Nonlinear temporal dynamics of cerebral small vessel disease: The RUN DMC study

Prediction of early neurologic deterioration in patients with perforating artery territory infarction using machine learning: a retrospective study

Background

Early neurological deterioration (END) is a frequent complication in patients with perforating artery territory infarction (PAI), leading to poorer outcomes. Therefore, we aimed to apply machine learning (ML) algorithms to predict the occurrence of END in PAI and investigate related risk factors.

Methods

This retrospective study analyzed a cohort of PAI patients, excluding those with severe stenosis of the parent artery. We included demographic characteristics, clinical features, laboratory data, and imaging variables. Recursive feature elimination with cross-validation (RFECV) was performed to identify critical features. Seven ML algorithms, namely logistic regression, random forest, adaptive boosting, gradient boosting decision tree, histogram-based gradient boosting, extreme gradient boosting, and category boosting, were developed to predict END in PAI patients using these critical features. We compared the accuracy of these models in predicting outcomes. Additionally, SHapley Additive exPlanations (SHAP) values were introduced to interpret the optimal model and assess the significance of input features.

Results

The study enrolled 1,020 PAI patients with a mean age of 60.46 (range 49.11-71.81) years. Of these, 30.39% were women, and 129 (12.65%) experienced END. RFECV selected 13 critical features, including blood urea nitrogen (BUN), total cholesterol (TC), low-density-lipoprotein cholesterol (LDL-C), apolipoprotein B (apoB), atrial fibrillation, loading dual antiplatelet therapy (DAPT), single antiplatelet therapy (SAPT), argatroban, the basal ganglia, the thalamus, the posterior choroidal arteries, maximal axial infarct diameter (measured at < 15 mm), and stroke subtype. The gradient-boosting decision tree had the highest area under the curve (0.914) among the seven ML algorithms. The SHAP analysis identified apoB as the most significant variable for END.

Conclusion

Our results suggest that ML algorithms, especially the gradient-boosting decision tree, are effective in predicting the occurrence of END in PAI patients.

Decoding the Best Automated Segmentation Tools for Vascular White Matter Hyperintensities in the Aging Brain: A Clinician's Guide to Precision and Purpose

Cerebrovascular damage from small vessel disease (SVD) occurs in healthy and pathological aging. SVD markers, such as white matter hyperintensities (WMH), are commonly found in individuals over 60 and increase in prevalence with age. WMHs are detectable on standard MRI by adhering to the STRIVE criteria. Currently, visual assessment scales are used in clinical and research scenarios but is time-consuming and has rater variability, limiting its practicality. Addressing this issue, our study aimed to determine the most precise WMH segmentation software, offering insights into methodology and usability to balance clinical precision with practical application. This study employed a dataset comprising T1, FLAIR, and DWI images from 300 cognitively healthy older adults. WMHs in this cohort were evaluated using four automated neuroimaging tools: Lesion Prediction Algorithm (LPA) and Lesion Growth Algorithm (LGA) from Lesion Segmentation Tool (LST), Sequence Adaptive Multimodal Segmentation (SAMSEG), and Brain Intensity Abnormalities Classification Algorithm (BIANCA). Additionally, clinicians manually segmented WMHs in a subsample of 45 participants to establish a gold standard. The study assessed correlations with the Fazekas scale, algorithm performance, and the influence of WMH volume on reliability. Results indicated that supervised algorithms were superior, particularly in detecting small WMHs, and can improve their consistency when used in parallel with unsupervised tools. The research also proposed a biomarker for moderate vascular damage, derived from the top 95th percentile of WMH volume in healthy individuals aged 50 to 60. This biomarker effectively differentiated subgroups within the cohort, correlating with variations in brain structure and behavior.

Sporadic cerebral small vessel disease and cognitive decline in healthy older adults: A systematic review and meta-analysis

We performed a systematic review and meta-analysis on prospective studies that provided risk estimates for the impact of 3 different MRI markers of small vessel disease (SVD), namely white matter hyperintensities (WMH), cerebral microbleeds (CMB) and lacunes, on cognitive decline in relatively healthy older adults without cognitive deficits at baseline. A total of 23 prospective studies comprising 11,486 participants were included for analysis. Extracted data was pooled, reviewed and meta-analysed separately for global cognition, executive function, memory and attention. The pooled effect size for the association between cerebral SVD and cognitive decline was for global cognition -0.10 [-0.14; -0.05], for executive functioning -0.18 [-0.24; - 0.11], for memory -0.12 [-0.17; -0.07], and for attention -0.17 [-0.23; -0.11]. Results for the association of individual MRI markers of cerebral SVD were statistically significant for WMH and global cognition -0.15 [-0.24; -0.06], WMH and executive function -0.23 [-0.33; -0.13], WMH and memory -0.19 [-0.29; -0.09], WMH and attention -0.24 [-0.39; -0.08], CMB and executive function -0.07 [-0.13; -0.02], CMB and memory -0.11 [-0.21; -0.02] and CMB and attention -0.13 [-0.25; -0.02]. In conclusion, presence of MRI markers of cerebral SVD were found to predict an increased risk of cognitive decline in relatively healthy older adults. While WMH were found to significantly affect all cognitive domains, CMB influenced decline in executive functioning over time as well as (in some studies) decline in memory and attention.

Structural Network Efficiency Predicts Conversion to Incident Parkinsonism in Patients With Cerebral Small Vessel Disease

BACKGROUND

To investigate whether structural network disconnectivity is associated with parkinsonian signs and their progression, as well as with an increased risk of incident parkinsonism.

METHODS

In a prospective cohort (Radboud University Nijmegen Diffusion Tensor and Magnetic Resonance Cohort study) consisting of 293 participants with small vessel disease (SVD), we assessed parkinsonian signs and incident parkinsonism over an 8-year follow-up. In addition, we reconstructed the white matter network followed by graph-theoretical analyses to compute the network metrics. Conventional magnetic resonance imaging markers for SVD were assessed.

RESULTS

We included 293 patients free of parkinsonism at baseline (2011), with a mean age 68.8 (standard deviation [SD] 8.4) years, and 130 (44.4%) were men. Nineteen participants (6.5%) developed parkinsonism during a median (SD) follow-up time of 8.3 years. Compared with participants without parkinsonism, those with all-cause parkinsonism had higher Unified Parkinson's Disease Rating scale (UPDRS) scores and lower global efficiency at baseline. Baseline global efficiency was associated with UPDRS motor scores in 2011 (β = -0.047, p < .001) and 2015 (β = -0.84, p < .001), as well as with the changes in UPDRS scores during the 4-year follow-up (β = -0.63, p = .004). In addition, at the regional level, we identified an inter-hemispheric disconnected network associated with an increased UPDRS motor score. Besides, lower global efficiency was associated with an increased risk of all-cause and vascular parkinsonism independent of SVD markers.

CONCLUSIONS

Our findings suggest that global network efficiency is associated with a gradual decline in motor performance, ultimately leading to incident parkinsonism in the elderly with SVD. Global network efficiency may have the added value to serve as a useful marker to capture changes in motor signs.

Pattern of Brain Parenchymal Damage Related to Cerebral Small Vessel Disease in Carriers of Rare NOTCH3 Variants

BACKGROUND AND OBJECTIVES

Previous studies reported that carriers of rare NOTCH3 variants comprised more than 10% of the general population and are susceptible to a heavy overall burden of cerebral small vessel disease while the injury patterns remain uncovered. This study aimed to investigate the imaging features in relation to rare NOTCH3 variants and the interaction between cortical atrophy and white matter lesions from a longitudinal view, with respect to spatial and dynamic patterns.

METHODS

As part of a community-based cohort, we included participants with complete whole-exome sequencing and brain MRI in the baseline analysis. All participants were invited for a 5-year follow-up MRI, and those who did not complete the follow-up were excluded from the longitudinal analysis. NOTCH3 variants with minor allele frequency <1% in all 4 public population databases were defined as rare variants. We used general linear models to compare the volume of white matter hyperintensity (WMH) volume and brain parenchymal fraction between rare NOTCH3 variant carriers and noncarriers. In addition, we compared the WMH probability map and vertex-wise cortex maps at a voxel/vertex-wise level.

RESULTS

A total of 1,054 participants were included in baseline analysis (13.56% carried rare NOTCH3 variants), among whom 661 had a follow-up brain MRI (13.76% carried rare NOTCH3 variants). Rare NOTCH3 variant carriers had a heavier white matter hyperintensity burden (1.65 vs 0.85 mL, p = 0.025) and had more extensive WMH distributed in the periventricular areas. We also found that rare NOTCH3 variant carriers were susceptible to worse cortical atrophy (β = -0.004, SE = 0.002, p = 0.057, adjusted for age and sex). Cortical atrophy of multiple regions in the frontal and parietal lobes was related to white matter hyperintensity progression.

DISCUSSION

Individuals with rare NOTCH3 variants have a distinct pattern of brain parenchymal damage related to CSVD. Our findings uncover the important genetic predisposition in age-related cerebral small vessel disease in the general population.

Cerebrovascular Reactivity in Patients With Small Vessel Disease: A Cross-Sectional Study

BACKGROUND

Cerebrovascular reactivity (CVR) is inversely related to white matter hyperintensity severity, a marker of cerebral small vessel disease (SVD). Less is known about the relationship between CVR and other SVD imaging features or cognition. We aimed to investigate these cross-sectional relationships.

METHODS

Between 2018 and 2021 in Edinburgh, we recruited patients presenting with lacunar or cortical ischemic stroke, whom we characterized for SVD features. We measured CVR in subcortical gray matter, normal-appearing white matter, and white matter hyperintensity using 3T magnetic resonance imaging. We assessed cognition using Montreal Cognitive Assessment. Statistical analyses included linear regression models with CVR as outcome, adjusted for age, sex, and vascular risk factors. We reported regression coefficients with 95% CIs.

