Intracranial atherosclerosis and dementia: The Atherosclerosis Risk in Communities (ARIC) Study

Small-Vessel Disease and Intracranial Large Artery Disease in Brain MRI Predict Dementia and Acute Coronary Syndrome, Respectively: A Prospective, Observational Study in the Population at High Vascular Risk

BACKGROUND

We aimed to clarify the predictive value of cerebral small-vessel disease and intracranial large artery disease (LAD) observed in magnetic resonance imaging of the brain and magnetic resonance angiography on future vascular events and cognitive impairment.

METHODS AND RESULTS

Data were derived from a Japanese cohort with evidence of cerebral vessel disease on magnetic resonance imaging. This study included 862 participants who underwent magnetic resonance angiography after excluding patients with a modified Rankin Scale score >1 and Mini-Mental State Examination score <24. We evaluated small-vessel disease such as white matter hyperintensities and lacunes in magnetic resonance imaging and LAD with magnetic resonance angiography. Outcomes were incident stroke, dementia, acute coronary syndrome, and all-cause death. Over a median follow-up period of 4.5 years, 54 incident stroke, 39 cases of dementia, and 27 cases of acute coronary syndrome were documented. Both small-vessel disease (white matter hyperintensities and lacunes) and LAD were associated with stroke; however, only white matter hyperintensities were related to dementia. In contrast, only LAD was associated with acute coronary syndrome. Among the 357 patients with no prior history of stroke, coronary or peripheral artery disease, or atrial fibrillation, white matter hyperintensities emerged as the sole predictor of future stroke and dementia, while LAD was the sole predictor of acute coronary syndrome.

CONCLUSIONS

Among cerebral vessels, small-vessel disease could underlie the cognitive impairment while LAD was associated with coronary artery disease as atherosclerotic vessel disease.

The guardian of intracranial vessels: Why the pericyte?

Intracranial atherosclerotic stenosis (ICAS) is a pathological condition characterized by progressive narrowing or complete blockage of intracranial blood vessels caused by plaque formation. This condition leads to reduced blood flow to the brain, resulting in cerebral ischemia and hypoxia. Ischemic stroke (IS) resulting from ICAS poses a significant global public health challenge, especially among East Asian populations. However, the underlying causes of the notable variations in prevalence among diverse populations, as well as the most effective strategies for preventing and treating the rupture and blockage of intracranial plaques, remain incompletely comprehended. Rupture of plaques, bleeding, and thrombosis serve as precipitating factors in the pathogenesis of luminal obstruction in intracranial arteries. Pericytes play a crucial role in the structure and function of blood vessels and face significant challenges in regulating the Vasa Vasorum (VV)and preventing intraplaque hemorrhage (IPH). This review aims to explore innovative therapeutic strategies that target the pathophysiological mechanisms of vulnerable plaques by modulating pericyte biological function. It also discusses the potential applications of pericytes in central nervous system (CNS) diseases and their prospects as a therapeutic intervention in the field of biological tissue engineering regeneration.

Pathology-based brain arterial disease phenotypes and their radiographic correlates

INTRODUCTION

Brain arterial diseases, including atherosclerosis, vasculitis, and dissections, are major contributors to cerebrovascular morbidity and mortality worldwide. These diseases not only increase the risk of stroke but also play a significant role in neurodegeneration and dementia. Clear and unambiguous terminology and classification of brain arterial disease phenotypes is crucial for research and clinical practice.

MATERIAL AND METHODS

This review aims to summarize and harmonize the terminology used for brain large and small arterial phenotypes based on pathology studies and relate them to imaging phenotypes used in medical research and clinical practice.

CONCLUSIONS AND RESULTS

Arteriosclerosis refers to hardening of the arteries but does not specify the underlying etiology. Specific terms such as atherosclerosis, calcification, or non-atherosclerotic fibroplasia are preferred. Atherosclerosis is defined pathologically by an atheroma. Other brain arterial pathologies occur and should be distinguished from atherosclerosis given therapeutic implications. On brain imaging, intracranial arterial luminal stenosis is usually attributed to atherosclerosis in the presence of atherosclerotic risk factors but advanced high-resolution arterial wall imaging has the potential to more accurately identify the underlying pathology. Regarding small vessel disease, arteriosclerosis is ambiguous and arteriolosclerosis is often used to denote the involvement of arterioles rather than arteries. Lipohyalinosis is sometimes used synonymously with arteriolosclerosis, but less accurately describes this common small vessel thickening which uncommonly shows lipid. Specific measures of small vessel wall thickness, the relationship to the lumen as well as changes in the layer composition might convey objective, measurable data regarding the status of brain small vessels.

Alzheimer's disease and its treatment-yesterday, today, and tomorrow

Alois Alzheimer described the first patient with Alzheimer's disease (AD) in 1907 and today AD is the most frequently diagnosed of dementias. AD is a multi-factorial neurodegenerative disorder with familial, life style and comorbidity influences impacting a global population of more than 47 million with a projected escalation by 2050 to exceed 130 million. In the USA the AD demographic encompasses approximately six million individuals, expected to increase to surpass 13 million by 2050, and the antecedent phase of AD, recognized as mild cognitive impairment (MCI), involves nearly 12 million individuals. The economic outlay for the management of AD and AD-related cognitive decline is estimated at approximately 355 billion USD. In addition, the intensifying prevalence of AD cases in countries with modest to intermediate income countries further enhances the urgency for more therapeutically and cost-effective treatments and for improving the quality of life for patients and their families. This narrative review evaluates the pathophysiological basis of AD with an initial focus on the therapeutic efficacy and limitations of the existing drugs that provide symptomatic relief: acetylcholinesterase inhibitors (AChEI) donepezil, galantamine, rivastigmine, and the N-methyl-D-aspartate receptor (NMDA) receptor allosteric modulator, memantine. The hypothesis that amyloid-β (Aβ) and tau are appropriate targets for drugs and have the potential to halt the progress of AD is critically analyzed with a particular focus on clinical trial data with anti-Aβ monoclonal antibodies (MABs), namely, aducanumab, lecanemab and donanemab. This review challenges the dogma that targeting Aβ will benefit the majority of subjects with AD that the anti-Aβ MABs are unlikely to be the "magic bullet". A comparison of the benefits and disadvantages of the different classes of drugs forms the basis for determining new directions for research and alternative drug targets that are undergoing pre-clinical and clinical assessments. In addition, we discuss and stress the importance of the treatment of the co-morbidities, including hypertension, diabetes, obesity and depression that are known to increase the risk of developing AD.

Risk of Dementia in Patients with Diabetes Using Sodium-Glucose Transporter 2 Inhibitors (SGLT2i): A Systematic Review, Meta-Analysis, and Meta-Regression

INTRODUCTION

Dementia is quite prevalent and among the leading causes of death worldwide. According to earlier research, diabetes may increase the possibility of developing dementia. However, the association between antidiabetic agents and dementia is not yet clear. This investigation examines the association between the use of sodium-glucose transporter 2 inhibitors (SGLT2i) and the risk of dementia in patients with diabetes.

METHODS

Up to April 18, 2023, four databases-Europe PMC, Medline, Scopus, and Cochrane Library-were searched for relevant literature. We included all studies that examine dementia risk in adults with diabetes who use SGLT2i. Random-effect models were used to compute the outcomes in this investigation, producing pooled odds ratios (OR) with 95% confidence intervals (CI).

RESULTS

Pooled data from seven observational studies revealed that SGLT2i use was linked to a lower risk of dementia in people with diabetes (OR 0.45, 95% CI 0.34-0.61; p < 0.00001, I2 = 97%). The reduction in the risk of dementia due to SGLT2i's neuroprotective effect was only significantly affected by dyslipidemia (p = 0.0004), but not by sample size (p = 0.2954), study duration (p = 0.0908), age (p = 0.0805), sex (p = 0.5058), hypertension (p = 0.0609), cardiovascular disease (p = 0.1619), or stroke (p = 0.2734).

CONCLUSIONS

According to this research, taking SGLT2i reduces the incidence of dementia in people with diabetes by having a beneficial neuroprotective impact. Randomized controlled trials (RCTs) are still required in order to verify the findings of our research.

Balloon Angioplasty for Symptomatic Intracranial Artery Stenosis (BASIS): protocol of a prospective, multicentre, randomised, controlled trial

BACKGROUND

The superiority of balloon angioplasty plus aggressive medical management (AMM) to AMM alone for symptomatic intracranial artery stenosis (sICAS) on efficacy and safety profiles still lacks evidence from randomised controlled trials (RCTs).

AIM

To demonstrate the design of an RCT on balloon angioplasty plus AMM for sICAS.

DESIGN

Balloon Angioplasty for Symptomatic Intracranial Artery Stenosis (BASIS) trial is a multicentre, prospective, randomised, open-label, blinded end-point trial to investigate whether balloon angioplasty plus AMM could improve clinical outcome compared with AMM alone in patients with sICAS. Patients eligible in BASIS were 35-80 years old, with a recent transient ischaemic attack within the past 90 days or ischaemic stroke between 14 days and 90 days prior to enrolment due to severe atherosclerotic stenosis (70%-99%) of a major intracranial artery. The eligible patients were randomly assigned to receive balloon angioplasty plus AMM or AMM alone at a 1:1 ratio. Both groups will receive identical AMM, including standard dual antiplatelet therapy for 90 days followed by long-term single antiplatelet therapy, intensive risk factor management and life-style modification. All participants will be followed up for 3 years.

STUDY OUTCOMES

Stroke or death in the next 30 days after enrolment or after balloon angioplasty procedure of the qualifying lesion during follow-up, or any ischaemic stroke or revascularisation from the qualifying artery after 30 days but before 12 months of enrolment, is the primary outcome.

DISCUSSION

BASIS trail is the first RCT to compare the efficacy and safety of balloon angioplasty plus AMM to AMM alone in sICAS patients, which may provide an alternative perspective for treating sICAS.

TRIAL REGISTRATION NUMBER

NCT03703635; https://www.

CLINICALTRIALS

gov.

