Small vessel disease: mechanisms and clinical implications

Visit-to-visit blood pressure variability and progression of white matter hyperintensities over 14 years

Purpose: There is evidence that blood pressure variability (BPV) is associated with cerebral small vessel disease (SVD) and may therefore increase the risk of stroke and dementia. It remains unclear if BPV is associated with SVD progression over years. We examined whether visit-to-visit BPV is associated with white matter hyperintensity (WMH) progression over 14 years and MRI markers after 14 years.

Materials and methods: We included participants with SVD from the Radboud University Nijmegen Diffusion tensor Magnetic resonance-imaging Cohort (RUNDMC) who underwent baseline assessment in 2006 and follow-up in 2011, 2015 and 2020. BPV was calculated as coefficient of variation (CV) of BP at all visits. Association between WMH progression rates over 14 years and BPV was examined using linear-mixed effects (LME) model. Regression models were used to examine association between BPV and MRI markers at final visit in participants.

Results: A total of 199 participants (60.5 SD 6.6 years) who underwent four MRI scans and BP measurements were included, with mean follow-up of 13.7 (SD 0.5) years. Systolic BPV was associated with higher progression of WMH (β = 0.013, 95% CI 0.005 - 0.022) and higher risk of incident lacunes (OR: 1.10, 95% CI 1.01-1.21). There was no association between systolic BPV and grey and white matter volumes, Peak Skeleton of Mean Diffusivity (PSMD) or microbleed count after 13.7 years.

Conclusions: Visit-to-visit systolic BPV is associated with increased progression of WMH volumes and higher risk of incident lacunes over 14 years in participants with SVD. Future studies are needed to examine causality of this association.

Association of longitudinal changes in 24-h blood pressure level and variability with cognitive decline

OBJECTIVE

A high office blood pressure (BP) is associated with cognitive decline. However, evidence of 24-h ambulatory BP monitoring is limited, and no studies have investigated whether longitudinal changes in 24-h BP are associated with cognitive decline. We aimed to test whether higher longitudinal changes in 24-h ambulatory BP measurements are associated with cognitive decline.

METHODS

We included 437 dementia-free participants from the Maracaibo Aging Study with prospective data on 24-h ambulatory BP monitoring and cognitive function, which was assessed using the selective reminding test (SRT) and the Mini-Mental State Examination (MMSE). Using multivariate linear mixed regression models, we analyzed the association between longitudinal changes in measures of 24-h ambulatory BP levels and variability with cognitive decline.

RESULTS

Over a median follow-up of 4 years (interquartile range, 2-5 years), longitudinal changes in 24-h BP level were not associated with cognitive function ( P  ≥ 0.09). Higher longitudinal changes in 24-h and daytime BP variability were related to a decline in SRT-delayed recall score; the adjusted scores lowered from -0.10 points [95% confidence interval (CI), -0.16 to -0.04) to -0.07 points (95% CI, -0.13 to -0.02). We observed that a higher nighttime BP variability during follow-up was associated with a decline in the MMSE score (adjusted score lowered from -0.08 to -0.06 points).

CONCLUSION

Higher 24-h BP variability, but not BP level, was associated with cognitive decline. Prior to or in the early stages of cognitive decline, 24-h ambulatory BP monitoring might guide strategies to reduce the risk of major dementia-related disorders including Alzheimer's disease.

Systemic determinants of brain health in ageing

Preservation of brain health is a worldwide priority. The traditional view is that the major threats to the ageing brain lie within the brain itself. Consequently, therapeutic approaches have focused on protecting the brain from these presumably intrinsic pathogenic processes. However, an increasing body of evidence has unveiled a previously under-recognized contribution of peripheral organs to brain dysfunction and damage. Thus, in addition to the well-known impact of diseases of the heart and endocrine glands on the brain, accumulating data suggest that dysfunction of other organs, such as gut, liver, kidney and lung, substantially affects the development and clinical manifestation of age-related brain pathologies. In this Review, a framework is provided to indicate how organ dysfunction can alter brain homeostasis and promote neurodegeneration, with a focus on dementia. We delineate the associations of subclinical dysfunction in specific organs with dementia risk and provide suggestions for public health promotion and clinical management.

Computational imaging for rapid detection of grade-I cerebral small vessel disease (cSVD)

An early identification and subsequent management of cerebral small vessel disease (cSVD) grade 1 can delay progression into grades II and III. Machine learning algorithms have shown considerable promise in medical image interpretation automation. An experimental cross-sectional study aimed to develop an automated computer-aided diagnostic system based on AI (artificial intelligence) tools to detect grade 1-cSVD with improved accuracy. Patients with Fazekas grade 1 cSVD on Non-Contrast Magnetic Resonance Imaging (MRI) Brain of age >40 years of both genders were included. The dataset was pre-processed to be fed into a 3D convolutional neural network (CNN) model. A 3D stack with the shape (120, 128, 128, 1) containing axial slices from the brain magnetic resonance image was created. The model was created from scratch and contained four convolutional and three fully connected (FC) layers. The dataset was preprocessed by making a 3D stack, and normalizing, resizing, and completing the stack was performed. A 3D-CNN model architecture was designed to train and test preprocessed images. We achieved an accuracy of 93.12 % when 2D axial slices were used. When the 2D slices of a patient were stacked to form a 3D image, an accuracy of 85.71 % was achieved on the test set. Overall, the 3D-CNN model performed very well on the test set. The earliest and the most accurate diagnosis from computational imaging methods can help reduce the huge burden of cSVD and its associated morbidity in the form of vascular dementia.

Vascular Pathogenesis in Acute and Long COVID: Current Insights and Therapeutic Outlook

Long coronavirus disease 2019 (COVID-19)-a postacute consequence of severe acute respiratory syndrome coronavirus 2 infection-manifests with a broad spectrum of relapsing and remitting or persistent symptoms as well as varied levels of organ damage, which may be asymptomatic or present as acute events such as heart attacks or strokes and recurrent infections, hinting at complex underlying pathogenic mechanisms. Central to these symptoms is vascular dysfunction rooted in thrombotic endothelialitis. We review the scientific evidence that widespread endothelial dysfunction (ED) leads to chronic symptomatology. We briefly examine the molecular pathways contributing to endothelial pathology and provide a detailed analysis of how these cellular processes underpin the clinical picture. Noninvasive diagnostic techniques, such as flow-mediated dilation and peripheral arterial tonometry, are evaluated for their utility in identifying ED. We then explore mechanistic, cellular-targeted therapeutic interventions for their potential in treating ED. Overall, we emphasize the critical role of cellular health in managing Long COVID and highlight the need for early intervention to prevent long-term vascular and cellular dysfunction.

Logistic regression model for predicting risk factors and contribution of cerebral microbleeds using renal function indicators

Background

The brain and kidneys share similar low-resistance microvascular structures, receiving blood at consistently high flow rates and thus, are vulnerable to blood pressure fluctuations. This study investigates the causative factors of cerebral microbleeds (CMBs), aiming to quantify the contribution of each risk factor by constructing a multivariate model via stepwise regression.

Methods

A total of 164 hospitalized patients were enrolled from January 2022 to March 2023 in this study, employing magnetic susceptibility-weighted imaging (SWI) to assess the presence of CMBs. The presence of CMBs in patients was determined by SWI, and history, renal function related to CMBs were analyzed.

Results

Out of 164 participants in the safety analysis, 36 (21.96%) exhibited CMBs and 128 (78.04%) did not exhibit CMBs, and the median age of the patients was 66 years (range: 49-86 years). Multivariate logistic regression identified hypertension (OR = 13.95%, 95% CI: 4.52, 50.07%), blood urea nitrogen (BUN) (OR = 1.57, 95% CI: 1.06-2.40), cystatin C (CyC) (OR = 4.90, 95% CI: 1.20-22.16), and urinary β-2 microglobulin, (OR = 2.11, 95% CI: 1.45-3.49) as significant risk factors for CMBs. The marginal R-square (R M 2 ) was 0.25. Among all determinants, hypertension (47.81%) had the highest weight, followed by UN (11.42%). Quasi-curves plotted using the bootstrap method (999 times) showed good agreement between the predictive model and actual observations.

Conclusion

Hypertension, BUN, urinary β-2 microglobulin, CyC were risk factors for CMBs morbidity, and controlling the above indicators within a reasonable range will help to reduce the incidence of CMBs.

A cell-autonomous role for border-associated macrophages in ApoE4 neurovascular dysfunction and susceptibility to white matter injury

Apolipoprotein E4 (ApoE4), the strongest genetic risk factor for sporadic Alzheimer's disease, is also a risk factor for microvascular pathologies leading to cognitive impairment, particularly subcortical white matter injury. These effects have been attributed to alterations in the regulation of the brain blood supply, but the cellular source of ApoE4 and the underlying mechanisms remain unclear. In mice expressing human ApoE3 or ApoE4, we report that border-associated macrophages (BAMs), myeloid cells closely apposed to neocortical microvessels, are both sources and effectors of ApoE4 mediating the neurovascular dysfunction through reactive oxygen species. ApoE4 in BAMs is solely responsible for the increased susceptibility to oligemic white matter damage in ApoE4 mice and is sufficient to enhance damage in ApoE3 mice. The data unveil a new aspect of BAM pathobiology and highlight a previously unrecognized cell-autonomous role of BAM in the neurovascular dysfunction of ApoE4 with potential therapeutic implications.

