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

A window into the brain: multimodal MRI assessment of vascular cognitive impairment

Vascular cognitive impairment (VCI) encompasses a diverse range of syndromes, including mild cognitive impairment and vascular dementia (VaD), primarily attributed to cerebrovascular lesions and vascular risk factors. Its prevalence ranks second only to Alzheimer's disease (AD) in neuro diseases. The advancement of medical imaging technology, particularly magnetic resonance imaging (MRI), has enabled the early detection of structural, functional, metabolic, and cerebral connectivity alterations in individuals with VCI. This paper examines the utility of multimodal MRI in evaluating structural changes in the cerebral cortex, integrity of white matter fiber tracts, alterations in the blood-brain barrier (BBB) and glymphatic system (GS) activity, alteration of neurovascular coupling function, assessment of brain connectivity, and assessment of metabolic changes in patients with VCI.

Enlarged perivascular spaces correlate with blood-brain barrier leakage and cognitive impairment in Alzheimer's disease

BackgroundThe clinical significance of enlarged perivascular spaces (EPVS) in Alzheimer' s disease (AD) was ambiguous.ObjectiveTo investigate whether EPVS contribute to blood-brain barrier (BBB) leakage and cognition in AD.MethodsThe study included a total of 64 participants (26 healthy controls and 38 patients with AD). The evaluation of EPVS and BBB permeability was performed in specific anatomical locations: the centrum semiovale (CSO), basal ganglia, and hippocampus. The EPVS ratings were performed according to Potter's instructions. BBB permeability was evaluated using dynamic contrast-enhanced-MRI. The relationship between EPVS and global cognition (Mini-Mental State Examination and Montreal Cognitive Assessment), cognitive subdomains, and BBB permeability were examined in both groups. Finally, the relationship between CSO BBB permeability and cognition in AD patients was investigated.ResultsHigh-grade CSO EPVS was found associated with AD (OR: 3.40, 95% CI: 1.11-11.90, p = 0.04). In the AD group, a significant correlation was observed between high-grade CSO EPVS and lower MMSE score (r = -0.36, p = 0.03) and verbal fluency (r = -0.44, p = 0.01). High-grade CSO EPVS positively correlated with BBB leakage (r = 0.58, p < 0.001). The BBB permeability of CSO negatively correlated with verbal fluency (r = -0.52, p < 0.001) and attention (r = -0.40, p = 0.01).ConclusionsHigh-grade CSO EPVS is related to BBB leakage, which contributes to cognitive impairment in AD patients, especially verbal frequency. CSO EPVS can function as a convenient AD marker for intervention and therapy.

Brain 18F-fluorodeoxyglucose positron emission tomography: An efficient tool at the initial diagnosis of nonlesional late onset epilepsy

OBJECTIVE

This study evaluates the diagnostic performance and prognostic value of brain 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) at the initial diagnosis of patients with nonlesional late onset epilepsy (NLLOE).

METHODS

In this cohort study at the University Hospital of Nancy, France, newly diagnosed NLLOE patients, >50 years old, were consecutively included from June 2017 to January 2021 and systematically underwent brain 18F-FDG PET. They were categorized into four presumed etiological NLLOE subtypes: neurodegenerative subtype (NDS; patients with a diagnosis of neurodegenerative disease), microvascular subtype (MVS; patients with ≥3 cardiovascular risk factors and ≥2 vascular lesions on magnetic resonance imaging), inflammatory subtype (IFS; patients meeting international criteria for encephalitis), and unlabeled subtype (ULS). A systematic patient follow-up (at least 2 years) allowed assessment of cognitive outcomes under antiseizure medication by comparing for each patient the proportion of preserved/altered scores between initial and second neuropsychological assessment. Brain 18F-FDG PET was analyzed using a combined visual and semiquantitative approach at the individual level.

RESULTS

Eighty-seven patients were included (NDS, n = 18; MVS, n = 22; IFS, n = 7; ULS, n = 40). A normal 18F-FDG PET was observed in 46% of patients, with the final diagnosis of 88% of these patients excluding a neurodegenerative or inflammatory disorder. 18F-FDG PET had a negative predictive value of 94% for a cognitive decline at follow-up, similar for the overall population (n = 71) and the ULS population (n = 32). Moreover, a PET hypometabolic pattern suggestive of a neurodegenerative disorder was indicative of cognitive decline at follow-up in 74% of cases.

