MRI-Visible Perivascular Spaces in the Centrum Semiovale Are Associated with Brain Amyloid Deposition in Patients with Alzheimer Disease-Related Cognitive Impairment

Lifetime history of head injury is associated with reduced perivascular space number in acute mild traumatic brain injury

Traumatic brain injury impairs function of the glymphatic system, a perivascular network involved in waste clearance. Enlarged perivascular spaces visible on MRI are an emerging biomarker of glymphatic function. This study characterized enlarged perivascular spaces in acute head injury with 7 T MRI. Healthy controls (n = 8) and patients (n = 11) with mild traumatic brain injury underwent MRI within 7 days of injury and were evaluated for lifetime history of head injury, neurobehavioral symptoms and sleep disturbances. MRI-visible perivascular spaces were quantified and assessed according to published criteria. The number of enlarged perivascular spaces was significantly higher in traumatic brain injury patients than controls (P = 0.015). Among healthy controls, 6/8 scored 'none' or 'mild' on the perivascular space rating scale, while 10/11 patients scored 'moderate', 'frequent' or 'severe'. There was an inverse relationship between perivascular space number and number of lifetime head injuries. Patients with more prior head injuries exhibited fewer enlarged perivascular spaces (P = 0.014). These results indicate that mild head injury results in acute alterations in perivascular space number, and this effect is mediated by previous head injury history. Enlarged perivascular spaces may reflect a glymphatic response that is diminished after multiple head injuries, although this will require further study.

A "glympse" into neurodegeneration: Diffusion MRI and cerebrospinal fluid aquaporin-4 for the assessment of glymphatic system in Alzheimer's disease and other dementias

The glymphatic system (GS) is a whole-brain perivascular network, consisting of three compartments: the periarterial and perivenous spaces and the interposed brain parenchyma. GS dysfunction has been implicated in neurodegenerative diseases, particularly Alzheimer's disease (AD). So far, comprehensive research on GS in humans has been limited by the absence of easily accessible biomarkers. Recently, promising non-invasive methods based on magnetic resonance imaging (MRI) along with aquaporin-4 (AQP4) quantification in the cerebrospinal fluid (CSF) were introduced for an indirect assessment of each of the three GS compartments. We recruited 111 consecutive subjects presenting with symptoms suggestive of degenerative cognitive decline, who underwent 3 T MRI scanning including multi-shell diffusion-weighted images. Forty nine out of 111 also underwent CSF examination with quantification of CSF-AQP4. CSF-AQP4 levels and MRI measures-including perivascular spaces (PVS) counts and volume fraction (PVSVF), white matter free water fraction (FW-WM) and mean kurtosis (MK-WM), diffusion tensor imaging analysis along the perivascular spaces (DTI-ALPS) (mean, left and right)-were compared among patients with AD (n = 47) and other neurodegenerative diseases (nAD = 24), patients with stable mild cognitive impairment (MCI = 17) and cognitively unimpaired (CU = 23) elderly people. Two runs of analysis were conducted, the first including all patients; the second after dividing both nAD and AD patients into two subgroups based on gray matter atrophy as a proxy of disease stage. Age, sex, years of education, and scanning time were included as confounding factors in the analyses. Considering the whole cohort, patients with AD showed significantly higher levels of CSF-AQP4 (exp(b) = 2.05, p = .005) and FW-WM FW-WM (exp(b) = 1.06, p = .043) than CU. AQP4 levels were also significantly higher in nAD in respect to CU (exp(b) = 2.98, p < .001). CSF-AQP4 and FW-WM were significantly higher in both less atrophic AD (exp(b) = 2.20, p = .006; exp(b) = 1.08, p = .019, respectively) and nAD patients (exp(b) = 2.66, p = .002; exp(b) = 1.10, p = .019, respectively) compared to CU subjects. Higher total (exp(b) = 1.59, p = .013) and centrum semiovale PVS counts (exp(b) = 1.89, p = .016), total (exp(b) = 1.50, p = .036) and WM PVSVF (exp(b) = 1.89, p = .005) together with lower MK-WM (exp(b) = 0.94, p = .006), mean and left ALPS (exp(b) = 0.91, p = .043; exp(b) = 0.88, p = .010 respectively) were observed in more atrophic AD patients in respect to CU. In addition, more atrophic nAD patients exhibited higher levels of AQP4 (exp(b) = 3.39, p = .002) than CU. Our results indicate significant changes in putative MRI biomarkers of GS and CSF-AQP4 levels in AD and in other neurodegenerative dementias, suggesting a close interaction between glymphatic dysfunction and neurodegeneration, particularly in the case of AD. However, the usefulness of some of these biomarkers as indirect and standalone indices of glymphatic activity may be hindered by their dependence on disease stage and structural brain damage.

