White Matter Hyperintensities Burden Research Articles

The relationship between amyloid pathology, cerebral small vessel disease, glymphatic dysfunction, and cognition: a study based on Alzheimer’s disease continuum participants

BackgroundGlymphatic dysfunction is a crucial pathway for dementia. Alzheimer’s disease (AD) pathologies co-existing with cerebral small vessel disease (CSVD) is the most common pathogenesis for dementia. We hypothesize that AD pathologies and CSVD could be associated with glymphatic dysfunction, contributing to cognitive impairment.MethodParticipants completed with amyloid PET, diffusion tensor imaging (DTI), and T2 fluid-attenuated inversion-recovery (FLAIR) sequences were included from the Alzheimer’s Disease Neuroimaging Initiative (ADNI). White matter hyperintensities (WMH), the most common CSVD marker, was evaluated from T2FLAIR images and represented the burden of CSVD. Amyloid PET was used to assess Aβ aggregation in the brain. We used diffusion tensor image analysis along the perivascular space (DTI-ALPS) index, the burden of enlarged perivascular spaces (PVS), and choroid plexus volume to reflect glymphatic function. The relationships between WMH burden/Aβ aggregation and these glymphatic markers as well as the correlations between glymphatic markers and cognitive function were investigated. Furthermore, we conducted mediation analyses to explore the potential mediating effects of glymphatic markers in the relationship between WMH burden/Aβ aggregation and cognition.ResultsOne hundred and thirty-three participants along the AD continuum were included, consisting of 40 CN − , 48 CN + , 26 MCI + , and 19 AD + participants. Our findings revealed that there were negative associations between whole-brain Aβ aggregation (r = − 0.249, p = 0.022) and WMH burden (r = − 0.458, p < 0.001) with DTI-ALPS. Additionally, Aβ aggregation (r = 0.223, p = 0.041) and WMH burden (r = 0.294, p = 0.006) were both positively associated with choroid plexus volume. However, we did not observe significant correlations with PVS enlargement severity. DTI-ALPS was positively associated with memory (r = 0.470, FDR-p < 0.001), executive function (r = 0.358, FDR-p = 0.001), visual-spatial (r = 0.223, FDR-p < 0.040), and language (r = 0.419, FDR-p < 0.001). Conversely, choroid plexus volume showed negative correlations with memory (r = − 0.315, FDR-p = 0.007), executive function (r = − 0.321, FDR-p = 0.007), visual-spatial (r = − 0.233, FDR-p = 0.031), and language (r = − 0.261, FDR-p = 0.021). There were no significant correlations between PVS enlargement severity and cognitive performance. In the mediation analysis, we found that DTI-ALPS acted as a mediator in the relationship between WMH burden/Aβ accumulation and memory and language performances.ConclusionOur study provided evidence that both AD pathology (Aβ) and CSVD were associated with glymphatic dysfunction, which is further related to cognitive impairment. These results may provide a theoretical basis for new targets for treating AD.

Depression, Vascular Burden, and Dementia Prevalence in Late Middle-Aged and Older Black Adults.

Late-life depression and white matter hyperintensities (WMH) have been linked to increased dementia risk. However, there is a dearth of literature examining these relationships in Black adults. We investigated whether depression or WMH volume are associated with a higher likelihood of dementia diagnosis in a sample of late middle-aged to older Black adults, and whether dementia prevalence is highest in individuals with both depression and higher WMH volume. Secondary data analysis involved 443 Black participants aged 55+ with brain imaging within 1 year of baseline visit in the National Alzheimer's Coordinating Center Uniform Data Set. Chi-square analyses and logistic regression models controlling for demographic variables examined whether active depression in the past 2 years, WMH volume, or their combination were associated with higher odds of all-cause dementia. Depression and higher WMH volume were associated with a higher prevalence of dementia. These associations remained after controlling for demographic factors, as well as vascular disease burden. Dementia risk was highest in the depression/high WMH volume group compared to the depression-only group, high WMH volume-only group, and the no depression/low WMH volume group. Post hoc analyses comparing the Black sample to a demographically matched non-Hispanic White sample showed associations of depression and the combination of depression and higher WMH burden with dementia were greater in Black compared to non-Hispanic White individuals. Results suggest late-life depression and WMH have independent and joint relationships with dementia and that Black individuals may be particularly at risk due to these factors.