Integrative MR Imaging Interpretation in Cognitive Impairment with Alzheimer's Disease, Small Vessel Disease, and Glymphatic Function-Related MR Parameters

RATIONALE AND OBJECTIVES

The role of MR imaging in patients with cognitive impairment is to evaluate each component of Alzheimer's disease (AD), small vessel disease (SVD), and glymphatic function. We want to validate the diagnostic performance of the comprehensive interpretation of these parameters to predict the cognitive impairment stage. MATERIALS AND METHODS: This retrospective single-center study included 359 patients with cognitive impairment who had undergone MRI (FLAIR, T2WI, 3D-T1WI, susceptibility-weighted imaging, and diffusion tensor imaging [DTI]) and a neuropsychological screening battery between January 2020 and July 2022. Each AD and SVD-related MR parameter was visually evaluated, and DTI analysis along the perivascular space (ALPS) index was calculated. Volumetry analysis was performed using Neurophet AQUA AI-based software. Using logistic regression analysis, four types of models were developed and compared by adding the components in the following order: (1) clinical factors and AD, (2) SVD, (3) glymphatic function-related MR parameters, and (4) volumetric data. Chi-square automatic interaction detection algorithm was used to develop diagnostic tree analysis (DTA) model to predict late-stage cognitive impairment.

RESULTS

APOE4 status, years of education, medial temporal lobe atrophy score, Fazekas scale score, DTI-ALPS index, and white matter hyperintensity were significant predictors of late-stage cognitive impairment. The performance of the prediction model increased from Model 1 to Model 4 (AUC: 0.880, 0.899, 0.914, and 0.945, respectively). The overall accuracy of the DTA model was 87.47%.

CONCLUSION

Integrative brain MRI assessments in patients with cognitive impairment, AD, SVD, and glymphatic function-related MR parameters, improve the prediction of late-stage cognitive impairment.

Progressive brain structural abnormality in cerebral small vessel disease assessed with MR imaging by using causal network analysis

AIMS

Cerebral small vessel disease (CSVD) is a complex condition characterized by a combination of microcirculation disorders and neurodegenerative processes, CSVD is associated with structural abnormalities in multiple brain regions. However, the progressive pattern of structural changes remains unknown.

METHODS

In order to detail the progressive structural changes in CSVD patients according to the degree of cognitive impairment, we recruited 121 CSVD patients and 104 healthy controls (HCs). Voxel-based morphometry was employed to measure the gray matter volume (GMV) of each participant. According to the VICCCS-2 diagnostic criteria, patients were initially divided into three stage groups, then we investigated the GMV changes in each stage and their causal relationships using causal structure covariance network (CaSCN) analysis.

RESULTS

Overall, patients with CSVD presented stage-specific GMV alterations compared with HCs. With the worsening of cognitive impairment, the decrease in gray matter volume starts from the right hippocampus and gradually spreads to the cortical-subcortical brain regions. Importantly, the right hippocampus in CSVD patients plays a driving role in the directional network and forms both positive and negative causal effect networks with cortical-subcortical brain regions.

CONCLUSIONS

This study reveals the significance of the right hippocampus as an early pathological area in CSVD patients and its causal impact on brain GMV changes with disease progression, shedding light on structural brain damage hierarchy and compensatory mechanisms.

Impact of amyloid and cardiometabolic risk factors on prognostic capacity of plasma neurofilament light chain for neurodegeneration

BACKGROUND

Plasma neurofilament light chain (NfL) is a blood biomarker of neurodegeneration, including Alzheimer's disease. However, its usefulness may be influenced by common conditions in older adults, including amyloid-β (Aβ) deposition and cardiometabolic risk factors like hypertension, diabetes mellitus (DM), impaired kidney function, and obesity. This longitudinal observational study using the Alzheimer's Disease Neuroimaging Initiative cohort investigated how these conditions influence the prognostic capacity of plasma NfL.

METHODS

Non-demented participants (cognitively unimpaired or mild cognitive impairment) underwent repeated assessments including the Alzheimer's Disease Assessment Scale-Cognitive subscale (ADAS-Cog) scores, hippocampal volumes, and white matter hyperintensity (WMH) volumes at 6- or 12-month intervals. Linear mixed-effect models were employed to examine the interaction between plasma NfL and various variables of interest, such as Aβ (evaluated using Florbetapir positron emission tomography), hypertension, DM, impaired kidney function, or obesity.

RESULTS

Over a mean follow-up period of 62.5 months, participants with a mean age of 72.1 years (n = 720, 48.8% female) at baseline were observed. Higher plasma NfL levels at baseline were associated with steeper increases in ADAS-Cog scores and WMH volumes, and steeper decreases in hippocampal volumes over time (all p-values < 0.001). Notably, Aβ at baseline significantly enhanced the association between plasma NfL and longitudinal changes in ADAS-Cog scores (p-value 0.005) and hippocampal volumes (p-value 0.004). Regarding ADAS-Cog score and WMH volume, the impact of Aβ was more prominent in cognitively unimpaired than in mild cognitive impairment. Hypertension significantly heightened the association between plasma NfL and longitudinal changes in ADAS-Cog scores, hippocampal volumes, and WMH volumes (all p-values < 0.001). DM influenced the association between plasma NfL and changes in ADAS-Cog scores (p-value < 0.001) without affecting hippocampal and WMH volumes. Impaired kidney function did not significantly alter the association between plasma NfL and longitudinal changes in any outcome variables. Obesity heightened the association between plasma NfL and changes in hippocampal volumes only (p-value 0.026).

CONCLUSION

This study suggests that the prognostic capacity of plasma NfL may be amplified in individuals with Aβ or hypertension. This finding emphasizes the importance of considering these factors in the NfL-based prognostic model for neurodegeneration in non-demented older adults.

Transcranial focused ultrasound stimulation enhances cerebrospinal fluid movement: Real-time in vivo two-photon and widefield imaging evidence

BACKGROUND

Cerebrospinal fluid (CSF) flow is crucial for brain homeostasis and its dysfunction is highly associated with neurodegenerative diseases. Restoring CSF circulation is proposed as a key strategy for the treatment of the diseases. Among the methods to improve CSF circulation, focused ultrasound (FUS) stimulation has emerged as a promising non-invasive brain stimulation technique, with effectiveness evidenced by ex vivo studies. However, due to technical disturbances in in vivo imaging combined with FUS, direct evidence of real-time in vivo CSF flow enhancement by FUS remains elusive.

OBJECTIVE

To investigate whether FUS administered through the skull base can enhance CSF influx in living animals with various real-time imaging techniques.

METHODS

We demonstrate a novel method of applying FUS through the skull base, facilitating cortical CSF influx, evidenced by diverse in vivo imaging techniques. Acoustic simulation confirmed effective sonication of our approach through the skull base. After injecting fluorescent CSF tracers into cisterna magna, FUS was administered at the midline of the jaw through the skull base for 30 min, during which imaging was performed concurrently.

RESULTS

Enhanced CSF influx was observed in macroscopic imaging, demonstrated by the influx area and intensity of the fluorescent dyes after FUS. In two-photon imaging, increased fluorescence was observed in the perivascular space (PVS) after stimulation. Moreover, particle tracking of microspheres showed more microspheres entering the imaging field, with increased mean speed after FUS.

CONCLUSION

Our findings provide direct real-time in vivo imaging evidence that FUS promotes CSF influx and flow in the PVS.

Incident Infarcts in Patients With Stroke and Cerebral Small Vessel Disease: Frequency and Relation to Clinical Outcomes

BACKGROUND AND OBJECTIVES

Factors associated with cerebral small vessel disease (SVD) progression, including incident infarcts, are unclear. We aimed to determine the frequency of incident infarcts over 1 year after minor stroke and their relation to baseline SVD burden, vascular risks, and recurrent stroke and cognitive outcomes.

METHODS

We recruited patients with lacunar or nondisabling cortical stroke. After diagnostic imaging, we repeated structural MRI at 3-6 monthly intervals for 12 months, visually assessing incident infarcts on diffusion-weighted imaging or FLAIR. We used logistic regression to determine associations of baseline vascular risks, SVD score, and index stroke subtype with subsequent incident infarcts. We assessed cognitive and functional outcomes at 1 year using Montreal Cognitive Assessment (MoCA) and modified Rankin scale (mRS), adjusting for baseline age, mRS, MoCA, premorbid intelligence, and SVD score.

RESULTS

We recruited 229 participants, mean age 65.9 (SD 11.1). Over half of all participants, 131 of 229 (57.2%) had had an index lacunar stroke. From baseline to 1-year MRI, we detected 117 incident infarcts in n = 57/229 (24.8%) participants. Incident infarcts were mainly of the small subcortical (86/117 [73.5%] in n = 38/57 [66.7%]) vs cortical infarct subtype (n = 19/57 [33.3%]). N = 39/57 participants had incident infarcts at 1 visit; 18 of 57 at 2 or more visits; and 19 of 57 participants had multiple infarcts at a single visit. Only 7 of 117 incident infarcts corresponded temporally to clinical stroke syndromes. The baseline SVD score was the strongest predictor of incident infarcts (adjusted odds ratio [OR] 1.87, 95% CI 1.39-2.58), while mean arterial pressure was not associated. All participants with incident infarcts were prescribed an antiplatelet or anticoagulant. Lower 1-year MoCA was associated with lower baseline MoCA (β 0.47, 95% CI 0.33-0.61), lower premorbid intelligence, and older age. Higher 1-year mRS was associated with higher baseline mRS only (OR 5.57 [3.52-9.10]). Neither outcome was associated with incident infarcts.

DISCUSSION

In the year after stroke in a population enriched for lacunar stroke, incident infarcts occurred in one-quarter and were associated with worse baseline SVD. Most incident infarcts detected on imaging did not correspond to clinical stroke/transient ischemic attack. Worse 1-year cognition and function were not associated with incident infarcts.

Association of oral frailty and gait characteristics in patients with cerebral small vessel disease

BACKGROUND

The objectives of this study were twofold: (1) to compare gait characteristics between cerebral small vessel disease (CSVD) patients with low-risk oral frailty (OF) and high-risk OF, particularly during dual-task walking (DTW); (2) to investigate the association of OF, the gait characteristics of DTW, and falls among older adults patients with CSVD.

METHODS

A total of 126 hospitalized patients diagnosed with CSVD were recruited and classified into a low-risk group (n = 90) and a high-risk group (n = 36) based on OF status in our study. Comprehensive data pertaining to basic parameters (cadence, as well as stride time, velocity and length), variability, asymmetry, and coordination were gathered during both single-task walking (STW) and DTW. Additionally, the number of falls was calculated. Subsequently, t-test or chi-squared test was used for comparison between the two groups. Furthermore, linear regression analysis was employed to elucidate the association of the OF index-8 score and gait parameters during cognitive DTW. Also, logistic regression models were utilized to assess the independent association of OF risk and falls.