RESULTS

Of 208 patients, 182 had processable CVR data sets (median age, 68.2 years; 68% men). Although the strength of association depended on tissue type, lower CVR in normal-appearing tissues and white matter hyperintensity was associated with larger white matter hyperintensity volume (BNAWM=-0.0073 [95% CI, -0.0133 to -0.0014] %/mm Hg per 10-fold increase in percentage intracranial volume), more lacunes (BNAWM=-0.00129 [95% CI, -0.00215 to -0.00043] %/mm Hg per lacune), more microbleeds (BNAWM=-0.00083 [95% CI, -0.00130 to -0.00036] %/mm Hg per microbleed), higher deep atrophy score (BNAWM=-0.00218 [95% CI, -0.00417 to -0.00020] %/mm Hg per score point increase), higher perivascular space score (BNAWM=-0.0034 [95% CI, -0.0066 to -0.0002] %/mm Hg per score point increase in basal ganglia), and higher SVD score (BNAWM=-0.0048 [95% CI, -0.0075 to -0.0021] %/mm Hg per score point increase). Lower CVR in normal-appearing tissues was related to lower Montreal Cognitive Assessment without reaching convention statistical significance (BNAWM=0.00065 [95% CI, -0.00007 to 0.00137] %/mm Hg per score point increase).

CONCLUSIONS

Lower CVR in patients with SVD was related to more severe SVD burden and worse cognition in this cross-sectional analysis. Longitudinal analysis will help determine whether lower CVR predicts worsening SVD severity or vice versa.

REGISTRATION

URL: https://www.isrctn.com; Unique identifier: ISRCTN12113543.

Blood-Brain Barrier Breakdown is a Sensitive Biomarker of Cognitive and Language Impairment in Patients with White Matter Hyperintensities

INTRODUCTION

Similar white matter hyperintensities (WMH) burden may have varied cognitive outcomes in patients with cerebral small vessel disease (CSVD). This study aimed to evaluate whether blood-brain barrier (BBB) permeability is associated with cognitive impairment (CI) heterogeneity in patients with WMH.

METHODS

We recruited 51 participants with WMH. We evaluated WMH burden using the Fazekas scale and WMH volume on structural magnetic resonance imaging (MRI), and assessed BBB permeability using dynamic contrast-enhanced (DCE)-MRI. We used permeability-surface area product (PS) from the Patlak model to represent BBB permeability. All patients underwent Mini-Mental State Examination (MMSE), Boston Naming Test (BNT) and animal verbal fluency test (VFT) for cognitive assessment. We divided patients into CI and non-CI groups based on their MMSE scores (< 27 or ≥ 27) and used multiple linear regression models to investigate the associations between MRI parameters and cognitive function.

RESULTS

Patients in the two groups did not differ in Fazekas scores and WMH volume. However, patients in the CI group showed significantly higher PS in the WMH regions than those in non-CI group (1.89 × 10-3 versus 1.00 × 10-3, p = 0.032 in periventricular WMH [PVWMH]; 1.27 × 10-3 versus 0.74 × 10-3, p = 0.043 in deep WMH [DWMH]), indicating the breakdown of BBB in the CI group. In all patients with WMH, increased BBB permeability in PVWMH and DWMH was significantly associated with lower cognitive and language function after adjustment for age, education level (EL) and intracranial volume (ICV). In the CI group, this correlation remained significant. WMH volume was not associated with cognitive performance in either all patients or those with CI.

CONCLUSION

BBB impairment might be a more sensitive indicator for cognitive and language dysfunction than WMH volume in patients with WMH and possibly explains the heterogeneity of cognitive performance in patients with similar WMH burden.

How often does white matter hyperintensity volume regress in cerebral small vessel disease?

BACKGROUND AND OBJECTIVES

It has been suggested that white matter hyperintensity lesions (WMHs), which typically progress over time, can also regress, and that this might be associated with favorable cognitive performance. We determined the prevalence of WMH regression in patients with cerebral small vessel disease (SVD) and examined which demographic, clinical, and radiological markers were associated with this regression.

METHODS

We used semi-automated lesion marking methods to quantify WMH volume at multiple timepoints in three cohorts with symptomatic SVD; two with moderate-to-severe symptomatic SVD (the SCANS observational cohort and the control arm of the PRESERVE interventional trial) and one with mild-to-moderate SVD (the RUN DMC observational cohort). Mixed-effects ordered logistic regression models were used to test which factors predicted participants to show WMH regression.

RESULTS

No participants (0/98) in SCANS, 6/42 (14.3%) participants in PRESERVE, and 6/276 (2.2%) in RUN DMC showed WMH regression. On multivariate analysis, only lower WMH volume (OR: 0.36, 95% CI: 0.23-0.56) and better white matter microstructural integrity assessed by fractional anisotropy using diffusion tensor imaging (OR: 1.55, 95% CI: 1.07-2.24) predicted participant classification as regressor versus stable or progressor.

DISCUSSION

Only a small proportion of participants demonstrated WMH regression across the three cohorts, when a blinded standardized assessment method was used. Subjects who showed regression had less severe imaging markers of disease at baseline. Our results show that lesion regression is uncommon in SVD and unlikely to be a major factor affecting the use of WMH quantification as an outcome for clinical trials.

A Scoping Review on Biomarkers of Endothelial Dysfunction in Small Vessel Disease: Molecular Insights from Human Studies

Small vessel disease (SVD) is a highly prevalent disorder of the brain's microvessels and a common cause of dementia as well as ischaemic and haemorrhagic strokes. Though much about the underlying pathophysiology of SVD remains poorly understood, a wealth of recently published evidence strongly suggests a key role of microvessel endothelial dysfunction and a compromised blood-brain barrier (BBB) in the development and progression of the disease. Understanding the causes and downstream consequences associated with endothelial dysfunction in this pathological context could aid in the development of effective diagnostic and prognostic tools and provide promising avenues for potential therapeutic interventions. In this scoping review, we aim to summarise the findings from clinical studies examining the role of the molecular mechanisms underlying endothelial dysfunction in SVD, focussing on biochemical markers of endothelial dysfunction detectable in biofluids, including cell adhesion molecules, BBB transporters, cytokines/chemokines, inflammatory markers, coagulation factors, growth factors, and markers involved in the nitric oxide cascade.

Predicting incident dementia in cerebral small vessel disease: comparison of machine learning and traditional statistical models

Background

Cerebral small vessel disease (SVD) contributes to 45% of dementia cases worldwide, yet we lack a reliable model for predicting dementia in SVD. Past attempts largely relied on traditional statistical approaches. Here, we investigated whether machine learning (ML) methods improved prediction of incident dementia in SVD from baseline SVD-related features over traditional statistical methods.

Methods

We included three cohorts with varying SVD severity (RUN DMC, n = 503; SCANS, n = 121; HARMONISATION, n = 265). Baseline demographics, vascular risk factors, cognitive scores, and magnetic resonance imaging (MRI) features of SVD were used for prediction. We conducted both survival analysis and classification analysis predicting 3-year dementia risk. For each analysis, several ML methods were evaluated against standard Cox or logistic regression. Finally, we compared the feature importance ranked by different models.

Results

We included 789 participants without missing data in the survival analysis, amongst whom 108 (13.7%) developed dementia during a median follow-up of 5.4 years. Excluding those censored before three years, we included 750 participants in the classification analysis, amongst whom 48 (6.4%) developed dementia by year 3. Comparing statistical and ML models, only regularised Cox/logistic regression outperformed their statistical counterparts overall, but not significantly so in survival analysis. Baseline cognition was highly predictive, and global cognition was the most important feature.

Conclusions

When using baseline SVD-related features to predict dementia in SVD, the ML survival or classification models we evaluated brought little improvement over traditional statistical approaches. The benefits of ML should be evaluated with caution, especially given limited sample size and features.

Past antihypertensive medication use is associated with lower levels of small vessel disease and lower Aβ plaque stage in the brains of older individuals

AIMS

This study assesses the association of antihypertensive medication use on the severities of neuropathological cerebrovascular disease (CVD excluding lobar infarction) in older individuals.

METHODS

Clinical and neuropathological data were retrieved for 149 autopsy cases >75 years old with or without CVD or Alzheimer's disease and no other neuropathological diagnoses. Clinical data included hypertension status, hypertension diagnosis, antihypertensive medication use, antihypertensive medication dose (where available) and clinical dementia rating (CDR). Neuropathological CVD severity was evaluated for differences with anti-hypertensive medication usage.

RESULTS

Antihypertensive medication use was associated with less severe white matter small vessel disease (SVD, mainly perivascular dilatation and rarefaction), with a 5.6-14.4 times greater likelihood of less severe SVD if medicated. No significant relationship was detected between infarction (presence, type, number and size), lacunes or cerebral amyloid angiopathy and antihypertensive medication use. Only increased white matter rarefaction/oedema and not perivascular dilation was associated with Alzheimer's pathology, with a 4.3 times greater likelihood of reduced Aβ progression through the brain if white matter rarefaction severity was none or mild. Antihypertensive medication use was associated with reduced Aβ progression but only in those with moderate to severe white matter SVD.

CONCLUSIONS

This histopathological study provides further evidence that antihypertensive medication use in older individuals is associated with white matter SVD and not with other CVD pathologies. This is mainly due to a reduction in white matter perivascular dilation and rarefaction/oedema. Even in those with moderate to severe white matter SVD, antihypertensive medication use reduced rarefaction and Aβ propagation through the brain.