Abstract WP186: The Burden of White Matter Hyperintensities on Function Outcomes in Patients Treated for Acute Ischemic Stroke: A Post-Hoc Analysis of the IMS-III Trial

Objective: This study is a post-hoc analysis of the Interventional Management of Stroke (IMS) III trial investigating the burden of white matter hyperintensities (WMH), using the van Swieten Scale (VSS), on functional outcomes for acute ischemic stroke (AIS) patients treated with either intravenous thrombolysis (IVT) or IVT with mechanical thrombectomy (MT). Background: WMH are a well-established marker for underlying cerebral microvascular disease. VSS quantifies the disease burden from zero to four with higher numbers signifying more advanced disease. A higher burden of WMH is associated with poor functional outcomes after IVT. However, early studies regarding WMH and outcomes after MT have been conflicting. Methods: We included IMS-III trial patients in either treatment arm whose VSS was graded on initial brain CT and 90-day function outcomes were not missing. The primary study outcome was a 90-days modified Rankin Scale of 0-2, termed good outcome. Results: There was a total of 656 patients enrolled in the trial and 618 patients were included in this analysis. The VSS grades of WMH range from 0-4 and included 476 (77.02%), 56 (9.06%), 38 (6.15%), 24 (3.88%), and 24 (3.88%) patients, respectively. Overall, higher VSS grade was associated with a lower probability of achieving a good functional outcome, even after adjustments (Figure 1). Of the 142 patients with any degree of WMH, only 22.5% had a good functional outcome compared to 46.6% of 476 patients without WMH (Table 1). Conclusions: Patients enrolled in the IMS-III trial with any burden of WMH on brain CT had a statistically significant lower odds of a good functional outcome compared to patients without WMH.

Abstract TP166: White Matter Hyperintensity Burden Associated With Stroke Severity, Aphasia, and Motor Deficits During Intracerebral Hemorrhage Hospitalization

Introduction: Cerebral Small Vessel Disease (CSVD) is associated with cognitive disruptions after intracerebral hemorrhage (ICH), however evidence connecting CSVD to specific neurological deficits after ICH is limited. Methods: Electronic medical record data were retrieved for adult patients (&gt;18 years) with admission for primary non-traumatic ICH, available admission NIHSS scores, and CSVD assessment. CSVD burden was graded from 0-4, with 1 point assessed for: 1) deep Fazekas white matter hyperintensity (WMH) score of 2-3 or periventricular (PV) Fazekas score of 3; 2) cerebral microbleed presence; 3) lacune presence; 4) &gt; 20 basal ganglia perivascular spaces. Severe CSVD was assessed scores ≥ 3, and individual marker severity was assessed using the same criteria. The primary outcome was moderate-severe stroke (total NIHSS score ≥5). Secondary outcomes were severe motor deficit (motor score &gt;12), complete aphasia (language score = 3), and cortical deficit (any impairment in language, extinction, and gaze). Associations between CSVD and NIHSS were determined using multivariable logistic regression, adjusting for major clinical and demographic factors. Adjusted odds ratios (aOR) and 95% confidence interval (CI) are reported. Results: The cohort included 1024 patients (median age [interquartile range]: 71 [61-79], 53% male). Patients were 22% Hispanic and had a racial distribution of 61% White, 24% Black, 8% Asian, 7% other. The median NIHSS score was 4 [1-11]; 477 (47%) showed moderate-severe NIHSS scores and 262 (26%) showed severe CSVD. Severe PV WMH burden was independently associated with moderate-severe NIHSS score (vs non-severe; aOR, 95% CI: 1.55, [1.02-2.36]). Severe deep WMH burden (vs non-severe) was independently associated with aphasia (1.97, [1.02-3.81]), and motor deficit (3.95, [1.22-12.73]) (Figure 1). Conclusion: Severe WMH burdens increase odds of neurological deficit among patients with primary ICH.

Abstract TP25: Model-Free Dynamic Contrast-Enhanced MRI in Cerebral Small Vessel Disease: Test-Retest Reliability and Association With WMH Lesion Burden