RESULTS

During cognitive DTW, the high-risk group demonstrated inferior performance in terms of basic parameters (p < 0.01), coefficient of variation (CV) of velocity and stride length (p < 0.05), as well as phase coordination index (PCI) when compared with the low-risk group (p < 0.05). Notably, differences in basic gait parameters were observed in cognitive DTW and STW conditions between the two groups (p < 0.01). However, only the high-risk group evinced significant variations in CV and PCI during cognitive DTW, as opposed to those during STW (p < 0.05). Furthermore, our findings also revealed the association of OF, the gait characteristics of cognitive DTW, (p < 0.01) and falls (p < 0.05).

CONCLUSION

CSVD patients with a high risk of OF need to pay more attention to their gait variability or coordination. Also, they are recommended to undergo training involving dual-task activities while walking in daily life, thereby reducing the deterioration and mitigating the risk of falls. Besides, this study has confirmed an association of OF and DTW gait as well as falls in patients with CSVD.

Whole-Brain Vascular Architecture Mapping Identifies Region-Specific Microvascular Profiles In Vivo

BACKGROUND AND PURPOSE

The novel MR imaging technique of vascular architecture mapping allows in vivo characterization of local changes in cerebral microvasculature, but reference ranges for vascular architecture mapping parameters in healthy brain tissue are lacking, limiting its potential applicability as an MR imaging biomarker in clinical practice. We conducted whole-brain vascular architecture mapping in a large cohort to establish vascular architecture mapping parameter references ranges and identify region-specific cortical and subcortical microvascular profiles.

MATERIALS AND METHODS

This was a single-center examination of adult patients with unifocal, stable low-grade gliomas with multiband spin- and gradient-echo EPI sequence at 3T using parallel imaging. Voxelwise plotting of resulting values for gradient-echo (R2*) versus spin-echo (R2) relaxation rates during contrast agent bolus administration generates vessel vortex curves that allow the extraction of vascular architecture mapping parameters representative of, eg, vessel type, vessel radius, or CBV in the underlying voxel. Averaged whole-brain parametric maps were calculated for 9 parameters, and VOI analysis was conducted on the basis of a standardized brain atlas and individual cortical GM and WM segmentation.

RESULTS

Prevalence of vascular risk factors among subjects (n = 106; mean age, 39.2 [SD, 12.5] years; 56 women) was similar to those in the German population. Compared with WM, we found cortical GM to have larger mean vascular calibers (5.80 [SD, 0.59] versus 4.25 [SD, 0.62] P < .001), increased blood volume fraction (20.40 [SD, 4.49] s-1 versus 11.05 [SD, 2.44] s-1; P < .001), and a dominance of venous vessels. Distinct microvascular profiles emerged for cortical GM, where vascular architecture mapping vessel type indicator differed, eg, between the thalamus and cortical GM (mean, -2.47 [SD, 4.02] s-2 versus -5.41 [SD, 2.84] s-2; P < .001). Intraclass correlation coefficient values indicated overall high test-retest reliability for vascular architecture mapping parameter mean values when comparing multiple scans per subject.

CONCLUSIONS

Whole-brain vascular architecture mapping in the adult brain reveals region-specific microvascular profiles. The obtained parameter reference ranges for distinct anatomic and functional brain areas may be used for future vascular architecture mapping studies on cerebrovascular pathologies and might facilitate early discovery of microvascular changes, in, eg, neurodegeneration and neuro-oncology.

Horizontal analysis and longitudinal cohort study of chronic renal failure correlates and cerebral small vessel disease relationship using peak width of skeletonized mean diffusivity

Background and purpose

Peak width of skeletonized mean diffusivity (PSMD) is an MRI-based biomarker that may reflect white matter lesions (WML). PSMD is based on skeletonization of MR DTI data and histogram analysis. Both chronic renal failure (CRF) and WML may be affected by multisystemic small-vessel disorder. We aimed to explore the relationship between PSMD and estimated glomerular filtration rate (eGFR).

Methods

Fifty followed-up CRF patients matched for age, sex, hypertension and smoking status were enrolled and classified into a progressive group (n = 16) and stable group (n = 34) based on eGFR levels. Longitudinal and horizontal differences of PSMD were compared between the progressive and stable groups at the initial and follow-up time points. Pearson's correlation was used for correlation of eGFR with PSMD and WML (per Fazekas scale score). ROC was used to measure the sensitivity of PSMD and WML score to changes of eGFR.

Results

At the follow-up time point, PSMD of the progressive group was significantly higher than at the initial time point (p < 0.001), and PSMD of the progressive group was significantly higher than stable group (p < 0.001). PSMD and eGFR were significantly correlated. AUC curves explored that ΔPSMD (PSMD changes at the follow-up and initial time points) and follow-up PSMD was better for the classification of progressive and stable groups.

Conclusion

PSMD has significant correlation with eGFR, PSMD can reveal a close relationship between WML and CRF.

Assessing Cerebral Microvascular Volumetric Pulsatility with High-Resolution 4D CBV MRI at 7T

Arterial pulsation is crucial for promoting fluid circulation and for influencing neuronal activity. Previous studies assessed the pulsatility index based on blood flow velocity pulsatility in relatively large cerebral arteries of human. Here, we introduce a novel method to quantify the volumetric pulsatility of cerebral microvasculature across cortical layers and in white matter (WM), using high-resolution 4D vascular space occupancy (VASO) MRI with simultaneous recording of pulse signals at 7T. Microvascular volumetric pulsatility index (mvPI) and cerebral blood volume (CBV) changes across cardiac cycles are assessed through retrospective sorting of VASO signals into cardiac phases and estimating mean CBV in resting state (CBV0) by arterial spin labeling (ASL) MRI at 7T. Using data from 11 young (28.4±5.8 years) and 7 older (61.3±6.2 years) healthy participants, we investigated the aging effect on mvPI and compared microvascular pulsatility with large arterial pulsatility assessed by 4D-flow MRI. We observed the highest mvPI in the cerebrospinal fluid (CSF) on the cortical surface (0.19±0.06), which decreased towards the cortical layers as well as in larger arteries. In the deep WM, a significantly increased mvPI (p = 0.029) was observed in the older participants compared to younger ones. Additionally, mvPI in deep WM is significantly associated with the velocity pulsatility index (vePI) of large arteries (r = 0.5997, p = 0.0181). We further performed test-retest scans, non-parametric reliability test and simulations to demonstrate the reproducibility and accuracy of our method. To the best of our knowledge, our method offers the first in vivo measurement of microvascular volumetric pulsatility in human brain which has implications for cerebral microvascular health and its relationship research with glymphatic system, aging and neurodegenerative diseases.

Cerebral small vessel disease and glymphatic system dysfunction in multiple sclerosis: A narrative review

As the multiple sclerosis (MS) population ages, the prevalence of vascular comorbidities increases, potentially accelerating disease progression and brain atrophy. Recent studies highlight the prevalence of cerebral small vessel disease (CSVD) in MS, suggesting a potential link between vascular comorbidities and accelerated disability. CSVD affects the brain's small vessels, often leading to identifiable markers on MRI such as enlarged perivascular spaces (EPVS). EPVS are increasingly recognized also in MS and have been associated with vascular comorbidities, lower percentage of MS-specific perivenular lesions, brain atrophy and aging. The exact sequence of event leading to MRI visible EPVS is yet to be determined, but an impaired perivascular brain fluid drainage appears a possible physiopathological explanation for EPVS in both CSVD and MS. In this context, a dysfunction of the brain fluid clearance system - also known as "glymphatic system" - appears associated in MS to aging, neuroinflammation, and vascular dysfunction. Advanced imaging techniques show an impaired glymphatic function in both MS and CSVD. Additionally, lifestyle factors such as physical exercise, diet, and sleep quality appear to influence glymphatic function, potentially revealing novel therapeutic strategies to mitigate microangiopathy and neuroinflammation in MS. This review underscores the potential role of glymphatic dysfunction in the complex and not-yet elucidated interplay between neuroinflammation and CSVD in MS.

Air pollution: a latent key driving force of dementia

Many researchers have studied the role of air pollutants on cognitive function, changes in brain structure, and occurrence of dementia. Due to the wide range of studies and often contradictory results, the present systematic review was conducted to try and clarify the relationship between air pollutants and dementia. To identify studies for this review, a systematic search was conducted in Scopus, PubMed, and Web of Science databases (without historical restrictions) until May 22, 2023. The PECO statement was created to clarify the research question, and articles that did not meet the criteria of this statement were excluded. In this review, animal studies, laboratory studies, books, review articles, conference papers and letters to the editors were avoided. Also, studies focused on the effect of air pollutants on cellular and biochemical changes (without investigating dementia) were also excluded. A quality assessment was done according to the type of design of each article, using the checklist developed by the Joanna Briggs Institute (JBI). Finally, selected studies were reviewed and discussed in terms of Alzheimer's dementia and non-Alzheimer's dementia. We identified 14,924 articles through a systematic search in databases, and after comprehensive reviews, 53 articles were found to be eligible for inclusion in the current systematic review. The results showed that chronic exposure to higher levels of air pollutants was associated with adverse effects on cognitive abilities and the presence of dementia. Studies strongly supported the negative effects of PM2.5 and then NO2 on the brain and the development of neurodegenerative disorders in old age. Because the onset of brain structural changes due to dementia begins decades before the onset of disease symptoms, and that exposure to air pollution is considered a modifiable risk factor, taking preventive measures to reduce air pollution and introducing behavioral interventions to reduce people's exposure to pollutants is advisable.