Quantitative assessment of enlarged perivascular spaces via deep-learning in community-based older adults reveals independent associations with vascular neuropathologies, vascular risk factors and cognition

Enlarged perivascular spaces (EPVS) are common in older adults, but their neuropathologic correlates are unclear mainly because most work to date has relied on visual rating scales and/or clinical cohorts. The present study first developed a deep-learning model for automatic segmentation, localization and quantification of EPVS in ex vivo brain MRI, and then used this model to investigate the neuropathologic, clinical and cognitive correlates of EPVS in 817 community-based older adults that underwent autopsy. The new method exhibited high sensitivity in detecting EPVS as small as 3 mm3, good segmentation accuracy and consistency. Most EPVS were located in the frontal lobe, but the highest density was observed in the basal ganglia. EPVS in the cerebrum and specifically in the frontal lobe were associated with infarcts independent of other neuropathologies, while temporal and occipital EPVS were associated with cerebral amyloid angiopathy. EPVS in most brain lobes were also associated with diabetes mellitus independently of neuropathologies, while basal ganglia EPVS were independently associated with hypertension, supporting the notion of independent pathways from diabetes and hypertension to EPVS. Finally, EPVS were associated with lower cognitive performance independently of neuropathologies and clinical variables, suggesting that EPVS represent additional abnormalities contributing to lower cognition.

Association between Perivascular Spaces Burden and Future Stroke Risk in Ischemic Stroke and Transient Ischemic Attack: A Systematic Review and Meta-Analysis

INTRODUCTION

This meta-analysis aimed to explore the association of perivascular spaces (PVS) burden with the risks of future stroke events and mortality in patients with ischemic stroke and transient ischemic attack (TIA).

METHODS

We systematically searched PubMed, Embase, and Cochrane database from inception to December 31, 2023. We included eligible studies that reported adjusted estimated effects for future intracranial hemorrhage (ICH), ischemic stroke, and mortality with baseline PVS burden in patients with ischemic stroke and TIA. Data were pooled using an inverse-variance method for the fixed effects (FE) model and a restricted maximum likelihood method for the random effects (RE) model.

RESULTS

Thirteen observational studies (5 prospective, 8 retrospective) were included, comprising 20,256 patients. Compared to 0-10 PVS at basal ganglia (BG-PVS), a higher burden (>10) of BG-PVS was significantly associated with an increased risk of future ICH (adjusted hazards ratio [aHR] 2.79, 95% confidence interval [CI]: 1.16-6.73, RE model; aHR 2.14, 95% CI: 1.34-3.41, FE model; I2 = 64%, n = 17,084 from four studies) followed up for at least 1 year. There was no significant association between >10 BG-PVS and ICH within 7 days after reperfusion therapy (adjusted odds ratio [aOR] 1.69, 95% CI: 0.74-3.88, RE model; aOR 1.43, 95% CI: 0.89-2.88, FE model; I2 = 67%, n = 1,176 from four studies). We did not detect a significant association of recurrent ischemic stroke, mortality, or disability with BG-PVS burden. Neither >10 PVS at centrum semiovale (CSO-PVS) nor increasing CSO-PVS burden was significantly associated with the risk of future intracranial hemorrhage or ischemic stroke recurrence.

CONCLUSIONS

Current evidence suggests that a higher BG-PVS burden may be associated with an increased risk of future ICH in patients with ischemic stroke and TIA.

Parenchymal CSF fraction is a measure of brain glymphatic clearance and positively associated with amyloid beta deposition on PET

INTRODUCTION

Mapping of microscopic changes in the perivascular space (PVS) of the cerebral cortex, beyond magnetic resonance-visible PVS in white matter, may enhance our ability to diagnose Alzheimer's disease (AD) early.