Introduction: Dynamic contrast enhanced (DCE)-MRI has been used to study blood-brain barrier (BBB) disruption in cerebral small vessel disease (CSVD), but complex kinetic modeling of DCE MRI is sensitive to noise and is not robust in detecting subtle BBB impairments. In contrast, model-free DCE is simple and does not require arterial input function and complex computation. In this study, we aimed to evaluate the test-retest repeatability of model-free DCE and its association with white matter hyperintensity (WMH) burden. Methods: Patients with CSVD were recruited. DCE-MRI, FLAIR, and T1 MPRage scans were acquired. A subgroup of patients had two repeated DCE MRI scans with an average interval of 41 days. WMH segmentation was performed to obtain the relative volume of WMH (rVwmh). Ten subjects had DCE-MRI data in two sessions for test-retest repeatability analysis. DCE-MRI were acquired using a Siemens volumetric interpolated breath-hold examination (VIBE) gradient echo sequence with a temporal resolution of 49 seconds and an acquisition time of ~20 minutes. The wash-out slope (WOS), which indicates the rate of contrast agent leaving the tissue, was computed. Results: 64 patients (mean (SD) age = 68.6 (8.51), 37 females) with CSVD were studied. WOS demonstrated good test-retest repeatability for WM and GM with an intra-class correlation coefficient (ICC) of 0.626 and 0.671 in cerebrum WM and GM, respectively. WMH WOS has a significant negative correlation with rVwmh (r=-0.31; p&lt;0.02). Conclusions: A slow contrast wash-out (small WOS) is expected in the presence of BBB impairment. WMH burdens are associated with BBB impairments manifested by decreased WOS. WOS is computationally less intense and demonstrates good repeatability. It may offer an alternative to model-based DCE in evaluating BBB dysfunction in patients with CSVD.

Comparison of brain imaging and physical health between research and clinical neuroimaging cohorts of ageing.

To compare brain MRI measures between Adult Changes in Thought (ACT) participants who underwent research, clinical, or both MRI scans, and clinical health measures across the groups and non-MRI subjects. Retrospective cohort study leveraging MRI, clinical, demographic, and medication data from ACT. Three neuroradiologists reviewed MRI scans using NIH Neuroimaging Common Data Elements (CDEs). Total brain and white matter hyperintensity (WMH) volumes, clinical characteristics, and outcome measures of brain and overall health were compared between groups. 1166 MRIs were included (77 research, 1043 clinical, and 46 both) and an additional 3146 participants with no MRI were compared. Compared to the group with research MRI only, the clinical MRI group had higher prevalence of the following: acute infarcts, chronic haematoma, subarachnoid haemorrhage, subdural haemorrhage, haemorrhagic transformation, and hydrocephalus (each P < .001). Quantitative WMH burden was significantly lower (P < .001) and total brain volume significantly higher (P < .001) in research MRI participants compared to other MRI groups. Prevalence of hypertension, self-reported cerebrovascular disease, congestive heart failure, dementia, and recent hospitalization (all P < .001) and diabetes (P = .002) differed significantly across groups, with smaller proportions in the research MRI group. In ageing populations, significant differences were observed in MRI metrics between research MRI and clinical MRI groups, and clinical health metric differences between research MRI, clinical MRI, and no-MRI groups. This questions whether research cohorts can adequately represent the greater ageing population undergoing imaging. These findings may also be useful to radiologists when interpreting neuroimaging of ageing.

Abstract TP35: A 2-Stage Recruitment Design to Reduce MRI Screening Costs for a Theoretical Clinical Trial of WMH Progression

Background: White matter hyperintensities (WMH) are associated with risk of dementia and stroke, so are an important therapeutic target for clinical trials. The cost of broad MRI screening to identify those individuals with significant WMH, however, limits the feasibility of designing clinical trials which target WMH presence and which test treatments that slow progression. Hypothesis: A low-cost retinal or clinical screening measure prior to an MRI screening stage reduces the cost of recruiting persons with significant WMH burden in a hypothetical clinical trial vs an MRI-only screening design. Method: Data were from participants in the Atherosclerosis Risk in Communities-Neurocognitive study with clinical, retinal and WMH measurements ( N = 1311) at ages 53-70 years. Significant WMH burden was defined as a Cardiovascular Health Study score &gt;2. Three low-cost pre-screening measures were assessed: (1) retinal: a score incorporating multiple markers of abnormal retinal vasculature, (2) clinical: a score incorporating hypertension, diabetes, and age, (3) combined retinal-clinical: a score incorporating retinal and clinical factors. Given a prior published target sample for a WMH clinical trial (N= 646), we calculated a theoretical screening sample size based on the proportion of each pre-screening measure in the population multiplied by the proportion of significant WMH burden among those with a prevalent pre-screening feature. Total recruitment cost was calculated using standard retinal ($32.50) and MRI ($650) cost estimates. Results: Compared to the estimated cost of MRI-only screening (&gt;$4.24M, requiring MRI screening 6,526 participants), pre-screening for a high clinical score reduced total cost to $2.47M, but increased the initial screening group to 52,778 participants, of whom 3,801 would be screened by MRI). A high retinal-clinical score cutoff reduced costs to $2.9M while only requiring 13,572 screened participants (of these only 3,801 would require MRI). Conclusion: A 2-stage recruitment design with a low-cost pre-screening retinal and clinical measure is a promising approach, resulting in a reduction of theoretical recruitment costs for recruiting persons with significant WMH burden compared to an MRI-only design.