Associations of Intracranial Artery Length and Branch Number on Time-of-Flight MRA With Cognitive Impairment in Hypertensive Older Males

BACKGROUND

Hypertension-induced impairment of the cerebral artery network contributes to cognitive impairment. Characterizing the structure and function of cerebral arteries may facilitate the understanding of hypertension-related pathological mechanisms and lead to the development of new indicators for cognitive impairment.

PURPOSE

To investigate the associations between morphological features of the intracranial arteries distal to the circle of Willis on time-of-flight MRA (TOF-MRA) and cognitive performance in a hypertensive cohort.

STUDY TYPE

Prospective observational study.

POPULATION

189 hypertensive older males (mean age 64.9 ± 7.2 years).

FIELD STRENGTH/SEQUENCE

TOF-MRA sequence with a 3D spoiled gradient echo readout and arterial spin labeling perfusion imaging sequence with a 3D stack-of-spirals fast spin echo readout at 3T.

ASSESSMENT

The intracranial arteries were segmented from TOF-MRA and the total length of distal arteries (TLoDA) and number of arterial branches (NoB) were calculated. The mean gray matter cerebral blood flow (GM-CBF) was extracted from arterial spin labeling perfusion imaging. The cognitive level was assessed with short-term and long-term delay-recall auditory verbal learning test (AVLT) scores, and with montreal cognitive assessment.

STATISTICAL TESTS

Univariable and multivariable linear regression were used to analyze the associations between TLoDA, NoB, GM-CBF and the cognitive assessment scores, with P < 0.05 indicating significance.

RESULTS

TLoDA (r = 0.314) and NoB (r = 0.346) were significantly correlated with GM-CBF. Multivariable linear regression analyses showed that TLoDA and NoB, but not GM-CBF (P = 0.272 and 0.141), were significantly associated with short-term and long-term delay-recall AVLT scores. These associations remained significant after adjusting for GM-CBF.

DATA CONCLUSION

The TLoDA and NoB of distal intracranial arteries on TOF-MRA are significantly associated with cognitive impairment in hypertensive subjects.

LEVEL OF EVIDENCE

2 TECHNICAL EFFICACY: Stage 3.

Lifestyle and factors of vascular and metabolic health and inflammation are associated with sensorineural-neurocognitive aging in older adults

This study's aim was to identify risk factors associated with sensorineural and neurocognitive function (brain aging) in older adults. In N = 1,478 Epidemiology of Hearing Loss Study participants (aged 64-100 years, 59% women), we conducted sensorineural and cognitive tests, which were combined into a summary measure using Principal Component Analysis (PCA). Participants with a PCA score <-1 standard deviation (SD) were considered to have brain aging. Incident brain aging was defined as PCA score <-1 SD at 5-year follow-up among participants who had a PCA score ≥-1 SD at baseline. Logistic regression and Poisson models were used to estimate associations between baseline risk factors of lifestyle, vascular and metabolic health, and inflammation and prevalent or incident brain aging, respectively. In an age-sex adjusted multivariable model, not consuming alcohol (odds ratio(OR) = 1.77, 95% confidence Interval (CI) = 1.18,2.66), higher interleukin-6 levels (OR = 1.30, 95% CI = 1.03,1.64), and depressive symptoms (OR = 2.44, 95% CI = 1.63,3.67) were associated with a higher odds of having brain aging, while higher education had protective effects (OR = 0.55, 95% CI = 0.33,0.94). A history of stroke, arterial stiffness, and obesity were associated with an increased risk of developing brain aging during the five years of follow-up. Lifestyle, vascular, metabolic and inflammatory factors were associated with brain aging in older adults, which adds to the evidence of shared pathways for sensorineural and neurocognitive declines in aging. Targeting these shared central processing etiological factors with interventions may lead to retention of better neurological function, benefiting multiple systems, i.e., hearing, smell, and cognition, ultimately helping older adults retain independence and higher quality of life longer.

Central arterial stiffening and intracranial atherosclerosis: the atherosclerosis risk in communities neurocognitive study (ARIC-NCS): Aortic stiffness & intracranial atherosclerosis

OBJECTIVES

Previous studies suggest an association between central arterial stiffness (CAS) and intracranial atherosclerotic disease (ICAD) among Asian participants with stroke or hypertension; this association has not been evaluated in United States populations. We assessed the cross-sectional association of CAS with ICAD presence and burden in late-life, and differences in association by age, sex, and race.

MATERIALS AND METHODS

We conducted a cross-sectional analysis of 1,285 Atherosclerosis Risk in Communities Study participants [mean age 75 (standard deviation: 5) years, 38 % male, 20  % Black] at Visit 5 (2011-2013). CAS was measured as carotid-femoral pulse wave velocity (cfPWV) using the Omron VP-1000 Plus. ICAD was assessed using high-resolution vessel wall MRI and MR angiography. We evaluated associations of a 1 standard deviation (SD) cfPWV (3.02 m/s) and high vs. non-high cfPWV (≥ 13.57 m/s vs. < 13.57 m/s) with presence of plaques (yes/no) and plaque number (0, 1-2, and >2) using multivariable logistic and ordinal logistic regression models adjusted for covariates.

RESULTS

Each one SD greater cfPWV was associated with higher odds of plaque presence (odds ratio (OR)=1.32, 95 % confidence interval (CI): 1.22, 1.43), and an incrementally higher odds of number of plaques (OR 1-2 vs. 0 plaques = 1.21, 95 % CI: 1.10, 1.33; OR >2 vs. 0 plaques = 1.51, 95 % CI: 1.33,1.71). Results suggested differences by race, with greater magnitude associations among Black participants.

CONCLUSIONS

CAS was positively associated with ICAD presence and burden; cfPWV may be a useful subclinical vascular measure for identification of individuals who are at high risk for cerebrovascular disease.

Association of ischemic heart disease with long-term risk of cognitive decline and dementia: A cohort study

INTRODUCTION

The independent and joint effect of ischemic heart disease (IHD) and coexisting atrial fibrillation (AF) and heart failure (HF) on dementia risk is largely unknown.

METHODS

This population-based cohort study included 2568 dementia-free participants (age ≥60 years) in SNAC-K, who were regularly examined from 2001-2004 through 2013-2016. Dementia was diagnosed following the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV) criteria. Global cognitive function was assessed using a global cognitive composite z-score derived from five cognitive domains. Data were analyzed using Cox, Fine-Gray, and linear mixed-effects models.

RESULTS

Overall, IHD at baseline was associated with multivariable-adjusted hazard ratio (HR) of 1.39 (95% confidence interval = 1.06-1.82) for dementia and multivariable-adjusted β-coefficient of -0.02 (-0.03 to -0.01) for annual changes in global cognitive z-score, independent of AF, HF, and cerebrovascular disease. Coexisting AF or HF did not add further risk to dementia and cognitive decline.

DISCUSSION

IHD is independently associated with dementia and cognitive decline in older adults, whereas coexisting AF/HF is not associated with an increased risk.

HIGHLIGHTS

Is a history of ischemic heart disease (IHD) associated with a risk for dementia? How do coexisting heart diseases affect this association? IHD was an independent risk factor for dementia in older adults. This association was independent of coexisting heart and cerebrovascular diseases. The coexistence of heart diseases did not confer additional risk for dementia.

Association of remnant cholesterol with intracranial atherosclerosis in community-based population: The ARIC study

OBJECTIVE

To evaluate the association between remnant cholesterol (remnant-C) and intracranial atherosclerotic disease (ICAD) in the Atherosclerosis Risk in Communities Neurocognitive Study (ARIC-NCS).

METHODS

We studied 1,564 participants with data on lipid profiles and high-resolution vessel wall MRI (VWMRI) from the ARIC-NCS. Remnant-C was computed as total cholesterol minus high-density lipoprotein cholesterol minus low-density lipoprotein cholesterol (LDL-C). The primary outcomes were the presence of intracranial plaques and luminal stenosis. Contributors were separated into four different groups based on remnant-C (22 mg/dL) and LDL-C (100 mg/dL) levels to investigate the function of remnant-C vs. LDL-C on ICAD. Multivariable logistic regression models were utilized to estimate the correlation among the discordant/concordant remnant-C and LDL-C, and ICAD.

RESULTS

A total of 1,564 participants were included (age 76.2 ± 5.3). After multivariable adjustment, log remnant-C was correlated with greater ICAD risk [odds ratio (OR) 1.36, 95% confidence interval (CI) 1.01 to 1.83]. The lower remnant-C/higher LDL-C group and the higher remnant-C/lower LDL-C group manifested a 1.53-fold (95% CI 1.06 to 2.20) and 1.52-fold (95% CI 1.08 to 2.14) greater risk of ICAD, relative to those having lower remnant-C/low LDL-C. Additionally, remnant-C ≥ 22 mg/dL distinguished participants at a greater risk of the presence of any stenosis compared to those at lower levels, even in participants with optimal levels of LDL-C.

CONCLUSIONS

Elevated levels of remnant-C were connected to ICAD independent of LDL-C and traditional risk factors. The mechanisms of remnant-C association with ICAD probably offer insight into preventive risk-factor of ischemic stroke.

Cerebral amyloid-β deposition in patients with heart disease or carotid occlusive disease: A systematic review and meta-analysis

BACKGROUND

Cardiovascular disease is an important contributor to cognitive impairment. This likely involves prototypical vascular disease mechanisms like ischemia, but cardiovascular disease might also impact the brain by accelerating cerebral amyloid-β accumulation. We aimed to determine whether there is an association between heart disease or carotid occlusive disease (COD) and cerebral amyloid-β burden.

METHODS

We conducted a systematic review of studies investigating cerebral amyloid-β burden, measured with positron emission tomography, in adults with and without heart disease or COD. Where possible, we obtained standardized mean differences (SMD) of amyloid-β standardized uptake volume ratios (SUVr) for meta-analysis.