Prevalence of small vessel disease and incidental DWI-positive lesions in patients with aneurysmal subarachnoid hemorrhage versus intracerebral hemorrhage

INTRODUCTION

Aneurysmal subarachnoid hemorrhage (aSAH) and intracerebral hemorrhage (ICH) are main forms of hemorrhagic stroke. Data regarding cerebral small vessel disease (SVD) burden and incidental small lesions on diffusion-weighted imaging (DWI) following aSAH are sparse.

PATIENTS AND METHODS

We retrospectively analyzed a prospective cohort of aSAH and ICH patients with brain MRI within 30 days after onset from March 2015 to January 2023. White matter hyperintensity (WMH), lacune, perivascular space, cerebral microbleed (CMB), total SVD score, and incidental DWI lesions were assessed and compared between aSAH and ICH. Clinical and radiological characteristics associated with small DWI lesions in aSAH were investigated.

RESULTS

We included 180 patients with aSAH (median age [IQR] 53 [47-61] years) and 299 with ICH (63 [53-73] years). DWI lesions were more common in aSAH than ICH (47.8% vs 14.4%, p < 0.001). Higher total SVD score was associated with ICH versus aSAH irrespective of hematoma location, whereas DWI lesions and strictly lobar CMBs were correlated with aSAH. Multivariable analysis showed that shorter time from onset to MRI, anterior circulation aneurysm rupture, CMB ⩾ 5, and total SVD score were associated with DWI lesions in aSAH.

DISCUSSION AND CONCLUSION

Incidental DWI lesions and strictly lobar CMBs were more frequent in aSAH versus ICH whereas ICH had higher SVD burden. Incidental DWI lesions in aSAH were associated with multiple clinical and imaging factors. Longitudinal studies to investigate the dynamic change and prognostic value of the covert hemorrhagic and ischemic lesions in aSAH seem justified.

Dysfunction of neurovascular coupling in patients with cerebral small vessel disease: A combined resting-state fMRI and arterial spin labeling study

BACKGROUND

Cerebral small vessel disease (CSVD) closely correlates to cognitive impairment, but its pathophysiology and the neurovascular mechanisms of cognitive deficits were unclear. We aimed to explore the dysfunctional patterns of neurovascular coupling (NVC) in patients with CSVD and further investigate the neurovascular mechanisms of CSVD-related cognitive impairment.

METHODS

Forty-three patients with CSVD and twenty-four healthy controls were recruited. We adopted resting-state functional magnetic resonance imaging combined with arterial spin labeling to investigate the NVC dysfunctional patterns in patients with CSVD. The Human Brain Atlas with 246 brain regions was applied to extract the NVC coefficients for each brain region. Partial correlation analysis and mediation analysis were used to explore the relationship between CSVD pathological features, NVC dysfunctional patterns, and cognitive decline.

RESULTS

8 brain regions with NVC dysfunction were found in patients with CSVD (p < 0.025, Bonferroni correction). The NVC dysfunctional patterns in regions of the default mode network and subcortical nuclei were negatively associated with lacunes, white matter hyperintensities burden, and the severity of CSVD (FDR correction, q < 0.05). The NVC decoupling in regions located in the default mode network positively correlated with delayed recall deficits (FDR correction, q < 0.05). Mediation analysis suggested that the decreased NVC pattern of the left superior frontal gyrus partially mediated the impact of white matter hyperintensities on delayed recall (Mediation effect: -0.119; 95%CI: -11.604,-0.458; p < 0.05).

CONCLUSION

The findings of this study reveal the NVC dysfunctional pattern in patients with CSVD and illustrate the neurovascular mechanism of CSVD-related cognitive impairment. The NVC function in the left superior frontal gyrus may serve as a promising biomarker and therapeutic target for memory deficits in patients with CSVD.

Genome-Wide Mendelian Randomization Study Reveals Druggable Genes for Cerebral Small Vessel Disease

BACKGROUND

Cerebral small vessel disease (CSVD) is a group of neurological disorders that affect the small blood vessels within the brain, for which no effective treatments are currently available. We conducted a Mendelian randomization (MR) study to identify candidate therapeutic genes for CSVD.

METHODS

We retrieved genome-wide association study data from 6 recently conducted, extensive investigations focusing on CSVD magnetic resonance imaging markers and performed a 2-sample MR analysis to assess the potential causal effects of gene expression and protein level within druggable genes on CSVD in blood and brain tissues. Colocalization analyses and repeat studies were undertaken to verify the relationship. Additionally, mediation analysis was conducted to explore the potential mechanisms involving druggable genes and known risk factors for CSVD. Finally, phenome-wide MR analyses were applied to evaluate the potential adverse effects related to the identified druggable genes for CSVD treatment.

RESULTS

Overall, 5 druggable genes consistently showed associations with CSVD in MR analyses across both the discovery and validation cohorts. Notably, the ALDH2 and KLHL24 genes were identified as associated with CSVD in both blood and brain tissues, whereas the genes ADRB1, BTN3A2, and EFEMP1 were exclusively detected in brain tissue. Moreover, mediation analysis elucidated the proportion of the total effects mediated by CSVD risk factors through candidate druggable genes, which ranged from 5.5% to 18.5%, and offered potential explanations for the observed results. A comprehensive phenome-wide MR analysis further emphasized both the therapeutic benefits and potential side effects of targeting these candidate druggable genes.

CONCLUSIONS

This study provides genetic evidence supporting the potential therapeutic benefits of targeting druggable genes for treating CSVD, which will be useful for prioritizing CSVD drug development.

Macro- and microvascular contributions to cerebral structural alterations in patients with asymptomatic carotid artery stenosis

Atherosclerosis can underly internal carotid artery stenosis (ICAS), a major risk factor for ischemic stroke, as well as small vessel disease (SVD). This study aimed to investigate hemodynamics and structural alterations associated with SVD in ICAS patients. 28 patients with unilateral asymptomatic ICAS and 30 age-matched controls underwent structural (T1-/T2-weighted and diffusion tensor imaging [DTI]) and hemodynamic (pseudo-continuous arterial spin labeling and dynamic susceptibility contrast) magnetic resonance imaging. SVD-related alterations were assessed using free water (FW), FW-corrected DTI, and peak-width of skeletonized mean diffusivity (PSMD). Furthermore, cortical thickness, cerebral blood flow (CBF), and capillary transit time heterogeneity (CTH) were analyzed. Ipsilateral to the stenosis, cortical thickness was significantly decreased in the posterior dorsal cingulate cortex (p = 0.024) and temporal pole (p = 0.028). ICAS patients exhibited elevated PSMD (p = 0.005), FW (p < 0.001), and contralateral alterations in FW-corrected DTI metrics. We found significantly lateralized CBF (p = 0.011) and a tendency for lateralized CTH (p = 0.067) in the white matter (WM) related to ICAS. Elevated PSMD and FW may indicate a link between SVD and WM changes. Contralateral alterations were seen in FW-corrected DTI, whereas hemodynamic and cortical changes were mainly ipsilateral, suggesting SVD might influence global brain changes concurrent with ICAS-related hemodynamic alterations.

The relationship between cortical thickness and white matter hyperintensities in mid to late life

White matter hyperintensities (WMH) are associated with cortical thinning. Although they are primarily detected in older participants, these lesions can appear in younger and midlife individuals. Here, we tested whether WMH are associated with cortical thinning in relatively younger (26-50 years) and relatively older (58-84) participants who were free of dementia, and how these associations are moderated by WMH localization. WMH were automatically quantified and categorized according to the localization of three classes of white matter tracts: association, commissural and projection fibers. Mediation analyses were used to infer whether differences in cortical thickness between younger and older participants were explained by WMH. Our results revealed that total WMH explained between 20.6 % and 65.5 % of the effect of age on cortical thickness in AD-signature regions including the lateral temporal lobes and supramarginal gyrus, among others. This mediation was slightly stronger for projection WMH, although it was still significant for association and commissural WMH. These results suggest that there is an interplay between vascular and AD causes of cognitive impairment that starts at younger ages.

Collagen IV deficiency causes hypertrophic remodeling and endothelium-dependent hyperpolarization in small vessel disease with intracerebral hemorrhage

BACKGROUND

Genetic variants in COL4A1 and COL4A2 (encoding collagen IV alpha chain 1/2) occur in genetic and sporadic forms of cerebral small vessel disease (CSVD), a leading cause of stroke, dementia and intracerebral haemorrhage (ICH). However, the molecular mechanisms of CSVD with ICH and COL4A1/COL4A2 variants remain obscure.

METHODS

Vascular function and molecular investigations in mice with a Col4a1 missense mutation and heterozygous Col4a2 knock-out mice were combined with analysis of human brain endothelial cells harboring COL4A1/COL4A2 mutations, and brain tissue of patients with sporadic CSVD with ICH.

FINDINGS

Col4a1 missense mutations cause early-onset CSVD independent of hypertension, with enhanced vasodilation of small arteries due to endothelial dysfunction, vascular wall thickening and reduced stiffness. Mechanistically, the early-onset dysregulated endothelium-dependent hyperpolarization (EDH) is due to reduced collagen IV levels with elevated activity and levels of endothelial Ca2+-sensitive K+ channels. This results in vasodilation via the Na/K pump in vascular smooth muscle cells. Our data support this endothelial dysfunction preceding development of CSVD-associated ICH is due to increased cytoplasmic Ca2+ levels in endothelial cells. Moreover, cerebral blood vessels of patients with sporadic CSVD show genotype-dependent mechanisms with wall thickening and lower collagen IV levels in those harboring common non-coding COL4A1/COL4A2 risk alleles.

INTERPRETATION

COL4A1/COL4A2 variants act in genetic and sporadic CSVD with ICH via dysregulated EDH, and altered vascular wall thickness and biomechanics due to lower collagen IV levels and/or mutant collagen IV secretion. These data highlight EDH and collagen IV levels as potential treatment targets.

FUNDING

MRC, Wellcome Trust, BHF.