METHODS

We used the cerebrospinal fluid (CSF) water fraction (CSFF), a magnetic resonance imaging-based biomarker, to characterize brain parenchymal CSF water, reflecting microscopic PVS in parenchyma. We measured CSFF and amyloid beta (Aβ) using 11 C Pittsburgh compound B positron emission tomography to investigate their relationship at both the subject and voxel levels.

RESULTS

Our research has demonstrated a positive correlation between the parenchymal CSFF, a non-invasive imaging biomarker indicative of parenchymal glymphatic clearance, and Aβ deposition, observed at both individual and voxel-based assessments in the posterior cingulate cortex.

DISCUSSION

This study shows that an increased parenchymal CSFF is associated with Aβ deposition, suggesting that CSFF could serve as a biomarker for brain glymphatic clearance, which can be used to detect early fluid changes in PVS predisposing individuals to the development of AD.

HIGHLIGHTS

Cerebrospinal fluid fraction (CSFF) could be a biomarker of parenchymal perivascular space. CSFF is positively associated with amyloid beta (Aβ) deposition at subject level. CSFF in an Aβ+ region is higher than in an Aβ- region in the posterior cingulate cortex. Correspondence is found between Aβ deposition and glymphatic clearance deficits measured by CSFF.

Blood-Brain Barrier Disruption and Perivascular Spaces in Small Vessel Disease and Neurodegenerative Diseases: A Review on MRI Methods and Insights

Perivascular spaces (PVS) and blood-brain barrier (BBB) disruption are two key features of cerebral small vessel disease (cSVD) and neurodegenerative diseases that have been linked to cognitive impairment and are involved in the cerebral waste clearance system. Magnetic resonance imaging (MRI) offers the possibility to study these pathophysiological processes noninvasively in vivo. This educational review provides an overview of the MRI techniques used to assess PVS functionality and BBB disruption. MRI-visible PVS can be scored on structural images by either (subjectively) counting or (automatically) delineating the PVS. We highlight emerging (diffusion) techniques to measure proxies of perivascular fluid and its movement, which may provide a more comprehensive understanding of the role of PVS in diseases. For the measurement of BBB disruption, we explain the most commonly used MRI technique, dynamic contrast-enhanced (DCE) MRI, as well as a more recently developed technique based on arterial spin labeling (ASL). DCE MRI and ASL are thought to measure complementary characteristics of the BBB. Furthermore, we describe clinical studies that have utilized these MRI techniques in cSVD and neurodegenerative diseases, particularly Alzheimer's disease (AD). These studies demonstrate the role of PVS and BBB dysfunction in these diseases and provide insight into the large overlap, but also into the differences between cSVD and AD. Overall, MRI techniques may provide valuable insights into the pathophysiological mechanisms underlying these diseases and have the potential to be used as markers for disease progression and treatment response. LEVEL OF EVIDENCE: 3 TECHNICAL EFFICACY: Stage 2.

Effects of sleep on brain perivascular space in a cognitively healthy population

The magnetic resonance imaging (MRI) visible perivascular space (PVS) reportedly clears amyloid-β and metabolic waste during sleep. Previous studies reported an association between sleep and the PVS in small vessel disease, traumatic brain injury, and Alzheimer's disease. However, this relationship in a healthy cohort is still unclear. Here, we used the Human Connectome Project Aging dataset to analyze the relationship between sleep and the PVS in cognitively healthy adults across the aging continuum. We measured sleep parameters using the self-reported Pittsburgh Sleep Quality Index questionnaire. We found that older adults who had better sleep quality and sleep efficiency presented with a larger PVS volume fraction in the basal ganglia (BG). However, sleep measures were not associated with PVS volume fraction in the centrum semiovale (CSO). In addition, we found that body mass index (BMI) influenced the BG-PVS across middle-aged and older participants. In the entire cognitively healthy cohort, the effect of sleep quality on PVS volume fraction was mediated by BMI. However, BMI did not influence this effect in the older cohort. Furthermore, there are significant differences in PVS volume fraction across racial/ethnic cohorts. In summary, the effect of sleep on the PVS volume alteration was different in the middle-aged adults and older adults.

