MRI-visible perivascular spaces in basal ganglia but not centrum semiovale or hippocampus were related to deep medullary veins changes

Simultaneous measurement of cerebral blood flow and cerebrospinal fluid flow using pseudo-continuous arterial spin labeling

In the brain clearance system, the movement of cerebrospinal fluid (CSF) plays a key role in processing waste products. Previous studies have shown that CSF flow interacts significantly with cerebral blood flow (CBF) during brain waste clearance, but there are no simultaneous measurements and comparisons of these two metrics in humans. This study introduces a novel method for simultaneously measuring CSF pulsatile movement and CBF using pseudo-continuous arterial spin labeling (pCASL) MRI. We conducted a comparative analysis of the correlation between CBF and CSF pulsatile movement in human subjects during breath-holding and motor task conditions. Our findings demonstrate the effectiveness of our proposed technique in measuring CSF pulsatile movement, as validated by comparing results with phase-contrast MRI at corresponding locations. Importantly, we observed a robust positive correlation between CBF and CSF pulsation concurrently measured through pCASL during breath-holding. Furthermore, through inter-subject comparisons of regional CBF and CSF pulsation, we established that higher blood perfusion in putamen, caudate, and pallidum regions, which are included in basal ganglia structure, corresponds to greater CSF pulsatile movement. Our motor tasks significantly increased CBF in the motor cortex, and CSF pulsation measured in the dorsal part around cisterna magna showed a decreasing tendency in the motor condition compared to the resting state, aligning with the Monroe-Kelly doctrine. Accordingly, these results demonstrate the feasibility of simultaneous measurement of CBF and CSF pulsation using the proposed pCASL technique in humans, which warrants further investigation.

Unveiling connections between venous disruption and cerebral small vessel disease using diffusion tensor image analysis along perivascular space (DTI-ALPS): A 7-T MRI study

BACKGROUND

Cerebral venous disruption is one of the characteristic findings in cerebral small vessel disease (CSVD), and its disruption may impede perivascular glymphatic drainage. And lower diffusivity along perivascular space (DTI-ALPS) index has been suggested to be with the presence and severity of CSVD. However, the relationships between venous disruption, DTI-ALPS index, and CSVD neuroimaging features remain unclear.

AIMS

To investigate the association between venous integrity and perivascular diffusion activity, and explore the mediating role of DTI-ALPS index between venous disruption and CSVD imaging features.

METHODS

In this cross-sectional study, 31 patients (mean age, 59.0 ± 9.9 years) were prospectively enrolled and underwent 7-T magnetic resonance (MR) imaging. DTI-ALPS index was measured to quantify the perivascular diffusivity. The visibility and continuity of deep medullary veins (DMVs) were evaluated based on a brain region-based visual score on high-resolution susceptibility-weighted imaging. White matter hyperintensity (WMH) and perivascular space (PVS) were assessed using qualitative and quantitative methods. Linear regression and mediation analysis were performed to analyze the relationships among DMV scores, DTI-ALPS index, and CSVD features.

RESULTS

The DTI-ALPS index was significantly associated with the parietal DMV score (β = -0.573, p corrected = 0.004). Parietal DMV score was associated with WMH volume (β = 0.463, p corrected = 0.013) and PVS volume in basal ganglia (β = 0.415, p corrected = 0.028). Mediation analyses showed that DTI-ALPS index manifested a full mediating effect on the association between parietal DMV score and WMH (indirect effect = 0.115, Pm = 43.1%), as well as between parietal DMV score and PVS volume in basal ganglia (indirect effect = 0.161, Pm = 42.8%).

CONCLUSION

Cerebral venous disruption is associated with glymphatic activity, and with WMH and PVS volumes. Our results suggest cerebral venous integrity may play a critical role in preserving perivascular glymphatic activity; while disruption of small veins may impair the perivascular diffusivity, thereby contributing to the development of WMH and PVS enlargement.

Association of decreased visibility on deep medullary vein gray-matter volume mediated by increased extracellular fluid in the white matter of patients with cerebral small vessel disease

Background

The visibility and signal continuity of deep medullary veins (DMVs) play an important role in cerebral small vessel disease (CSVD). However, the relationship between DMV and gray-matter atrophy remains unclear. This study sought to investigate the link between DMV scores, extracellular fluid, and gray-matter atrophy in patients with CSVD.

Methods

We reviewed the clinical and multimodal magnetic resonance imaging data from 123 patients diagnosed with CSVD between January and December 2022. The DMV score was assessed using a scoring system (0 to 3 points) based on DMV visibility on susceptibility-weighted images across six anatomical regions, yielding a final score from 0 to 18. Extracellular fluid was assessed through the metric of free water (FW) in normal-appearing white matter (NAWM). Normalized gray-matter volume (GM_N) was used to quantify the gray-matter volume, defined as the ratio of gray-matter volume to intracranial volume. Spearman correlation, general linear model, and mediation analyses were employed to evaluate the relationships among variables.