RESULTS

Eight cross-sectional studies were identified (1478 participants, aged 60-81 years, 51% female). Three studies on heart disease (two on atrial fibrillation (AF) only, one on AF, coronary artery disease and heart failure) did not find a difference in amyloid-β burden between patients and controls. The pooled difference for 746 participants with and without AF did not reach significance (SMD SUVr 0.14, 95%CI -0.06-0.34). Of the five studies on COD (one on differences between participants with and without COD, four on differences between hemispheres in unilateral COD), four did not find a difference in amyloid-β between participants or hemispheres. The pooled difference in amyloid-β load between hemispheres in 24 patients with unilateral COD was not significant (SMD SUVr -0.13, 95%CI -0.70-0.43).

CONCLUSION

Based on current studies, although limited and heterogeneous, there is insufficient evidence to support the hypothesis that heart disease or COD are associated with increased cerebral amyloid-β burden.

Bioinformatic identification of potential biomarkers and therapeutic targets in carotid atherosclerosis and vascular dementia

Background

Vascular disease is the second most common cause of dementia. The prevalence of vascular dementia (VaD) has increased over the past decade. However, there are no licensed treatments for this disease. Carotid atherosclerosis (CAS) is highly prevalent and is the main cause of ischemic stroke and VaD. We studied co-expressed genes to understand the relationships between CAS and VaD and further reveal the potential biomarkers and therapeutic targets of CAS and VaD.

Methods

CAS and VaD differentially expressed genes (DEGs) were identified through bioinformatic analysis Gene Expression Omnibus (GEO) datasets GSE43292 and GSE122063, respectively. Furthermore, a variety of target prediction methods and network analysis approaches were used to assess the protein-protein interaction (PPI) networks, the Gene Ontology (GO) terms, and the pathway enrichment for DEGs, and the top 7 hub genes, coupled with corresponding predicted miRNAs involved in CAS and VaD, were assessed as well.

Result

A total of 60 upregulated DEGs and 159 downregulated DEGs were identified, of which the top 7 hub genes with a high degree of connectivity were selected. Overexpression of these hub genes was associated with CAS and VaD. Finally, the top 7 hub genes were coupled with corresponding predicted miRNAs. hsa-miR-567 and hsa-miR-4652-5p may be significantly associated with CAS and VaD.

Nomogram to Predict Cognitive Impairment in Patients with Asymptomatic Middle Cerebral Artery Stenosis

Purpose

This study aims to investigate the characteristics and influencing factors of cognitive impairment in patients with asymptomatic middle cerebral artery stenosis (aMCAS) and to construct a nomogram to predict the risk of cognitive impairment in patients with aMCAS.

Patients and Methods

We collected 54 patients with aMCAS and 35 healthy controls to investigate the impaired cognitive domains and pathogenesis in patients with aMCAS. All patients underwent a cranial MRI, CT perfusion, transcranial Doppler ultrasound, blood tests, and a comprehensive neuropsychological evaluation. According to the MoCA score, patients were divided into cognitively normal and cognitively impaired groups. To construct the nomogram, we conducted univariate and multivariate logistic regression analyses to identify factors that affect cognitive function. And the performance of nomogram was evaluated by ROC curves, calibration curves, decision curve analysis (DCA), and clinical impact curve (CIC).

Results

In 54 patients with aMCAS, 24 patients presented with cognitive normal, and 30 patients presented with cognitive impairment. The results of multivariate logistic regression suggested that perfusion decompensation, middle cerebral artery mean flow velocity, and LDL-cholesterol levels were independent influencing factors of cognitive impairment. In the following step, a nomogram was constructed. The AUC of the nomogram is 0.862. Calibrating curves show good agreement between nomogram predictions and actual observations, while DCA and CIC show great clinical usefulness.

Conclusion

Patients with aMCAS have cognitive impairment in multiple cognitive domains, and impaired executive function was observed during the perfusion compensation period. Furthermore, a nomogram was constructed and validated to predict the risk of cognitive impairment in patients with aMCAS, which can help clinicians to identify at an early stage and improve the management of patients.

Associations of Midlife Lifestyle and Health Factors with Long-Term Changes in Blood-Based Biomarkers of Alzheimer's Disease and Neurodegeneration

BACKGROUND

Pathological biomarkers of Alzheimer's disease (AD) and other dementias can change decades before clinical symptoms. Lifestyle and health factors might be relevant modifiable risk factors for dementia. Many previous studies have been focusing on associations of lifestyle and health-related factors with clinical outcomes later in life.

OBJECTIVE

We aimed to determine to what extent midlife factors of lifestyle, inflammation, vascular, and metabolic health were associated with long-term changes in blood-based biomarkers of AD (amyloid beta (Aβ)) and neurodegeneration (neurofilament light chain (NfL); total tau(TTau)).

METHODS

In 1,529 Beaver Dam Offspring Study (BOSS) participants (mean age 49 years, standard deviation (SD) = 9; 54% were women), we applied mixed-effects models with baseline risk factors as determinants and 10-year serum biomarker change as outcomes.

RESULTS

We found that education and inflammatory markers were associated with levels and/or change over time across all three markers of AD and neurodegeneration in the blood. There were baseline associations of measures of cardiovascular health with lower Aβ42/Aβ40. TTau changed little over time and was higher in individuals with diabetes. Individuals with lower risk in a number of cardiovascular and metabolic risk factors, including diabetes, hypertension, and atherosclerosis had slower accumulation of neurodegeneration over time, as determined by NfL levels.

CONCLUSION

Various lifestyle and health factors, including education and inflammation, were associated with longitudinal changes of neurodegenerative and AD biomarker levels in midlife. If confirmed, these findings could have important implications for developing early lifestyle and health interventions that could potentially slow processes of neurodegeneration and AD.

eICAB: A novel deep learning pipeline for Circle of Willis multiclass segmentation and analysis

BACKGROUND

The accurate segmentation, labeling and quantification of cerebral blood vessels on MR imaging is important for basic and clinical research, yet results are not generalizable, and often require user intervention. New methods are needed to automate this process.

PURPOSE

To automatically segment, label and quantify Circle of Willis (CW) arteries on Magnetic Resonance Angiography images using deep convolutional neural networks.

MATERIALS AND METHODS

MRA images were pooled from three public and private databases. A total of 116 subjects (mean age 56 years ± 21 [standard deviation]; 72 women) were used to make up the training set (N=101) and the testing set (N=15). In each image, fourteen arterial segments making up or surrounding the CW were manually annotated and validated by a clinical expert. Convolutional neural network (CNN) models were trained on a training set to be finally combined in an ensemble to develop eICAB. Model performances were evaluated using (1) quantitative analysis (dice score on test set) and (2) qualitative analysis (external datasets, N=121). The reliability was assessed using multiple MRAs of healthy participants (ICC of vessel diameters and volumes on test-retest).

RESULTS

Qualitative analysis showed that eICAB correctly predicted the large, medium and small arteries in 99±0.4%, 97±1% and 88±7% of all images, respectively. For quantitative assessment, the average dice score coefficients for the large (ICAs, BA), medium (ACAs, MCAs, PCAs-P2), and small (AComm, PComm, PCAs-P1) vessels were 0.76±0.07, 0.76±0.08 and 0.41±0.27, respectively. These results were similar and, in some cases, statistically better (p<0.05) than inter-expert annotation variability and robust to image SNR. Finally, test-retest analysis showed that the model yielded high diameter and volume reliability (ICC=0.99).

CONCLUSION

We have developed a quick and reliable open-source CNN-based method capable of accurately segmenting and labeling the CW in MRA images. This method is largely independent of image quality. In the future, we foresee this approach as a critical step towards fully automated analysis of MRA databases in basic and clinical research.

The Associations Between Intracranial Stenosis, Brain Amyloid-beta, and Cognition in a Memory Clinic Sample

BACKGROUND

Intracranial stenosis (ICS) and brain amyloid-beta (Aβ) have been associated with cognition and dementia. We aimed to investigate the association between ICS and brain Aβ and their independent and joint associations with cognition.

METHODS

We conducted a cross-sectional study of 185 patients recruited from a memory clinic. ICS was measured on 3-dimensional time-of-flight magnetic resonance angiography and defined as stenosis ≥50%. Brain Aβ was measured with [ 11 C] Pittsburgh compound B-positron emission tomography imaging. Cognition was assessed with a locally validated neuropsychological battery.

RESULTS

A total of 17 (9.2%) patients had ICS, and the mean standardized uptake value ratio was 1.4 (±0.4 SD). ICS was not significantly associated with brain Aβ deposition. ICS was significantly associated with worse global cognition (β: -1.26, 95% CI: -2.25; -0.28, P =0.013), executive function (β: -1.04, 95% CI: -1.86; -0.22, P =0.015) and visuospatial function (β: -1.29, 95% CI: -2.30; -0.27, P =0.015). Moreover, in ICS patients without dementia (n=8), the presence of Aβ was associated with worse performance on visuomotor speed.

CONCLUSIONS

ICS was significantly associated with worse cognition and showed interaction with brain Aβ such that patients with both pathologies performed worse on visuomotor speed specifically in those without dementia. Further studies may clarify if ICS and brain Aβ deposition indeed have a synergistic association with cognition.

The impact of smoking status on cognition and brain morphology in schizophrenia spectrum disorders

BACKGROUND

Cigarette smoking is associated with worse cognition and decreased cortical volume and thickness in healthy cohorts. Chronic cigarette smoking is prevalent in schizophrenia spectrum disorders (SSD), but the effects of smoking status on the brain and cognition in SSD are not clear. This study aimed to understand whether cognitive performance and brain morphology differed between smoking and non-smoking individuals with SSD compared to healthy controls.

METHODS

Data were obtained from the Australian Schizophrenia Research Bank. Cognitive functioning was measured in 299 controls and 455 SSD patients. Cortical volume, thickness and surface area data were analysed from T1-weighted structural scans obtained in a subset of the sample (n = 82 controls, n = 201 SSD). Associations between smoking status (cigarette smoker/non-smoker), cognition and brain morphology were tested using analyses of covariance, including diagnosis as a moderator.

RESULTS

No smoking by diagnosis interactions were evident, and no significant differences were revealed between smokers and non-smokers across any of the variables measured, with the exception of a significantly thinner left posterior cingulate in smokers compared to non-smokers. Several main effects of smoking in the cognitive, volume and thickness analyses were initially significant but did not survive false discovery rate (FDR) correction.