Enlarged Perivascular Spaces in Relation to Cumulative Blood Pressure Exposure and Cognitive Impairment

BACKGROUND

Hypertension and enlarged perivascular spaces (EPVS) are thought to be associated with cognitive impairment. However, the correlations among hypertension, EPVS, and cognitive impairment have not been studied yet. We aimed to investigate the relationships between cumulative blood pressure (cBP) exposure with EPVS and cognitive impairment and whether EPVS may mediate the relationship between cBP and cognitive impairment.

METHODS

A total of 1507 subjects from the Kailuan prospective cohort study were enrolled. cBP was calculated from 2006 to 2022. The effects of cBP, EPVS scores, and cognitive impairment were evaluated using a logistic regression model. The relationships among cBP, EPVS score, and cognitive impairment were analyzed using a mediation model.

RESULTS

An increase in cBP was positively correlated with an increase in EPVS score. For every SD increase in cBP, the odds ratios (95% CI) of increased EPVS score of the centrum semiovale were 1.67 (1.43-1.95), 1.63 (1.4-1.9), and 1.35 (1.17-1.56), respectively; the odds ratios (95% CI) of increased EPVS score of the basal ganglia were 1.83 (1.56-2.15), 2.01 (1.7-2.36), and 1.31 (1.13-1.52), respectively; and the odds ratios (95% CI) of developing cognitive impairment were 1.28 (1.06-1.53), 1.13 (0.95-1.34), and 1.28 (1.07-1.5), respectively. Basal ganglia-EPVS score accounted for 10.46% to 18.32% of the mediating effects on the relationships of cBP/SD with cognitive impairment.

CONCLUSIONS

High cBP exposure was an independent risk factor for EPVS, and basal ganglia-EPVS score mediated the effects of cBP on cognitive impairment.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: ChiCTR-TNRC-11001489.

Enlarged perivascular spaces and plasma Aβ42/Aβ40 ratio in older adults without dementia

Dilation of perivascular spaces (PVS) in the brain may indicate poor fluid drainage due to the accumulation of perivascular cell debris, waste, and proteins, including amyloid-beta (Aβ). No prior study has assessed whether plasma Aβ levels are related to PVS in older adults without dementia. Independently living older adults (N = 56, mean age = 68.2 years; Standard deviation (SD) = 6.5; 30.4% male) free of dementia or clinical stroke were recruited from the community and underwent brain MRI and venipuncture. PVS were qualitatively scored and dichotomized to low PVS burden (scores 0-1,) or high PVS burden (score>1). Plasma was assayed using a Quanterix Simoa Kit to quantify Aβ42 and Aβ40 levels. A significant difference was observed in plasma Aβ42/Aβ40 ratio between low and high PVS burden, controlling for age (F[1, 53] = 5.59, p = 0.022, η2 = 0.10), with lower Aβ42/Aβ40 ratio in the high PVS burden group. Dilation of PVS is associated with a lower plasma Aβ42/Aβ40 ratio, which may indicate higher cortical amyloid deposition. Future longitudinal studies examining PVS changes, and the pathogenesis of AD are warranted.

Association between enlarged perivascular spaces and cerebrospinal fluid aquaporin-4 and tau levels: report from a memory clinic

Background

Perivascular spaces (PVS) are fluid-filled compartments that dilate in response to many different conditions. A high burden of enlarged PVS (EPVS) in the centrum semiovale (CSO) has been linked to neurodegeneration. Moreover, an increase in cerebrospinal fluid (CSF) levels of aquaporin-4 (AQP4), a water channel expressed on PVS-bounding astrocytes, has been described in patients with neurodegenerative dementia. Our aim was to investigate the relationship between neurodegenerative diseases and two putative glymphatic system biomarkers: AQP4 and EPVS.

Methods

We included 70 individuals, 54 patients with neurodegenerative diseases and 16 subjects with non-degenerative conditions. EPVS were visually quantified on MRI-scans applying Paradise's scale. All subjects underwent lumbar puncture for the measurement of AQP4 levels in the cerebrospinal fluid (CSF). CSF levels of amyloid-β-1-42, phosphorylated and total tau (tTau) were also measured. Linear regression analyses were adjusted for age, sex, education and disease duration, after excluding outliers.