Exploring cognitive related microstructural alterations in normal appearing white matter and deep grey matter for small vessel disease: A quantitative susceptibility mapping study

Brain microstructural alterations possibly occur in the normal-appearing white matter (NAWM) and grey matter of small vessel disease (SVD) patients, and may contribute to cognitive impairment. The aim of this study was to explore cognitive related microstructural alterations in white matter and deep grey matter nuclei in SVD patients using magnetic resonance (MR) quantitative susceptibility mapping (QSM). 170 SVD patients, including 103 vascular mild cognitive impairment (VaMCI) and 67 no cognitive impairment (NCI), and 21 healthy control (HC) subjects were included, all underwent a whole-brain QSM scanning. Using a white matter and a deep grey matter atlas, subregion-based QSM analysis was conducted to identify and characterize microstructural alterations occurring within white matter and subcortical nuclei. Significantly different susceptibility values were revealed in NAWM and in several specific white matter tracts including anterior limb of internal capsule, corticospinal tract, medial lemniscus, middle frontal blade, superior corona radiata and tapetum among VaMCI, NCI and HC groups. However, no difference was found in white matter hyperintensities between VaMCI and NCI. A trend toward higher susceptibility in the caudate nucleus and globus pallidus of VaMCI patients compared to HC, indicating elevated iron deposition in these areas. Interestingly, some of these QSM parameters were closely correlated with both global and specific cognitive function scores, controlling age, gender and education level. Our study suggested that QSM may serve as a useful imaging tool for monitoring cognitive related microstructural alterations in brain. This is especially meaningful for white matter which previously lacks of attention.

Correlation analysis and predictive model construction of metabolic syndrome, complete blood count-derived inflammatory markers, and overall burden of cerebral small vessel disease

Background

The high burden of cerebral small vessel disease (CSVD) on neuroimaging is a significant risk factor for stroke, cognitive dysfunction, and emotional disorders. Currently, there is a lack of studies investigating the correlation between metabolic syndrome (MetS), complete blood count-derived inflammatory markers, and total CSVD burden. This study aims to evaluate the total CSVD imaging load using machine learning (ML) algorithms and to explore further the relationship between MetS, complete blood count-derived inflammatory markers, and CSVD load.

Methods

We included CSVD patients from Xijing Hospital (2012-2022). Univariate and lasso regression analyses identified variables linked to CSVD neuroimaging burden. Six ML models predicted CSVD burden based on MetS and inflammatory markers. Model performance was evaluated using ROCauc, PRauc, DCA, and calibration curves. The SHAP method validated model interpretability. The best-performing model was selected to develop a web-based calculator using the Shiny package.

Results

The Logistic regression model outperformed others in predicting CSVD burden. The model incorporated MetS, neutrophil-to-lymphocyte ratio (NLR), homocysteine (Hcy), age, smoking status, cystatin C (CysC), uric acid (UA), and prognostic nutritional index (PNI).

Conclusion

MetS, NLR, Hcy and CSVD high load were positively correlated, and the Logistic regression model could accurately predict the total CSVD load degree.

Cerebral blood flow and cognition after 3 months tadalafil treatment in small vessel disease (ETLAS-2): study protocol for a randomized controlled trial

BACKGROUND

Targeted treatment is highly warranted for cerebral small vessel disease, a causal factor of one in four strokes and a major contributor to vascular dementia. Patients with cerebral small vessel disease have impaired cerebral blood flow and vessel reactivity. Tadalafil is a specific phosphodiesterase 5 inhibitor shown to improve vascular reactivity in the brain.

METHODS

The ETLAS-2 trial is a phase 2 double-blind, randomized placebo-controlled, parallel trial with the feasibility of tadalafil as the primary outcome. The trial aims to include 100 patients with small vessel occlusion stroke or transitory ischemic attacks and signs of cerebral small vessel disease more than 6 months before administration of study medication. Patients are treated for 3 months with tadalafil 20 mg or placebo daily and undergo magnetic resonance imaging (MRI) to evaluate changes in small vessel disease according to the STandards for ReportIng Vascular changes on nEuroimaging (STRIVE) criteria as well as cerebral blood flow, cerebrovascular reactivity, and neurovascular coupling in a functional MRI sub-study. The investigation includes comprehensive cognitive testing using paper-pencil tests and Cambridge Neuropsychological Test Automated Battery (CANTAB) tests in a cognitive sub-study.

DISCUSSION

The ETLAS-2 trial tests the feasibility of long-term treatment with tadalafil and explores vascular and cognitive effects in cerebral small vessel disease in trial sub-studies. The study aims to propose a new treatment target and improve the understanding of small vessel disease. Currently, 64 patients have been included and the trial is estimated to be completed in the year 2024.

TRIAL REGISTRATION

Clinicaltrials.gov, NCT05173896. Registered on 30 December 2021.

Associations of polygenic risk scores with risks of stroke and its subtypes in Chinese

BACKGROUND AND PURPOSE

Previous studies, mostly focusing on the European population, have reported polygenic risk scores (PRSs) might achieve risk stratification of stroke. We aimed to examine the association strengths of PRSs with risks of stroke and its subtypes in the Chinese population.

METHODS

Participants with genome-wide genotypic data in China Kadoorie Biobank were split into a potential training set (n=22 191) and a population-based testing set (n=72 150). Four previously developed PRSs were included, and new PRSs for stroke and its subtypes were developed. The PRSs showing the strongest association with risks of stroke or its subtypes in the training set were further evaluated in the testing set. Cox proportional hazards regression models were used to estimate the association strengths of different PRSs with risks of stroke and its subtypes (ischaemic stroke (IS), intracerebral haemorrhage (ICH) and subarachnoid haemorrhage (SAH)).

RESULTS

In the testing set, during 872 919 person-years of follow-up, 8514 incident stroke events were documented. The PRSs of any stroke (AS) and IS were both positively associated with risks of AS, IS and ICH (p<0.05). The HR for per SD increment (HRSD) of PRSAS was 1.10 (95% CI 1.07 to 1.12), 1.10 (95% CI 1.07 to 1.12) and 1.13 (95% CI 1.07 to 1.20) for AS, IS and ICH, respectively. The corresponding HRSD of PRSIS was 1.08 (95% CI 1.06 to 1.11), 1.08 (95% CI 1.06 to 1.11) and 1.09 (95% CI 1.03 to 1.15). PRSICH was positively associated with the risk of ICH (HRSD=1.07, 95% CI 1.01 to 1.14). PRSSAH was not associated with risks of stroke and its subtypes. The addition of current PRSs offered little to no improvement in stroke risk prediction and risk stratification.

CONCLUSIONS

In this Chinese population, the association strengths of current PRSs with risks of stroke and its subtypes were moderate, suggesting a limited value for improving risk prediction over traditional risk factors in the context of current genome-wide association study under-representing the East Asian population.

Cerebral small vessel disease modifies outcomes after minimally invasive surgery for intracerebral haemorrhage

BACKGROUND

Minimally invasive surgery (MIS) for spontaneous supratentorial intracerebral haemorrhage (ICH) is controversial but may be beneficial if end-of-treatment (EOT) haematoma volume is reduced to ≤15 mL. We explored whether MRI findings of cerebral small vessel disease (CSVD) modify the effect of MIS on long-term outcomes.

METHODS

Prespecified blinded subgroup analysis of 288 subjects with qualified imaging sequences from the phase 3 Minimally Invasive Surgery Plus Alteplase for Intracerebral Haemorrhage Evacuation (MISTIE) trial. We tested for heterogeneity in the effects of MIS and MIS+EOT volume ≤15 mL on the trial's primary outcome of good versus poor function at 1 year by the presence of single CSVD features and CSVD scores using multivariable models.

RESULTS

Of 499 patients enrolled in MISTIE III, 288 patients had MRI, 149 (51.7%) randomised to MIS and 139 (48.3%) to standard medical care (SMC). Median (IQR) ICH volume was 42 (30-53) mL. In the full MRI cohort, there was no statistically significant heterogeneity in the effects of MIS versus SMC on 1-year outcomes by any specific CSVD feature or by CSVD scores (all Pinteraction >0.05). In 94 MIS patients with EOT ICH volume ≤15 mL, significant reduction in odds of poor outcome was found with cerebral amyloid angiopathy score <2 (OR, 0.14 (0.05-0.42); Pinteraction=0.006), absence of lacunes (OR, 0.37 (0.18-0.80); Pinteraction=0.02) and absence of severe white matter hyperintensities (WMHs) (OR, 0.22 (0.08-0.58); Pinteraction=0.03).

CONCLUSIONS

Following successful haematoma reduction by MIS, we found significantly lower odds of poor functional outcome with lower total burden of CSVD in addition to absence of lacunes and severe WMHs. CSVD features may have utility for prognostication and patient selection in clinical trials of MIS.

Sleep Disordered Breathing and Neurocognitive Disorders

Sleep-disordered breathing (SDB), which includes conditions such as obstructive sleep apnea (OSA) and central sleep apnea (CSA), is an independent risk factor for cerebral small vessel disease (CSVD), stroke, heart failure, arrhythmias, and other cardiovascular disorders. The influence of OSA on brain structure and cognitive function has become an essential focus in the heart-brain axis, given its potential role in developing neurocognitive abnormalities. In this review, we found that OSA plays a significant role in the cardio-neural pathway that leads to the development of cerebral small vessel disease and neurocognitive decline. Although data is still limited on this topic, understanding the critical role of OSA in the heart-brain axis could lead to the utilization of imaging modalities to simultaneously identify early signs of pathology in both organ systems based on the known OSA-driven pathological pathways that result in a disease state in both the cardiovascular and cerebrovascular systems. This narrative review aims to summarize the current link between OSA and neurocognitive disorders, cardio-neural pathophysiology, and the treatment options available for patients with OSA-related neurocognitive disorders.

Integrating clinical and biochemical markers: a novel nomogram for predicting lacunes in cerebral small vessel disease

Background

Lacunes, a characteristic feature of cerebral small vessel disease (CSVD), are critical public health concerns, especially in the aging population. Traditional neuroimaging techniques often fall short in early lacune detection, prompting the need for more precise predictive models.