Integrated intravoxel incoherent motion tensor and diffusion tensor brain MRI in a single fast acquisition

The acquisition of intravoxel incoherent motion (IVIM) data and diffusion tensor imaging (DTI) data from the brain can be integrated into a single measurement, which offers the possibility to determine orientation-dependent (tensorial) perfusion parameters in addition to established IVIM and DTI parameters. The purpose of this study was to evaluate the feasibility of such a protocol with a clinically feasible scan time below 6 min and to use a model-selection approach to find a set of DTI and IVIM tensor parameters that most adequately describes the acquired data. Diffusion-weighted images of the brain were acquired at 3 T in 20 elderly participants with cerebral small vessel disease using a multiband echoplanar imaging sequence with 15 b-values between 0 and 1000 s/mm² and six non-collinear diffusion gradient directions for each b-value. Seven different IVIM-diffusion models with 4 to 14 parameters were implemented, which modeled diffusion and pseudo-diffusion as scalar or tensor quantities. The models were compared with respect to their fitting performance based on the goodness of fit (sum of squared fit residuals, chi² ) and their Akaike weights (calculated from the corrected Akaike information criterion). Lowest chi² values were found using the model with the largest number of model parameters. However, significantly highest Akaike weights indicating the most appropriate models for the acquired data were found with a nine-parameter IVIM-DTI model (with isotropic perfusion modeling) in normal-appearing white matter (NAWM), and with an 11-parameter model (IVIM-DTI with additional pseudo-diffusion anisotropy) in white matter with hyperintensities (WMH) and in gray matter (GM). The latter model allowed for the additional calculation of the fractional anisotropy of the pseudo-diffusion tensor (with a median value of 0.45 in NAWM, 0.23 in WMH, and 0.36 in GM), which is not accessible with the usually performed IVIM acquisitions based on three orthogonal diffusion-gradient directions.

Chronic cerebral hypoperfusion alters the CypA-EMMPRIN-gelatinase pathway: Implications for vascular dementia

Chronic cerebral hypoperfusion (CCH) is postulated to underlie multiple pathophysiological processes in vascular dementia (VaD), including extracellular matrix dysfunction. While several extracellular matrix proteins, namely cyclophilin A (CypA), extracellular matrix metalloproteinase inducer (EMMPRIN) and gelatinases (matrix metalloproteinases, MMP-2 and -9) have been investigated in acute stroke, their involvement in CCH and VaD remains unclear. In this study, CypA-EMMPRIN-gelatinase proteins were analysed in a clinical cohort of 36 aged, cognitively unimpaired subjects and 48 VaD patients, as well as in a bilateral carotid artery stenosis mouse model of CCH. Lower CypA and higher EMMPRIN levels were found in both VaD serum and CCH mouse brain. Furthermore, gelatinases were differentially altered in CCH mice and VaD patients, with significant MMP-2 increase in CCH brain and serum, whilst serum MMP-9 was elevated in VaD but reduced in CCH, suggesting complex CypA-EMMPRIN-gelatinase regulatory mechanisms. Interestingly, subjects with cortical infarcts had higher serum MMP-2, while white matter hyperintensities, cortical infarcts and lacunes were associated with higher serum MMP-9. Taken together, our data indicate that perturbations of CypA-EMMPRIN signalling may be associated with gelatinase-mediated vascular sequelae, highlighting the potential utility of the CypA-EMMPRIN-gelatinase pathway as clinical biomarkers and therapeutic targets in VaD.

Classification of white matter lesions and characteristics of small vessel disease markers

OBJECTIVES

Radiological markers for cerebral small vessel disease (SVD) may have different biological underpinnings in their development. We attempted to categorize SVD burden by integrating white matter signal abnormalities (WMSA) features and secondary presence of lacunes, microbleeds, and enlarged perivascular spaces.

METHODS

Data were acquired from 610 older adults (aged > 40 years) who underwent brain magnetic resonance imaging exam as part of a health checkup. The WMSA were classified individually by the number and size of non-contiguous lesions, distribution, and contrast. Age-detrended lacunes, microbleeds, and enlarged perivascular space were quantified to further categorize individuals. Clinical and laboratory values were compared across the individual classes.

RESULTS

Class I was characterized by multiple, small, deep WMSA but a low burden of lacunes and microbleeds; class II had large periventricular WMSA and a high burden of lacunes and microbleeds; and class III had limited juxtaventricular WMSA and lacked lacunes and microbleeds. Class II was associated with older age, diabetes, and a relatively higher neutrophil-to-lymphocyte ratio. Smoking and higher uric acid levels were associated with an increased risk of class I.

CONCLUSION

The heterogeneity of SVD was categorized into three classes with distinct clinical correlates. This categorization will improve our understanding of SVD pathophysiology, risk stratification, and outcome prediction.

KEY POINTS

• Classification of white matter signal abnormality (WMSA) features was associated with different characteristic of lacunes, microbleeds, and enlarged perivascular space and clinical variability. • Class I was characterized by multiple, small, deep WMSA but a low burden of lacunes and microbleeds. Class II had large periventricular WMSA and a high burden of lacunes and microbleeds. Class III had limited juxtaventricular WMSA and lacked lacunes and microbleeds. • Class II was associated with older age, diabetes, and higher neutrophil-to-lymphocyte ratio. Smoking and higher uric acid levels were associated with an increased risk of class I.

Role of small acute hyperintense lesions in long-term progression of cerebral small vessel disease and clinical outcome: a 14-year follow-up study

BACKGROUND

Small hyperintense lesions are found on diffusion-weighted imaging (DWI) in patients with sporadic small vessel disease (SVD). Their exact role in SVD progression remains unclear due to their asymptomatic and transient nature. The main objective is to investigate the role of DWI+lesions in the radiological progression of SVD and their relationship with clinical outcomes.

METHODS

Participants with SVD were included from the Radboud University Nijmegen Diffusion tensor MRI Cohort. DWI+lesions were assessed on four time points over 14 years. Outcome measures included neuroimaging markers of SVD, cognitive performance and clinical outcomes, including stroke, all-cause dementia and all-cause mortality. Linear mixed-effect models and Cox regression models were used to examine the outcome measures in participants with a DWI+lesion (DWI+) and those without a DWI+lesion (DWI-).

RESULTS

DWI+lesions were present in 45 out of 503 (8.9%) participants (mean age: 66.7 years (SD=8.3)). Participants with DWI+lesions and at least one follow-up (n=33) had higher white matter hyperintensity progression rates (β=0.36, 95% CI=0.05 to 0.68, p=0.023), more incident lacunes (incidence rate ratio=2.88, 95% CI=1.80 to 4.67, p<0.001) and greater cognitive decline (β=-0.03, 95% CI=-0.05 to -0.01, p=0.006) during a median follow-up of 13.2 (IQR: 8.8-13.8) years compared with DWI- participants. No differences were found in risk of all-cause mortality, stroke or dementia.

CONCLUSION

Presence of a DWI+lesion in patients with SVD is associated with greater radiological progression of SVD and cognitive decline compared with patients without DWI+lesions.

Advanced MRI in cerebral small vessel disease

Cerebral small vessel disease (cSVD) is a major cause of stroke and dementia. This review summarizes recent developments in advanced neuroimaging of cSVD with a focus on clinical and research applications. In the first section, we highlight how advanced structural imaging techniques, including diffusion magnetic resonance imaging (MRI), enable improved detection of tissue damage, including characterization of tissue appearing normal on conventional MRI. These techniques enable progression to be monitored and may be useful as surrogate endpoint in clinical trials. Quantitative MRI, including iron and myelin imaging, provides insights into tissue composition on the molecular level. In the second section, we cover how advanced MRI techniques can demonstrate functional or dynamic abnormalities of the blood vessels, which could be targeted in mechanistic research and early-stage intervention trials. Such techniques include the use of dynamic contrast enhanced MRI to measure blood-brain barrier permeability, and MRI methods to assess cerebrovascular reactivity. In the third section, we discuss how the increased spatial resolution provided by ultrahigh field MRI at 7 T allows imaging of perforating arteries, and flow velocity and pulsatility within them. The advanced MRI techniques we describe are providing novel pathophysiological insights in cSVD and allow improved quantification of disease burden and progression. They have application in clinical trials, both in assessing novel therapeutic mechanisms, and as a sensitive endpoint to assess efficacy of interventions on parenchymal tissue damage. We also discuss challenges of these advanced techniques and suggest future directions for research.

Multi-Site Cross-Site Inter-Rater and Test-Retest Reliability and Construct Validity of the MarkVCID White Matter Hyperintensity Growth and Regression Protocol

BACKGROUND

White matter hyperintensities (WMH) that occur in the setting of vascular cognitive impairment and dementia (VCID) may be dynamic increasing or decreasing volumes or stable over time. Quantifying such changes may prove useful as a biomarker for clinical trials designed to address vascular cognitive-impairment and dementia and Alzheimer's Disease.

OBJECTIVE

Conducting multi-site cross-site inter-rater and test-retest reliability of the MarkVCID white matter hyperintensity growth and regression protocol.

METHODS

The NINDS-supported MarkVCID Consortium evaluated a neuroimaging biomarker developed to track WMH change. Test-retest and cross-site inter-rater reliability of the protocol were assessed. Cognitive test scores were analyzed in relation to WMH changes to explore its construct validity.

RESULTS

ICC values for test-retest reliability of WMH growth and regression were 0.969 and 0.937 respectively, while for cross-site inter-rater ICC values for WMH growth and regression were 0.995 and 0.990 respectively. Word list long-delay free-recall was negatively associated with WMH growth (p < 0.028) but was not associated with WMH regression.

CONCLUSIONS

The present data demonstrate robust ICC validity of a WMH growth/regression protocol over a one-year period as measured by cross-site inter-rater and test-retest reliability. These data suggest that this approach may serve an important role in clinical trials of disease-modifying agents for VCID that may preferentially affect WMH growth, stability, or regression.

Longitudinal Changes of White Matter Hyperintensities in Sporadic Small Vessel Disease: A Systematic Review and Meta-analysis

BACKGROUND AND OBJECTIVES

White matter hyperintensities (WMHs) are frequent imaging features of small vessel disease (SVD) and related to poor clinical outcomes. WMH progression over time is well described, but regression was also noted recently, although the frequency and associated factors are unknown. This systematic review and meta-analysis aims to assess longitudinal intraindividual WMH volume changes in sporadic SVD.