Results

Cerebrospinal fluid (CSF)-AQP4 levels were independent predictors of total (β = 0.28, standard error [SE] = 0.08, p = 0.001), basal ganglia (β = 0.20, SE = 0.08, p = 0.009) and centrum semiovale EPVS (β = 0.37, SE = 0.12, p = 0.003). tTau levels predicted CSO-EPVS (β = 0.30, SE = 0.15, p = 0.046). Moreover, increased levels of AQP4 were strongly associated with higher levels of tTau in the CSF (β = 0.35, SE = 0.13, p = 0.008).

Conclusion

We provide evidence that CSO-EPVS and CSF-AQP4 might be clinically meaningful biomarkers of glymphatic dysfunction and associated neurodegeneration.

Inflammatory biomarkers and MRI visible perivascular spaces: The Framingham Heart Study

We studied the association between inflammatory biomarkers and magnetic resonance imaging (MRI) visible perivascular spaces (PVS) in Framingham Heart Study participants free of stroke and dementia. PVS in the basal ganglia (BG) and centrum semiovale (CSO) were rated with validated methods and categorized based on counts. A mixed score of high PVS burden in neither, one or both regions was also evaluated. We related biomarkers representing various inflammatory mechanisms to PVS burden using multivariable ordinal logistic regression analysis accounting for vascular risk factors and other MRI markers of cerebral small vessel disease. Among 3604 participants (mean age 58±13 years, 47% males), significant associations were observed for intercellular adhesion molecule1, fibrinogen, osteoprotegerin, and P-selectin in relation to BG PVS, P-selectin for CSO PVS, and tumor necrosis factor receptor 2, osteoprotegerin and cluster of differentiation 40 ligand for mixed topography PVS. Therefore, inflammation may have a role in the pathogenesis of cerebral small vessel disease and perivascular drainage dysfunction represented by PVS, with different and shared inflammatory biomarkers depending on PVS topography.

Perivascular spaces in Alzheimer's disease are associated with inflammatory, stress-related, and hypertension biomarkers

Perivascular spaces (PVS) are fluid-filled spaces surrounding the brain vasculature. Literature suggests that PVS may play a significant role in aging and neurological disorders, including Alzheimer's disease (AD). Cortisol, a stress hormone, has been implicated in the development and progression of AD. Hypertension, a common condition in older adults, has been found to be a risk factor for AD. Hypertension may contribute to PVS enlargement, impairing the clearance of waste products from the brain and promoting neuroinflammation. This study aims to understand the potential interactions between PVS, cortisol, hypertension, and inflammation in the context of cognitive impairment. Using MRI scans acquired at 1.5T, PVS were quantified in a cohort of 465 individuals with cognitive impairment. PVS was calculated in the basal ganglia and centrum semiovale using an automated segmentation approach. Levels of cortisol and angiotensin-converting enzyme (ACE) (an indicator of hypertension) were measured from plasma. Inflammatory biomarkers, such as cytokines and matrix metalloproteinases, were analyzed using advanced laboratory techniques. Main effect and interaction analyses were performed to examine the associations between PVS severity, cortisol levels, hypertension, and inflammatory biomarkers. In the centrum semiovale, higher levels of inflammation reduced cortisol associations with PVS volume fraction. For ACE, an inverse association with PVS was seen only when interacting with TNFr2 (a transmembrane receptor of TNF). There was also a significant inverse main effect of TNFr2. In the PVS basal ganglia, a significant positive association was found with TRAIL (a TNF receptor inducing apoptosis). These findings show for the first time the intricate relationships between PVS structure and the levels of stress-related, hypertension, and inflammatory biomarkers. This research could potentially guide future studies regarding the underlying mechanisms of AD pathogenesis and the potential development of novel therapeutic strategies targeting these inflammation factors.

Imaging features of small vessel disease in cerebral amyloid angiopathy among patients with Alzheimer's disease

BACKGROUND AND PURPOSE

Cerebral small vessel disease biomarkers including white matter hyperintensities (WMH), lacunes, and enlarged perivascular spaces (ePVS) are under investigation to identify those specific to cerebral amyloid angiopathy (CAA). In subjects with Alzheimer's disease (AD), we assessed characteristic features and amounts of WMH, lacunes, and ePVS in four CAA categories (no, mild, moderate and severe CAA) and correlated these with Clinical Dementia Rating sum of boxes (CDRsb) score, ApoE genotype, and neuropathological changes at autopsy.