Methods

In this retrospective study, 587 patients from the Neurology Department of the Affiliated Hospital of Hebei University who underwent cranial MRI were assessed. A nomogram for predicting lacune incidence was developed using LASSO regression and binary logistic regression analysis for variable selection. The nomogram's performance was quantitatively assessed using AUC-ROC, calibration plots, and decision curve analysis (DCA) in both training (n = 412) and testing (n = 175) cohorts.

Results

Independent predictors identified included age, gender, history of stroke, carotid atherosclerosis, hypertension, creatinine, and homocysteine levels. The nomogram showed an AUC-ROC of 0.814 (95% CI: 0.791-0.870) for the training set and 0.805 (95% CI: 0.782-0.843) for the testing set. Calibration and DCA corroborated the model's clinical value.

Conclusion

This study introduces a clinically useful nomogram, derived from binary logistic regression, that significantly enhances the prediction of lacunes in patients undergoing brain MRI for various indications, potentially advancing early diagnosis and intervention. While promising, its retrospective design and single-center context are limitations that warrant further research, including multi-center validation.

Deep learning-based segmentation in MRI-(immuno)histological examination of myelin and axonal damage in normal-appearing white matter and white matter hyperintensities

The major vascular cause of dementia is cerebral small vessel disease (SVD). Its diagnosis relies on imaging hallmarks, such as white matter hyperintensities (WMH). WMH present a heterogenous pathology, including myelin and axonal loss. Yet, these might be only the "tip of the iceberg." Imaging modalities imply that microstructural alterations underlie still normal-appearing white matter (NAWM), preceding the conversion to WMH. Unfortunately, direct pathological characterization of these microstructural alterations affecting myelinated axonal fibers in WMH, and especially NAWM, is still missing. Given that there are no treatments to significantly reduce WMH progression, it is important to extend our knowledge on pathological processes that might already be occurring within NAWM. Staining of myelin with Luxol Fast Blue, while valuable, fails to assess subtle alterations in white matter microstructure. Therefore, we aimed to quantify myelin surrounding axonal fibers and axonal- and microstructural damage in detail by combining (immuno)histochemistry with polarized light imaging (PLI). To study the extent (of early) microstructural damage from periventricular NAWM to the center of WMH, we refined current analysis techniques by using deep learning to define smaller segments of white matter, capturing increasing fluid-attenuated inversion recovery signal. Integration of (immuno)histochemistry and PLI with post-mortem imaging of the brains of individuals with hypertension and normotensive controls enables voxel-wise assessment of the pathology throughout periventricular WMH and NAWM. Myelin loss, axonal integrity, and white matter microstructural damage are not limited to WMH but already occur within NAWM. Notably, we found that axonal damage is higher in individuals with hypertension, particularly in NAWM. These findings highlight the added value of advanced segmentation techniques to visualize subtle changes occurring already in NAWM preceding WMH. By using quantitative MRI and advanced diffusion MRI, future studies may elucidate these very early mechanisms leading to neurodegeneration, which ultimately contribute to the conversion of NAWM to WMH.

Association and causal impact of TERT genetic variants on peripheral blood leukocyte telomere length and cerebral small vessel disease risk in a Chinese Han population: a mendelian randomization analysis

BACKGROUND

Previous observational studies have highlighted potential relationships between the telomerase reverse transcriptase (TERT) gene, short leukocyte telomere length (LTL), and cerebrovascular disease. However, it remains to be established as to whether TERT gene variants are associated with an elevated risk of cerebral small vessel disease (CSVD), and whether there is a causal relationship between LTL and CSVD.

METHODS

Five TERT single nucleotide polymorphisms (SNPs) were analyzed in 307 CSVD patients and 320 healthy controls in whom LTL values were quantified. Allele models and four genetic models were used to explore the relationship between these SNP genotypes and CSVD risk. A Mendelian randomization analysis of CSVD risk was then performed using LTL-related SNPs and the polygenic risk score (PRS) constructed from these SNPs as genetic instrumental variables to predict the causal relationship between LTL and CSVD risk.

RESULTS

Model association analyses identified two SNPs that were significantly associated with CSVD risk. LTL was significantly correlated with age (P < 0.001), and the MR analysis revealed an association between short LTL and an elevated risk of CSVD. PRS-based genetic prediction of short LTLs was also significantly related to an elevated CSVD risk.

CONCLUSION

Multiple genetic models and MR results indicate that TERT gene SNPs may be related to an elevated risk of CSVD, and that shorter LTL may be causally linked to such CSVD risk.

Lipids, Apolipoproteins, Lipid-Lowering Drugs, and the Risk of Cerebral Small Vessel Disease: A Mendelian Randomization Study

BACKGROUND

Serum lipids are causally involved in the occurrence of atherosclerosis, but their roles in cerebral small vessel disease remain unclear. This study aimed to investigate the causal roles of lipid or apolipoprotein traits in cerebral small vessel disease and to determine the effects of lipid-lowering interventions on this disease.

METHODS AND RESULTS

Data on genetic instruments of lipids/apolipoproteins, as well as characteristic cerebral small vessel disease manifestations, including small vessel stroke (SVS) and white matter hyperintensity (WMH), were obtained from publicly genome-wide association studies. Through 2-sample Mendelian randomization analyses, it was found that decreased levels of high-density lipoprotein cholesterol (odds ratio [OR], 0.85, P=0.007) and apolipoprotein A-I (OR, 0.83, P=0.005), as well as increased level of triglycerides (OR, 1.16, P=0.025) were associated with a higher risk of SVS. A low level of high-density lipoprotein cholesterol (OR, 0.93, P=0.032) was associated with larger WMH volume. Specifically, the genetically determined expressions of lipid fractions in various size-defined lipoprotein particles were more closely related to the risk of SVS than WMH. Moreover, it was found that the hypertension trait ranked at the top in mediating the causal effect of hyperlipidemia on SVS and WMH by using Mendelian randomization-based mediation analysis. For drug-target Mendelian randomization, the low-density lipoprotein cholesterol-reducing genetic variation alleles at HMGCR and NL1CL1 genes and the high-density lipoprotein cholesterol-raising genetic variation alleles at the CETP gene were predicted to decrease the risk of SVS.

CONCLUSIONS

The present Mendelian randomization study indicates that genetically determined hyperlipidemia is closely associated with a higher risk of cerebral small vessel disease, especially SVS. Lipid-lowering drugs could be potentially considered for the therapies and preventions of SVS rather than WMH.

Causal relationship of inflammatory cytokines and serum metabolites in cerebral small vessel disease: a two-step Mendelian randomization study

BACKGROUND AND PURPOSE

The aim was to investigate the causal relationships of inflammatory cytokines and serum metabolites in cerebral small vessel disease (CSVD).

METHODS

Bidirectional Mendelian randomization was first conducted to screen inflammatory cytokines and serum metabolites that were associated with imaging features of CSVD, including white matter hyperintensities, recent small subcortical infarcts, cortical cerebral microinfarcts, cerebral microbleeds, lacunes and enlarged perivascular spaces. Sensitivity analyses were performed to evaluate the robustness and pleiotropy of these results. Subsequently, inflammatory cytokines and serum metabolites that were associated with CSVD were subjected to functional enrichment. Finally, mediation analysis was employed to investigate whether inflammatory cytokines or serum metabolites acted as an intermediary for the other in their causal relationship with CSVD.

RESULTS

Of the inflammatory cytokines, five were risk factors (e.g., tumour-necrosis-factor-related apoptosis-inducing ligand) and five (e.g., fibroblast growth factor 19) were protective factors for CSVD. Eleven serum metabolites that increased CSVD risk and 13 metabolites that decreased CSVD risk were also identified. The majority of these markers of CSVD susceptibility were lipid metabolites. Natural killer cell receptor sub-type 2B4 was determined to act as a mediating factor of an unidentified metabolite for the enlargement of perivascular spaces.

CONCLUSION

Several inflammatory cytokines and serum metabolites had causal relationships with imaging features of CSVD. A natural killer cell receptor mediated in part the promotional effect of a metabolite on perivascular space enlargement.

Causal effect of cerebral small vessel disease on unexplained dizziness: A Mendelian randomization study

BACKGROUND

Previous cohort studies have suggested an association between cerebral small vessel disease (cSVD) and "unexplained dizziness". The causality of this link remains uncertain, but it would be of significant clinical importance, considering the substantial number of patients presenting with unexplained dizziness is large. We aimed to investigate the causal effect of cSVD-related phenotypes on unexplained dizziness using a Mendelian randomization approach.

METHODS

Genetic instruments for each cSVD-related phenotype - white matter hyperintensity (WMH) volume, lacunar stroke (LS), perivascular spaces (PVS), and cerebral microbleeds (CMBs) - as well as unexplained dizziness were identified through large-scale genome-wide association studies. We conducted 2-sample Mendelian randomization analyses. The random-effects inverse-variance weighted (IVW) method was chosen for the primary analysis. For sensitivity analyses, we employed the weighted-median, MR-Egger, MR pleiotropy residual sum and outlier (MR-PRESSO), and leave-one-out analysis methods were implemented for the sensitivity analyses.

RESULTS

We successfully identified a significant causal effect of WMH volume on unexplained dizziness (odds ratio [95% CI], 1.12 [1.01-1.23]). However, we were unable to detect any significant causal effects of the other cSVD-related phenotypes on unexplained dizziness, with odds ratios [95% CI] of 1.03 [0.98-1.09] for LS, 0.75 [0.55-1.02] for white matter PVS, 1.02 [0.68-1.52] for basal ganglia PVS, 0.80 [0.43-1.51] for hippocampal PVS, 0.95 [0.90-1.00] for lobar CMBs, and 0.97 [0.92-1.01] for mixed CMBs respectively. The results from the sensitivity analyses were generally consistent with those of the primary analyses.

CONCLUSIONS

This MR study supports a causal relationship between WMH, a phenotype associated with cSVD, and the risk of unexplained dizziness, but does not support such a relationship between other cSVD-related phenotypes and unexplained dizziness. These findings require further validation through randomized controlled trials, larger cohort studies, and MR studies based on more extensive GWASs.