Results

Spearman correlation analysis revealed a positive correlation between DMV score and FW in NAWM (r=0.603; P<0.001). General linear model analysis confirmed this association as independent [β=0.656, 95% confidence interval (CI) 0.521-0.790; P<0.001]. Conversely, FW in NAWM showed a negative correlation with GM_N (r=-0.485; P<0.001), with an independent association confirmed by general linear model analysis (β=-0.630, 95% CI: -0.769 to -0.491; P<0.001). Additionally, the DMV score was negatively correlated with GM_N (r=-0.390; P<0.001), as supported by a significant association in general linear model analysis (β=-0.502, 95% CI: -0.657 to 0.348; P<0.001). Mediation analysis indicated a significant indirect effect of FW in NAWM on the relationship between DMV score and GM_N (β=-0.346, 95% CI: -0.534 to -0.187; P<0.001). All associations were remained significant after adjustments were made for age, gender, vascular risk factors, normalized white-matter hyperintensity volume, and CSVD burden.

Conclusions

The observed link between DMV disruption and FW in NAWM-GM_N suggests that DMV dysfunction may contribute to gray-matter atrophy in CSVD by increasing extracellular fluid. This identifies DMV changes as a key factor in CSVD pathology and supports the potential of targeting extracellular fluid as a therapeutic strategy to mitigate gray-matter loss.

Salidroside promotes pro-angiogenesis and repair of blood brain barrier via Notch/ITGB1 signal path in CSVD Model

INTRODUCTION

Salidroside (SAL), extracted from Rhodiola rosea, has been widely used in coronary heart disease and myocardial ischemia for decades. Previous studies have demonstrated that SAL could reduce arteriosclerosis, and thus combat ischemic brain damage. However, the in-depth function of the salidroside in Cerebral Small Vascular Disease (CSVD) has not been discovered, and related molecular mechanism is still unclear.

OBJECTIVES

The present study aims to explore the effects of salidroside in angiogenesis as well as repair of blood brain barrier (BBB) and its possible mechanisms.

METHODS

We established a rat model of SHR via 2-vessel gradual occlusion (SHR-2VGO) to mimic the CSVD. Subsequently, the MRI, pathomorphism, as well as Morriss water maze test were conducted to determine CSVD-related indicators. 8 weeks post-surgery, animals were randomly administered SAL, DAPT, ATN161 or saline.The aim was to explore the protective effects of SAL in CSVD as well as its possible mechanism.

RESULTS

Here we found that SAL could attenuate cerebral hypoperfusion-induced BBB disruption, promote the pro-angiogenesis through enhancing the cell budding. Further investigations demonstrated that SAL could significantly increase the expression of Notch1, Hes1, Hes5, and ITGB1. In addition, we confirmed that SAL could activate Notch signal path, and then up-regulate ITGB1 to promote pro-angiogenesis and thus protect BBB from disruption.

CONCLUSION

The aforementioned findings demonstrated that SAL could protect BBB integrity through Notch-ITGB1 signaling path in CSVD, which indicated that SAL could be a potential medicine candidate for CSVD treatment.

Spatial Similarity of MRI-Visible Perivascular Spaces in Healthy Young Adult Twins

PURPOSE

This study aimed to determine whether genetic factors affect the location of dilated perivascular spaces (dPVS) by comparing healthy young twins and non-twin (NT) siblings.

MATERIALS AND METHODS

A total of 700 healthy young adult twins and NT siblings [138 monozygotic (MZ) twin pairs, 79 dizygotic (DZ) twin pairs, and 133 NT sibling pairs] were collected from the Human Connectome Project dataset. dPVS was automatically segmented and normalized to standard space. Then, spatial similarity indices [mean squared error (MSE), structural similarity (SSIM), and dice similarity (DS)] were calculated for dPVS in the basal ganglia (BGdPVS) and white matter (WMdPVS) between paired subjects before and after propensity score matching of dPVS volumes between groups. Within-pair correlations for the regional volumes of dVPS were also assessed using the intraclass correlation coefficient.

RESULTS

The spatial similarity of dPVS was significantly higher in MZ twins [higher DS (median, 0.382 and 0.310) and SSIM (0.963 and 0.887) and lower MSE (0.005 and 0.005) for BGdPVS and WMdPVS, respectively] than in DZ twins [DS (0.121 and 0.119), SSIM (0.941 and 0.868), and MSE (0.010 and 0.011)] and NT siblings [DS (0.106 and 0.097), SSIM (0.924 and 0.848), and MSE (0.016 and 0.017)]. No significant difference was found between DZ twins and NT siblings. Similar results were found even after the subjects were matched according to dPVS volume. Regional dPVS volumes were also more correlated within pairs in MZ twins than in DZ twins and NT siblings.

CONCLUSION

Our results suggest that genetic factors affect the location of dPVS.

Deep medullary vein damage correlates with small vessel disease in small vessel occlusion acute ischemic stroke

OBJECTIVES

We aim to investigate whether cerebral small vessel disease (cSVD) imaging markers correlate with deep medullary vein (DMV) damage in small vessel occlusion acute ischemic stroke (SVO-AIS) patients.

METHODS

The DMV was divided into six segments according to the regional anatomy. The total DMV score (0-18) was calculated based on segmental continuity and visibility. The damage of DMV was grouped according to the quartiles of the total DMV score. Neuroimaging biomarkers of cSVD including white matter hyperintensity (WMH), cerebral microbleed (CMB), perivascular space (PVS), and lacune were identified. The cSVD score were further analyzed.