Abstract WP122: Statins May Increase White Matter Hyperintensity Burden in Older Adults: A Systematic Review and Meta-Analysis

Introduction: White matter hyperintensities (WMH) are a hallmark radiographic finding of cerebral microangiopathy. Longitudinal studies have shown varying effects of statins on accrual of WMH over time. We aimed to understand the impact of statins on WMH volume over time through a systematic review and meta-analysis. Methods: We performed a systematic review using standard search and risk of bias assessment practices. We included statin-exposed and statin-naive adults with longitudinal brain MRIs with computer-generated WMH volumetric analyses. The primary outcome was change in WMH volume (mL). Allowing for curvilinear change, a mixed-effects model was applied to capture the dynamic change over time. Model forecasts were used to visualize results, comparing changes over time among younger cohorts (60 years) and older cohorts (75 years) based on the the cohort mean age standard deviation. A p value ≤ 0.05 was considered significant. Results: We identified 6 studies enrolling 1911 participants from China, Europe, and North America (2 studies each); mean age 67.5 (± 7.5). The maximal study duration was 60-months. All studies had a least some degree of bias. Control groups had steady increase in WMH volume over time, Figures. The younger statin-exposed cohort developed statistically less WMH after 40 months of use. Older statin exposed patients had an increase in WMH volume compared with naïve patients which remained over the study duration. Conclusion: The impact of statins on WMH volume may be age dependent whereby older patients may have an accelerated accumulation. Further studies are warranted to confirm this data and investigate underlying mechanisms leading to this finding.

Serum Placental Growth Factor as a Marker of Cerebrovascular Disease Burden in Alzheimer's Disease.

Concomitant cerebrovascular diseases (CeVD) have been identified as an important determinant of Alzheimer's disease (AD) progression. Development of robust blood-based biomarkers will provide critical tools to evaluate prognosis and potential interventional strategies for AD with CeVD. This study investigated circulating placental growth factor (PlGF), a potent pro-angiogenic factor related to endothelial dysfunction and vascular inflammation, in an Asian memory clinic cohort of non-demented individuals as well as AD, including its associations with neuroimaging markers of CeVD. 109 patients with AD, 76 cognitively impaired with no dementia (CIND), and 56 non-cognitively impaired (NCI) were included in this cross-sectional study. All subjects underwent 3T brain magnetic resonance imaging to assess white matter hyperintensities (WMH), lacunes, cortical infarcts, and cerebral microbleeds (CMBs). Serum PlGF concentrations were measured by electrochemiluminescence immunoassays. Serum PlGF was elevated in AD, but not CIND, compared to the NCI controls. Adjusted concentrations of PlGF were associated with AD only in the presence of significant CeVD. Elevated PlGF was significantly associated with higher burden of WMH and with CMBs in AD patients. Serum PlGF has potential utility as a biomarker for the presence of CeVD, specifically WMH and CMBs, in AD. Further studies are needed to elucidate the underlying pathophysiological mechanisms linking PlGF to CeVD, as well as to further assess PlGF's clinical utility.

Association of Mean Upper Cervical Spinal Cord Cross-Sectional Area With Cerebral Small Vessel Disease: A Community-Based Cohort Study.

The purpose of this study was to investigate the association between the mean upper cervical spinal cord cross-sectional area (MUCCA) and the risk and severity of cerebral small vessel disease (CSVD). Community-dwelling residents in Lishui City, China, from the cross-sectional survey in the PRECISE cohort study (Polyvascular Evaluation for Cognitive Impairment and Vascular Events) conducted from 2017 to 2019. We included 1644 of 3067 community-dwelling adults in the PRECISE study after excluding those with incorrect, incomplete, insufficient, or missing clinical or imaging data. Total and modified total CSVD scores, as well as magnetic resonance imaging features, including white matter hyperintensity, lacunes, cerebral microbleeds, enlarged perivascular spaces, and brain atrophy, were assessed at the baseline. The Spinal Cord Toolbox was used to measure the upper cervical spinal cord cross-sectional area of the C1 to C3 segments of the spinal cord and its average value was taken as MUCCA. Participants were divided into 4 groups according to quartiles of MUCCA. Associations were analyzed using linear regression models adjusted for age, sex, current smoking and drinking, medical history, intracranial volume, and total cortical volume. The means±SD age of the participants was 61.4±6.5 years, and 635 of 1644 participants (38.6%) were men. The MUCCA was smaller in patients with CSVD than those without CSVD. Using the total CSVD score as a criterion, the MUCCA was 61.78±6.12 cm2 in 504 of 1644 participants with CSVD and 62.74±5.94 cm2 in 1140 of 1644 participants without CSVD. Using the modified total CSVD score, the MUCCA was 61.81±6.04 cm2 in 699 of 1644 participants with CSVD and 62.91±5.94 cm2 in 945 of 1644 without CSVD. There were statistical differences between the 2 groups after adjusting for covariates in 3 models. The MUCCA was negatively associated with the total and modified total CSVD scores (adjusted β value, -0.009 [95% CI, -0.01 to -0.003] and -0.007 [95% CI, -0.01 to -0.0006]) after adjustment for covariates. Furthermore, the MUCCA was negatively associated with the white matter hyperintensity burden (adjusted β value, -0.01 [95% CI, -0.02 to -0.003]), enlarged perivascular spaces in the basal ganglia (adjusted β value, -0.005 [95% CI, -0.009 to -0.001]), lacunes (adjusted β value, -0.004 [95% CI, -0.007 to -0.0007]), and brain atrophy (adjusted β value, -0.009 [95% CI, -0.01 to -0.004]). The MUCCA and CSVD were correlated. Spinal cord atrophy may serve as an imaging marker for CSVD; thus, small vessel disease may involve the spinal cord in addition to being intracranial.