SIGNIFICANCE

18F-FDG PET as part of the initial diagnosis of NLLOE patients may have a significant impact on both NLLOE diagnosis and cognitive prognosis. For almost half of NLLOE patients, a normal 18F-FDG PET could help to exclude neurodegenerative and inflammatory epilepsy etiologies as well as future cognitive decline.

Presumed aetiologies and clinical outcomes of non-lesional late-onset epilepsy

BACKGROUND AND PURPOSE

Our objective was to define phenotypes of non-lesional late-onset epilepsy (NLLOE) depending on its presumed aetiology and to determine their seizure and cognitive outcomes at 12 months.

METHODS

In all, 146 newly diagnosed NLLOE patients, >50 years old, were prospectively included and categorized by four presumed aetiological subtypes: neurodegenerative subtype (patients with a diagnosis of neurodegenerative disease) (n = 31), microvascular subtype (patients with three or more cardiovascular risk factors and two or more vascular lesions on MRI) (n = 39), inflammatory subtype (patient meeting international criteria for encephalitis) (n = 9) and unlabelled subtype (all individuals who did not meet the criteria for other subtypes) (n = 67). Cognitive outcome was determined by comparing for each patient the proportion of preserved/altered scores between initial and second neuropsychological assessment.

RESULTS

The neurodegenerative subtype had the most severe cognitive profile at diagnosis with cognitive complaint dating back several years. The microvascular subtype was mainly evaluated through the neurovascular emergency pathway. Their seizures were characterized by transient phasic disorders. Inflammatory subtype patients were the youngest. They presented an acute epilepsy onset with high rate of focal status epilepticus. The unlabelled subtype presented fewer comorbidities with fewer lesions on brain imaging. The neurodegenerative subtype had the worst seizure and cognitive outcomes. In other groups, seizure control was good under antiseizure medication (94.7% seizure-free) and cognitive performance was stabilized or even improved.

CONCLUSION

This new characterization of NLLOE phenotypes raises questions regarding the current International League Against Epilepsy aetiological classification which does not individualize neurodegenerative and microvascular aetiology per se.

Perivascular spaces and where to find them - MR imaging and evaluation methods

BACKGROUND

Perivascular spaces (synonym: Virchow-Robin spaces) were first described over 150 years ago. They are defined as the fluid-filled spaces surrounding the small penetrating cerebral vessels. They gained growing scientific interest especially with the postulation of the so-called glymphatic system and their possible role in neurodegenerative and neuroinflammatory diseases.

METHODS

PubMed was used for a systematic search with a focus on literature regarding MRI imaging and evaluation methods of perivascular spaces. Studies on human in-vivo imaging were included with a focus on studies involving healthy populations. No time frame was set. The nomenclature in the literature is very heterogeneous with terms like "large", "dilated", "enlarged" perivascular spaces whereas borders and definitions often remain unclear. This work generally talks about perivascular spaces.

RESULTS

This review article discusses the morphologic MRI characteristics in different sequences. With the continual improvement of image quality, more and tinier structures can be depicted in detail. Visual analysis and semi or fully automated segmentation methods are briefly discussed.

CONCLUSION

If they are looked for, perivascular spaces are apparent in basically every cranial MRI examination. Their physiologic or pathologic value is still under debate.

KEY POINTS

· Perivascular spaces can be seen in basically every cranial MRI examination.. · Primarily T2-weighend sequences are used for visual analysis. Additional sequences are helpful for distinction from their differential diagnoses.. · There are promising approaches for the semi or fully automated segmentation of perivascular spaces with the possibility to collect more quantitative parameters..

CITATION FORMAT

· Seehafer S, Larsen N, Aludin S et al. Perivascular spaces and where to find them - MRI imaging and evaluation methods. Fortschr Röntgenstr 2024; 196: 1029 - 1036.

Meta-analysis of the relationship between the number and location of perivascular spaces in the brain and cognitive function

BACKGROUND

Cerebral perivascular spaces are part of the cerebral microvascular structure and play a role in lymphatic drainage and the removal of waste products from the brain. Relationships of the number and location of such spaces with cognition are unclear.

OBJECTIVE

To meta-analyze available data on potential associations of severity and location of perivascular spaces with cognitive performance.