Age-associated gadolinium leakage into ocular structures in patients with acute traumatic brain injury

BACKGROUND

Gadolinium Leakage into Ocular Structures (GLOS) is common following acute cerebrovascular events. The objective of this study was to investigate the occurrence of GLOS in an acute traumatic brain injury (TBI) cohort without acute cerebrovascular injury and to explore associated factors.

METHODS

Enrolled acute TBI patients had a baseline MRI ≤48 h of injury (TP1) and follow-up MRI ≤72 h after baseline (TP2). Vitreous chamber enhancement and signal intensity ratios (SIRs) were calculated using pre- and post-contrast Fluid Attenuated Inversion Recovery (FLAIR). White matter hyperintensities (WMHs) were assessed using the Fazekas scale.

RESULTS

Of the 128 TBI patients included, median age was 47 years, 70% male, and 66% presented with Glasgow Coma Scale of 15. No GLOS was detected at TP1 but was present in 23% of patients at TP2. GLOS+ patients were older (68 years [56-76] vs 39 years [27-53], p < 0.001), more likely to report falls as injury mechanism (62% vs 36%, p = 0.006), report history of hypertension (41% vs 19%, p = 0.025), and had a higher burden of WMHs (59% vs 14% with a total Fazekas ≥2, p < 0.001). Quantitative SIRs confirmed qualitative assessments: GLOS+ patients had higher SIRs at TP2 (0.43 vs 0.22, p < 0.001). Age (OR 3.28, 95%CI [1.88-5.71], p < 0.001) and prior TBI history (OR 4.99, 95%CI [1.46-17.06], p = 0.010) were independent predictors of GLOS. When age was removed, total Fazekas score (OR 2.53, 95%CI [1.60-4.00], p < 0.001) was an independent predictor of GLOS.

CONCLUSIONS

GLOS is primarily associated with age and may serve as another imaging marker of chronic vascular disease.

Insulin resistance and white matter microstructural abnormalities in nondiabetic adult: A population-based study

BACKGROUND

Insulin resistance (IR) is of growing concern yet its association with white matter integrity remains controversial. We aimed to investigate the association between IR and white matter integrity in nondiabetic adults.

METHODS

This cross-sectional analysis was conducted based on the PolyvasculaR Evaluation for Cognitive Impairment and vaScular Events (PRECISE) study. A total of 1709 nondiabetic community-dwelling adults with available diffusion-weighted imaging based on brain magnetic resonance imaging and completed oral glucose tolerance test were included. IR was measured noninvasively by insulin sensitivity indices (ISI), including ISIcomposite and ISI0,120, as well as homeostasis model assessment of insulin resistance (HOMA-IR). White matter microstructure abnormalities were identified by diffusion-weighted imaging along with tract-based spatial statistical analysis to compare diffusion metrics between groups. The multivariable linear regression models were applied to measure the association between white matter microstructure abnormalities and IR.

RESULTS

A total of 1709 nondiabetic individuals with a mean age of 60.8 ± 6.4 years and 54.1% female were included. We found that IR was associated with a significant increase in mean diffusivity, axial diffusivity, and radial diffusivity extensively in cerebral white matter in regions such as the anterior corona radiata, superior corona radiata, anterior limb of internal capsule, external capsule, and body of corpus callosum. The pattern of associations was more marked for ISIcomposite and ISI0,120. However, the effect of IR on white matter integrity was attenuated after, in addition, adjustment for history of hypertension and cardiovascular disease and antihypertensive medication use.

CONCLUSION

Our findings indicate a significant association between IR and white matter microstructural abnormalities in nondiabetic middle-aged community residents, while these associations were greatly influenced by the history of hypertension and cardiovascular disease, and antihypertensive medication use. Further investigation is needed to clarify the role of IR in white matter integrity, whereas prophylactic strategies of maintaining a low IR status may ameliorate disturbances in white matter integrity.

DATA ACCESSIBILITY STATEMENT

The data that support the findings of this study are available from the corresponding authors upon reasonable request.

Cerebral arterial stiffness is linked to white matter hyperintensities and perivascular spaces in older adults - A 4D flow MRI study

White matter hyperintensities (WMH), perivascular spaces (PVS) and lacunes are common MRI features of small vessel disease (SVD). However, no shared underlying pathological mechanism has been identified. We investigated whether SVD burden, in terms of WMH, PVS and lacune status, was related to changes in the cerebral arterial wall by applying global cerebral pulse wave velocity (gcPWV) measurements, a newly described marker of cerebral vascular stiffness. In a population-based cohort of 190 individuals, 66-85 years old, SVD features were estimated from T1-weighted and FLAIR images while gcPWV was estimated from 4D flow MRI data. Additionally, the gcPWV's stability to variations in field-of-view was analyzed. The gcPWV was 10.82 (3.94) m/s and displayed a significant correlation to WMH and white matter PVS volume (r = 0.29, p < 0.001; r = 0.21, p = 0.004 respectively from nonparametric tests) that persisted after adjusting for age, blood pressure variables, body mass index, ApoB/A1 ratio, smoking as well as cerebral pulsatility index, a previously suggested early marker of SVD. The gcPWV displayed satisfactory stability to field-of-view variations. Our results suggest that SVD is accompanied by changes in the cerebral arterial wall that can be captured by considering the velocity of the pulse wave transmission through the cerebral arterial network.

A novel rat model of cerebral small vessel disease based on vascular risk factors of hypertension, aging, and cerebral hypoperfusion

Cerebral small vessel disease (CSVD) is a major cause of vascular cognitive impairment and functional loss in elderly patients. Progressive remodeling of cerebral microvessels due to arterial hypertension or other vascular risk factors, such as aging, can cause dementia or stroke. Typical imaging characteristics of CSVD include cerebral microbleeds (CMB), brain atrophy, small subcortical infarctions, white matter hyperintensities (WMH), and enlarged perivascular spaces (EPVS). Nevertheless, no animal models that reflect all the different aspects of CSVD have been identified. Here, we generated a new CSVD animal model using D-galactose (D-gal) combined with cerebral hypoperfusion in spontaneously hypertensive rats (SHR), which showed all the hallmark pathological features of CSVD and was based on vascular risk factors. SHR were hypodermically injected with D-gal (400 mg/kg/d) and underwent modified microcoil bilateral common carotid artery stenosis surgery. Subsequently, neurological assessments and behavioral tests were performed, followed by vascular ultrasonography, electron microscopy, flow cytometry, and histological analyses. Our rat model showed multiple cerebrovascular pathologies, such as CMB, brain atrophy, subcortical small infarction, WMH, and EPVS, as well as the underlying causes of CSVD pathology, including oxidative stress injury, decreased cerebral blood flow, structural and functional damage to endothelial cells, increased blood-brain barrier permeability, and inflammation. The use of this animal model will help identify new therapeutic targets and subsequently aid the development and testing of novel therapeutic interventions. Main process of the study: Firstly, we screened for optimal conditions for mimicking aging by injecting D-gal into rats for 4 and 8 weeks. Subsequently, we performed modified microcoil BCAS intervention for 4 and 8 weeks in rats to screen for optimal hypoperfusion conditions. Finally, based on these results, we combined D-gal for 8 weeks and modified microcoil BCAS for 4 weeks to explore the changes in SHR.

Mismatch of MRI White Matter Hyperintensities and Gait Function in Patients With Cerebral Small Vessel Disease

BACKGROUND

Cerebral small vessel disease (CSVD) is closely related to gait disorders. Previous studies have found a negative correlation between the severity of MRI white matter hyperintensities (WMH) and gait speed. However, not every individual with WMH experiences a gait disorder.

PURPOSE

To investigate the mechanisms underlying the mismatch between the severity of MRI WMH and gait impairment, in particular in subjects with severe WMH (Fazekas 3, scale 0-3) resulting from vascular disease.

STUDY TYPE

Cohort.

POPULATION

54 subjects with severe WMH and gait disorder (WMH-GD; 29 males) and 114 subjects with severe WMH with no gait disorder (WMH-nGD; 60 males).

FIELD STRENGTH/SEQUENCE

3T/diffusion tensor imaging (DTI), and T1-weighted, T2-weighted, FLAIR, DWI, SWI.

ASSESSMENT

Trace-based spatial statistics analysis (TBSS) approach (fractional anisotropy, FA; mean diffusivity; radial diffusivity; axial diffusivity); Cognitive assessment; Conventional MRI markers of CSVD (WMH, enlarged perivascular spaces, lacunae, and cerebral microbleeds); Gait parameters (gait speed; cadence; stride length; gait cycle duration; step duration; time-up-and-go test, TUG). Gait disorder was defined as a TUG time exceeding 12 sec.

STATISTICAL TESTS

The t-tests, Mann-Whitney U tests, Chi-square tests, and partial correlation analysis (Pearson or Spearman) were used. P < 0.05 with threshold-free cluster enhancement corrected was considered statistically significant for TBSS.

RESULTS

After adjusting for age, sex, height, and other conventional MRI markers of CSVD, the WMH-nGD group showed significantly decreased FA values in the corpus callosum, bilateral superior longitudinal fasciculus, left corona radiata, and left posterior thalamic radiation. There was a significant association between FA values and TUG time, gait speed, and stride length in multiple WM tracts, independent of other conventional CSVD markers.

DATA CONCLUSION

This study provides evidence for microstructural damage of specific fibers in WMH-GD subjects compared to WMH-nGD subjects. This may explain the mismatch between WMH and gait impairment in subjects with severe WMH.