RESULTS

We included 229 SVO-AIS patients, the mean age was 63.7 ± 23.1 years, the median NIHSS score was 3 (IQR, 2-6). In the severe DMV burden group (the 4th quartile), the NIHSS score grade (6 (3-9)) was significantly higher than other groups (p < 0.01). The grade scores for basal ganglia PVS (BG-PVS) were positively correlated with the degree of DMV (R = 0.67, p < 0.01), rather than centrum semivole PVS (CS-PVS) (R = 0.17, p = 0.1). In multivariate analysis, high CMB burden (adjusted odds ratio [aOR], 25.38; 95% confidence interval [CI], 1.87-345.23) was associated with severe DMV scores. In addition, BG-PVS was related to severe DMV burden in a dose-dependent manner: when BG-PVS score was 3 and 4, the aORs of severe DMV burden were 18.5 and 12.19, respectively.

CONCLUSION

The DMV impairment was associated with the severity of cSVD, which suggests that DMV burden may be used for risk stratification in SVO-AIS patients.

CLINICAL RELEVANCE STATEMENT

The DMV damage score, based on the association between small vessel disease and the deep medullary veins impairment, is a potential new imaging biomarker for the prognosis of small vessel occlusion acute ischemic stroke, with clinical management implications.

KEY POINTS

• The damage to the deep medullary vein may be one mechanism of cerebral small vessel disease. • Severe burden of the basal ganglia perivascular space and cerebral microbleed is closely associated with significant impairment to the deep medullary vein. • The deep medullary vein damage score may reflect a risk of added vascular damage in small vessel occlusion acute ischemic stroke patients.

Discontinuity of deep medullary veins in SWI is associated with deep white matter hyperintensity volume and cognitive impairment in cerebral small vessel disease

BACKGROUND

Discontinuation of the deep medullary veins (DMVs) may be an early imaging marker for identifying cognitive impairment caused by cerebral small vessel disease (CSVD). However, this method lacks mechanistic exploration. We aimed to investigate whether the DMV score is related to CSVD imaging markers and cognitive impairment in patients with CSVD.

METHODS

This retrospective study included patients with CSVD who completed DMV score and cognition (e.g., MMSE, MoCA) assessments, and underwent MRI scanning (T2-FLAIR for white matter hyperintensities (WMH) volume, T1-weighted MRI for brain parenchymal fractions (BPF) analysis, and SWI for assessment of DMV score). The CSVD imaging markers were quantitatively assessed using the AccuBrain® system. We assessed the diagnostic value of neuroimaging biomarkers for detecting CSVD-related cognitive impairment. In addition, we explored the relationship between the DMV score, CSVD imaging markers, and cognition using mediation analysis.

RESULTS

Ninety-four patients with CSVD were divided into a cognitive impairment group (n = 39) and a non-cognitive impairment group (n = 55). Higher DMV scores, larger WMH volumes, and smaller BPF were observed in the cognitive impairment group than those in the non-cognitive impairment group. Receiver operating characteristics (ROC) analysis revealed that the discovery value of the integration of patient age, BPF, whole WMH volume, and DMV score for cognitive impairment was 0.742, with a sensitivity and specificity of 79.5 % and 61.5 %, respectively. Mediation analysis showed mediation by WMH and BPF in the relationship between DMV score and cognitive impairment (all P < 0.05).

LIMITATIONS

This study did not evaluate the DMV score in subregions according to DMV anatomy.

CONCLUSIONS

The DMV score is significantly associated with cognitive impairment in patients with CSVD, and this association is mediated through WMH and BPF.

Enlarged perivascular spaces predict malignant cerebral edema after acute large hemispheric infarction

INTRODUCTION

Enlarged perivascular spaces (EPVS) are considered early manifestations of impaired clearance mechanisms in the brain; however, it is unclear whether EPVS they are associated with the development of malignant cerebral edema (MCE) after large hemispheric infarction (LHI). Therefore, we investigated the predictive value of EPVS in predicting MCE in LHI.

METHODS

Patients suffering from acute LHI were consecutively enrolled. EPVS were rated after the stroke with validated rating scales from magnetic resonance imagess. Patients were divided into two groups according to the occurrence of MCE. Logistic regression was used to analyze the relationship between EPVS and MCE in the basal ganglia (BG) and centrum semiovale (CS) regions. Receiver operating characteristic (ROC) curves assessed the ability of EPVS individually and with other factors in predicting MCE.

RESULTS

We included a total of 255 patients, of whom 98 were MCE patients (58 [59.2%] males, aged 70 [range=61.75-78] years) and found that atrial fibrillation, National Institutes of Health Stroke Scale score, infarct volume, neutrophil-lymphocyte ratio, and moderate-to-severe CS-EPVS were positively associated with MCE. After adjusting for confounds, moderate-to-severe CS-EPVS remained independent risk factor of MCE (odds ratio=16.212, p＜0.001). According to the ROC analysis, MCE was highly suspected when CS-EPVS > 14 (sensitivity=0.82, specificity=0.48), and the guiding value were higher when CS-EPVS combined with other MCE predictors (area under the curve=0.90, sensitivity=0.74, specificity=0.90).