Association of Vascular Risk Factors and CSF and Imaging Biomarkers With White Matter Hyperintensities in Former American Football Players.

Recent data link exposure to repetitive head impacts (RHIs) from American football with increased white matter hyperintensity (WMH) burden. WMH might have unique characteristics in the context of RHI beyond vascular risk and normal aging processes. We evaluated biological correlates of WMH in former American football players, including markers of amyloid, tau, inflammation, axonal injury, neurodegeneration, and vascular health. Participants underwent clinical interviews, MRI, and lumbar puncture as part of the Diagnostics, Imaging, and Genetics Network for the Objective Study and Evaluation of Chronic Traumatic Encephalopathy Research Project. Structural equation modeling tested direct and indirect effects between log-transformed total fluid-attenuated inversion recovery (FLAIR) lesion volumes (TLV) and the revised Framingham stroke risk profile (rFSRP), MRI-derived global metrics of cortical thickness and fractional anisotropy (FA), and CSF levels of amyloid β1-42, p-tau181, soluble triggering receptor expressed on myeloid cells 2 (sTREM2), and neurofilament light. Covariates included age, race, education, body mass index, APOE ε4 carrier status, and evaluation site. Models were performed separately for former football players and a control group of asymptomatic men unexposed to RHI. In 180 former football players (mean age = 57.2, 36% Black), higher log(TLV) had direct associations with the following: higher rFSRP score (B = 0.26, 95% CI 0.07-0.40), higher p-tau181 (B = 0.17, 95% CI 0.01-0.43), lower FA (B = -0.28, 95% CI -0.42 to -0.13), and reduced cortical thickness (B = -0.25, 95% CI -0.45 to -0.08). In 60 asymptomatic unexposed men (mean age = 59.3, 40% Black), there were no direct effects on log(TLV) (rFSRP: B = -0.03, 95% CI -0.48 to 0.57; p-tau181: B = -0.30, 95% CI -1.14 to 0.37; FA: B = -0.07, 95% CI -0.48 to 0.42; or cortical thickness: B = -0.28, 95% CI -0.64 to 0.10). The former football players showed stronger associations between log(TLV) and rFSRP (1,069% difference in estimates), p-tau181 (158%), and FA (287%) than the unexposed men. Risk factors and biological correlates of WMH differed between former American football players and asymptomatic unexposed men. In addition to vascular health, p-tau181 and diffusion tensor imaging indices of white matter integrity showed stronger associations with WMH in the former football players. FLAIR WMH may have specific risk factors and pathologic underpinnings in RHI-exposed individuals.

