Low Pre-Existing Gray Matter Volume in the Medial Temporal Lobe and White Matter Lesions Are Associated with Postoperative Cognitive Dysfunction after Cardiac Surgery

Abstract Background White matter hyperintensities (WMH) are frequently found in Alzheimer’s disease (AD). Commonly considered as a marker of cerebrovascular disease, regional WMH may be related to pathological hallmarks of AD, including beta-amyloid (Aβ) plaques and neurodegeneration. The aim of this study was to examine the regional distribution of WMH associated with Aβ burden, glucose hypometabolism, and gray matter volume reduction. Methods In a total of 155 participants (IMAP+ cohort) across the cognitive continuum from normal cognition to AD dementia, FLAIR MRI, AV45-PET, FDG-PET, and T1 MRI were acquired. WMH were automatically segmented from FLAIR images. Mean levels of neocortical Aβ deposition (AV45-PET), temporo-parietal glucose metabolism (FDG-PET), and medial-temporal gray matter volume (GMV) were extracted from processed images using established AD meta-signature templates. Associations between AD brain biomarkers and WMH, as assessed in region-of-interest and voxel-wise, were examined, adjusting for age, sex, education, and systolic blood pressure. Results There were no significant associations between global Aβ burden and region-specific WMH. Voxel-wise WMH in the splenium of the corpus callosum correlated with greater Aβ deposition at a more liberal threshold. Region- and voxel-based WMH in the posterior corpus callosum, along with parietal, occipital, and frontal areas, were associated with lower temporo-parietal glucose metabolism. Similarly, lower medial-temporal GMV correlated with WMH in the posterior corpus callosum in addition to parietal, occipital, and fontal areas. Conclusions This study demonstrates that local white matter damage is correlated with multimodal brain biomarkers of AD. Our results highlight modality-specific topographic patterns of WMH, which converged in the posterior white matter. Overall, these cross-sectional findings corroborate associations of regional WMH with AD-typical Aß deposition and neurodegeneration.

Download Full-text

CHARACTERIZATION OF COGNITIVE PERFORMANCE, GRAY MATTER VOLUME AND WHITE MATTER MICROSTRUCTURE IN COGNITIVELY UNIMPAIRED ADULTS WITH INSOMNIA SYMPTOMS

Alzheimer s & Dementia ◽

10.1016/j.jalz.2019.06.4549 ◽

2019 ◽

Vol 15 (7) ◽

pp. P207-P209

Author(s):

Oriol Grau-Rivera ◽

Grégory Operto ◽

Carles Falcon ◽

Raffaele Cacciaglia ◽

Gonzalo Sánchez-Benavides ◽

...

Keyword(s):

White Matter ◽

Cognitive Performance ◽

Gray Matter ◽

Gray Matter Volume ◽

Matter Volume ◽

White Matter Microstructure ◽

Insomnia Symptoms

Download Full-text

Association of Age at Onset With Gray Matter Volume and White Matter Microstructural Abnormalities in People With Multiple Sclerosis

Neurology ◽

10.1212/wnl.0000000000012869 ◽

2021 ◽

pp. 10.1212/WNL.0000000000012869

Author(s):

Raffaello Bonacchi ◽

Alessandro Meani ◽

Elisabetta Pagani ◽

Olga Marchesi ◽

Andrea Falini ◽

...

Keyword(s):

Multiple Sclerosis ◽

White Matter ◽

Gray Matter ◽

Linear Models ◽

Gray Matter Volume ◽

Age At Onset ◽

Healthy Controls ◽

Compensatory Mechanisms ◽

Cross Sectional ◽

Matter Volume

Objective:To investigate whether age at onset influences brain gray matter volume (GMV) and white matter (WM) microstructural abnormalities in adult multiple sclerosis (MS) patients, given its influence on clinical phenotype and disease course.Method:In this hypothesis-driven cross-sectional study, we enrolled 67 pediatric-onset MS (POMS) patients and 143 sex- and disease duration (DD)-matched randomly-selected adult-onset MS (AOMS) patients, together with 208 healthy controls. All subjects underwent neurological evaluation and 3T MRI acquisition. MRI variables were standardized based on healthy controls, to remove effects of age and sex. Associations with DD in POMS and AOMS patients were studied with linear models. Time to reach clinical and MRI milestones was assessed with product-limit approach.Results:At DD=1 year, GMV and WM fractional anisotropy (FA) were abnormal in AOMS but not in POMS patients. Significant interaction of age at onset (POMS vs AOMS) into the association with DD was found for GMV and WM FA. The crossing point of regression lines in POMS and AOMS patients was at 20 years of DD for GMV and 14 for WM FA. For POMS and AOMS patients, median DD was 29 and 19 years to reach Expanded Disability Status Scale=3 (p<0.001), 31 and 26 years to reach abnormal Paced Auditory Serial Addition Task-3 (p=0.01), 24 and 18 years to reach abnormal GMV (p=0.04), and 19 and 17 years to reach abnormal WM FA (p=0.36).Conclusions:Younger patients are initially resilient to MS-related damage. Then, compensatory mechanisms start failing with loss of WM integrity, followed by GM atrophy and finally disability.

Download Full-text

A Correlational Study between Microstructural White Matter Properties and Macrostructural Gray Matter Volume Across Normal Ageing: Conjoint DTI and VBM Analysis

Magnetic Resonance Insights ◽

10.1177/1178623x18799926 ◽

2018 ◽

Vol 11 ◽

pp. 1178623X1879992 ◽

Cited By ~ 4

Author(s):

Vikas Pareek ◽

VP Subramanyam Rallabandi ◽

Prasun K Roy

Keyword(s):

White Matter ◽

Life Span ◽

Fractional Anisotropy ◽

Gray Matter ◽

Healthy Aging ◽

Gray Matter Volume ◽

Mean Diffusivity ◽

Radial Diffusivity ◽

Axial Diffusivity ◽

Matter Volume

We investigate the relationship between Gray matter’s volume vis-a-vis White matter’s integrity indices, such Axial diffusivity, Radial diffusivity, Mean diffusivity, and Fractional anisotropy, in individuals undergoing healthy aging. We investigated MRI scans of 177 adults across 20 to 85 years. We used Voxel-based morphometry, and FDT-FSL analysis for estimation of Gray matter volume and White matter’s diffusion indices respectively. Across the life span, we observed an inter-relationship between the Gray matter and White matter, namely that both Axial diffusivity and Mean Diffusivity show strong correlation with Gray matter volume, along the aging process. Furthermore, across all ages the Fractional anisotropy and Mean diffusivity are found to be significantly reduced in females when compared to males, but there are no significant gender differences in Axial Diffusivity and Radial diffusivity. We conclude that for both genders across all ages, the Gray matter’s Volume is strongly correlated with White matter’s Axial Diffusivity and Mean Diffusivity, while being weakly correlated with Fractional Anisotropy. Our study clarifies the multi-scale relationship in brain tissue, by elucidating how the White matter’s micro-structural parameters influences the Gray matter’s macro-structural characteristics, during healthy aging across the life-span.

Download Full-text