METHODS

We searched EMBASE and MEDLINE for articles up to 28 January 2022 on WMH volume changes using MRI on ≥2 time points in adults with sporadic SVD. We classified populations (healthy/community-dwelling, stroke, cognitive, other vascular risk factors, and depression) based on study characteristics. We performed random-effects meta-analyses with Knapp-Hartung adjustment to determine mean WMH volume change (change in milliliters, percentage of intracranial volume [%ICV], or milliliters per year), 95% CI, and prediction intervals (PIs, limits of increase and decrease) using unadjusted data. Risk of bias assessment tool for nonrandomized studies was used to assess risk of bias. We followed Preferred Reporting in Systematic Review and Meta-Analysis guidelines.

RESULTS

Forty-one articles, 12,284 participants, met the inclusion criteria. Thirteen articles had low risk of bias across all domains. Mean WMH volume increased over time by 1.74 mL (95% CI 1.23-2.26; PI -1.24 to 4.73 mL; 27 articles, N = 7,411, mean time interval 2.7 years, SD = 1.65); 0.25 %ICV (95% CI 0.14-0.36; PI -0.06 to 0.56; 6 articles, N = 1,071, mean time interval 3.5 years, SD = 1.54); or 0.58 mL/y (95% CI 0.35-0.81; PI -0.26 to 1.41; 8 articles, N = 3,802). In addition, 13 articles specifically mentioned and/or provided data on WMH regression, which occurred in asymptomatic, stroke, and cognitive disorders related to SVD.

DISCUSSION

Net mean WMH volume increases over time mask wide-ranging change (e.g., mean increase of 1.75 mL ranging from 1.25 mL decrease to 4.75 mL increase), with regression documented explicitly in up to one-third of participants. More knowledge on underlying mechanisms, associated factors, and clinical correlates is needed, as WMH regression could be an important intervention target.

Characterization of perivascular space pathology in a rat model of cerebral small vessel disease by in vivo magnetic resonance imaging

One of the most common causes of dementia is cerebral small vessel disease (SVD), which is associated with enlarged perivascular spaces (PVS). Clinically, PVS are visible as hyperintensities on T2-weighted (T2w) magnetic resonance images (MRI). While rodent SVD models exhibit arteriolosclerosis, PVS have not been robustly documented by MRI casting doubts on their clinical relevance. Here we established that the severity of SVD in spontaneously hypertensive stroke prone (SHRSP) rats correlated to 'moderate' SVD in human post-mortem tissue. We then developed two approaches for detecting PVS in SHRSP rats: 1) T2w imaging and 2) T1-weighted imaging with administration of gadoteric acid into cerebrospinal fluid. We applied the two protocols to six Wistar-Kyoto (WKY) control rats and thirteen SHRSP rats at ∼12 month of age. The primary endpoint was the number of hyperintense lesions. We found more hyperintensities on T2w MRI in the SHRSP compared to WKY rats (p-value = 0.023). CSF enhancement with gadoteric acid increased the visibility of PVS-like lesions in SHRSP rats. In some of the SHRSP rats, the MRI hyperintensities corresponded to enlarged PVS on histopathology. The finding of PVS-like hyperintensities on T2w MRI support the SHRSP rat's clinical relevance for studying the underlying pathophysiology of SVD.

Dietary oily fish intake and progression of diffuse subcortical damage of vascular origin: A longitudinal prospective study in community-dwelling older adults

INTRODUCTION

Oily fish intake may reduce the progression of white matter hyperintensities (WMH) of presumed vascular origin due to their high content of omega-3 polyunsaturated fatty acids and other nutrients. However, information on this relationship is limited. We aimed to assess the association between oily fish intake and WMH progression in older adults living in rural coastal Ecuador.

METHODS

Participants of the Atahualpa Project Cohort received baseline clinical interviews and brain MRIs. Oily fish intake was calculated at every annual door-to-door survey from enrollment to the end of the study. Individuals who also received a follow-up brain MRI were included. Poisson regression models were fitted to assess the incidence rate ratio (IRR) of WMH progression according to the amount of oily fish intake, after adjusting for demographics, level of education and traditional vascular risk factors.

RESULTS

The study included 263 individuals of Amerindian ancestry aged ⩾60 years (mean age: 65.7 ± 6.2 years; 57% women). The mean oily fish intake was 8.3 ± 4 servings per week. Follow-up MRIs demonstrated WMH progression in 103 (39%) individuals after a median follow-up of 6.5 years. A multivariate Poisson regression model showed an inverse relationship between oily fish intake and WMH progression (IRR: 0.89; 95% CI: 0.84-0.95; p < 0.001). A similar model also revealed an inverse relationship between tertiles of oily fish intake and probabilities of WMH progression, which became significant when individuals allocated to the third tertile were compared to those in the first and second tertiles.

CONCLUSION

Study results show an inverse relationship between the amount of oily fish intake and WMH progression in frequent fish consumers of Amerindian ancestry.

Superficial white matter microstructure affects processing speed in cerebral small vessel disease

White matter hyperintensities (WMH) are a typical feature of cerebral small vessel disease (CSVD), which contributes to about 50% of dementias worldwide. Microstructural alterations in deep white matter (DWM) have been widely examined in CSVD. However, little is known about abnormalities in superficial white matter (SWM) and their relevance for processing speed, the main cognitive deficit in CSVD. In 141 CSVD patients, processing speed was assessed using Trail Making Test Part A. White matter abnormalities were assessed by WMH burden (volume on T2-FLAIR) and diffusion MRI measures. SWM imaging measures had a large contribution to processing speed, despite a relatively low SWM WMH burden. Across all imaging measures, SWM free water (FW) had the strongest association with processing speed, followed by SWM mean diffusivity (MD). SWM FW was the only marker to significantly increase between two subgroups with the lowest WMH burdens. When comparing two subgroups with the highest WMH burdens, the involvement of WMH in the SWM was accompanied by significant differences in processing speed and white matter microstructure. Mediation analysis revealed that SWM FW fully mediated the association between WMH volume and processing speed, while no mediation effect of MD or DWM FW was observed. Overall, results suggest that the SWM has an important contribution to processing speed, while SWM FW is a sensitive imaging marker associated with cognition in CSVD. This study extends the current understanding of CSVD-related dysfunction and suggests that the SWM, as an understudied region, can be a potential target for monitoring pathophysiological processes.

Research Progress on MRI for White Matter Hyperintensity of Presumed Vascular Origin and Cognitive Impairment

White matter hyperintensity of presumed vascular origin (WMH) is a common medical imaging manifestation in the brains of middle-aged and elderly individuals. WMH can lead to cognitive decline and an increased risk of cognitive impairment and dementia. However, the pathogenesis of cognitive impairment in patients with WMH remains unclear. WMH increases the risk of cognitive impairment, the nature and severity of which depend on lesion volume and location and the patient's cognitive reserve. Abnormal changes in microstructure, cerebral blood flow, metabolites, and resting brain function are observed in patients with WMH with cognitive impairment. Magnetic resonance imaging (MRI) is an indispensable tool for detecting WMH, and novel MRI techniques have emerged as the key approaches for exploring WMH and cognitive impairment. This article provides an overview of the association between WMH and cognitive impairment and the application of dynamic contrast-enhanced MRI, structural MRI, diffusion tensor imaging, 3D-arterial spin labeling, intravoxel incoherent motion, magnetic resonance spectroscopy, and resting-state functional MRI for examining WMH and cognitive impairment.

Determinants and Temporal Dynamics of Cerebral Small Vessel Disease: 14-Year Follow-Up

BACKGROUND

The aim of this study is to investigate the temporal dynamics of small vessel disease (SVD) and the effect of vascular risk factors and baseline SVD burden on progression of SVD with 4 neuroimaging assessments over 14 years in patients with SVD.

METHODS

Five hundred three patients with sporadic SVD (50-85 years) from the ongoing prospective cohort study (RUN DMC [Radboud University Nijmegen Diffusion Tensor and Magnetic Resonance Cohort]) underwent baseline assessment in 2006 and follow-up in 2011, 2015, and 2020. Vascular risk factors and magnetic resonance imaging markers of SVD were evaluated. Linear mixed-effects model and negative binomial regression model were used to examine the determinants of temporal dynamics of SVD markers.

RESULTS

A total of 382 SVD patients (mean [SD] 64.1 [8.4]; 219 men and 163 women) who underwent at least 2 serial brain magnetic resonance imaging scans were included, with mean (SD) follow-up of 11.15 (3.32) years. We found a highly variable temporal course of SVD. Mean (SD) WMH progression rate was 0.6 (0.74) mL/y (range, 0.02-4.73 mL/y) and 13.6% of patients had incident lacunes (1.03%/y) over the 14-year follow-up. About 4% showed net WMH regression over 14 years, whereas 38 out of 361 (10.5%), 5 out of 296 (2%), and 61 out of 231 (26%) patients showed WMH regression for the intervals 2006 to 2011, 2011 to 2015, and 2015 to 2020, respectively. Of these, 29 (76%), 5 (100%), and 57 (93%) showed overall progression across the 14-year follow-up, and the net overall WMH change between first and last scan considering all participants was a net average WMH progression over the 14-year period. Older age was a strong predictor for faster WMH progression and incident lacunes. Patients with mild baseline WMH rarely progressed to severe WMH. In addition, both baseline burden of SVD lesions and vascular risk factors independently and synergistically predicted WMH progression, whereas only baseline SVD burden predicted incident lacunes over the 14-year follow-up.

CONCLUSIONS

SVD shows pronounced progression over time, but mild WMH rarely progresses to clinically severe WMH. WMH regression is noteworthy during some magnetic resonance imaging intervals, although it could be overall compensated by progression over the long follow-up.