CONCLUSION

CS-EPVS were important risk factor for MEC in patients with acute LHI and can help identify patients at risk for MCE.

Deep vein diameters and perivascular space scores are associated with deep medullary vein hypo-visibility in patients with white matter hyperintensity

Background

Deep medullary vein (DMV) hypo-visibility is correlated with white matter hyperintensity (WMH), but the underlying causes remain unclear. This study aimed to explore the relationship between deep vein diameters and perivascular space (PVS) scores, and DMV hypo-visibility in the presence of WMH.

Methods

This cross-sectional study prospectively analyzed the clinical and imaging data of 190 cerebral small vessel disease patients with WMH and 40 healthy controls from the Lishui Hospital of Traditional Chinese Medicine affiliated with Zhejiang Chinese Medical University. PVS scores ranging from 0 to 4 were determined according to the PVS counts in the basal ganglia area on T2-weighted magnetic resonance images; high-grade PVS was defined as a PVS score >1. The diameters of the deep cerebral veins, including the bilateral septal veins (SVs), thalamostriate veins (TSVs), lateral ventricular veins (LVVs), and internal cerebral veins, were measured using susceptibility weighted imaging (SWI). Left and right DMV scores, ranging from 0 to 9, were calculated based on the visibility of the DMV on SWI in the ipsilateral frontal, parietal, and occipital lobes.

Results

The deep cerebral vein diameters, left and right DMV scores, and high-grade PVS differed between the healthy controls and WMH patients (P<0.05). Left DMV scores were independently associated with age {β [95% confidence interval (CI)]: 0.050 (0.018, 0.082)}, high-grade PVS [β (95% CI): 0.998 (0.262, 1.737)], and the diameters of the ipsilateral SVs [β (95% CI): -1.114 (-1.754, -0.475)], SVs [β (95% CI): -0.734 (-1.191, -0.277)], and LVVs [β (95% CI): -0.921 (-1.567, -0.275)] [all false discovery rate (FDR)-corrected P<0.05]. Right DMV scores were independently associated with age [β (95% CI): 0.071 (0.037, 0.105)], high-grade PVS [β (95% CI): 0.873 (0.111, 1.635)], and the diameters of the ipsilateral SVs [β (95% CI): -0.837 (-1.386, -0.289)], TSVs [β (95% CI): -0.875 (-1.331, -0.419)], and LVVs [β (95% CI): -1.813 (-2.484, -1.142)] (all FDR-corrected P<0.05).

Conclusions

Decreased hypo-visibility of DMVs on SWI was associated with a higher age, the presence of high-grade PVS, and smaller diameters of the ipsilateral deep cerebral veins in individuals with WMH. Our findings provide novel insights into the probable mechanisms leading to high DMV scores.

Causal relationship between inflammatory factors and cerebral small vessel disease: Univariate, multivariate, and summary-data-based mendelian randomization analysis

OBJECTIVE

To explore the impact of inflammatory factors on the incidence of cerebral small vessel disease (CSVD), we performed a mendelian randomization (MR) study to analyze the causal relationship between multiple inflammatory factors and CSVD imaging markers and utilized summary-data-based mendelian randomization (SMR) analysis to infer whether the impact of instrumental variables (IVs) on disease is mediated by gene expression or DNA methylation.

METHODS

Using public databases such as UKB and IEU, and original genome-wide association studies, we obtained IVs related to exposure (inflammatory factors) and outcome (CSVD imaging markers). We performed the inverse variance weighted, weighted median, and MR-Egger methods to assess causal effects between exposure and outcome in univariate MR analysis. To evaluate their heterogeneity, a series of sensitivity analyses were conducted, including the Cochrane Q test, MR-Egger intercept test, MR-Presso, and leave-one-out analysis. We also applied mediation and multivariate MR analysis to explore the interactions between positive exposures on the same outcome. Additionally, we conducted the SMR, which utilizes instruments within or near relevant genes in blood or brain tissues, to elucidate the causal associations with CSVD markers.

RESULTS

ABO Univariate MR of multiple cohorts revealed that the risk of small vessel stroke (SVS) increases with elevated levels of TNF-related apoptosis-inducing ligand (TRAIL, OR, 1.23, 95% CI, 1.08-1.39) and interleukin-1 receptor-like 2, (IL-1RL2, OR, 1.29, 95% CI, 1.04-1.61). IL-18 was a potential risk factor for extensive basal ganglia perivascular space burden (BGPVS, OR, 1.02, 95% CI, 1.00-1.05). Moreover, the risk of extensive white matter perivascular space burden (WMPVS) decreased with rising levels of E-selectin (OR, .98, 95% CI, .97-1.00), IL-1RL2 (OR, .97, 95% CI, .95-1.00), IL-3 receptor subunit alpha (IL-3Ra, OR, .98, 95% CI, .97-1.00), and IL-5 receptor subunit alpha (IL-5Ra, OR, .98, 95% CI, .97-1.00). Mediation and multivariate MR analysis indicated that E-selectin and IL-3Ra might interact during the pathogenesis of WMPVS. SMR estimates showed that TRAIL-related IVs rs5030044 and rs2304456 increased the risk of SVS by increasing the expression of gene Kininogen-1 (KNG1) in the cerebral cortex, particularly in the frontal cortex (βsmr = .10, Psmr = .003, FDR = .04). Instruments (rs507666 and rs2519093) related to E-selectin and IL-3Ra could increase the risk of WMPVS by enhancing DNA methylation of the gene ABO in blood tissue (βsmr = .01-.02, Psmr = .001, FDR = .01-.03).