Clinical Markers for Small Vessel Pathology in Alzheimer’s Disease

Background:White matter hyperintensities (WMH) and cerebral microhemorrhages (MH) are common small vessel pathologies that often co-occur with hallmarks of Alzheimer’s Disease (AD) including amyloid-β and tau deposition, neurodegeneration, and decreased cognition. We investigated the relationship among these pathologies to better understand their roles in AD pathogenesis.&#x0D; Methods:A sample from the AD Neuroimaging Initiative (ADNI) with baseline WMH volume WMHV), MH counts, and serum lipids measurements using the Nightingale Health metabolomics platform included cognitively normal, mild cognitive impairment, and AD participants. Spearman rank correlations coefficient and rank regression models were generated to assess the relationship between vascular pathology and mean arterial pressure (MAP), history of hypertension, and serum biomarkers. Models were covaried for age, sex, APOE status, BMI, and years of education. Further analysis was conducted by dividing participants based on APOE status. False discovery rate was controlled by the Benjamini-Hochberg method.&#x0D; Results:WMHV and MH were weakly positively associated (ρ=0.197, p&lt;1*10-10). MH and MAP were positively correlated (p&lt;.05), but MH was not related to history of hypertension, or serum lipids. WMHV was negatively associated with serum VLDL cholesterol (p&lt;1*10-12), LDL cholesterol (p&lt;.0001), and remnant cholesterol (p&lt;1*10-11). In APOE4 carriers only, WMHV was negatively associated with triglycerides (p&lt;.001) and total fatty acids (p&lt;.001), and positively associated with HDL cholesterol (p&lt;.002). WMHV was not related to MAP or history of hypertension.&#x0D; Conclusion:Vascular imaging markers have distinct risk factors with lipid profiles most associated with WMH burden, whereas MAP was predictive of MH. Counterintuitively, lipids associated with higher risk of systemic vascular pathology appeared protective against WMH in the ADNI sample. This phenomenon was particularly notable in APOE4 carriers. Further investigation should be conducted to better understand the relationship between serum lipids and small vessel pathology, and how these contribute to AD pathogenesis.

A pilot study of longitudinal changes in neurocognition, white matter hyperintensities, and cortical thickness in atrial fibrillation patients following catheter ablation vs medical management

BackgroundCerebral microembolization and atrophy complicate atrial fibrillation (AF). ObjectivesWe aimed to compare changes in neuroimaging findings between AF patients treated with catheter ablation and those treated with medical therapy. MethodsIn this pilot study, we evaluated differences in the change in regional white matter hyperintensity burden (WMHb) and cognitive function from baseline to 6-weeks and 1-year in patients treated with AF ablation (ABL, n=12) and patients treated with medical management alone (MM, n=11). Change in cortical thickness in Alzheimer’s Disease (AD)-risk, aging-associated or shared AD-risk/aging regions was also compared between groups. ResultsThe mean age was 69.7±5.0, 78% of patients were male, 39% had persistent AF, and all received oral anticoagulation. There were no significant differences between groups in the change in cognitive function. At 6-weeks, there were no significant differences in periventricular WMHb changes between groups (0.00 vs. 0.04; p=0.12), but changes in attention/concentration were inversely correlated with periventricular (p=0.01) and total WMHb (p=0.03). MM patients demonstrated significantly greater cortical thinning in AD-risk regions from baseline to 1-year (p=0.003). ConclusionsAF patients who underwent ablation demonstrated less cortical thinning in regions associated with AD risk than patients treated with medical therapy. Larger, prospective studies are needed to better understand the relationship between AF therapies and the development of cognitive decline.

Serum Brevican as a Biomarker of Cerebrovascular Disease in an Elderly Cognitively Impaired Cohort.

In the brain, the extracellular matrix (ECM) composition shapes the neuronal microenvironment and can undergo substantial changes with cerebral pathology. Brevican is integral to the formation of the ECM's neuroprotective perineuronal nets (PNNs). Decreased brevican levels were reported in vascular dementia (VaD) but not in Alzheimer's disease (AD). However, the status of brevican in clinical cohorts with high concomitance of AD pathological burden and cerebrovascular disease (CeVD) is unclear. In this study, 32 non-cognitively impaired (NCI), 97 cognitively impaired no dementia (CIND), 46 AD, and 23 VaD participants recruited from memory clinics based in Singapore underwent neuropsychological and neuroimaging assessments, together with measurements of serum brevican. Association analyses were performed between serum brevican and neuroimaging measures of CeVDs, including white matter hyperintensities (WMHs), lacunes, cortical infarcts, and cerebral microbleeds. Using an aggregated score for CeVD burden, only CIND participants showed lower brevican levels with higher CeVD compared to those with lower CeVD burden (p = 0.006). Among the CeVD subtypes assessed, only elevated WMH burden was associated with lower brevican levels (OR = 2.7; 95% CI = 1.3-5.5). Our findings suggest that brevican deficits may play a role in early cerebrovascular damage in participants at risk of developing dementia.