CONCLUSIONS

Despite the general absence of significant FDR-corrected findings, trend-level effects suggest the possibility that subtle smoking-related effects exist but were not uncovered due to low statistical power. An investigation of this topic is encouraged to confirm and expand on our findings.

European Stroke Organisation guidelines on treatment of patients with intracranial atherosclerotic disease

The aim of the present European Stroke Organisation guideline is to provide clinically useful evidence-based recommendations on the management of patients with intracranial atherosclerotic disease (ICAD). The guidelines were prepared following the Standard Operational Procedure of the European Stroke Organisation guidelines and according to GRADE methodology. ICAD represents a major cause of ischemic stroke worldwide, and patients affected by this condition are exposed to a high risk for future strokes and other major cardiovascular events, despite best medical therapy available. We identified 11 relevant clinical problems affecting ICAD patients and formulated the corresponding Population Intervention Comparator Outcomes (PICO) questions. The first two questions refer to the asymptomatic stage of the disease, which is being increasingly detected thanks to the routine use of noninvasive vascular imaging. We were not able to provide evidence-based recommendations regarding the optimal detection strategy and management of asymptomatic ICAD, and further research in the field is encouraged as subclinical ICAD may represent a big opportunity to improve primary stroke prevention. The second block of PICOs (3-5) is dedicated to the management of acute large vessel occlusion (LVO) ischemic stroke caused by ICAD, a clinical presentation of this disease that is becoming increasingly relevant and problematic, since it is associated with more refractory endovascular reperfusion procedures. An operational definition of probable ICAD-related LVO is proposed in the guideline. Despite the challenging context, no dedicated randomized clinical trials (RCTs) were identified, and therefore the guideline can only provide with suggestions derived from observational studies and our expert consensus, such as the escalated use of glycoprotein IIb-IIIa inhibitors and angioplasty/stenting in cases of refractory thrombectomies due to underlying ICAD. The last block of PICOs is devoted to the secondary prevention of patients with symptomatic ICAD. Moderate-level evidence was found to recommend against the use of oral anticoagulation as preferred antithrombotic drug, in favor of antiplatelets. Low-level evidence based our recommendation in favor of double antiplatelet as the antithrombotic treatment of choice in symptomatic ICAD patients, which we suggest to maintain during 90 days as per our expert consensus. Endovascular therapy with intracranial angioplasty and or stenting is not recommended as a treatment of first choice in high-grade symptomatic ICAD (moderate-level evidence). Regarding neurosurgical interventions, the available evidence does not support their use as front line therapies in patients with high-grade ICAD. There is not enough evidence as to provide any specific recommendation regarding the use of remote ischemic conditioning in ICAD patients, and further RCTs are needed to shed light on the utility of this promising therapy. Finally, we dedicate the last PICO to the importance of aggressive vascular risk factor management in ICAD, although the evidence derived from RCTs specifically addressing this question is still scarce.

Better cognitive function in younger generations - Insights from two cohort studies of middle-aged to older adults in Wisconsin

BACKGROUND

Understanding generational trends in dementia and cognitive decline is essential to quantify future healthcare needs and may help identify interventions and preventions. We aimed to determine whether individuals from more recent generations showed better neurocognitive function.

METHODS

This cross-sectional study combined data from 4439 participants (mean age 64 years (SD = 13); 57% were women) from the Epidemiology of Hearing Loss Study and Beaver Dam Offspring Study. We assessed participants' birth cohort (1901-1924, Greatest Generation; 1925-1945, Silent Generation; 1946-1964, Baby Boom Generation; 1965-1984, Generation X) and neurocognition (Trail-Making Tests A and B, Digit Symbol Substitution Test, Auditory Verbal Learning Test, Verbal Fluency Test). Multivariable linear regression models were utilized.

RESULTS

Adjusted for age, sex, education, and known risk factors for cognitive decline, more recent generations showed better processing speed, executive function, attention, and verbal fluency than the Greatest Generation. Largest benefits were found in the Baby Boom Generation. Compared with the Greatest Generation, individuals from the Baby Boom Generation performed better on Trail-Making Tests A (-0.21 ln(time in s); 95% confidence interval (CI) -0.29, -0.13) and B (-0.31 ln(time in s); 95% CI -0.40, -0.22), Digit Symbol Substitution Test (6.07 numbers correct; 95% CI 3.61, 8.52) and Verbal Fluency Test (8.75 numbers correct; 95% CI 5.07, 12.42 in women; 5.28 numbers correct; 95% CI 0.79, 9.78 in men), with effect sizes similar to effects of 11-15 years of less aging.

CONCLUSIONS

This indicates that some benefits of younger generations might be related to yet unknown and potentially modifiable environmental, health-related or lifestyle factors and motivates research of such underlying factors to promote healthy cognitive aging.

Vascular pathology and pathogenesis of cognitive impairment and dementia in older adults

It is well recognized that brains of older people often harbor cerebrovascular disease pathology including vessel disease and vascular-related tissue injuries and that this is associated with vascular cognitive impairment and contributes to dementia. Here we review vascular pathologies, cognitive impairment, and dementia. We highlight the importance of mixed co-morbid AD/non-AD neurodegenerative and vascular pathology that has been collected in multiple clinical pathologic studies, especially in community-based studies. We also provide an update of vascular pathologies from the Rush Memory and Aging Project and Religious Orders Study cohorts with special emphasis on the differences across age in persons with and without dementia. Finally, we discuss neuropathological perspectives on the interpretation of clinical-pathological studies and emerging data in community-based studies.

Relation of Progression of Coronary Artery Calcium to Dementia (from the Multi-Ethnic Study of Atherosclerosis)

Baseline coronary artery calcification has been shown to be associated with dementia. However, the value of coronary artery calcium (CAC) progression in the prediction of dementia remains unclear. In this study, we examined the association between CAC progression and dementia in the Multi-Ethnic Study of Atherosclerosis. The Multi-Ethnic Study of Atherosclerosis is a prospective study consisting of 6,814 participants 45 to 84 years of age, free of overt cardiovascular disease at baseline. A total of 5,570 subjects had baseline and follow-up CAC scans approximately 2.5 years apart and were included this analysis. A total of 4,173 of these participants completed cognitive testing with the Cognitive Abilities Screening Instrument (CASI) approximately 10 years after the baseline CAC scan. Dementia diagnoses were identified using International Classification of Diseases codes from hospitalizations, death certificates, and medications used to treat dementia. The absolute change between baseline and follow-up CAC was used to assess CAC progression. Cox proportional hazards and multivariable linear regression models were used to examine the association of CAC progression with incident dementia and with CASI score. Over a median follow-up of 13.2 (interquartile range: 11.2 to 15.3) years, 350 participants developed incident dementia. CAC progression showed no association with dementia risk after adjustment for age, gender, race/ethnicity, vascular risk factors, and baseline CAC score. There was no association of CAC progression with CASI score in any adjusted model. In conclusion, progression of CAC over approximately 2.5 years was not associated with increased risk of dementia after adjustment for demographic variables, vascular risk factors, and baseline CAC.

7T MRI for Intracranial Vessel Wall Lesions and Its Associated Neurological Disorders: A Systematic Review

Intracranial vessel wall lesions are involved in a variety of neurological diseases. The advanced technique 7T MRI provides greater efficacy in the diagnosis of the pathology changes in the vessel wall and helps to identify potential subtle lesions. The purpose of this literature review was to systematically describe and evaluate the existing literature focusing on the use of 7T MRI in the detection and characterization of intracranial vessel wall lesions and their associated neurological disorders, to highlight the current knowledge gaps, and to formulate a framework to guide future applications and investigations. We systematically reviewed the existing articles up to July 2021, seeking the studies that assessed intracranial vessel wall lesions and their associated neurological disorders using 7T MRI. The literature search provided 12 studies that met the inclusion criteria. The most common intracranial vessel wall lesions were changes related to intracranial atherosclerosis (n = 8) and aneurysms (n = 4), such as intracranial atherosclerosis burden and aneurysm wall enhancement. The associated neurological disorders included aneurysms, ischemic stroke or TIA, small vessel disease, cognitive decline, and extracranial atherosclerosis. No paper studied the use of 7T MRI for investigating vessel wall conditions such as moyamoya disease, small vessel disease, or neurological disorders related to central nervous vasculitis. In conclusion, the novel 7T MRI enables the identification of a wider spectrum of subtle changes and associations. Future research on cerebral vascular diseases other than intracranial atherosclerosis and aneurysms may also benefit from 7T MRI.

Impact of comorbidities on the disability progression in multiple sclerosis

OBJECTIVES

Investigation of the comorbidity burden in persons with multiple sclerosis (PwMS) has become increasingly important. The aim of this study was to investigate the relationships of cardiovascular disease (CVD) comorbidities and type 2 diabetes with the disability progression.

MATERIALS & METHODS

The retrospective cohort study was conducted at the Clinic of Neurology, Belgrade. The Belgrade MS population Registry, which comprises 2725 active MS cases, was used as the source of data. The mean duration of the disease was 21.6 ± 12.5 years. Expanded Disability Status Scale (EDSS) was followed in all PwMS in the Registry. In the statistical analysis, the Cox proportional hazard regression analysis and Kaplan-Meier curve were performed.

RESULTS

Hypertension statistically significantly contributed to more rapid reaching investigated levels of irreversible disability (EDSS 4.0, 6.0, and 7.0), while the presence of any of the investigated CVD comorbidities and type 2 diabetes significantly contributed to faster reaching EDSS 4.0 and EDSS 6.0. In a multivariable model, progression index (PI) was singled out (HR = 3.171, p < .001), indicating that higher progression index (PI) was an independent predictor of CVD occurrence in MS patients. In the case of type 2 diabetes, PI (p < .001) and MS phenotype (p = .015) were statistically significant in multivariable Cox regression analysis.

CONCLUSIONS

Our study confirms the impact of CVD comorbidities and type 2 diabetes in MS on the progression of disability as measured by EDSS in the large cohort of PwMS from the population Registry.