CONCLUSION

According to MR and SMR analysis, higher levels of TRAIL increased the risk of SVS by upregulating gene expression of KNG1 in brain cortex tissues. In addition, protective effects of E-selectin and IL-3a levels on WMPVS were regulated by increased DNA methylation of gene ABO in blood tissue.

MRI-visible enlarged perivascular spaces in basal ganglia rather than centrum semiovale was associated with aneurysmal subarachnoid hemorrhage

Background

The subarachnoid space is continuous with the perivascular compartment in the central nervous system. However, whether the topography and severity of enlarged perivascular spaces (EPVS) correlates with spontaneous subarachnoid hemorrhage (SAH) remains unknown. Based on the underlying arteriopathy distributions, we hypothesized that EPVS in basal ganglia (BG-EPVS) are more closely associated with aneurysmal subarachnoid hemorrhage (aSAH) than other SAH without aneurysm.

Methods

Magnetic resonance imaging (MRI) scans of 271 consecutive SAH survivors with and without aneurysm were analyzed for EPVS and other markers of imaging data. In the subgroup analysis, we compared the clinical characteristics and EPVS of SAH participants with and without pre-existing known risk factors (hypertension, diabetes, and smoking history) using multivariable logistic regression.

Results

Patients with aSAH (n = 195) had a higher severity of BG-EPVS and centrum semiovale EPVS (CSO-EPVS) than those without aneurysm (n = 76). Importantly, BG-EPVS predominance pattern (BG-EPVS>CSO-EPVS) only existed in aSAH survivors rather than other SAH without aneurysm. In the subgroup analysis, interestingly, we also found that a high degree of BG-EPVS showed an independent relationship with aSAH in patients without pre-existing risk factors (e.g., hypertension).

Conclusion

In this cohort study, BG-EPVS predominance pattern was associated with aSAH patients compared with those without aneurysm. Moreover, BG-EPVS still showed a strong association with aSAH survivors without pre-existing vascular risk factors. Our present study suggested the BG-EPVS as a potential MRI-visible characteristic would shed light on the pathogenesis of glymphatic function at the skull base for aSAH.

Imaging the neurovascular unit in health and neurodegeneration: a scoping review of interdependencies between MRI measures

The neurovascular unit (NVU) is a complex structure that facilitates nutrient delivery and metabolic waste clearance, forms the blood-brain barrier (BBB), and supports fluid homeostasis in the brain. The integrity of NVU subcomponents can be measured in vivo using magnetic resonance imaging (MRI), including quantification of enlarged perivascular spaces (ePVS), BBB permeability, cerebral perfusion and extracellular free water. The breakdown of NVU subparts is individually associated with aging, pathology, and cognition. However, how these subcomponents interact as a system, and how interdependencies are impacted by pathology remains unclear. This systematic scoping review identified 26 studies that investigated the inter-relationships between multiple subcomponents of the NVU in nonclinical and neurodegenerative populations using MRI. A further 112 studies investigated associations between the NVU and white matter hyperintensities (WMH). We identify two putative clusters of NVU interdependencies: a 'vascular' cluster comprising BBB permeability, perfusion and basal ganglia ePVS; and a 'fluid' cluster comprising ePVS, free water and WMH. Emerging evidence suggests that subcomponent coupling within these clusters may be differentially related to aging, neurovascular injury or neurodegenerative pathology.

Cerebral venous congestion alters brain metabolite profiles, impairing cognitive function

Vascular cognitive impairment (VCI) represents the second most common cause of dementia after Alzheimer's disease, and pathological changes in cerebral vascular structure and function are pivotal causes of VCI. Cognitive impairment caused by arterial ischemia has been extensively studied the whole time; the influence of cerebral venous congestion on cognitive impairment draws doctors' attention in recent clinical practice, but the underlying neuropathophysiological alterations are not completely understood. This study elucidated the specific pathogenetic role of cerebral venous congestion in cognitive-behavioral deterioration and possible electrophysiological mechanisms. Using cerebral venous congestion rat models, we found these rats exhibited decreased long-term potentiation (LTP) in the hippocampal dentate gyrus and impaired spatial learning and memory. Based on untargeted metabolomics, N-acetyl-L-cysteine (NAC) deficiency was detected in cerebral venous congestion rats; supplementation with NAC appeared to ameliorate synaptic deficits, rescue impaired LTP, and mitigate cognitive impairment. In a cohort of cerebral venous congestion patients, NAC levels were decreased; NAC concentration was negatively correlated with subjective cognitive decline (SCD) score but positively correlated with mini-mental state examination (MMSE) score. These findings provide a new perspective on cognitive impairment and support further exploration of NAC as a therapeutic target for the prevention and treatment of VCI.

Deep Medullary Vein and MRI Markers Were Related to Cerebral Hemorrhage Subtypes

BACKGROUND

To explore the performance of deep medullary vein (DMV) and magnetic resonance imaging (MRI) markers in different intracerebral hemorrhage (ICH) subtypes in patients with cerebral small vessel disease (CSVD).