White matter hyperintensity burden and collateral circulation in acute ischemic stroke with large artery occlusion

ObjectiveThis study aimed to investigate the association between white matter hyperintensity (WMH) burden and pial collaterals in acute strokes caused by intracranial large artery occlusion treated with mechanical thrombectomy in the anterior circulation, focusing on stroke subtypes.MethodsConsecutive patients undergoing mechanical thrombectomy between December 2019 and June 2022 were retrospectively screened. The Fazekas scale assessed WMH burden. Pial collaterals were categorized as either poor (0–2) or good (3–4) based on the Higashida score. A multivariable analysis was used to determine the relationship between WMH burden and pial collaterals. Subgroup analyses delved into associations stratified by stroke subtypes, namely cardioembolism (CE), tandem lesions (TLs), and intracranial atherosclerosis (ICAS).ResultsOf the 573 patients included, 274 (47.8%) demonstrated poor pial collaterals. Multivariable regression indicated a strong association between extensive WMH burden (Fazekas score of 3–6) and poor collaterals [adjusted OR 3.04, 95% CI 1.70–5.46, P < 0.001]. Additional independent predictors of poor collaterals encompassed ICAS-related occlusion (aOR 0.26, 95% CI 0.09–0.76, P = 0.014), female sex (aOR 0.63, 95% CI 0.41–0.96, P = 0.031), and baseline Alberta Stroke Program Early Computed Tomography scores (aOR 0.80, 95% CI 0.74–0.88, P < 0.001). Notably, an interaction between extensive WMH burden and stroke subtypes was observed in predicting poor collaterals (P = 0.001), being pronounced for CE (adjusted OR 2.30, 95% CI 1.21–4.37) and TLs (adjusted OR 5.09, 95% CI 2.32–11.16), but was absent in ICAS (adjusted OR 1.24, 95% CI 0.65–2.36).ConclusionsAmong patients treated with mechanical thrombectomy for anterior circulation large artery occlusion, extensive WMH burden correlates with poor pial collaterals in embolic occlusion cases (CE and TLs), but not in ICAS-related occlusion.

Investigating the relationship between sleep disturbances and white matter hyperintensities in older adults on the Alzheimer's disease spectrum.

While studies report that sleep disturbance can have negative effects on brain vasculature, its impact on cerebrovascular diseases such as white matter hyperintensities (WMHs) in beta-amyloid-positive older adults remains unexplored. Sleep disturbance, WMH burden, and cognition in normal controls (NCs), and individuals with mild cognitive impairment (MCI) and Alzheimer's disease (AD), were examined at baseline and longitudinally. A total of 912 amyloid-positive participants were included (198 NC, 504 MCI, and 210 AD). Individuals with AD reported more sleep disturbances than NC and MCI participants. Those with sleep disturbances had more WMHs than those without sleep disturbances in the AD group. Mediation analysis revealed an effect of regional WMH burden on the relationship between sleep disturbance and future cognition. These results suggest that WMH burden and sleep disturbance increase from aging to AD. Sleep disturbance decreases cognition through increases in WMH burden. Improved sleep could mitigate the impact of WMH accumulation and cognitive decline.

Mendelian Randomization Analysis to Assess Whether Magnetic Resonance Imaging Signs of Cerebral Small Vessel Disease Can Cause Cognitive Decline and Dementia.

Cognitive decline and dementia have been linked to cerebral small vessel disease, so we explored using Mendelian randomization whether cerebral small vessel disease visible as 10 neuroimaging signs may cause cognitive decline and dementia. We analyzed publicly available data from genome-wide association studies using two-sample Mendelian randomization involving inverse variance weighting, weighted median, MR-Egger, and MR-PRESSO approaches. Mendelian randomization suggested that cognitive decline can be caused by lacunar stroke (inverse variance weighting, β = -0.012, 95% CI -0.024 to -0.001, P = 0.033). Furthermore, an elevated burden of white matter hyperintensities was associated with an increased risk of Dementia due to Parkinson's disease (inverse variance weighting, OR 2.035, 95% CI 1.105 to 3.745, P = 0.023). Notably, no significant associations were observed between neuroimaging markers of Cerebral Small Vessel Disease and other types of dementia. This Mendelian randomization study provides evidence that lacunar stroke and white matter lesions can cause cognitive decline, and that white matter hyperintensity may increase risk of dementia due to Parkinson's disease. These results underscore the need for further investigations into the neurocognitive effects of cerebral small vessel disease.

Differential risk factor profile and neuroimaging markers of small vessel disease between lacunar ischemic stroke and deep intracerebral hemorrhage.