Neutrophil-to-Lymphocyte Ratio as a Predictive Biomarker for Stroke Severity and Short-Term Prognosis in Acute Ischemic Stroke With Intracranial Atherosclerotic Stenosis

Background: Neutrophil-to-lymphocyte ratio (NLR) is an indicator of poor prognosis in acute ischemic stroke (AIS), but associations between NLR with stroke severity and prognosis of intracranial atherosclerotic stenosis (ICAS)-related ischemic events have not been well-elucidated; therefore, we aimed to evaluate whether admission NLR levels correlate with the early stroke severity and short-term functional prognosis in patients with symptomatic intracranial atherosclerotic stenosis (sICAS). Methods: This retrospective study enrolled 899 consecutive patients with AIS attributed to ICAS at Xiangya Hospital stroke center between May 2016 and September 2020. The initial stroke severity was rated by the admission National Institutes of Health Stroke Scale (NIHSS) scores, and the short-term prognosis was evaluated using the 14-day modified Rankin Scale (mRS) scores after stroke onset. A severe stroke was defined as NIHSS >8; an unfavorable functional outcome was defined as mRS scores of 3-6. Admission NLR was determined based on circulating neutrophil and lymphocyte counts. Results: The median admission NLR of all patients was 2.80 [interquartile range (IQR), 2.00-4.00]. In univariate analysis, admission NLR was significantly elevated in patients with severe stroke and poor short-term prognosis. After multivariate adjustment, admission NLR levels were significantly correlated with severe stroke [odds ratio (OR), 1.132; 95% confidence interval (95% CI), 1.038-1.234; P = 0.005] and unfavorable short-term prognosis (OR, 1.102; 95% CI, 1.017-1.195; P = 0.018) in Model 1. In Model 2, the highest NLR tertile (≥3.533) remained an independent predictor of severe stroke (OR, 2.736; 95% CI, 1.590-4.708; P < 0.001) and unfavorable functional outcome (OR, 2.165; 95% CI, 1.416-3.311; P < 0.001) compared with the lowest NLR tertile (<2.231). The receiver operating characteristic (ROC) curves showed the predictability of NLR regarding the stroke severity [area under the curve (AUC), 0.659; 95% CI, 0.615-0.703; P < 0.001] and short-term prognosis (AUC, 0.613; 95% CI, 0.575-0.650; P < 0.001). The nomograms were constructed to create the predictive models of the severity and short-term outcome of sICAS. Conclusions: Elevated admission NLR levels were independently associated with the initial stroke severity and could be an early predictor of severity and poor short-term prognosis in AIS patients with ICAS, which might help us identify a target group timely for preventive therapies.

Association between coronary artery calcification and cognitive function in a Chinese community-based population

Background

Coronary atherosclerosis and cognitive impairment are both age-related diseases, with similar risk factors. Coronary artery calcium (CAC), a marker of coronary atherosclerosis, may play a role in early detection of individuals prone to cognitive decline. This study aimed to investigate the relationship between CAC and cognitive function, and the capability of CAC to identify participants with a high risk of dementia in a Chinese community-based population.

Methods

A total of 1332 participants, aged 40−80 years and free of dementia from a community located in Beijing were included. All participants completed neurocognitive questionnaires and noncontrast CT examinations. Cognitive performance tests (including verbal memory, semantic fluency, executive function, and global cognitive function tests), the Cardiovascular Risk Factors, Aging, and Incidence of Dementia (CIDE) risk score, and the CAC score (CACS) were evaluated by questionnaires and CT. A CAIDE score ≥ 10 was considered to indicate a high risk of dementia in late-life. Participants were divided into three groups according to CACS (0, 1−399, ≥ 400).

Results

After adjusting for risk factors, CACS was significantly associated with verbal memory (r = −0.083, P = 0.003) and global cognitive function (r = −0.070, P = 0.012). The prevalence of a high risk of dementia in the subgroups of CACS = 0, 1−399, and ≥ 400 was 4.67%, 13.66%, and 24.79%, respectively (P < 0.001). Individuals with CACS ≥ 400 had a higher risk of CAIDE score ≥ 10 [OR = 2.30 (1.56, 4.56), P = 0.014] than those with CACS = 0. The receiver-operating characteristic curves showed that the capability of CACS to identify participants with a high risk of dementia was moderate (AUC = 0.70, 95% CI: 0.67−0.72,P < 0.001).

Conclusions

CAC, a marker of subclinical atherosclerosis, was significantly associated with cognitive performance in verbal memory and global cognitive function. CAC had a moderate capability to identify participants with a high risk of dementia, independent of age, education, and other risk factors.

Association of self-measured home, ambulatory, and strictly measured office blood pressure and their variability with intracranial arterial stenosis

OBJECTIVE

Hypertension and intracranial artery stenosis (ICAS) are closely related; however, few studies have compared the strength of the relationship between strictly measured office and out-of-office blood pressure (BP) measurements. The relationship of day-by-day or short-term variability in BP to asymptomatic ICAS also remains unclear.

METHODS

In apparently healthy 677 men (mean age, 70 years) from a population-based cohort, we examined the association of strictly measured office BP and 7-day home BP with ICAS on magnetic resonance angiography. We conducted 24-h ambulatory BP monitoring in 468 of the men. Variability indices included day-by-day, daytime, and night-time variability, nocturnal decline, and morning pressor surge. Any ICAS was defined as either mild (1-49%) or severe (≥50%) stenosis.

RESULTS

We observed mild and severe ICAS in 153 (22.6%) and 36 (5.3%) participants, respectively. In multivariable-adjusted Poisson regression with robust error variance, higher SBP in office, home, or ambulatory BP monitoring was associated with the presence of any or severe ICAS. The associations with ICAS were comparable between office, home, and ambulatory SBP (all heterogeneity P values >0.1). Independent of mean SBP, greater nocturnal decline or morning pressor surge, but not day-by-day, daytime, or night-time variability, in SBP was associated with higher burden of any or severe ICAS.

CONCLUSION

The magnitude of association of strictly measured office BP for asymptomatic ICAS was comparable with that of BP measured at home or in ambulatory BP monitoring. Circadian BP variation based on ambulatory BP monitoring was positively associated with asymptomatic ICAS burden.

Olfactory Bulb Proteomics Reveals Widespread Proteostatic Disturbances in Mixed Dementia and Guides for Potential Serum Biomarkers to Discriminate Alzheimer Disease and Mixed Dementia Phenotypes

The most common form of mixed dementia (MixD) is constituted by abnormal protein deposits associated with Alzheimer's disease (AD) that coexist with vascular disease. Although olfactory dysfunction is considered a clinical sign of AD-related dementias, little is known about the impact of this sensorial impairment in MixD at the molecular level. To address this gap in knowledge, we assessed olfactory bulb (OB) proteome-wide expression in MixD subjects (n = 6) respect to neurologically intact controls (n = 7). Around 9% of the quantified proteins were differentially expressed, pinpointing aberrant proteostasis involved in synaptic transmission, nucleoside monophosphate and carbohydrate metabolism, and neuron projection regeneration. In addition, network-driven proteomics revealed a modulation in cell-survival related pathways such as ERK, AKT, and the PDK1-PKC axis. Part of the differential OB protein set was not specific of MixD, also being deregulated across different tauopathies, synucleinopathies, and tardopathies. However, the comparative functional analysis of OB proteome data between MixD and pure AD pathologies deciphered commonalities and differences between both related phenotypes. Finally, olfactory proteomics allowed to propose serum Prolow-density lipoprotein receptor-related protein 1 (LRP1) as a candidate marker to differentiate AD from MixD phenotypes.

Emerging Concepts in Vascular Dementia: A Review

OBJECTIVE

Vascular dementia (VaD) is the second most common cause of dementia and a major health concern worldwide. A comprehensive review on VaD is warranted for better understanding and guidance for the practitioner. We provide an updated overview of the epidemiology, pathophysiological mechanisms, neuroimaging patterns as well as current diagnostic and therapeutic approaches.

MATERIALS AND METHODS

A narrative review of current literature in VaD was performed based on publications from the database of PubMed, Scopus and Google Scholar up to January, 2021.

RESULTS

VaD can be the result of ischemic or hemorrhagic tissue injury in a particular region of the brain which translates into clinically significant cognitive impairment. For example, a cerebral infarct in the speech area of the dominant hemisphere would translate into clinically significant impairment as would involvement of projection pathways such as the arcuate fasciculus. Specific involvement of the angular gyrus of the dominant hemisphere, with resultant Gerstman's syndrome, could have a pronounced effect on functional ability despite being termed a "minor stroke". Small vessel cerebrovascular disease can have a cumulate effect on cognitive function over time. It is unfortunately well recognized that "good" functional recovery in acute ischemic or haemorrhagic stroke, including subarachnoid haemorrhage, does not necessarily translate into good cognitive recovery. The victim may often be left unable to have gainful employment, drive a car safely or handle their affairs independently.

CONCLUSIONS

This review should serve as a compendium of updated information on VaD and provide guidance in terms of newer diagnostic and potential therapeutic approaches.

Association of Type 2 Diabetes Mellitus and Glycemic Control With Intracranial Plaque Characteristics in Patients With Acute Ischemic Stroke

BACKGROUND

Type 2 diabetes mellitus (T2DM) has shown to be associated with carotid plaque vulnerability. However, the impact of T2DM on intracranial artery atherosclerosis is not well-understood.

PURPOSE

To evaluate the association of diabetes and glycemic control with intracranial atherosclerotic plaque characteristics identified by three-dimensional contrast enhanced MR vessel wall imaging in patients after acute ischemic stroke.

STUDY TYPE

Prospective.

POPULATION

Two hundred and eighty-eight symptomatic patients with acute ischemic stroke due to intracranial atherosclerotic plaque.

FIELD STRENGTH/SEQUENCE

T₁ WI volume isotropic turbo spin-echo acquisition sequence at 3.0 T.

ASSESSMENT

Clinical profiles, blood biomarkers, the number of intracranial plaques, plaque enhanced score, and the features (location, luminal stenotic rate, intraplaque hemorrhage, length, burden, enhancement grade, and ratio) of culprit plaque (defined as the most stenotic lesion ipsilateral to the ischemic event) and nonculprit plaque were analyzed by three radiologists.