High Social Risk Influence Progression of White Matter Hyperintensities of Presumed Vascular Origin: A Prospective Study in Community-Dwelling Older Adults

BACKGROUND

Information on cerebrovascular consequences of high social risk, as determined by the social determinants of health, is limited. We sought to evaluate the impact of high social risk on the progression of white matter hyperintensities (WMHs) of presumed vascular origin.

METHODS

Following a longitudinal prospective study design, participants of the Atahualpa Project Cohort received baseline social risk determinations by means of social determinants of health components included in the Gijon's Social-Familial Evaluation Scale together with clinical interviews and brain magnetic resonance imagings. Those who also received follow-up brain magnetic resonance imaging at the end of the study were included. We used Poisson regression models adjusted for demographics, education levels and traditional cardiovascular risk factors to assess the incidence rate ratio of WMH progression according to the Gijon's Social-Familial Evaluation Scale score.

RESULTS

The study included 263 individuals aged ≥60 years (mean age, 65.7±6.2 years; 57% women). The Gijon's Social-Familial Evaluation Scale mean score was 8.9±2.2 points. Follow-up magnetic resonance imagings revealed WMH progression in 103 (39%) individuals after a mean follow-up of 6.5 years (SD±1.4 years). Poisson regression models showed increased WMH progression rate among individuals in the third tertile of the Gijon's Social-Familial Evaluation Scale score compared with those in the first tertile (incidence rate ratio, 1.65 [95% CI, 1.05-2.61]; P=0.032). Separate Poisson regression models using individual social determinants of health components showed that poor social relationships (incidence rate ratio, 1.39 [95% CI, 1.10-1.77]; P=0.006) and deficient support networks (incidence rate ratio, 1.79 [95% CI, 1.19-2.69]; P=0.005) were independently associated with WMH progression, whereas family situation, economic status, and housing did not.

CONCLUSIONS

Poor social relationships and deficient support networks were significantly associated with WMH progression in community-dwelling older adults living in a rural setting. Our findings may help planning cost-effective preventive policies to reduce progression of cerebral small vessel disease among vulnerable populations.

Clinical Prediction Model for Screening Acute Ischemic Stroke Patients With More Than 10 Cerebral Microbleeds

Background

Hemorrhagic transformation is one of the most serious complications in intravenous thrombolysis. Studies show that the existence of more than 10 cerebral microbleeds is strongly associated with hemorrhagic transformation. The current study attempts to develop and validate a clinical prediction model of more than 10 cerebral microbleeds.

Methods

We reviewed the computed tomography markers of cerebral small vessel diseases and the basic clinical information of acute ischemic stroke patients who were investigated using susceptibility weighted imaging from 2018 to 2021. A clinical prediction model of more than 10 cerebral microbleeds was established. Discrimination, calibration, and the net benefit of the model were assessed. Finally, a validation was conducted to evaluate the accuracy and stability of the model.

Results

The multivariate logistic regression model showed hypertension, and some computed tomography markers (leukoaraiosis, lacunar infarctions, brain atrophy) were independent risk factors of more than 10 cerebral microbleeds. These risk factors were used for establishing the clinical prediction model. The area under the receiver operating characteristic curve (AUC) was 0.894 (95% CI: 0.870–0.919); Hosmer–Lemeshow chi-squared test yielded χ² = 3.946 (P = 0.862). The clinical decision cure of the model was higher than the two extreme lines. The simplified score of the model ranged from 0 to 12. The model in the internal and external validation cohort also had good discrimination (AUC 0.902, 95% CI: 0.868–0.937; AUC 0.914, 95% CI: 0.882–0.945) and calibration (P = 0.157, 0.247), and patients gained a net benefit from the model.

Conclusions

We developed and validated a simple scoring tool for acute ischemic stroke patients with more than 10 cerebral microbleeds; this tool may be beneficial for paradigm decision regarding intravenous recombinant tissue plasminogen activator therapy of acute ischemic stroke.

Development of cognition decline in non-acute symptomatic patients with cerebral small vessel disease: Non-Acute Symptomatic Cerebral Ischemia Registration study (NASCIR)-rationale and protocol for a prospective multicentre observational study

INTRODUCTION

Headaches, dizziness and memory loss of unspecific causes are the most common non-acute ischemia symptoms in the ageing population, which are often associated with cerebral small vessel disease (CSVD) imaging markers; however, there is insufficient evidence concerning their association with the development of cognitive decline. This study aims to investigate risk factors, clinical course, cerebral and retinal imaging changes, proteomics features of non-symptomatic ischaemia symptomatic patients with cognitive decline.

METHODS AND ANALYSIS

The Non-Acute Symptomatic Cerebral Ischemia Registration study is a multicentre, registry-based, prospective observational study, is designed to investigate the cognitive decline in non-acute ischaemia symptomatic patients. We will recruit 500 non-acute ischaemia symptomatic patients from four tertiary hospitals in China. For this study, non-acute ischaemia symptoms will be defined as headaches, dizziness and memory loss. Patients with headaches, dizziness or memory loss over 50 years of age will be included. Clinical features, cognitive assessment, cerebral and retinal imaging data, and a blood sample will be collected after recruitment. Patients will be followed up by structured telephone interviews at 1, 2, 3, 4, 5 years after recruitment. This study will improve our knowledge of the development of cognitive decline in non-acute ischaemia symptomatic patients and factors affecting the cognitive outcomes, which will eventually elucidate underlying pathways and mechanisms of cognitive decline in these patients and facilitate the optimisation of individualised interventions for its prevention and treatment.

ETHICS AND DISSEMINATION

Ethics approval is obtained from The Biomedical Research Ethics Committee of West China Hospital, Sichuan University (Reference No. 2016 (335)). We will present our findings at national and international conferences and peer-reviewed journals in stroke and neurology.

TRIAL REGISTRATION NUMBER

ChiCTR-COC-17013056.

Cerebral Vascular Dysfunctions Detected in Human Small Vessel Disease and Implications for Preclinical Studies

Cerebral small vessel disease (SVD) is highly prevalent and a common cause of ischemic and hemorrhagic stroke and dementia, yet the pathophysiology is poorly understood. Its clinical expression is highly varied, and prognostic implications are frequently overlooked in clinics; thus, treatment is currently confined to vascular risk factor management. Traditionally, SVD is considered the small vessel equivalent of large artery stroke (occlusion, rupture), but data emerging from human neuroimaging and genetic studies refute this, instead showing microvessel endothelial dysfunction impacting on cell-cell interactions and leading to brain damage. These dysfunctions reflect defects that appear to be inherited and secondary to environmental exposures, including vascular risk factors. Interrogation in preclinical models shows consistent and converging molecular and cellular interactions across the endothelial-glial-neural unit that increasingly explain the human macroscopic observations and identify common patterns of pathology despite different triggers. Importantly, these insights may offer new targets for therapeutic intervention focused on restoring endothelial-glial physiology.

Impact of Small Vessel Disease Progression on Long-term Cognitive and Functional Changes After Stroke

Background and Objectives

The severity of white matter hyperintensities (WMH) at presentation with stroke is associated with poststroke dementia and dependency. However, WMH can decrease or increase after stroke; prediction of cognitive decline is imprecise; and there are few data assessing longitudinal interrelationships among changing WMH, cognition, and function after stroke, despite the clinical importance.

Methods

We recruited patients within 3 months of a minor ischemic stroke, defined as NIH Stroke Scale (NIHSS) score <8 and not expected to result in a modified Rankin Scale (mRS) score >2. Participants repeated MRI at 1 year and cognitive and mRS assessments at 1 and 3 years. We ran longitudinal mixed-effects models assessing change in Addenbrooke’s Cognitive Examination–Revised (ACE-R) and mRS scores. For mRS score, we assessed longitudinal WMH volumes (cube root; percentage intracranial volume [ICV]), adjusting for age, NIHSS score, ACE-R, stroke subtype, and time to assessment. For ACE-R score, we additionally adjusted for ICV, mRS, premorbid IQ, and vascular risk factors. We then used a multivariate model to jointly assess changing cognition/mRS score, adjusted for prognostic variables, using all available data.

Results

We recruited 264 patients; mean age was 66.9 (SD 11.8) years; 41.7% were female; and median mRS score was 1 (interquartile range 1–2). One year after stroke, normalized WMH volumes were associated more strongly with 1-year ACE-R score (β = −0.259, 95% CI −0.407 to −0.111 more WMH per 1-point ACE-R decrease, p = 0.001) compared to subacute WMH volumes and ACE-R score (β = 0.105, 95% CI −0.265 to 0.054, p = 0.195). Three-year mRS score was associated with 3-year ACE-R score (β = −0.272, 95% CI −0.429 to −0.115, p = 0.001). Combined change in baseline-1-year jointly assessed ACE-R/mRS scores was associated with fluctuating WMH volumes (F = 9.3, p = 0.03).

Discussion

After stroke, fluctuating WMH mean that 1-year, but not baseline, WMH volumes are associated strongly with contemporaneous cognitive scores. Covarying longitudinal decline in cognition and independence after stroke, central to dementia diagnosis, is associated with increasing WMH volumes.

