age, 71±8.3) healthy non–cerebral controls (n=22; 68±6.3). Three raters (labeled 1, 2, 3) independently interpreted GRE SWI sequences (using phase-filtered magnitude image) blinded to clinical...
MRI white matter hyperintensity (WMH) volume is associated with cognitive impairment. We hypothesized that specific loci of WMH would correlate cognition even after accounting for total volume.Subjects were identified from a prospective community-based study: 40 had normal cognition, 94 mild impairment (defined here as Clinical Dementia Rating [CDR] score 0.5 without dementia), and 11 Alzheimer's dementia. Factor analysis 22-item neuropsychological battery yielded 4 factors (episodic memory,...
Decline in cognitive function begins by the 40s, and may be related to future dementia risk. We used data from a community-representative study determine whether there are age-related differences simple gait tests these were associated with covert cerebrovascular disease on magnetic resonance imaging (MRI).Between 2010 2012, 803 participants aged 40 75 years Prospective Urban Rural Epidemiological (PURE) study, recruited prespecified postal code regions centered 4 Canadian cities, underwent...
We used functional MRI (fMRI), transcranial Doppler ultrasound, and visual evoked potentials (VEPs) to determine the nature of blood flow responses brain activity carbon dioxide (CO2) inhalation in patients with cerebral amyloid angiopathy (CAA), their association markers CAA severity.In a cross-sectional prospective cohort study, fMRI, ultrasound CO2 reactivity, VEP data were compared between 18 probable (by Boston criteria) healthy controls, matched by sex age. Functional consisted task...
Background Harmonized protocols to collect imaging data must be devised, employed, and maintained in multicentric studies reduce interscanner variability subsequent analyses. Purpose To present a standardized protocol for research on dementia linked neurodegeneration aging, harmonized all three major vendor platforms. The includes common procedure qualification, quality control, assurance feasibility large‐scale studies. Study Type Prospective. Subjects study involved geometric phantom,...
Autopsy studies suggest that cerebral amyloid angiopathy (CAA) is associated with cognitive impairment and risk for dementia. We analyzed neuropsychological test data from a prospective cohort study of patients CAA to identify the prevalence its associations brain magnetic resonance imaging features apolipoprotein E genotype.Data were 34 CAA, 16 Alzheimer's disease, 69 mild impairment, 27 ischemic stroke participants. Neuropsychological results expressed as z scores in relation normative...
Abstract Introduction Impact of white matter hyperintensities (WMH) on cognition likely depends lesion location, but a comprehensive map strategic locations is lacking. We aimed to identify these in large multicenter study. Methods Individual patient data (n = 3525) from 11 memory clinic cohorts were harmonized. determined the association WMH location with attention and executive functioning, information processing speed, language, verbal performance using voxel‐based region interest...
The purpose of this study is to directly compare the dynamic responses phosphocreatine (PCr) and P(i) those oxygen uptake (VO2) measured at lung during transitions from moderate-intensity exercise. Changes in PCr were by 31P-nuclear magnetic resonance spectroscopy, changes VO2 breath mass spectroscopy square-wave ankle plantar flexion exercise 11 subjects (7 men 4 women; mean age 27 yr). Three repeated averaged for improvement signal-to-noise ratio phosphate data, 12 measurements. Averaged...
Definitions for chronic lacunar infarcts vary. Recent retrospective studies suggest that many acute strokes do not develop a cavitated appearance. We determined the characteristics of on follow-up MRI in consecutive patients participating prospective research studies.Patients with infarction diffusion-weighted imaging were selected from 3 cohort minor stroke imaged within <24 hours onset. Follow-up was performed at 30 days (Vascular Imaging Acute Stroke Identifying Predictors Clinical...
Aging is associated with decreased vascular compliance and diminished neurovascular- hypercapnia-evoked cerebral blood flow (CBF) responses. However, the interplay between arterial stiffness reduced CBF responses poorly understood. It was hypothesized that increased evoked to both, a flashing checkerboard visual stimulation (i.e., neurovascular coupling), hypercapnia. To test this hypothesis, twenty older (64±8y; mean±SD) ten young (30±5y) subjects underwent (VS) hypercapnic test. Blood...
Abstract INTRODUCTION White matter hyperintensities (WMH) are associated with key dementia etiologies, in particular arteriolosclerosis and amyloid pathology. We aimed to identify WMH locations vascular risk or cerebral amyloid‐β 1‐42 (Aβ42)‐positive status. METHODS Individual patient data ( n = 3,132; mean age 71.5 ± 9 years; 49.3% female) from 11 memory clinic cohorts were harmonized. volumes 28 regions related a compound score (VRCS) Aß42 status (based on cerebrospinal fluid positron...