Lacunar ischemic stroke (LIS) and deep intracerebral hemorrhage (dICH) are two stroke phenotypes of deep perforator arteriopathy. It is unclear what factors predispose individuals with deep perforator arteriopathy to either ischemic or hemorrhagic events. We aimed to investigate risk factors and neuroimaging features of small vessel disease (SVD) associated with LIS versus dICH in a cross-sectional study. We included patients with clinically presenting, magnetic resonance imaging-confirmed LIS or dICH from two tertiary hospitals between 2010 and 2021. We recorded vascular risk factors and SVD markers, including lacunes, white matter hyperintensities (WMH), perivascular spaces (PVS), and cerebral microbleeds (CMB). Logistic regression modeling was used to determine the association between vascular risk factors, SVD markers, and stroke phenotype. We further created WMH probability maps to compare WMH distribution between LIS and dICH. A total of 834 patients with LIS (mean age 61.7 ± 12.1 years) and 405 with dICH (57.7 ± 13.2 years) were included. Hypertension was equally frequent between LIS and dICH (72.3% versus 74.8%, p = 0.349). Diabetes mellitus, hyperlipidemia, smoking, and prior ischemic stroke were more associated with LIS [odds ratio (OR) (95% confidence interval (CI)), 0.35 (0.25-0.48), 0.32 (0.22-0.44), 0.31 (0.22-0.44), and 0.38 (0.18-0.75)]. Alcohol intake and prior ICH were more associated with dICH [OR (95% CI), 2.34 (1.68-3.28), 2.53 (1.31-4.92)]. Lacunes were more prevalent in LIS [OR (95% CI) 0.23 (0.11-0.43)], while moderate-to-severe basal-ganglia PVS and CMB were more prevalent in dICH [OR (95% CI) 2.63 (1.35-5.27), 4.95 (2.71-9.42)]. WMH burden and spatial distribution did not differ between groups. The microangiopathy underlying LIS and dICH reflects distinct risk profiles and SVD features, hence possibly SVD subtype susceptibility. Prospective studies with careful phenotyping and genetics are needed to clarify the mechanisms underlying this difference.

Blood pressure variability and white matter hyperintensities after ischemic stroke

BackgroundHigh blood pressure variability (BPV) may be a risk factor for stroke and dementia in patients with ischemic stroke, but the underlying mechanism is unknown. We aimed to investigate whether high BPV is associated with presence and progression of white matter hyperintensities (WMH). MethodsWe performed a post-hoc analysis on the MRI substudy of the PRoFESS trial, including 771 patients with ischemic stroke who underwent MRI at baseline and after a median of 2.1 years. WMH were rated with a semi-quantitative scale. Visit-to-visit BPV was expressed as the coefficient of variation (interval 3–6 months, median number of visits 7). The association of BPV with WMH burden and progression was assessed with linear and logistic regression analyses adjusted for confounders. ResultsBPV was associated with burden of periventricular WMH (β 0.36 95%CI 0.19–0.53, per one SD increase in BPV) and subcortical (log-transformed) WMH (β 0.25, 95%CI 0.08–0.42). BPV was not associated with periventricular (OR 1.09, 95%CI 0.94–1.27) and subcortical WMH progression (OR 1.15, 95%CI 0.99–1.35). Associations were independent of mean BP. ConclusionHigh visit-to-visit BPV was associated with both subcortical and periventricular WMH burden in patients with ischemic stroke, but not with WMH progression in this study.

Cerebrovascular lesion loads and accelerated brain aging: insights into the cognitive spectrum.

White matter hyperintensities (WMHs) and cerebral microbleeds are widespread among aging population and linked with cognitive deficits in mild cognitive impairment (MCI), vascular MCI (V-MCI), and Alzheimer's disease without (AD) or with a vascular component (V-AD). In this study, we aimed to investigate the association between brain age, which reflects global brain health, and cerebrovascular lesion load in the context of pathological aging in diverse forms of clinically-defined neurodegenerative conditions. We computed brain-predicted age difference (brain-PAD: predicted brain age minus chronological age) in the Comprehensive Assessment of Neurodegeneration and Dementia cohort of the Canadian Consortium on Neurodegeneration in Aging including 70 cognitively intact elderly (CIE), 173 MCI, 88 V-MCI, 50 AD, and 47 V-AD using T1-weighted magnetic resonance imaging (MRI) scans. We used a well-established automated methodology that leveraged fluid attenuated inversion recovery MRIs for precise quantification of WMH burden. Additionally, cerebral microbleeds were detected utilizing a validated segmentation tool based on the ResNet50 network, utilizing routine T1-weighted, T2-weighted, and T2* MRI scans. The mean brain-PAD in the CIE cohort was around zero, whereas the four categories showed a significantly higher mean brain-PAD compared to CIE, except MCI group. A notable association trend between brain-PAD and WMH loads was observed in aging and across the spectrum of cognitive impairment due to AD, but not between brain-PAD and microbleed loads. WMHs were associated with faster brain aging and should be considered as a risk factor which imperils brain health in aging and exacerbate brain abnormalities in the context of neurodegeneration of presumed AD origin. Our findings underscore the significance of novel research endeavors aimed at elucidating the etiology, prevention, and treatment of WMH in the area of brain aging.