STATISTICAL TESTS

Analysis of variance (ANOVA), Shapiro-Wilk normality test, Levene's test, ANOVA with Bonferroni post-hoc test, Kruskal Wallis H test with subsequent pairwise comparisons, chi-square with Bonferroni post-hoc test, generalized linear regression, Pearson correlation test, Kendall's W and intra-class correlation coefficient.

RESULTS

Two hundred and twenty-five participants (age 60 ± 10 years, 58.7% male) with 958 intracranial plaques were included. More intracranial plaques were found in the T2DM group than the non-T2DM group (4.80 ± 2.22 vs. 3.60 ± 1.78, P < 0.05). Patients with poorly-controlled T2DM exhibited higher culprit plaque enhancement ratio than patients with well-controlled T2DM and non-T2DM (2.32 ± 0.61 vs. 1.60 ± 0.62 and 1.39 ± 0.39; respectively, P < 0.05). After adjusting for other clinical variables, T2DM was independently associated with increased intracranial plaque number (β = 0.269, P < 0.05), and HbA1c level was independently associated with culprit plaque enhancement ratio (β = 0.641, P < 0.05) in multivariate analysis.

DATA CONCLUSION

T2DM is associated with an increased intracranial plaque number. Higher HbA1c is associated with stronger plaque enhancement. 3D contrast enhanced MR vessel wall imaging may help better understand the association of T2DM and glycemic control with intracranial plaque.

LEVEL OF EVIDENCE

1 TECHNICAL EFFICACY STAGE: 3.

Cholesterol, Atherosclerosis, and APOE in Vascular Contributions to Cognitive Impairment and Dementia (VCID): Potential Mechanisms and Therapy

Vascular contributions to cognitive impairment and dementia (VCID) are a common cause of cognitive decline, yet limited therapies exist. This cerebrovascular disease results in neurodegeneration via acute, chronic, local, and systemic mechanisms. The etiology of VCID is complex, with a significant impact from atherosclerosis. Risk factors including hypercholesterolemia and hypertension promote intracranial atherosclerotic disease and carotid artery stenosis (CAS), which disrupt cerebral blood flow and trigger ischemic strokes and VCID. Apolipoprotein E (APOE) is a cholesterol and phospholipid carrier present in plasma and various tissues. APOE is implicated in dyslipidemia and Alzheimer disease (AD); however, its connection with VCID is less understood. Few experimental models for VCID exist, so much of the present information has been drawn from clinical studies. Here, we review the literature with a focus on the clinical aspects of atherosclerotic cerebrovascular disease and build a working model for the pathogenesis of VCID. We describe potential intermediate steps in this model, linking cholesterol, atherosclerosis, and APOE with VCID. APOE4 is a minor isoform of APOE that promotes lipid dyshomeostasis in astrocytes and microglia, leading to chronic neuroinflammation. APOE4 disturbs lipid homeostasis in macrophages and smooth muscle cells, thus exacerbating systemic inflammation and promoting atherosclerotic plaque formation. Additionally, APOE4 may contribute to stromal activation of endothelial cells and pericytes that disturb the blood-brain barrier (BBB). These and other risk factors together lead to chronic inflammation, atherosclerosis, VCID, and neurodegeneration. Finally, we discuss potential cholesterol metabolism based approaches for future VCID treatment.

The effect of intracranial stenosis on cognitive decline in a memory clinic cohort

BACKGROUND AND PURPOSE

Intracranial stenosis (ICS) is a risk factor for cognitive impairment and dementia in cross-sectional studies. However, data examining the effect of ICS on cognitive decline are limited. We investigated the effect of ICS on cognition over a period of 3 years in a memory clinic cohort.

METHODS

Patients were recruited from the National University Hospital in Singapore. Data were collected using a standardised questionnaire, physical examination, and 3-T magnetic resonance imaging (MRI) at baseline. ICS was defined as arterial narrowing that exceeded 50% of the luminal diameter in any intracranial vessel. Cognition was measured at baseline and annually for 3 years using the Mini-Mental State Examination, the Montreal Cognitive Assessment, and a detailed neuropsychological test battery. The association between ICS and cognitive decline was analysed using generalised estimating equations.

RESULTS

A total of 364 patients were included in the analysis. The mean (±SD) age was 71.9 (±8.0) years, and 164 (45.1%) patients were male. A total of 66 (18.1%) patients had ICS. ICS was associated with worse executive function (β = -0.37, 95% confidence interval = -0.68 to -0.05, p = 0.022) and modified the effect of follow-up time on memory (p = 0.005) and visuomotor speed (p = 0.047). These results remained significant after controlling for demographics, overall diagnosis, cardiovascular risk factors, and MRI markers of cerebrovascular disease.

CONCLUSIONS

Intracranial stenosis was independently associated with worse executive function across all time points, and cognitive decline in memory and visuomotor speed over 3 years of follow-up. This suggests that ICS may be a useful indicator of vascular brain damage leading to cognitive decline and may warrant consideration of antiatherosclerotic treatment in clinical trials.

Association of Intracranial Atherosclerotic Disease With Brain β-Amyloid Deposition: Secondary Analysis of the ARIC Study

Importance

Intracranial atherosclerotic disease (ICAD) is an important cause of stroke and has also been recently identified as an important risk factor for all-cause dementia, but the mechanism of its association with cognitive performance is not fully understood.

Objective

To test the hypothesis that ICAD is associated with cerebral β-amyloid deposition as a marker of Alzheimer disease.

Design, Setting, and Participants

This cross-sectional analysis of data collected from August 2011 through November 2014 was a community-based cohort study conducted in 3 US communities. Of 346 adults without dementia aged 70 to 90 years who were sequentially recruited from 3 of 4 sites of the larger Atherosclerosis Risk in Communities study into a study of brain florbetapir positron emission tomography (ARIC-PET), 300 met inclusion criteria. A total of 589 were approached about recruitment, of whom 346 (58.7%) consented (the remainder either met exclusion criteria for ARIC-PET or refused to participate). Data were analyzed from July 2017 through October 2019.

Exposures

Intracranial atherosclerotic disease presence, frequency, and extent of stenosis, by high-resolution vessel wall magnetic resonance imaging.

Main Outcomes and Measures

Global cortical standardized uptake value ratio (SUVR) of greater than 1.2 as measured by florbetapir PET. Models were conducted using logistic regression methods. In secondary analyses, we tested effect modifications by apolipoprotein E ε4 genotype with interaction terms and in stratified models and evaluated regional patterns of associations.

Results

In 300 participants (mean [SD] age, 76 [5] years; 132 African American individuals [44%], 167 women [56%], and 94 carriers of at least 1 apolipoprotein E ε4 allele [31%]), ICAD was found in 105 participants (35%) and mean (SD) SUVR was higher in individuals with vs without intracranial plaques (1.34 [0.29] vs 1.27 [0.23]; P = .03). In adjusted models, ICAD presence (plaque presence [adjusted odds ratio (aOR), 1.20; 95% CI, 0.69-2.07] and frequency [aOR, 1.10; 95% CI, 0.96-1.26]) was not associated significantly with elevated SUVR in the total sample. Furthermore, modest stenosis of the intracranial vessels (defined as >50% stenosis) was not associated with elevated SUVR (aOR, 2.33; 95% CI, 0.82-6.60).

Conclusions and Relevance

In this community-based cohort of adults without dementia, intracranial atherosclerotic plaque or stenosis was not associated with brain β-amyloid deposition.

Subclinical Atherosclerosis and Brain Metabolism in Middle-Aged Individuals: The PESA Study

BACKGROUND

Atherosclerosis has been linked to cognitive decline in late life; however, the impact of cardiovascular risk factors (CVRFs) and subclinical atherosclerosis on brain metabolism at earlier stages remains unexplored.

OBJECTIVES

This study sought to determine the association between brain metabolism, subclinical atherosclerosis, and CVRFs in middle-aged asymptomatic individuals.

METHODS

This study included 547 asymptomatic middle-aged participants (50 ± 4 years, 82% men) from the PESA (Progression of Early Subclinical Atherosclerosis) study with evidence of subclinical atherosclerosis. Participants underwent ¹⁸F-fluorodeoxyglucose (FDG)-positron emission tomography. Global brain FDG uptake and voxel-wise analyses were used to evaluate the associations of cerebral metabolism with CVRFs and atherosclerotic plaque burden in carotids and femorals assessed by 3-dimensional vascular ultrasound.

RESULTS

Global FDG uptake showed an inverse correlation with 30-year Framingham Risk Score (FRS) (β = -0.15, p < 0.001). This association was mainly driven by the presence of hypertension (d = 0.36, p < 0.001). Carotid plaque burden was inversely associated with global brain FDG uptake (β = -0.16, p < 0.001), even after adjusting for 30-year FRS. Voxel-wise approaches revealed that the brain areas most strongly affected by hypometabolism in association with 30-year FRS, hypertension, and carotid plaque burden were parietotemporal regions (angular, supramarginal, and inferior/middle temporal gyri) and the cingulate gyrus.

CONCLUSIONS

In asymptomatic middle-aged individuals, cardiovascular risk is associated with brain hypometabolism, with hypertension being the modifiable CVRF showing the strongest association. Subclinical carotid plaque burden is also linked to reduced brain metabolism independently of CVRFs. Cerebral areas showing hypometabolism include those known to be affected in dementia. These data reinforce the need to control CVRFs early in life in order to potentially reduce the brain's midlife vulnerability to future cognitive dysfunction.

Infarct Recurrence in Intracranial Atherosclerosis: Results from the MyRIAD Study

BACKGROUND

Intracranial atherosclerotic disease (ICAD) is a common cause of ischemic stroke with a high risk of clinical stroke recurrence. Multiple mechanisms may underlie cerebral ischemia in this condition. The study's objective is to discern the mechanisms of recurrent ischemia in ICAD through imaging biomarkers of impaired antegrade flow, poor distal perfusion, abnormal vasoreactivity, and artery-to-artery embolism.