Effects of white matter hyperintensities distribution and clustering on late-life cognitive impairment

White matter hyperintensities (WMH) are a key hallmark of subclinical cerebrovascular disease and are known to impair cognition. Here, we parcellated WMH using a novel system that segments WMH based on both lobar regions and distance from the ventricles, dividing the brain into a coordinate system composed of 36 distinct parcels (‘bullseye’ parcellation), and then investigated the effect of distribution on cognition using two different analytic approaches. Data from a well characterized sample of healthy older adults (58 to 84 years) who were free of dementia were included. Cognition was evaluated using 12 computerized tasks, factored onto 4 indices representing episodic memory, speed of processing, fluid reasoning and vocabulary. We first assessed the distribution of WMH according to the bullseye parcellation and tested the relationship between WMH parcellations and performance across the four cognitive domains. Then, we used a data-driven approach to derive latent variables within the WMH distribution, and tested the relation between these latent components and cognitive function. We observed that different, well-defined cognitive constructs mapped to specific WMH distributions. Speed of processing was correlated with WMH in the frontal lobe, while in the case of episodic memory, the relationship was more ubiquitous, involving most of the parcellations. A principal components analysis revealed that the 36 bullseye regions factored onto 3 latent components representing the natural aggrupation of WMH: fronto-parietal periventricular (WMH principally in the frontal and parietal lobes and basal ganglia, especially in the periventricular region); occipital; and temporal and juxtacortical WMH (involving WMH in the temporal lobe, and at the juxtacortical region from frontal and parietal lobes). We found that fronto-parietal periventricular and temporal & juxtacortical WMH were independently associated with speed of processing and episodic memory, respectively. These results indicate that different cognitive impairment phenotypes might present with specific WMH distributions. Additionally, our study encourages future research to consider WMH classifications using parcellations systems other than periventricular and deep localizations.

Fixel based analysis of white matter alterations in early stage cerebral small vessel disease

Cerebral small vessel disease (CSVD) is a common cause of morbidity and cognitive decline in the elderly population. However, characterizing the disease pathophysiology and its association with potential clinical sequelae in early stages is less well explored. We applied fixel-based analysis (FBA), a novel framework of investigating microstructural white matter integrity by diffusion-weighted imaging, to data of 921 participants of the Hamburg City Health Study, comprising middle-aged individuals with increased cerebrovascular risk in early stages of CSVD. In individuals in the highest quartile of white matter hyperintensity loads (n = 232, median age 63 years; IQR 15.3 years), FBA detected significantly reduced axonal density and increased atrophy of transcallosal fiber tracts, the bilateral superior longitudinal fasciculus, and corticospinal tracts compared to participants in the lowest quartile of white matter hyperintensities (n = 228, mean age 55 years; IQR 10 years). Analysis of all participants (N = 921) demonstrated a significant association between reduced fiber density and worse executive functions operationalized by the Trail Making Test. Findings were confirmed by complementary analysis of diffusion tensor metrics.

Patterns of progression of cerebral small vessel disease markers in older adults of Amerindian ancestry: a population-based, longitudinal prospective cohort study

BACKGROUND

Progression of cerebral small vessel disease (cSVD) markers has been studied in different races/ethnic groups. However, information from individuals of Amerindian ancestry is lacking. We sought to evaluate progression patterns of cSVD markers in community-dwelling older adults of Amerindian ancestry.

METHODS

Following a longitudinal prospective study design, participants of the Atahualpa Project Cohort aged ≥ 60 years received a baseline brain MRI and clinical interviews. Those who also received a brain MRI at the end of the study were included. Poisson regression models were fitted to assess cSVD markers progression according to their baseline load after a median follow-up of 6.5 ± 1.4 years. Logistic regression models were fitted to assess interrelations in the progression of the different cSVD markers at the end of the study.

RESULTS

The study included 263 individuals (mean age: 65.7 ± 6.2 years). Progression of white matter hyperintensities (WMH) was noticed in 103 (39%) subjects, cerebral microbleeds in 25 (12%), lacunes in 12 (5%), and enlarged basal ganglia-perivascular spaces (BG-PVS) in 56 (21%). Bivariate Poisson regression models showed significant associations between WMH severity at baseline and progression of WMH and enlarged BG-PVS. These associations became non-significant in multivariate models adjusted for clinical covariates. Logistic regression models showed interrelated progressions of WMH, cerebral microbleeds and enlarged BG-PVS. The progression of lacunes was independent.

CONCLUSIONS

Patterns of cSVD marker progression in this population of Amerindians are different than those reported in other races/ethnic groups. The independent progression of lacunes suggests different pathogenic mechanisms with other cSVD markers.

Prediction of dementia using diffusion tensor MRI measures: the OPTIMAL collaboration

OBJECTIVES

It has been suggested that diffusion tensor imaging (DTI) measures sensitive to white matter (WM) damage may predict future dementia risk not only in cerebral small vessel disease (SVD), but also in mild cognitive impairment. To determine whether DTI measures were associated with cognition cross-sectionally and predicted future dementia risk across the full range of SVD severity, we established the International OPtimising mulTImodal MRI markers for use as surrogate markers in trials of Vascular Cognitive Impairment due to cerebrAl small vesseL disease collaboration which included six cohorts.

METHODS

Among the six cohorts, prospective data with dementia incidences were available for three cohorts. The associations between six different DTI measures and cognition or dementia conversion were tested. The additional contribution to prediction of other MRI markers of SVD was also determined.

RESULTS

The DTI measure mean diffusivity (MD) median correlated with cognition in all cohorts, demonstrating the contribution of WM damage to cognition. Adding MD median significantly improved the model fit compared to the clinical risk model alone and further increased in all single-centre SVD cohorts when adding conventional MRI measures. Baseline MD median predicted dementia conversion. In a study with severe SVD (SCANS) change in MD median also predicted dementia conversion. The area under the curve was best when employing a multimodal MRI model using both DTI measures and other MRI measures.

CONCLUSIONS

Our results support a central role for WM alterations in dementia pathogenesis in all cohorts. DTI measures such as MD median may be a useful clinical risk predictor. The contribution of other MRI markers varied according to disease severity.

Personality Impact on Alzheimer's Disease-Signature and Vascular Imaging Markers: A PET-MRI Study

BACKGROUND

Several studies postulated that personality is an independent determinant of cognitive trajectories in old age.

OBJECTIVE

This study explores the impact of personality on widely used Alzheimer's disease (AD) and vascular imaging markers.

METHODS

We examined the association between personality and three classical AD imaging markers (centiloid-based-amyloid load, MRI volumetry in hippocampus, and media temporal lobe atrophy), and two vascular MRI parameters (Fazekas score and number of cortical microbleeds) assessed at baseline and upon a 54-month-follow-up. Personality was assessed with the Neuroticism Extraversion Openness Personality Inventory-Revised. Regression models were used to identify predictors of imaging markers including sex, personality factors, presence of APOE ɛ4 allele and cognitive evolution over time.

RESULTS

Cortical GM volumes were negatively associated with higher levels of Conscientiousness both at baseline and follow-up. In contrast, higher scores of Openness were related to better preservation of left hippocampal volumes in these two time points and negatively associated with medial temporal atrophy at baseline. Amyloid load was not affected by personality factors. Cases with higher Extraversion scores displayed higher numbers of cortical microbleeds at baseline.

CONCLUSION

Personality impact on brain morphometry is detected only in some among the routinely used imaging markers. The most robust associations concern the positive role of high levels of Conscientiousness and Openness on AD-signature MRI markers. Higher extraversion levels are associated with increased vulnerability to cortical microbleeds pointing to the fact that the socially favorable traits may have a detrimental effect on brain integrity in old age.

Risk factors of cerebral small vessel disease: A systematic review and meta-analysis

BACKGROUND

Cerebral small vessel disease (CSVD) is a common neurological disease under the effect of multiple factors. Although some literature analyzes and summarizes the risk factors of CSVD, the conclusions are controversial. To determine the risk factors of CSVD, we conducted this meta-analysis.

METHODS

Five authoritative databases of PubMed, Embase, Cochrane Library, CNKI, and Wan Fang were searched to find related studies published before November 30, 2020. The literature was screened according to the inclusion and exclusion criteria. We used RevMan 5.4 software to analyze the data after extraction.

RESULTS

A total of 29 studies involving 16,587 participants were included. The meta-analysis showed that hypertension (odds ratio [OR] 3.16, 95% confidence interval [CI] 2.22-4.49), diabetes (OR 2.15, 95% CI 1.59-2.90), hyperlipidemia (OR 1.64, 95% CI 1.11-2.40), smoking (OR 1.47, 95% CI 1.15-1.89) were significantly related to the risk of lacune, while drinking (OR 1.03, 95% CI 0.87-1.23) was not. And hypertension (OR 3.31, 95% CI 2.65-4.14), diabetes (OR 1.66, 95% CI 2.65-1.84), hyperlipidemia (OR 1.88, 95% CI 1.08-3.25), smoking (OR 1.48, 95% CI 1.07-2.04) were significantly related to the risk of white matter hyperintensity, while drinking (OR 1.41, 95% CI 0.97-2.05) was not.

CONCLUSIONS

This study suggested that hypertension, diabetes, hyperlipidemia, and smoking are risk factors of CSVD, and we should take measures to control these risk factors for the purpose of preventing CSVD.

Rate of, and risk factors for, white matter hyperintensity growth: a systematic review and meta-analysis with implications for clinical trial design

BACKGROUND

White matter hyperintensities (WMHs) are a highly prevalent MRI marker of cerebral small vessel disease (SVD), which predict stroke and dementia risk, and are being increasingly used as a surrogate marker in clinical trials. However, the influence of study population selection on WMH progression rate has not been studied and the effect of individual patient factors for WMH growth are not fully understood.

METHODS

We performed a systematic review and meta-analysis of the literature on progression of WMHs in longitudinal studies to determine rates of WMH growth, and how these varied according to population characteristics and cardiovascular risk factors. We used these data to calculate necessary sample sizes for clinical trials using WMH as an endpoint.

RESULTS

WMH growth rate was highest in SVD (2.50cc/year), intermediate in unselected stroke patients (1.29cc/year) and lower in patients with non-stroke cardiovascular disease, and with cognitive impairment. Age was significantly associated with progression (correlation coefficient 0.15cc/year, 95% CI 0.02 to 0.28cc/year) as was baseline lesion volume (0.6cc/year, 95% CI 0.13 to 1.06 cc/year). Both hypertension (OR 1.72, 95% CI 1.19 to 2.46) and current smoking (OR 1.48, 95% CI 1.02 to 2.16) were associated with WMH growth. Sample sizes for a clinical trial varied greatly with patient population selection and baseline lesion volume; estimates are provided.