METHODS

In total, 232 cases of CSVD with ICH were included in this study. The clinical and image data were retrospectively analyzed. Patients were divided into hypertensive arteriopathy (HTNA)-related ICH, cerebral amyloid angiopathy (CAA)-related ICH, and mixed ICH groups. The DMV score was determined in the cerebral hemisphere contralateral to the ICH.

RESULTS

The DMV score was different between the HTNA-related and mixed ICH groups (p < 0.01). The MRI markers and CSVD burden score were significant among the ICH groups (p < 0.05). Compared to mixed ICH, HTNA-related ICH diagnosis was associated with higher deep white matter hyperintensity (DWMH) (OR: 0.452, 95% CI: 0.253-0.809, p < 0.05) and high-degree perivascular space (PVS) (OR: 0.633, 95% CI: 0.416-0.963, p < 0.05), and CAA-related ICH diagnosis was associated with increased age (OR: 1.074; 95% CI: 1.028-1.122, p = 0.001). The DMV score correlated with cerebral microbleed (CMB), PVS, DWMH, periventricular white matter hyperintensity (PWMH), and CSVD burden score (p < 0.05) but not with lacuna (p > 0.05). Age was an independent risk factor for the severity of DMV score (OR: 1.052; 95% CI: 0.026-0.076, p < 0.001).

CONCLUSION

DMV scores, CSVD markers, and CSVD burden scores were associated with different subtypes of ICH. In addition, DMV scores were associated with the severity of CSVD and CSVD markers.

Potential role of plasma branched-chain amino acids in the differential diagnosis of acute cerebral venous thrombosis

Cerebral venous thrombosis (CVT) is a special and easily misdiagnosed or undiagnosed subtype of stroke. To identify specific biomarkers with a high predictive ability for the diagnosis of acute CVT, we performed metabolomic analysis in plasma samples from acute CVT patients and healthy controls and confirmed the results in validation cohorts. In the discovery stage, there were 343 differential metabolites, and the caffeine metabolism pathway and the biosynthesis pathway for the branched chain amino acids (BCAAs) valine, leucine, and isoleucine were two significant pathways between the CVT and healthy cohorts. The area under the curve (AUC) for metabolites associated with valine, leucine, and isoleucine biosynthesis was 0.934. In the validation stage, the BCAA concentrations demonstrated an AUC of 0.935 to differentiate patients with acute CVT from the control cohort. In addition, BCAAs combined with D-dimer levels were used to establish a diagnostic model for CVT, and the AUC was 0.951, showing good diagnostic efficacy of separating CVT patients from the control cohort. BCAAs as plasma biomarkers deserve to be further studied and even developed in clinical CVT management.

Examining temporal features of BOLD-based cerebrovascular reactivity in clinical populations

Background

Conventional cerebrovascular reactivity (CVR) estimation has demonstrated that many brain diseases and/or conditions are associated with altered CVR. Despite the clinical potential of CVR, characterization of temporal features of a CVR challenge remains uncommon. This work is motivated by the need to develop CVR parameters that characterize individual temporal features of a CVR challenge.

Methods

Data were collected from 54 adults and recruited based on these criteria: (1) Alzheimer's disease diagnosis or subcortical Vascular Cognitive Impairment, (2) sleep apnea, and (3) subjective cognitive impairment concerns. We investigated signal changes in blood oxygenation level dependent (BOLD) contrast images with respect to hypercapnic and normocapnic CVR transition periods during a gas manipulation paradigm. We developed a model-free, non-parametric CVR metric after considering a range of responses through simulations to characterize BOLD signal changes that occur when transitioning from normocapnia to hypercapnia. The non-parametric CVR measure was used to examine regional differences across the insula, hippocampus, thalamus, and centrum semiovale. We also examined the BOLD signal transition from hypercapnia back to normocapnia.

Results

We found a linear association between isolated temporal features of successive CO₂ challenges. Our study concluded that the transition rate from hypercapnia to normocapnia was significantly associated with the second CVR response across all regions of interest (p < 0.001), and this association was highest in the hippocampus (R² = 0.57, p < 0.0125).

Conclusion

This study demonstrates that it is feasible to examine individual responses associated with normocapnic and hypercapnic transition periods of a BOLD-based CVR experiment. Studying these features can provide insight on between-subject differences in CVR.

Associations of deep medullary veins with vascular risk factors, laboratory indicators, and cerebral small vessel disease: A population-based study

OBJECTIVE

Deep medullary veins (DMVs) were not considered a typical marker of cerebral small vessel disease (CSVD) due to limited understanding of their involvement in pathology of CSVD. This study aimsto investigate potential vascular risk factors for DMVs and their associations with CSVD.

METHODS

In total, 1909 community-dwelling participants were included in this analysis. Demographic, clinical, laboratory, and imaging data were collected. DMV scores (0-18) werecalculated as the sum of bilateral frontal, parietal, and occipital regional scores using a semiquantitative visual scale (0-3). The presence, total burden, and imaging markers of CSVD were assessed. Linear regression analyses were conducted to explore potential vascular factors for DMV scores. Binary and ordinal logistic regression analyses were performed to investigate the associations of DMV scores with CSVD and its markers.