METHODS

The study included patients with a clinical diagnosis of dementia due to AD and neuropathological confirmation of AD and CAA in the National Alzheimer's Coordinating Center (NACC) database. The WMH, lacunes, and ePVS were evaluated using semi-quantitative scales. Statistical analyses compared the WMH, lacunes, and ePVS values in the four CAA groups with vascular risk factors and AD severity treated as covariates, and to correlate the imaging features with CDRsb score, ApoE genotype, and neuropathological findings.

RESULTS

The study consisted of 232 patients, of which 222 patients had FLAIR data available and 105 patients had T2-MRI. Occipital predominant WMH were significantly associated with the presence of CAA (p = 0.007). Among the CAA groups, occipital predominant WMH was associated with severe CAA (β = 1.22, p = 0.0001) compared with no CAA. Occipital predominant WMH were not associated with the CDRsb score performed at baseline (p = 0.68) or at follow-up 2-4 years after the MRI (p = 0.92). There was no significant difference in high grade ePVS in the basal ganglia (p = 0.63) and centrum semiovale (p = 0.95) among the four CAA groups. The WMH and ePVS on imaging did not correlate with the number of ApoE ε4 alleles but the WMH (periventricular and deep) correlated with the presence of infarcts, lacunes and microinfarcts on neuropathology.

CONCLUSION

Among patients with AD, occipital predominant WMH is more likely to be found in patients with severe CAA than in those without CAA. The high-grade ePVS in centrum semiovale were common in all AD patients regardless of CAA severity.

Lighter sleep is associated with higher enlarged perivascular spaces burden in middle-aged and elderly individuals

BACKGROUND

While healthy sleep is suggested to promote glymphatic clearance in the brain, poorer sleep may be associated with higher enlarged perivascular spaces (ePVS) burden, potentially representing impaired perivascular drainage. This study aims to evaluate the association between ePVS burden and polysomnographic sleep characteristics in a large community-based sample.

METHODS

552 dementia and stroke-free Framingham Heart Study participants (age: 58.6 ± 8.9 years; 50.4% men) underwent a full-night in-home polysomnography. Three years later on average, participants underwent a brain MRI. ePVS were rated in the basal ganglia and centrum semiovale, and dichotomized as low burden (<20 counts, grades 1 and 2) or high burden (>20 counts, grades 3 and 4). Logistic regression analyses relating sleep variables to subsequent ePVS burden were used, adjusted for age, sex, time interval between polysomnography and MRI, ApoE ε4 allele carrier status, hypertension, and smoking.

RESULTS

Longer N1 sleep and shorter N3 sleep duration were associated with higher ePVS burden in the centrum semiovale. When stratifying these associations by subpopulations, longer N1 sleep duration with ePVS burden was observed especially in older individuals and hypertensive participants. Associations between ePVS burden and other sleep characteristics such as total sleep time and REM sleep duration varied according to ApoE ε4 allele carrier status.

CONCLUSIONS

Lighter sleep, as characterized by longer N1 sleep and shorter slow-wave sleep, is associated with higher ePVS burden. These findings suggest that sleep architecture may be involved in glymphatic clearance and cerebral small vessel disease, which could be an important biological link between sleep and dementia risk.

Perivascular Space Predicts Brain Hypometabolism of Individuals with Underlying Amyloid Pathology