CONCLUSIONS

WMH progression varies markedly according to the characteristics of the population being studied and this will have a major impact on sample sizes required in a clinical trial. Our sample size estimates provide data for planning clinical trials using WMH as an outcome measure.

PROSPERO REGISTRATION NUMBER

CRD42020191781.

Diffusion MRI harmonization enables joint-analysis of multicentre data of patients with cerebral small vessel disease

OBJECTIVES

Acquisition-related differences in diffusion magnetic resonance imaging (dMRI) hamper pooling of multicentre data to achieve large sample sizes. A promising solution is to harmonize the raw diffusion signal using rotation invariant spherical harmonic (RISH) features, but this has not been tested in elderly subjects. Here we aimed to establish if RISH harmonization effectively removes acquisition-related differences in multicentre dMRI of elderly subjects with cerebral small vessel disease (SVD), while preserving sensitivity to disease effects.

METHODS

Five cohorts of patients with SVD (N = 397) and elderly controls (N = 175) with 3 Tesla MRI on different systems were included. First, to establish effectiveness of harmonization, the RISH method was trained with data of 13 to 15 age and sex-matched controls from each site. Fractional anisotropy (FA) and mean diffusivity (MD) were compared in matched controls between sites using tract-based spatial statistics (TBSS) and voxel-wise analysis, before and after harmonization. Second, to assess sensitivity to disease effects, we examined whether the contrast (effect sizes of FA, MD and peak width of skeletonized MD - PSMD) between patients and controls within each site remained unaffected by harmonization. Finally, we evaluated the association between white matter hyperintensity (WMH) burden, FA, MD and PSMD using linear regression analyses both within individual cohorts as well as with pooled scans from multiple sites, before and after harmonization.

RESULTS

Before harmonization, significant differences in FA and MD were observed between matched controls of different sites (p < 0.05). After harmonization these site-differences were removed. Within each site, RISH harmonization did not alter the effect sizes of FA, MD and PSMD between patients and controls (relative change in Cohen's d = 4 %) nor the strength of association with WMH volume (relative change in R2 = 2.8 %). After harmonization, patient data of all sites could be aggregated in a single analysis to infer the association between WMH volume and FA (R2 = 0.62), MD (R2 = 0.64), and PSMD (R2 = 0.60).

CONCLUSIONS

We showed that RISH harmonization effectively removes acquisition-related differences in dMRI of elderly subjects while preserving sensitivity to SVD-related effects. This study provides proof of concept for future multicentre SVD studies with pooled datasets.

Differences in cerebral small vessel disease magnetic resonance imaging markers between lacunar stroke and non-Lobar intracerebral hemorrhage

Introduction

It is unclear why cerebral small vessel disease (SVD) leads to lacunar stroke in some and to non–lobar intracerebral hemorrhage (ICH) in others. We investigated differences in MRI markers of SVD in patients with lacunar stroke or non–lobar ICH.

Patients and methods

We included patients from two prospective cohort studies with either lacunar stroke (RUN DMC) or non–lobar ICH (FETCH). Differences in SVD markers (white matter hyperintensities [WMH], lacunes, cerebral microbleeds [CMB]) between groups were investigated with univariable tests; multivariable logistic regression analysis, adjusted for age, sex, and vascular risk factors; spatial correlation analysis and voxel–wise lesion symptom mapping.

Results

We included 82 patients with lacunar stroke (median age 63, IQR 57–72) and 54 with non-lobar ICH (66, 59–75). WMH volumes and distribution were not different between groups. Lacunes were more frequent in patients with a lacunar stroke (44% vs. 17%, adjusted odds ratio [aOR] 5.69, 95% CI [1.66–22.75]) compared to patients with a non–lobar ICH. CMB were more frequent in patients with a non–lobar ICH (71% vs. 23%, aOR for lacunar stroke vs non–lobar ICH 0.08 95% CI [0.02–0.26]), and more often located in non–lobar regions compared to CMB in lacunar stroke.

Discussion

Although we obserd different types of MRI markers of SVD within the same patient, ischemic markers of SVD were more frequent in the ischemic type of lacunar stroke, and hemorrhagic markers were more prevalent in the hemorrhagic phenotype of non-lobar ICH.

Conclusion

There are differences between MRI markers of SVD between patients with a lacunar stroke and those with a non-lobar ICH.

Longitudinal relation between structural network efficiency, cognition, and gait in cerebral small vessel disease

Background

To investigate changes in gait performance over time and how these changes are associated with the decline in structural network efficiency and cognition in older patients with cerebral small vessel disease (SVD).

Methods

In a prospective, single-center cohort with 217 older participants with SVD, we performed 1.5T MRI scans, cognitive tests, and gait assessments evaluated by Timed UP and Go (TUG) test twice over 4 years. We reconstructed the white matter network for each subject based on diffusion tensor imaging tractography, followed by graph-theoretical analyses to compute the global efficiency. Conventional MRI markers for SVD, that is, white matter hyperintensity (WMH) volume, number of lacunes, and microbleeds, were assessed.

Results

Baseline global efficiency was not related to changes in gait performance, while decline in global efficiency over time was significantly associated with gait decline (ie, increase in TUG time), independent of conventional MRI markers for SVD. Neither baseline cognitive performance nor cognitive decline was associated with gait decline.

Conclusions

We found that disruption of the white matter structural network was associated with gait decline over time, while the effect of cognitive decline was not. This suggests that structural network disruption has an important role in explaining the pathophysiology of gait decline in older patients with SVD, independent of cognitive decline.

Development of a protocol to assess within-subject, regional white matter hyperintensity changes in aging and dementia

BACKGROUND

White matter hyperintensities (WMH), associated with both dementia risk and progression, can individually progress, remain stable, or even regress influencing cognitive decline related to specific cerebrovascular-risks. This study details the development and validation of a registration protocol to assess regional, within-subject, longitudinal WMH changes (ΔWMH) that is currently lacking in the field.

NEW METHOD

3D-FLAIR images (baseline and one-year-visit) were used for protocol development and validation. The method was validated by assessing the correlation between forward and reverse longitudinal registration, and between summated regional progression-regression volumes and Global ΔWMH. The clinical relevance of growth-regression ΔWMH were explored in relation to an executive function test.

RESULTS

MRI scans for 79 participants (73.5 ± 8.8 years) were used in this study. Global ΔWMH vs. summated regional progression-regression volumes were highly associated (r2 = 0.90; p-value < 0.001). Bi-directional registration validated the registration method (r2 = 0.999; p-value < 0.001). Growth and regression, but not overall ΔWMH, were associated with one-year declines in performance on Trial-Making-Test-B.

COMPARISON WITH EXISTING METHOD(S)

This method presents a unique registration protocol for maximum tissue alignment, demonstrating three distinct patterns of longitudinal within-subject ΔWMH (stable, growth and regression).

CONCLUSIONS

These data detail the development and validation of a registration protocol for use in assessing within-subject, voxel-level alterations in WMH volume. The methods developed for registration and intensity correction of longitudinal within-subject FLAIR images allow regional and within-lesion characterization of longitudinal ΔWMH. Assessing the impact of associated cerebrovascular-risks and longitudinal clinical changes in relation to dynamic regional ΔWMH is needed in future studies.

ESO Guideline on covert cerebral small vessel disease

'Covert' cerebral small vessel disease (ccSVD) is common on neuroimaging in persons without overt neurological manifestations, and increases the risk of future stroke, cognitive impairment, dependency, and death. These European Stroke Organisation (ESO) guidelines provide evidence-based recommendations to assist with clinical decisions about management of ccSVD, specifically white matter hyperintensities and lacunes, to prevent adverse clinical outcomes. The guidelines were developed according to ESO standard operating procedures and Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) methodology. We prioritised the clinical outcomes of stroke, cognitive decline or dementia, dependency, death, mobility and mood disorders, and interventions of blood pressure lowering, antiplatelet drugs, lipid lowering, lifestyle modifications, glucose lowering and conventional treatments for dementia. We systematically reviewed the literature, assessed the evidence, formulated evidence-based recommendations where feasible, and expert consensus statements. We found little direct evidence, mostly of low quality. We recommend patients with ccSVD and hypertension to have their blood pressure well controlled; lower blood pressure targets may reduce ccSVD progression. We do not recommend antiplatelet drugs such as aspirin in ccSVD. We found little evidence on lipid lowering in ccSVD. Smoking cessation is a health priority. We recommend regular exercise which may benefit cognition, and a healthy diet, good sleep habits, avoiding obesity and stress for general health reasons. In ccSVD, we found no evidence for glucose control in the absence of diabetes or for conventional Alzheimer dementia treatments. Randomised controlled trials with clinical endpoints are a priority for ccSVD.

Correlations in post-mortem imaging-histopathology studies of sporadic human cerebral small vessel disease: A systematic review

AIMS

Sporadic human cerebral small vessel disease (SVD) commonly causes stroke and dementia but its pathogenesis is poorly understood. There are recognised neuroimaging and histopathological features. However, relatively few studies have examined the relationship between the radiological and pathological correlates of SVD; better correlation would promote greater insight into the underlying biological changes.

METHODS

We performed a systematic review to collate and appraise the information derived from studies that correlated histological with neuroimaging-defined SVD lesions. We searched for studies describing post-mortem imaging and histological tissue examination in adults, extracted data from published studies, categorised the information and compiled this narrative.

RESULTS

We identified 38 relevant studies, including at least 1146 subjects, 342 of these with SVD: 29 studies focussed on neuroradiological white matter lesions (WML), six on microinfarcts and three on dilated perivascular spaces (PVS) and lacunes. The histopathology terminology was diverse with few robust definitions. Reporting and methodology varied widely between studies, precluding formal meta-analysis. PVS and 'oedema' were frequent findings in WML, being described in at least 94 and 18 radiological WML, respectively, in addition to myelin pallor. Histopathological changes extended beyond the radiological lesion margins in at least 33 radiological WML. At least 43 radiological lesions not seen pathologically and at least 178 histological lesions were not identified on imaging.