METHODS

This prospective multicenter observational study enrolled patients with recent (≤21 days) ischemic stroke or transient ischemic attack (TIA) caused by ICAD with 50-99% stenosis treated medically. We obtained baseline quantitative MRA (QMRA), perfusion MRI (PWI), transcranial Doppler vasoreactivity (VMR), and emboli detection studies (EDS). The primary outcome was ischemic stroke in the territory of the stenotic artery within 1 year of follow-up; secondary outcomes were TIA at 1 year and new infarcts in the territory on MRI at 6-8 weeks.

RESULTS

Amongst 102 of 105 participants with clinical follow-up (mean 253±131 days), the primary outcome occurred in 8.8% (12.7/100 patient-years), while 5.9% (8.5/100 patient-years) had a TIA. A new infarct in the territory of the symptomatic artery was noted in 24.7% at 6-8 weeks. A low flow state on QMRA was noted in 25.5%, poor distal perfusion on PWI in 43.5%, impaired vasoreactivity on VMR in 67.5%, and microemboli on EDS in 39.0%. No significant association was identified between these imaging biomarkers and primary or secondary outcomes.

CONCLUSIONS

Despite intensive medical management in ICAD, there is a high risk of clinical cerebrovascular events at 1 year and an even higher risk of new imaging-evident infarcts in the subacute period after index stroke. Hemodynamic and plaque instability biomarkers did not identify a higher risk group. Further work is needed to identify mechanisms of ischemic stroke and infarct recurrence and their consequence on long-term physical and cognitive outcomes.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT02121028.

Vascular contributions to cognitive impairment and dementia (VCID): A report from the 2018 National Heart, Lung, and Blood Institute and National Institute of Neurological Disorders and Stroke Workshop

Vascular contributions to cognitive impairment and dementia (VCID) are characterized by the aging neurovascular unit being confronted with and failing to cope with biological insults due to systemic and cerebral vascular disease, proteinopathy including Alzheimer's biology, metabolic disease, or immune response, resulting in cognitive decline. This report summarizes the discussion and recommendations from a working group convened by the National Heart, Lung, and Blood Institute and the National Institute of Neurological Disorders and Stroke to evaluate the state of the field in VCID research, identify research priorities, and foster collaborations. As discussed in this report, advances in understanding the biological mechanisms of VCID across the wide spectrum of pathologies, chronic systemic comorbidities, and other risk factors may lead to potential prevention and new treatment strategies to decrease the burden of dementia. Better understanding of the social determinants of health that affect risks for both vascular disease and VCID could provide insight into strategies to reduce racial and ethnic disparities in VCID.

Vessel wall MR imaging of intracranial atherosclerosis

Intracranial atherosclerotic disease (ICAD) is one of the most common causes of ischemic stroke worldwide. Along with high recurrent stroke risk from ICAD, its association with cognitive decline and dementia leads to a substantial decrease in quality of life and a high economic burden. Atherosclerotic lesions can range from slight wall thickening with plaques that are angiographically occult to severely stenotic lesions. Recent advances in intracranial high resolution vessel wall MR (VW-MR) imaging have enabled imaging beyond the lumen to characterize the vessel wall and its pathology. This technique has opened new avenues of research for identifying vulnerable plaque in the setting of acute ischemic stroke as well as assessing ICAD burden and its associations with its sequela, such as dementia. We now understand more about the intracranial arterial wall, its ability to remodel with disease and how we can use VW-MR to identify angiographically occult lesions and assess medical treatment responses, for example, to statin therapy. Our growing understanding of ICAD with intracranial VW-MR imaging can profoundly impact diagnosis, therapy, and prognosis for ischemic stroke with the possibility of lesion-based risk models to tailor and personalize treatment. In this review, we discuss the advantages of intracranial VW-MR imaging for ICAD, the potential of bioimaging markers to identify vulnerable intracranial plaque, and future directions of artificial intelligence and its utility for lesion scoring and assessment.

Intracranial atherosclerosis on 7T MRI and cognitive functioning: The SMART-MR study

OBJECTIVE

To investigate the association between intracranial atherosclerosis (ICAS) and cognitive functioning in patients with a history of vascular disease.

METHODS

Within the Second Manifestations of Arterial Disease-Magnetic Resonance (SMART-MR) study, cross-sectional analyses were performed in 130 patients (mean ± SD age 68 ± 9 years) with 7T vessel wall MRI data. Vessel wall lesions were rated according to established criteria and summed into a circulatory and artery-specific ICAS burden. Associations between ICAS burden and Z scores of memory, executive functioning, working memory, and processing speed were estimated using linear regression analyses adjusted for age, sex, education, reading ability, and vascular risk factors.

RESULTS

A total of 125 patients (96%) had ≥1 vessel wall lesion; the mean ICAS burden was 8.5 ± 5.7. A statistically nonsignificant association was found between total ICAS burden and memory (b = -0.03 per +1 lesion; 95% confidence interval [CI] -0.05 to 0.00). No associations were found for the other domains. A statistically significant association was found for ICAS burden of the posterior cerebral artery (PCA) and memory (b = -0.12 per +1 lesion; 95% CI -0.23 to -0.01) and executive functioning (b = -0.10 per +1 lesion; 95% CI -0.19 to -0.01). Statistically nonsignificant associations were found for the anterior cerebral artery (ACA) burden and memory (b = -0.13 per +1 lesion; 95% CI -0.26 to 0.01) and executive functioning (b = -0.11 per +1 lesion; 95% CI -0.22 to 0.01). Additional adjustments for large infarcts, white matter hyperintensities, lacunes, and ≥50% carotid stenosis produced similar results.

CONCLUSIONS

Our results suggest an artery-specific vulnerability of memory and executive functioning to ICAS, possibly due to strategic brain regions involved with these cognitive domains, which are located in the arterial territory of the PCA and ACA.

Association between kidney disease measures and intracranial atherosclerosis: The ARIC study

OBJECTIVE

To test the association between reduced kidney function (assessed by estimated glomerular filtration rate [eGFR] and cystatin C [CysC]) and kidney damage (assessed by urinary albumin-to-creatinine ratio [ACR]) and intracranial atherosclerotic disease (ICAD) by high-resolution vessel wall MRI (VWMRI) in the Atherosclerosis Risk in Communities Neurocognitive Study (ARIC-NCS).

METHODS

We conducted a cross-sectional analysis of ARIC participants with data on kidney measures and VWMRI in 2011 to 2013. The main outcomes were presence of intracranial plaques and luminal stenosis. Multivariable models were adjusted for demographics, cardiovascular risk factors, and use of antithrombotic medications.

RESULTS

A total of 1,762 participants (mean ± SD age, 76.3 ± 5.3) were included. eGFR based on CysC (eGFRcysc) <60 mL/min/1.73 m2 (vs ≥60 mL/min/1.73 m2) was associated with plaque presence (adjusted odds ratio [OR] 1.29, 95% confidence interval [CI] 1.04-1.60), any detectable stenosis (adjusted OR 1.31, 95% CI 1.04-1.63), and >70% stenosis or occlusion (adjusted OR 2.15, 95% CI 1.32-3.50). Neither ACR nor CysC showed statistically significant associations with ICAD features in adjusted models. In adjusted multinomial models, participants with eGFRcysc <60 mL/min/1.73 m2 (vs ≥60 mL/min/1.73 m2) had an increased OR of 1.41 (95% CI 1.06-1.87) for having 1 plaque (vs none) but no significant increase for multiple plaques; ACR ≥30 was associated with moderate (50%-70%) stenosis (OR 2.01, 95% CI 1.14-3.55) vs absent or less than 50% stenosis.

CONCLUSION

In community-dwelling older adults, reduced kidney function or elevated kidney damage was associated with ICAD measured by VWMRI. This finding may help to better identify a population at high risk for ICAD.

Mismatch of cognition and neural networks in asymptomatic middle cerebral artery steno-occlusive disease

BACKGROUND AND PURPOSE

The role of intracranial steno-occlusive disease in cognitive impairment and dementia is unclear and has not been well studied.

METHODS

A total of 32 consecutive patients (13 males, aged 54 ± 12 years) with asymptomatic steno-occlusive middle cerebral artery (MCA) disease, defined as >70% stenosis on maximum intensity projection images or a complete signal loss of MCA trunk on magnetic resonance angiography, and 20 age- and education-matched normal controls (12 males, 60 ± 8 years old) were compared for neuropsychological performance, gray matter volume and neural network analysis.

RESULTS

The patient group did not show a significant decrease in gray matter volume or cognitive tests except for their performance on the grooved pegboard test. However, graph analysis of resting-state functional magnetic resonance imaging showed significant decreases in network strength, global efficiency and the clustering coefficient, as well as a longer characteristic path length (P < 0.05). The diffusive decrease pattern was particularly located in interhemispheric connectivity and there was no compensatory hyperconnectivity in any brain regions.

CONCLUSION

In asymptomatic steno-occlusive MCA disease, cognition and neural network changes are mismatched and have underlying pathophysiological mechanisms that are different from those of neurodegenerative disease.

The Relationship of Coronary Artery Calcium and Clinical Coronary Artery Disease with Cognitive Function: A Systematic Review and Meta-Analysis

AIM

Coronary artery disease (CAD) and cognitive impairment are common in the elderly, with evidence for shared risk factors and pathophysiological processes. The coronary artery calcium (CAC) score is a marker of subclinical CAD, which may allow early detection of individuals prone to cognitive decline. Prior studies on associations of CAC and clinical CAD with cognitive impairment had discrepant results. This systematic review aims to evaluate the association of (sub)clinical CAD with cognitive function, cognitive decline, and diagnosis of mild cognitive impairment (MCI) or dementia.

METHODS

A systematic search was conducted in MEDLINE, Embase, and Web of Science until February 2019, supplemented with citations tracking. Two reviewers independently screened studies and extracted information including odds ratios (ORs) and hazard ratios (HRs).