Structural connectivity (SC) of white matter (WM) and functional (FC) cortical regions undergo changes in normal aging. As WM tracts form the underlying anatomical architecture that connects within resting state networks (RSNs), it is intuitive to expect SC FC with age are correlated. Studies investigated relationship between aging rare, have mainly compared groups elderly younger subjects. The objectives this work were investigate linear across healthy adult lifespan, define relationships...
To test the hypotheses that peak skeletonized mean diffusivity (PSMD), a measure of cerebral white matter microstructural disruption, is 1) increased in patients with amyloid angiopathy (CAA) compared to normal control (NC), mild cognitive impairment (MCI), and Alzheimer's disease (AD); 2) associated neuropsychological performance among CAA patients; 3) more quickly over one year than AD, MCI, NC. Ninety-two participants provided medical history, completed assessment, had magnetic resonance...
<h3>Background and Objectives</h3> Reduced cerebrovascular reactivity is proposed to be a feature of cerebral amyloid angiopathy (CAA) but has not been measured directly. Employing global vasodilatory stimulus (hypercapnia), this study assessed the relationships between MRI markers CAA cognitive function. <h3>Methods</h3> In cross-sectional study, individuals with probable CAA, mild impairment, or dementia due Alzheimer disease healthy controls underwent neuropsychological testing an that...
Molecular imaging with magnetic resonance (MRI) may benefit from the ferrimagnetic properties of magnetosomes, membrane-enclosed iron biominerals whose formation in magnetotactic bacteria is encoded by multiple genes. One such gene MagA, a putative transporter. We have examined expression MagA mouse neuroblastoma N2A cells and characterized their response to loading cellular MRI. augmented both Prussian blue staining elemental content cells, without altering cell proliferation, cultures...
Abstract Introduction The Meta VCI Map consortium performs meta‐analyses on strategic lesion locations for vascular cognitive impairment using lesion‐symptom mapping. Integration of data from different cohorts will increase sample sizes, to improve brain coverage and support comprehensive mapping studies. Methods Cohorts with available imaging white matter hyperintensities or infarcts testing were invited. We performed a pilot study test the feasibility multicenter processing analysis...
Cerebral amyloid angiopathy (CAA) contributes to brain neurodegeneration and cognitive decline, but the relationship between these two processes is incompletely understood.The purpose of this study examine cortical thickness its association with cognition neurodegenerative biomarkers in CAA.Data were collected from Functional Assessment Vascular Reactivity Calgary Normative Study. In total, 48 participants probable CAA, 72 cognitively normal healthy controls, 24 mild dementia due AD...
To assess cerebrovascular reactivity in response to a visual task participants with cerebral amyloid angiopathy (CAA), Alzheimer disease (AD), and mild cognitive impairment (MCI) using fMRI.This prospective cohort study included 40 patients CAA, 22 AD, 27 MCI, 25 healthy controls. Each participant underwent fMRI contrast-reversing checkerboard stimulus. Visual evoked potentials (VEPs) were used compare cortex neuronal activity 83 participants. General linear models least-squares means,...
White matter hyperintensities (WMHs) are found on magnetic resonance (MR) images of older individuals and associated with many neurodegenerative disorders, although the exactrole WMHs in Alzheimer's disease other dementias remains an open area research. Fluid-attenuated inversion recovery (FLAIR) MR imaging sequences show good image contrast. Manual segmentation FLAIR is widely accepted "gold standard", however, this step often time-consuming has a high inter-rater variability. The absence...
The spatial distribution of white matter hyperintensities (WMH) on MRI is often considered in the diagnostic evaluation patients with cognitive problems. In some patients, clinicians may classify WMH patterns as "unusual", but this largely based expert opinion, because detailed quantitative information about frequencies a memory clinic setting lacking. Here we report voxel wise 3D large multicenter dataset and also aimed to identify individuals unusual patterns. Individual participant data...
Abstract Typical quantitative T 2 (q ) analysis involves creating distributions using a regularized algorithm from region‐of‐interest averaged decay data. This study uses q of simulated and experimental signals to determine how (a) noise‐type, (b) regularization, (c) versus multivoxel analyses affect distributions. Our simulations indicate that regularization causes myelin water fraction intra/extracellular geometric mean underestimation worsens as the signal‐to‐noise ratio decreases. The...