CONCLUSIONS

Histopathological assessment of human SVD is hindered by inconsistent methodological approaches and unstandardised definitions. The data from this systematic review will help to develop standardised definitions to promote consistency in human SVD research.

Cognition mediates the relation between structural network efficiency and gait in small vessel disease

Cerebral small vessel disease (SVD), including white matter hyperintensities (WMH), microbleeds, lacunes, was related to gait disturbances, while the underlying mechanism is unclear. Here, we investigated the relation between structural network efficiency, cognition and gait performance in 272 elderly subjects with SVD. All participants underwent 1.5 T MRI, gait and neuropsychological assessment. Conventional MRI markers for SVD, i.e. WMH volume, number of lacunes and microbleeds, were assessed. Diffusion tensor imaging-based tractography was used to reconstruct the brain network for each individual, followed by graph-theoretical analyses to compute the well-established network measure, global efficiency. We found that lower global efficiency was associated with worse gait performance, including slower gait speed and shorter stride length, independent of conventional MRI markers for SVD. This association was partly mediated via cognitive function. We identified subnetworks of white matter connections associated with gait and cognition, characterized by dominant involvement of frontal tracts. Our findings suggest that network disruption is associated with gait disturbances through cognitive dysfunction in elderly with SVD. Gait is a highly cognitive process and the crucial role of cognition should be considered when investigating gait disturbances in the elderly with SVD.

Lacunar Stroke Lesion Extent and Location and White Matter Hyperintensities Evolution 1 Year Post-lacunar Stroke

Lacunar strokes are a common type of ischemic stroke. They are associated with long-term disability, but the factors affecting the dynamic of the infarcted lesion and the brain imaging features associated with them, reflective of small vessel disease (SVD) severity, are still largely unknown. We investigated whether the distribution, volume and 1-year evolution of white matter hyperintensities (WMH), one of these SVD features, relate to the extent and location of these infarcts, accounting for vascular risk factors. We used imaging and clinical data from all patients [n = 118, mean age 64.9 (SD 11.75) years old] who presented to a regional hospital with a lacunar stroke syndrome within the years 2010 and 2013 and consented to participate in a study of stroke mechanisms. All patients had a brain MRI scan at presentation, and 88 had another scan 12 months after. Acute lesions (i.e., recent small subcortical infarcts, RSSI) were identified in 79 patients and lacunes in 77. Number of lacunes was associated with baseline WMH volume (B = 0.370, SE = 0.0939, P = 0.000174). RSSI volume was not associated with baseline WMH volume (B = 3.250, SE = 2.117, P = 0.129), but predicted WMH volume change (B = 2.944, SE = 0.913, P = 0.00184). RSSI location was associated with the spatial distribution of WMH and the pattern of 1-year WMH evolution. Patients with the RSSI in the centrum semiovale (n = 33) had significantly higher baseline volumes of WMH, recent and old infarcts, than patients with the RSSI located elsewhere [median 33.69, IQR (14.37 50.87) ml, 0.001 ≤ P ≤ 0.044]. But patients with the RSSI in the internal/external capsule/lentiform nucleus experienced higher increase of WMH volume after a year [n = 21, median (IQR) from 18 (11.70 31.54) ml to 27.41 (15.84 40.45) ml]. Voxel-wise analyses of WMH distribution in patients grouped per RSSI location revealed group differences increased in the presence of vascular risk factors, especially hypertension and recent or current smoking habit. In our sample of patients presenting to the clinic with lacunar strokes, lacunar strokes extent influenced WMH volume fate; and RSSI location and WMH spatial distribution and dynamics were intertwined, with differential patterns emerging in the presence of vascular risk factors. These results, if confirmed in wider samples, open potential avenues in stroke rehabilitation to be explored further.

Orthostatic hypotension is not associated with small vessel disease progression or cognitive decline

INTRODUCTION

Cerebral hypoperfusion is thought to play an important role in the etiology of cerebral small vessel disease (SVD). Orthostatic hypotension (OH) is assumed to be a cause of cerebral hypoperfusion by causing recurrent hypoperfusion episodes, and might thus be related to progression of SVD. Here, we investigated whether presence of OH is associated with the progression of SVD MRI-markers and cognitive decline over a time period of 9 years in a cohort of sporadic SVD patients.

METHODS

This study included SVD patients from the RUN DMC study, a prospective longitudinal single-center cohort study. In total, 503 patients were included at baseline (2006), from whom 351 participated at first follow-up (2011), and 293 at second follow-up (2015). During all visits, patients underwent MRI and cognitive testing. Association between presence of OH at baseline and progression of SVD-markers on MRI and cognitive decline over time was estimated using linear mixed-effects models.

RESULTS

Of the 503 patients who participated at baseline, 46 patients (9.1%) had OH. Cross-sectional analysis of the baseline data showed that OH was associated with higher white matter hyperintensity (WMH) volume (β = 0.18, p = 0.03), higher mean diffusivity (MD; β = 0.02, p = 0.002), and with presence of microbleeds (OR 2.37 95% CI 1.16-4.68). Longitudinally, OH was however not associated with a progression of total WMH volume (β = -0.17, p = 0.96) or with higher MD (β = -0.001, p = 0.49). There was no association between OH and cognitive performance, both at baseline and over time.

CONCLUSION

In this longitudinal observational study, there was no evidence that presence of OH is associated with progression of SVD-markers or cognitive decline over time. Our findings indicate that OH may not be causally related to SVD progression over time.

Clinical management of cerebral small vessel disease: a call for a holistic approach

ABSTRACT

Cerebral small vessel disease (SVD) is a common global brain disease that causes cognitive impairment, ischemic or hemorrhagic stroke, problems with mobility, and neuropsychiatric symptoms. The brain damage, seen as focal white and deep grey matter lesions on brain magnetic resonance imaging (MRI) or computed tomography (CT), typically accumulates "covertly" and may reach an advanced state before being detected incidentally on brain scanning or causing symptoms. Patients have typically presented to different clinical services or been recruited into research focused on one clinical manifestation, perhaps explaining a lack of awareness, until recently, of the full range and complexity of SVD.In this review, we discuss the varied clinical presentations, established and emerging risk factors, relationship to SVD features on MRI or CT, and the current state of knowledge on the effectiveness of a wide range of pharmacological and lifestyle interventions. The core message is that effective assessment and clinical management of patients with SVD, as well as future advances in diagnosis, care, and treatment, will require a more "joined-up"' approach. This approach should integrate clinical expertise in stroke neurology, cognitive, and physical dysfunctions. It requires more clinical trials in order to improve pharmacological interventions, lifestyle and dietary modifications. A deeper understanding of the pathophysiology of SVD is required to steer the identification of novel interventions. An essential prerequisite to accelerating clinical trials is to improve the consistency, and standardization of clinical, cognitive and neuroimaging endpoints.

Serum Neurofilament Light Chain Is Associated with Incident Lacunes in Progressive Cerebral Small Vessel Disease

Background and Purpose

Serum neurofilament light (NfL)-chain is a circulating marker for neuroaxonal injury and is also associated with severity of cerebral small vessel disease (SVD) cross-sectionally. Here we explored the association of serum-NfL with imaging and cognitive measures in SVD longitudinally.

Methods

From 503 subjects with SVD, baseline and follow-up magnetic resonance imaging (MRI) was available for 264 participants (follow-up 8.7±0.2 years). Baseline serum-NfL was measured by an ultrasensitive single-molecule-assay. SVD-MRI-markers including white matter hyperintensity (WMH)-volume, mean diffusivity (MD), lacunes, and microbleeds were assessed at both timepoints. Cognitive testing was performed in 336 participants, including SVD-related domains as well as global cognition and memory. Associations with NfL were assessed using linear regression analyses and analysis of covariance (ANCOVA).

Results

Serum-NfL was associated with baseline WMH-volume, MD-values and presence of lacunes and microbleeds. SVD-related MRI- and cognitive measures showed progression during follow-up. NfL-levels were associated with future MRI-markers of SVD, including WMH, MD and lacunes. For the latter, this association was independent of baseline lacunes. Furthermore, NfL was associated with incident lacunes during follow-up (P=0.040). NfL-levels were associated with future SVD-related cognitive impairment (processing speed: β=–0.159; 95% confidence interval [CI], –0.242 to –0.068; P=0.001; executive function β=–0.095; 95% CI, –0.170 to –0.007; P=0.033), adjusted for age, sex, education, and depression. Dementia-risk increased with higher NfL-levels (hazard ratio, 5.0; 95% CI, 2.6 to 9.4; P<0.001), however not after adjusting for age.

Conclusions

Longitudinally, serum-NfL is associated with markers of SVD, especially with incident lacunes, and future cognitive impairment affecting various domains. NfL may potentially serve as an additional marker for disease monitoring and outcome in SVD, potentially capturing both vascular and neurodegenerative processes in the elderly.

Cardiorespiratory fitness diminishes the effects of age on white matter hyperintensity volume

White matter hyperintensities (WMHs) are among the most commonly observed marker of cerebrovascular disease. Age is a key risk factor for WMH development. Cardiorespiratory fitness (CRF) is associated with increased vessel compliance, but it remains unknown if high CRF affects WMH volume. This study explored the effects of CRF on WMH volume in community-dwelling older adults. We further tested the possibility of an interaction between CRF and age on WMH volume. Participants were 76 adults between the ages of 59 and 77 (mean age = 65.36 years, SD = 3.92) who underwent a maximal graded exercise test and structural brain imaging. Results indicated that age was a predictor of WMH volume (beta = .32, p = .015). However, an age-by-CRF interaction was observed such that higher CRF was associated with lower WMH volume in older participants (beta = -.25, p = .040). Our findings suggest that higher levels of aerobic fitness may protect cerebrovascular health in older adults.