METHODS

We searched PubMed, EMBASE, Web of Science and the Cochrane Central Registry of Controlled Trials for relevant studies published between January 2000 and July 2023. Performance on different cognitive domains was compared to the severity of perivascular spaces in different brain regions using comprehensive meta-analysis. When studies report unadjusted and adjusted means, we use adjusted means for meta-analysis. The study protocol is registered in the PROSPERO database (CRD42023443460).

RESULTS

We meta-analyzed data from 26 cross-sectional studies and two longitudinal studies involving 7908 participants. In most studies perivascular spaces was using a visual rating scale. A higher number of basal ganglia perivascular spaces was linked to lower general intelligence and attention. Moreover, increased centrum semiovale perivascular spaces were associated with worse general intelligence, executive function, language, and memory. Conversely, higher hippocampus perivascular spaces were associated with enhanced memory and executive function. Subgroup analyses revealed variations in associations among different disease conditions.

CONCLUSIONS

A higher quantity of perivascular spaces in the brain is correlated with impaired cognitive function. The location of these perivascular spaces and the underlying disease conditions may influence the specific cognitive domains that are affected.

SYSTEMATIC REVIEW REGISTRATION

The study protocol has been registered in the PROSPERO database (CRD42023443460).

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.

Combining ADC values in DWI with rCBF values in arterial spin labeling (ASL) for the diagnosis of mild cognitive impairment (MCI)

We aimed to investigate the role of combined apparent diffusion coefficient (ADC) values and relative cerebral blood flow (rCBF) values in the diagnosis of mild cognitive impairment (MCI) patients. The present prospective research enrolled 156 MCI patients and 58 healthy elderly people who came to our hospital from January 2021 to February 2023. T1W, T2W, diffusion-weighted imaging, and arterial spin labeling sequences were performed on all subjects, and ADC values and rCBF values were measured at the workstation. Clinical and demographic data of all patients were collected while mini-mental state examination (MMSE) and Montreal cognitive assessment (MoCA) scores were used to assess patients' cognitive abilities. The MCI group had significantly lower rCBF values in the left frontal lobe, left occipital lobe, right frontal lobe, and right occipital lobe than the HC group. The ADC values in the left frontal lobe as well as the right frontal lobe were remarkably elevated in the MCI group than in the HC group. MoCA and MMSE scores were positively correlated with rCBF values in the left frontal, right frontal, left occipital, and right occipital lobes and negatively correlated with ADC values in the left and right frontal lobes. Combined ADC values and rCBF values from the left frontal lobe for the diagnosis of MCI had a higher sensitivity and specificity with the AUC was 0.877, sensitivity 81.0%, specificity 82.7%. Additionally, pressure fasting plasma glucose, ADC of the left frontal lobe, right frontal lobe, rCBF of left frontal lobe and rCBF of left frontal lobe were the risk factors of patients with MCI. In summary, our results indicated that the ADC values and rCBF values were changed in MCI group compared to HC group and correlated with MMSE and MoCA scores.

MRI Visible Perivascular Spaces and the Risk of Incident Mild Cognitive Impairment in a Community Sample

BACKGROUND

Magnetic resonance imaging (MRI) visible perivascular spaces (PVS) are associated with the risk of incident dementia but their association with the early stages of cognitive impairment remains equivocal.

OBJECTIVE

We examined the association between MRI visible PVS and the risk of incident mild cognitive impairment (MCI) in the community-based Framingham Heart Study (FHS).

METHODS

FHS participants aged at least 50 years free of stroke, cognitive impairment, and dementia at the time of MRI were included. PVS were rated according to severity in the basal ganglia and centrum semiovale (CSO) using established criteria. Cox regression analyses were used to relate PVS to incident MCI adjusted for demographic and cardiovascular variables.

RESULTS

The mean age of the sample (1,314 participants) at MRI was 68 years (SD, 9; 54% women). There were 263 cases of incident MCI over a median 7.4 years follow-up (max, 19.8 years). MCI risk increased with higher PVS severity in the CSO. Relative to persons with the lowest severity rating, persons with the highest severity rating in the CSO had a higher risk of incident MCI (hazard ratio [HR] = 2.55; 95% confidence interval [CI], 1.48-4.37; p = 0.0007). In secondary analysis, this association seemed stronger in women. Risk of incident MCI was nominally higher for participants with the highest severity grade of PVS in the basal ganglia, though not statistically significant relative to the lowest grade (HR = 2.19; 95% CI, 0.78-6.14; p = 0.14).

CONCLUSIONS

PVS burden in the CSO may be a risk marker for early cognitive impairment.