Background: Reduced signal on fluorodeoxyglucose-positron emission tomography (FDG-PET) is a valid proxy for neurodegeneration in Alzheimer’s disease (AD). Perivascular space (PVS) is believed to be associated with AD pathology and cognitive decline. Objective: This study aimed to investigate the associations of PVS with FDG-PET and cognitive performance based on the burden of amyloid pathology. Methods: We used magnetic resonance imaging (MRI) data from the Alzheimer’s Disease Neuroimaging Initiative (ADNI). MRI-visible PVS in basal ganglia (BG) and centrum semi-oval (CSO) were visually classified as: none/mild, moderate or frequent/severe. The association of PVS with brain FDG-PET was explored based on the burden of amyloid pathology, where a cerebrospinal fluid (CSF) t-tau/Aβ42 with the ratio≥0.27 was defined as high amyloid pathology. Moreover, the relationships between PVS and cognitive performance variables (ADNI-MEM and ADNI-EF) were studied. Results: For participants with higher tau/Aβ42 ratio, CSO-PVS severity was independently associated with lower FDG-PET. There were significant interaction effects between moderate or frequent/severe CSO-PVS and time on FDG decline in people with high amyloid pathology. The interaction between CSO-PVS and time (follow-up) was consistently associated with ADNI-MEM and ADNI-EF decline in individuals with high amyloid pathology. Conclusion: The study established the differential utility of PVS in BG and CSO for predicting brain metabolism. These findings suggest that CSO-PVS serves as a contributing factor to brain metabolism and cognitive decline associated with amyloid pathology.

Enlarged Perivascular Spaces Are Negatively Associated With Montreal Cognitive Assessment Scores in Older Adults

Emerging evidence suggests that enlarged perivascular spaces (ePVS) may be a clinically significant neuroimaging marker of global cognitive function related to cerebral small vessel disease (cSVD). We tested this possibility by assessing the relationship between ePVS and both a standardized measure of global cognitive function, the Montreal Cognitive Assessment (MoCA), and an established marker of cSVD, white matter hyperintensity volume (WMH) volume. One hundred and eleven community-dwelling older adults (56-86) underwent neuroimaging and MoCA testing. Quantification of region-specific ePVS burden was performed using a previously validated visual rating method and WMH volumes were computed using the standard ADNI pipeline. Separate linear regression models were run with ePVS as a predictor of MoCA scores and whole brain WMH volume. Results indicated a negative association between MoCA scores and both total ePVS counts (P ≤ 0.001) and centrum semiovale ePVS counts (P ≤ 0.001), after controlling for other relevant cSVD variables. Further, WMH volumes were positively associated with total ePVS (P = 0.010), basal ganglia ePVS (P ≤ 0.001), and centrum semiovale ePVS (P = 0.027). Our results suggest that ePVS burden, particularly in the centrum semiovale, may be a clinically significant neuroimaging marker of global cognitive dysfunction related to cSVD.

Combined Score of Perivascular Space Dilatation and White Matter Hyperintensities in Patients with Normal Cognition, Mild Cognitive Impairment, and Dementia

Background and Objectives: Cerebral perivascular spaces (PVS) are part of the cerebral microvascular structure and play a role in lymphatic drainage and the removal of waste products from the brain. White matter hyperintensities (WMH) are hyperintense lesions on magnetic resonance imaging that are associated with cognitive impairment, dementia, and cerebral vascular disease. WMH and PVS are direct and indirect imaging biomarkers of cerebral microvascular integrity and health. In our research, we evaluated WMH and PVS enlargement in patients with normal cognition (NC), mild cognitive impairment (MCI), and dementia (D). Materials and Methods: In total, 57 participants were included in the study and divided into groups based on neurological evaluation and Montreal Cognitive Assessment results (NC group 16 participants, MCI group 29 participants, D group 12 participants). All participants underwent 3T magnetic resonance imaging. PVS were evaluated in the basal ganglia, centrum semiovale, and midbrain. WMHs were evaluated based on the Fazekas scale and the division between deep white matter (DWM) and periventricular white matter (PVWM). The combined score based on PVS and WMH was evaluated and correlated with the results of the MoCA. Results: We found statistically significant differences between groups on several measures. Centrum semiovale PVS dilatation was more severe in MCI and dementia group and statistically significant differences were found between D-MCI and D-NC pairs. PVWM was more severe in patients with MCI and dementia group, and statistically significant differences were found between D-MCI and D-NC pairs. Furthermore, we found statistically significant differences between the groups by analyzing the combined score of PVS dilatation and WMH. We did not find statistically significant differences between the groups in PVS dilation of the basal ganglia and midbrain and DWM hyperintensities. Conclusions: PVS assessment could become one of neuroimaging biomarkers for patients with cognitive decline. Furthermore, the combined score of WMH and PVS dilatation could facilitate diagnostics of cognitive impairment, but more research is needed with a larger cohort to determine the use of PVS dilatation and the combined score.