Mapping Neuroinflammation With Diffusion-Weighted Magnetic Resonance Imaging: A Randomized Crossover Study.

Background: The pathophysiology of neuroinflammation in psychiatric conditions remains poorly understood, highlighting the need for noninvasive tools that can measure neuroinflammation in vivo. We explored advanced diffusion-weighted magnetic resonance imaging (MRI) techniques for detection of low-level neuroinflammation induced by typhoid vaccine, with potential applications to psychiatric disorders.

Methods: Twenty healthy volunteers (10 males; median age 34, range 18-44 years) participated in a randomized, placebo-controlled, crossover design study.

Measurement of blood-brain barrier water exchange rate using diffusion-prepared and multi-echo arterial spin labelling: Comparison of quantitative values and age dependence.

Water exchange rate (Kw) across the blood-brain barrier (BBB) is an important physiological parameter that may provide new insight into ageing and neurodegenerative disease. Recently, two non-invasive arterial spin labelling (ASL) MRI methods have been developed to measure Kw, but results from the different methods have not been directly compared. Furthermore, the association of Kw with age for each method has not been investigated in a single cohort.

The role of awareness in shaping responses in human visual cortex.

The visual cortex contains information about stimuli even when they are not consciously perceived. However, it remains unknown whether the visual system integrates local features into global objects without awareness. Here, we tested this by measuring brain activity in human observers viewing fragmented shapes that were either visible or rendered invisible by fast counterphase flicker.

Retinotopic connectivity maps of human visual cortex with unconstrained eye movements.

Human visual cortex contains topographic visual field maps whose organization can be revealed with retinotopic mapping. Unfortunately, constraints posed by standard mapping hinder its use in patients, atypical subject groups, and individuals at either end of the lifespan. This severely limits the conclusions we can draw about visual processing in such individuals.

Detection of Neuroinflammation Induced by Typhoid Vaccine Using Quantitative Magnetization Transfer MR: A Randomized Crossover Study.

Background: The role of neuroinflammation in psychiatric disorders is not well-elucidated. A noninvasive technique sensitive to low-level neuroinflammation may improve understanding of the pathophysiology of these conditions.

Purpose: To test the ability of quantitative magnetization transfer (QMT) MR at 3 T for detection of low-level neuroinflammation induced by typhoid vaccine within a clinically reasonable scan time.

Imaging blood-brain barrier dysfunction: A state-of-the-art review from a clinical perspective.

The blood-brain barrier (BBB) consists of specialized cells that tightly regulate the in- and outflow of molecules from the blood to brain parenchyma, protecting the brain's microenvironment. If one of the BBB components starts to fail, its dysfunction can lead to a cascade of neuroinflammatory events leading to neuronal dysfunction and degeneration. Preliminary imaging findings suggest that BBB dysfunction could serve as an early diagnostic and prognostic biomarker for a number of neurological diseases.

Dementia Prevention Research Clinic: a longitudinal study investigating factors influencing the development of Alzheimer's disease in Aotearoa, New Zealand.

Aotearoa New Zealand's population is ageing. Increasing life expectancy is accompanied by increases in prevalence of Alzheimer's Disease (AD) and ageing-related disorders. The multicentre Dementia Prevention Research Clinic longitudinal study aims to improve understanding of AD and dementia in Aotearoa, in order to develop interventions that delay or prevent progression to dementia.

Reproducibility and repeatability of magnetic resonance imaging in dementia.

Purpose: Individualised predictive models of cognitive decline require disease-monitoring markers that are repeatable. For wide-spread adoption, such markers also need to be reproducible at different locations. This study assessed the repeatability and reproducibility of MRI markers derived from a dementia protocol.

Active conductive head cooling of normal and infarcted brain: A magnetic resonance spectroscopy imaging study.

Active conductive head cooling is a simple and non-invasive intervention that may slow infarct growth in ischemic stroke. We investigated the effect of active conductive head cooling on brain temperature using whole brain echo-planar spectroscopic imaging. A cooling cap (WElkins Temperature Regulation System, 2nd Gen) was used to administer cooling for 80 minutes to healthy volunteers and chronic stroke patients.

Spatial variation of perfusion MRI reflects cognitive decline in mild cognitive impairment and early dementia.

Cerebral blood flow (CBF) measured with arterial spin labelling (ASL) magnetic resonance imaging (MRI) reflects cerebral perfusion, related to metabolism, and arterial transit time (ATT), related to vascular health. Our aim was to investigate the spatial coefficient of variation (sCoV) of CBF maps as a surrogate for ATT, in volunteers meeting criteria for subjective cognitive decline (SCD), amnestic mild cognitive impairment (MCI) and probable Alzheimer's dementia (AD). Whole-brain pseudo continuous ASL MRI was performed at 3 T in 122 participants (controls = 20, SCD = 44, MCI = 45 and AD = 13) across three sites in New Zealand.

Late changes in blood-brain barrier permeability in a rat tMCAO model of stroke detected by gadolinium-enhanced MRI.

Objectives: After cerebral ischaemia the blood-brain barrier (BBB) may be compromised and this has been observed in both clinical and preclinical studies. The timing of BBB disruption after ischaemia has long been considered to be biphasic, however some groups contest this view. Therefore, the purpose of this study was to characterize the BBB permeability timecourse in a rat model at both acute and chronic time points.