RESULTS

Mean age was 61.8 (SD 6.5) years, and 1027 (53.8%) of participants were men. The median DMV scores were14 (IQR 12-16). DMV scores wererelated to age, male sex, body mass index, diastolic blood pressure, hypercholesterolaemia, atrial fibrillation, current drinking, total cholesterol, triglycerides, low-density lipoprotein, hemoglobin A1c, leukocytes, lymphocytes, hemoglobin, and platelets (p < .05). DMV scores wereassociated with the presence and total burden of CSVD (Rothwell's scale), modified white matter hyperintensity burden, and enlarged perivascular spaces in centrum semiovale (p < .05). However, these associations between DMV scores and CSVD disappeared after adjusting for potential confounders.

CONCLUSION

Several conventional vascular factors were associated with DMVs. The relationship between DMVs and CSVD was vulnerable, suggesting decreased visible and discontinuous DMVs may differ mechanistically from traditional markers of CSVD.

Effect of dynamic cerebral autoregulation on the association between deep medullary vein changes and cerebral small vessel disease

Changes in the deep medullary vein (DMV) are reported to be associated with cerebral small vessel disease (CSVD). While the mechanisms of this association are unclear, dynamic cerebral autoregulation (dCA) has been speculated to participate in this association. Thus, we aimed to verify the association between DMV changes and total CSVD burden and further investigate the effect of dCA function on this correlation. In this prospective study, 95 Asian patients aged ≥18 years were included in the final assessment. DMV scores and total CSVD burden were determined using magnetic resonance imaging sequences. Transfer function analysis was performed to analyze dCA function. Generalized linear regressions were used to assess the relationship between DMV changes and total CSVD burden as well as between DMV changes and dCA function. An interaction model was utilized to assess the effect of dCA function on the association between DMV changes and total CSVD burden. Generalized linear models showed a significant positive association between DMV changes and total CSVD burden (p = 0.039) and a significant negative association between DMV changes and dCA function (p = 0.018). The interaction model demonstrated a significant positive interaction of dCA impairment on the association between DMV changes and the total CSVD burden (p = 0.02). Thus, we came to the conclusion that changes in DMV were correlated independently with both CSVD and dCA impairment and furthermore, impaired dCA function play an interaction effect on the association between DMV changes and the total CSVD burden. Our results can help improve the understanding of the complex pathogenesis and progression of CSVD, thereby facilitating early intervention and treatment development.

Risk factors of impaired employability after cerebral venous thrombosis

AIMS

Cerebral venous thrombosis (CVT) is a major cause of stroke in young and middle-aged adults. This study aimed to evaluate the prevalence of post-CVT employability decline and identify factors associated with unemployment.

METHODS

We identified patients first diagnosed with acute/subacute CVT at Xuanwu Hospital, Capital Medical University (January 2018 to June 2021) and invited all survivors to a clinical 6-months follow-up visit after onset. Baseline data were collected from all patients at admission. A modified Rankin Scale (mRS) and employment status were used to assess functional outcomes. Multivariate logistic regression was used to identify independent factors associated with unemployment.

RESULTS

A total of 303 CVT patients were eligible for this study, 131 (42.23%) patients could not return to work 6-month after discharge. After adjusting for age and sex in multivariate analysis, motor deficits, aphasia, mental disorders, CVT recurrence, National Institutes of Health Stroke Scale (NIHSS) score at admission, and mRS 0-2 at 6-month follow-up were independently associated with employment after CVT. Among 263 patients whose mRS showed a favorable outcome, 102 patients were unable to return to their previous work and the risk factors for impaired ability to return to work were aphasia and CVT recurrence.

CONCLUSIONS

Impaired employability after CVT was associated with motor deficits, aphasia, mental status disorders, and NIHSS score at admission. Even if they recover from CVT without physical disability, patients with a good functional prognosis have a higher risk of employment failure due to their higher rates of aphasia and CVT recurrence.

The etiology and evolution of magnetic resonance imaging-visible perivascular spaces: Systematic review and meta-analysis

Objectives

Perivascular spaces have been involved in neuroinflammatory and neurodegenerative diseases. Upon a certain size, these spaces can become visible on magnetic resonance imaging (MRI), referred to as enlarged perivascular spaces (EPVS) or MRI-visible perivascular spaces (MVPVS). However, the lack of systematic evidence on etiology and temporal dynamics of MVPVS hampers their diagnostic utility as MRI biomarker. Thus, the goal of this systematic review was to summarize potential etiologies and evolution of MVPVS.

Methods

In a comprehensive literature search, out of 1,488 unique publications, 140 records assessing etiopathogenesis and dynamics of MVPVS were eligible for a qualitative summary. 6 records were included in a meta-analysis to assess the association between MVPVS and brain atrophy.

Results

Four overarching and partly overlapping etiologies of MVPVS have been proposed: (1) Impairment of interstitial fluid circulation, (2) Spiral elongation of arteries, (3) Brain atrophy and/or perivascular myelin loss, and (4) Immune cell accumulation in the perivascular space. The meta-analysis in patients with neuroinflammatory diseases did not support an association between MVPVS and brain volume measures [R: −0.15 (95%-CI −0.40–0.11)]. Based on few and mostly small studies in tumefactive MVPVS and in vascular and neuroinflammatory diseases, temporal evolution of MVPVS is slow.