RESULTS

Forty-six studies, 10 on CAC and 36 on clinical CAD, comprising 1,248,908 participants were included in the systematic review. Studies about associations of (sub)clinical CAD with cognitive function and cognitive decline had heterogeneous methodology and inconsistent findings. Two population-based studies investigated the association between CAC and risk of dementia over 6-12.2 years using different CAC scoring methods. Both found a tendency toward higher risk of dementia as CAC severity increased. Meta-analysis in 15 studies (663,250 individuals) showed an association between CAD and MCI/dementia (pooled OR 1.32, 95%CI 1.17-1.48) with substantial heterogeneity (I²=87.0%, p＜0.001). Pooled HR of CAD for incident MCI/dementia over 3.2-25.5 years in six longitudinal studies (70,060 individuals) was 1.51 (95%CI 1.24-1.85), with low heterogeneity (I²=14.1%, p=0.32). Sensitivity analysis did not detect any study that was of particular influence on the pooled OR or HR.

CONCLUSIONS

Limited evidence suggests the CAC score is associated with risk of dementia. In clinical CAD, risk of MCI and dementia is increased by 50%, as supported by stronger evidence.

Vascular Cognitive Impairment

PURPOSE OF REVIEW

This article provides an overview of vascular cognitive impairment; discusses its epidemiology, subtypes, and associations with other neurodegenerative diseases; and reviews the diagnostic evaluation and management of these disorders.

RECENT FINDINGS

Cerebrovascular disease is a common cause of dementia and frequently coexists with neurodegenerative causes. The heterogeneity of mechanisms leading to vascular cognitive impairment makes developing unifying clinical and research criteria difficult. Recognizing the neuroimaging hallmarks of different forms of vascular cognitive impairment can allow for individualized treatment and management. In individuals with mild vascular cognitive impairment, aerobic exercise appears to be a promising treatment but requires further investigation.

SUMMARY

Vascular cognitive impairment can be caused by several mechanisms. While treating vascular risk factors is rational to prevent worsening of cognitive impairment, well-designed studies are needed to demonstrate efficacy.

Intracranial Atherosclerotic Burden on 7T MRI Is Associated with Markers of Extracranial Atherosclerosis: The SMART-MR Study

BACKGROUND AND PURPOSE

Intracranial atherosclerosis, a major risk factor for ischemic stroke, is thought to have different atherogenic mechanisms than extracranial atherosclerosis. Studies investigating their relationship in vivo are sparse and report inconsistent results. We studied the relationship between intracranial atherosclerosis and extracranial atherosclerosis in a cohort of patients with a history of vascular disease.

MATERIALS AND METHODS

Within the Second Manifestations of ARTerial disease-Magnetic Resonance (SMART) study, cross-sectional analyses were performed in 130 patients (mean age, 68 ± 9 years) with a history of vascular disease and with assessable 7T intracranial vessel wall MR imaging data. Intracranial atherosclerosis burden was defined as the number of intracranial vessel wall lesions in the circle of Willis and its major branches. Age- and sex-adjusted unstandardized regression coefficients (b-value) were calculated with intracranial atherosclerosis burden as the dependent variable and extracranial atherosclerosis markers as independent variables.

RESULTS

Ninety-six percent of patients had ≥1 vessel wall lesion, with a mean intracranial atherosclerosis burden of 8.5 ± 5.7 lesions. Significant associations were observed between higher intracranial atherosclerosis burden and carotid intima-media thickness (b = 0.53 lesions per +0.1  mm; 95% CI, 0.1-1.0 lesions), 50%-100% carotid stenosis versus no stenosis (b = 6.6 lesions; 95% CI, 2.3-10.9 lesions), ankle-brachial index ≤ 0.9 versus >0.9 (b = 4.9 lesions; 95% CI, 1.7-8.0 lesions), and estimated glomerular filtration rate (b = -0.77 lesions per +10 mL/min; 95% CI, -1.50 to -0.03 lesions). No significant differences in intracranial atherosclerosis burden were found among different categories of vascular disease.

CONCLUSIONS

Intracranial atherosclerosis was associated with various extracranial markers of atherosclerosis, not supporting a different etiology.

Percutaneous Transluminal Angioplasty as Potentially Effective Treatment for Persistent Cognitive Decline due to Intracranial Carotid Artery Stenosis

Objective

We describe a male patient with covert sustained cognitive impairment who underwent endovascular treatment for severe stenosis in the left intracranial internal carotid artery (ICA).

Case Presentation

A 64-year-old man presented with transient dysarthria and dysphagia. Although he was alert, a cognitive evaluation revealed significant dysgraphia and a remarkable reduction in cognitive function. Diffusion-weighted imaging (DWI) revealed scattered high-intensity regions in the watershed area of the left cerebral hemisphere and severe stenosis in the C2 portion of the left ICA. Percutaneous transluminal angioplasty (PTA) was performed; a detailed examination revealed significantly improved cognitive function. One year later, the patient demonstrated further cognitive improvement, without any recurrent stroke.

Conclusions

We consider that patients with severe intracranial stenosis, who have covert cognitive decline without apparent sustained symptoms, might be promising candidates for revascularization. Higher brain function in patients with severe intracranial arterial stenosis should be carefully screened because cognitive decline might not be evident at the time of initial presentation.

A New Transcranial Doppler Scoring System for Evaluating Middle Cerebral Artery Stenosis

BACKGROUND AND PURPOSE

Transcranial Doppler (TCD) criteria for cerebrovascular stenosis are only based on velocity with unsatisfactory positive predictive value (PPV) in previous studies. We refined a published scoring system that integrates several characteristics of TCD data in diagnosing middle cerebral artery (MCA) stenosis.

METHODS

Using the TCD-digital subtraction angiography (DSA) database from Stroke Outcomes and Neuroimaging of Intracranial Atherosclerosis (SONIA) trial, velocity, spectrum pattern, diffuse ratio, and asymmetry ratio were assessed. The cutpoints were defined for each parameter and a point value was assigned to each category within that parameter. A summed score was calculated for each MCA. The accuracy was assessed for different cutpoints in predicting ≥50% MCA stenosis measured by DSA. Logistic regression and C-statistics were used for analysis.

RESULTS

A total of 114 MCAs were included in vessel-based and 87 patients were included in patient-based analysis. Compared to the velocity-only cutpoints in SONIA, the score results in much improved PPV while negative predictive value (NPV) remains unchanged. The score based on mean velocity (score 0: <140 cm/s, score 3: ≥140 cm/s), spectrum pattern (score 0: no turbulence; score 1: mild turbulence; 2: significant turbulence), and asymmetry ratio (score 0: ratio <1.5, score 1: ratio 1.5-2; score 2: ratio ≥2.1) has the highest NPV while PPV remains favorable (PPV: 72% [95% CI 54-90%]; NPV: 84% [95% CI: 75-93%], area under curve [AUC]: .76 [95% CI: .66-.86]).

CONCLUSIONS

The multiparameter scoring system incorporating several characteristics of TCD measures yielded higher PPV while maintaining high NPV compared with the single-parameter velocity criteria in diagnosing MCA ≥50% stenosis.

Subclinical Atherosclerosis Imaging in People Living with HIV

In many, but not all studies, people living with HIV (PLWH) have an increased risk of coronary artery disease (CAD) events compared to the general population. This has generated considerable interest in the early, non-invasive detection of asymptomatic (subclinical) atherosclerosis in PLWH. Ultrasound studies assessing carotid artery intima-media thickness (CIMT) have tended to show a somewhat greater thickness in HIV+ compared to HIV-, likely due to an increased prevalence of cardiovascular (CV) risk factors in PLWH. Coronary artery calcification (CAC) determination by non-contrast computed tomography (CT) seems promising to predict CV events but is limited to the detection of calcified plaque. Coronary CT angiography (CCTA) detects calcified and non-calcified plaque and predicts CAD better than either CAC or CIMT. A normal CCTA predicts survival free of CV events over a very long time-span. Research imaging techniques, including black-blood magnetic resonance imaging of the vessel wall and 18F-fluorodeoxyglucose positron emission tomography for the assessment of arterial inflammation have provided insights into the prevalence of HIV-vasculopathy and associated risk factors, but their clinical applicability remains limited. Therefore, CCTA currently appears as the most promising cardiac imaging modality in PLWH for the evaluation of suspected CAD, particularly in patients <50 years, in whom most atherosclerotic coronary lesions are non-calcified.

Re-thinking the Etiological Framework of Neurodegeneration

Neurodegenerative diseases are among the leading causes of disability and death worldwide. The disease-related socioeconomic burden is expected to increase with the steadily increasing life expectancy. In spite of decades of clinical and basic research, most strategies designed to manage degenerative brain diseases are palliative. This is not surprising as neurodegeneration progresses "silently" for decades before symptoms are noticed. Importantly, conceptual models with heuristic value used to study neurodegeneration have been constructed retrospectively, based on signs and symptoms already present in affected patients; a circumstance that may confound causes and consequences. Hence, innovative, paradigm-shifting views of the etiology of these diseases are necessary to enable their timely prevention and treatment. Here, we outline four alternative views, not mutually exclusive, on different etiological paths toward neurodegeneration. First, we propose neurodegeneration as being a secondary outcome of a primary cardiovascular cause with vascular pathology disrupting the vital homeostatic interactions between the vasculature and the brain, resulting in cognitive impairment, dementia, and cerebrovascular events such as stroke. Second, we suggest that the persistence of senescent cells in neuronal circuits may favor, together with systemic metabolic diseases, neurodegeneration to occur. Third, we argue that neurodegeneration may start in response to altered body and brain trophic interactions established via the hardwire that connects peripheral targets with central neuronal structures or by means of extracellular vesicle (EV)-mediated communication. Lastly, we elaborate on how lifespan body dysbiosis may be linked to the origin of neurodegeneration. We highlight the existence of bacterial products that modulate the gut-brain axis causing neuroinflammation and neuronal dysfunction. As a concluding section, we end by recommending research avenues to investigate these etiological paths in the future. We think that this requires an integrated, interdisciplinary conceptual research approach based on the investigation of the multimodal aspects of physiology and pathophysiology. It involves utilizing proper conceptual models, experimental animal units, and identifying currently unused opportunities derived from human data. Overall, the proposed etiological paths and experimental recommendations will be important guidelines for future cross-discipline research to overcome the translational roadblock and to develop causative treatments for neurodegenerative diseases.