LEVEL OF EVIDENCE

1 TECHNICAL EFFICACY: Stage 3.

The structural-functional-connectivity coupling of the aging brain

Aging primarily affects memory and executive functions, a relationship that may be underpinned by the fact that almost all adults over 60 years old develop small vessel disease (SVD). The fact that a wide range of neuropathologies could only explain up to 43% of the variation in age-related cognitive impairment suggests that other factors, such as cognitive reserve, may play a role in the brain's resilience against aging-related cognitive decline. This study aims to examine the relationship between structural-functional-connectivity coupling (SFC), and aging, cognitive abilities and reserve, and SVD-related neuropathologies using a cohort of n = 176 healthy elders from the Harvard Aging Brain Study. The SFC is a recently proposed biomarker that reflects the extent to which anatomical brain connections can predict coordinated neural activity. After controlling for the effect of age, sex, and years of education, global SFC, as well as the intra-network SFC of the dorsolateral somatomotor and dorsal attention networks, and the inter-network SFC between dorsolateral somatomotor and frontoparietal networks decreased with age. The global SFC decreased with total cognitive score. There were significant interaction effects between years of education versus white matter hyperintensities and between years of education versus cerebral microbleeds on inter-network SFC. Enlarged perivascular space in basal ganglia was associated with higher inter-network SFC. Our results suggest that cognitive ability is associated with brain coupling at the global level and cognitive reserve with brain coupling at the inter-functional-brain-cluster level with interaction effect from white matter hyperintensities and cerebral microbleed in a cohort of healthy elderlies.

The Spectrum of Cerebral Small Vessel Disease: Emerging Pathophysiologic Constructs and Management Strategies

Cerebral small vessel disease (CSVD) is a spectrum of disorders that affect small arterioles, venules, cortical and leptomeningeal vessels, perivascular spaces, and the integrity of neurovascular unit, blood brain barrier, and surrounding glia and neurons. CSVD is an important cause of lacunar ischemic stroke and sporadic hemorrhagic stroke, as well as dementia-which will constitute some of the most substantive population and public health challenges over the next century. This article provides an overview of updated pathophysiologic frameworks of CSVD; discusses common and underappreciated clinical and neuroimaging manifestations of CSVD; and reviews emerging genetic risk factors linked to sporadic CSVD.

Recurrent cerebrovascular events after recent small subcortical infarction

BACKGROUND

Recent small subcortical infarcts (RSSI) are the neuroimaging hallmark feature of small vessel disease (SVD)-related acute lacunar stroke. Long-term data on recurrent cerebrovascular events including their aetiology after RSSI are scarce.

PATIENTS AND METHODS

This retrospective study included all consecutive ischaemic stroke patients with an MRI-confirmed RSSI (in the supply area of a small single brain artery) at University Hospital Graz between 2008 and 2013. We investigated associations between clinical and SVD features on MRI (STRIVE criteria) and recurrent cerebrovascular events, using multivariable Cox regression adjusted for age, sex, vascular risk factors and MRI parameters.

RESULTS

We analysed 332 consecutive patients (mean age 68 years, 36% women; median follow-up time 12 years). A recurrent ischaemic cerebrovascular event occurred in 70 patients (21.1%; 54 ischaemic strokes, 22 transient ischaemic attacks) and was mainly attributed to SVD (68%). 26 patients (7.8%) developed intracranial haemorrhage. In multivariable analysis, diabetes (HR 2.43, 95% CI 1.44-3.88), severe white matter hyperintensities (HR 1.97, 95% CI 1.14-3.41), and cerebral microbleeds (HR 1.89, 95% CI 1.32-3.14) on baseline MRI were related to recurrent ischaemic stroke/TIA, while presence of cerebral microbleeds increased the risk for intracranial haemorrhage (HR 3.25, 95% CI 1.39-7.59). A widely used SVD summary score indicated high risks of recurrent ischaemic (HR 1.22, 95% CI 1.01-1.49) and haemorrhagic cerebrovascular events (HR 1.57, 95% CI 1.11-2.22).

CONCLUSION

Patients with RSSI have a substantial risk for recurrent cerebrovascular events-particularly those with coexisting chronic SVD features. Recurrent events are mainly related to SVD again.

Diagnostic Accuracy of Posterior/Anterior Periventricular WMH Ratio to Differentiate CAA From Hypertensive Arteriopathy

BACKGROUND

Periventricular white matter hyperintensities (PVWMHs) in cerebral amyloid angiopathy (CAA) have been reported posterior predominant using semiautomated segmentation method and logarithmic transformation. We aimed to compare PVWMH extent and posterior/anterior distribution between patients with CAA and patients with hypertensive arteriopathy with radiological tools available in daily practice.

METHODS

We retrospectively analyzed confluent PVWMH directly adjacent to lateral ventricles on axial FLAIR (fluid-attenuated inversion recovery) from 108 patients with CAA and 99 patients with hypertensive arteriopathy presenting with hemorrhage-related symptoms consecutively recruited in our stroke database (Nîmes University Hospital, France) between January 2015 and March 2022. For each of the left (L), right (R), anterior (A), and posterior (P) horns of lateral ventricles, the maximal distance between the outer PVWMH border and ventricle border was measured. The sum of anterior left PVWMH and anterior right PVWMH, and posterior left PVWMH and posterior right PVWMH resulted in anterior and posterior extent, respectively.

RESULTS

Compared with hypertensive arteriopathy, patients with CAA were older (median, 77 versus 71; P=0.0010) and less frequently male (46% versus 64%; P=0.012) and had less frequent hypertension (45% versus 63%; P=0.013) and more chronic hemorrhages (P<0.0001). CAA showed slightly more extensive anterior right PVWMH (median, 6.50 versus 5.90 mm; P=0.034), far more extensive (all P<0.0001) posterior left PVWMH (median, 13.95 versus 6.95 mm), posterior right PVWMH (median, 14.15 versus 5.45 mm), posterior (median, 27.95 versus 13.00 mm), and total (median, 39.60 versus 24.65 mm) PVWMH, and higher posterior/anterior ratios (median, 1.82 versus 1.01). Age-/sex-adjusted model predicting CAA incorporating total PVWMH extent and posterior/anterior ratios for the given score (-4.3683+0.0268×PVWMH-T+0.3749×posterior/anterior PVWMH ratio+0.0394×age+0.3046 when female) showed highest area under the curve (0.76 [0.70-0.83]), with a 72% [62.50-80.99] sensitivity and 76% [67.18-84.12] specificity. Values above the optimal threshold of 0.22 for the score showed a crude relative risk of 2.75 (2.26-2.37; P<0.0001).

CONCLUSIONS

Severe posterior PVWMH and high posterior/anterior PVWMH ratio assessed by radiological tools used in daily practice are associated with probable CAA versus hypertensive arteriopathy.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT05486897.

Associations between semi-quantitative evaluation of intracranial arterial calcification and total cerebral small vessel disease burden score: a retrospective case-control study

Background and purpose

Arteriosclerotic cerebral small vessel disease (aCSVD) is a cause of cognitive impairment, dementia, and stroke. Developing a better understanding of the risk factor of aCSVD is key to reducing the incidence of these conditions. This study investigated the association between intracranial arterial calcification (IAC) and total cerebral small vessel disease (CSVD) burden score.

Materials and methods

This is a retrospective study, the subjects were transient ischemic attack (TIA) or acute ischemic stroke (AIS) patients. The data of 303 inpatients admitted to our study hospital between December 2018 and July 2020 were analyzed. Four imaging markers of CSVD (lacunes, white matter hyperintensities, cerebral microbleeds, and enlarged perivascular spaces) were evaluated by magnetic resonance imaging, and a total CSVD burden score was calculated. The experimental group was divided into four subgroups according to total CSVD burden score (1-4 points). Patients without CSVD (0 points) served as the control group. Head computerized tomography (CT) scans were used to assess ICA, using Babiarz's method. The correlations between IAC and single imaging markers of CSVD were determined using Spearman's rank correlation. Binary logic regression analysis and multivariate ordered logic regression analysis were used to determine the associations between IAC and aCSVD.

Results

IAC was positively correlated with total CSVD burden score (r = 0.681), deep white matter hyperintensities (r = 0.539), periventricular white matter hyperintensities (r = 0.570), cerebral microbleeds (r = 0.479), lacunes (r = 0.541), and enlarged perivascular spaces (r = 0.554) (all p < 0.001). After adjusting for the confounding factors of age, diabetes, and hypertension, aCSVD was independently associated with IAC grade 1-2 [odds ratio (OR) = 23.747, 95% confidence interval (CI) = 8.376-67.327] and IAC grade 3-4 (OR = 30.166, 95% CI = 8.295-109.701). aCSVD severity was independently associated with IAC grade 3-4 (OR = 4.697, 95% CI = 1.349-16.346).

Conclusion

IAC is associated with the total CSVD burden score and single imaging signs.

Small vessel disease burden predicts incident stroke and all-cause death, but not acute coronary event

Total small vessel disease (SVD) score is used to measure the burden of SVD by incorporating four established neuroimaging markers; white matter hyperintensity, lacune, cerebral microbleed, and enlarged perivascular space, ranging from 0 to 4. Whether total SVD scores predict all vascular outcomes remains unclear. This study aimed to clarify the predictive value of the total SVD score for incident stroke, mortality, and acute coronary syndrome in independent outpatients with vascular risk factors. We derived data from The Tokyo Women's Medical University Cerebrovascular Disease registry, a prospective observational registry in which 1011 patients with evidence of cerebral vessel disease on magnetic resonance imaging were enrolled. They were followed up until March 2023. The primary outcomes were stroke, all-cause death, and acute coronary syndrome (ACS). After excluding those with a modified Rankin scale score >1, Mini-mental State Examination score <24, and missing T2* images, 692 patients were included. During a median follow-up period of 4.6 years, stroke, ACS, and all-cause death occurred in 52, 24, and 45 patients, respectively. In multivariate analysis, the total SVD score was independently associated with stroke, and all-cause death but not with acute coronary syndrome. Both cutoff values of the total SVD score for stroke, and all-cause death were 1. In conclusion, the total SVD score could predict stroke and mortality but not acute coronary syndrome. Our results suggest intensive management of patients with a total SVD score ≥1 to prevent stroke and all-cause death. Patients with higher total SVD scores were significantly more likely to have a stroke (A; P = 0.012) than those with lower total SVD scores. However, no association was observed between total SVD scores and acute coronary syndrome (B, P = 0.604). For incident stroke, total SVD scores of 1 and 2 were the cutoff levels.