Conclusion

Collectively, this study provides high-grade evidence for MVPVS etiopathogenesis and temporal dynamics. Although several potential etiologies for MVPVS emergence have been proposed, they are only partially supported by data. Advanced MRI methods should be employed to further dissect etiopathogenesis and evolution of MVPVS. This can benefit their implementation as an imaging biomarker.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=346564, identifier CRD42022346564.

Association of deep medullary veins with the neuroimaging burden of cerebral small vessel disease

Background

This study aimed to explore the association between deep medullary veins (DMVs) and the neuroimaging burden of cerebral small vessel disease (CSVD).

Methods

In this cross-sectional study based on a retrospective analysis, a total of 248 patients (183 males and 65 females; mean age ± standard deviation, 69.5±14.8 years) diagnosed with CSVD with complete imaging and clinical data were enrolled. Neuroimaging markers of CSVD, including white matter hyperintensities, lacunes, prominent perivascular spaces (PVSs), and cerebral microbleeds (CMBs), were identified, and the total burden of CSVD was scored. Both DMV number and DMV score were used for assessment using susceptibility-weighted imaging (SWI).

Results

With the exception of perivascular spaces, more severe neuroimaging markers were observed in patients with a higher DMV score. After adjustments were made for age and body mass index (BMI), a higher DMV score (β=1.39; P<0.001) and smaller DMV number (β=-2.55; P=0.001) were associated with an increased CSVD burden. The degree of CMBs was independently correlated with both DMV score (β=1.60; P<0.001) and DMV number (β=-2.27; P=0.009). The association between lacunes and DMV score was also significant (β=0.97; P=0.026).

Conclusions

Both DMV score and DMV number are potential imaging indicators of CSVD.

Different mechanisms in periventricular and deep white matter hyperintensities in old subjects

Objective

Although multiple pieces of evidence have suggested that there are different mechanisms in periventricular white matter hyperintensities (PWMHs) and deep white matter hyperintensities (DWMHs), the exact mechanism remains uncertain.

Methods

We reviewed clinical and imaging data of old participants from a local She Ethnic group. We assessed the cerebral blood flow of white matter (WM-CBF) on arterial spin-labeling, deep medullary veins (DMVs) visual score on susceptibility-weighted imaging, and index for diffusion tensor image analysis along the perivascular space (ALPS index), indicating glymphatic function on diffusion tensor imaging. Furthermore, we investigated their relationships with volumes of PWMHs and DWMHs.

Results

A total of 152 subjects were included, with an average age of 63 ± 8 years old. We found that higher age and history of hypertension were independently related to higher volumes of both PWMHs and DWMHs (all p &lt; 0.05). Lower ALPS index was independently associated with higher PWMHs volumes (β = 0.305, p &lt; 0.001), and this relationship was accounted for by the indirect pathway via DMVs score (β = 0.176, p = 0.017). Both lower ALPS index and WM-CBF were independent risk factors for higher DWMHs volumes (β = −0.146, p = 0.041; β = −0.147, p = 0.036).

Conclusions

Our study indicated that there were different mechanisms in PWMHs and DWMHs. PWMHs were mainly attributed to the damage of veins due to the dysfunction of the glymphatic pathway, while DWMHs could be affected by both ischemia-hypoperfusion and dysfunction of the glymphatic pathway.

Advances in knowledge

The relationship between glymphatic dysfunction and PWMHs might be accounted for by the indirect pathway via venous abnormalities, a glymphatic dysfunction, and lower CBF in white matter were independent risk factors for DWMHs.

The Underlying Role of the Glymphatic System and Meningeal Lymphatic Vessels in Cerebral Small Vessel Disease

There is a growing prevalence of vascular cognitive impairment (VCI) worldwide, and most research has suggested that cerebral small vessel disease (CSVD) is the main contributor to VCI. Several potential physiopathologic mechanisms have been proven to be involved in the process of CSVD, such as blood-brain barrier damage, small vessels stiffening, venous collagenosis, cerebral blood flow reduction, white matter rarefaction, chronic ischaemia, neuroinflammation, myelin damage, and subsequent neurodegeneration. However, there still is a limited overall understanding of the sequence and the relative importance of these mechanisms. The glymphatic system (GS) and meningeal lymphatic vessels (mLVs) are the analogs of the lymphatic system in the central nervous system (CNS). As such, these systems play critical roles in regulating cerebrospinal fluid (CSF) and interstitial fluid (ISF) transport, waste clearance, and, potentially, neuroinflammation. Accumulating evidence has suggested that the glymphatic and meningeal lymphatic vessels played vital roles in animal models of CSVD and patients with CSVD. Given the complexity of CSVD, it was significant to understand the underlying interaction between glymphatic and meningeal lymphatic transport with CSVD. Here, we provide a novel framework based on new advances in main four aspects, including vascular risk factors, potential mechanisms, clinical subtypes, and cognition, which aims to explain how the glymphatic system and meningeal lymphatic vessels contribute to the progression of CSVD and proposes a comprehensive insight into the novel therapeutic strategy of CSVD.