Carotid Artery Remodeling Is Segment Specific: An In Vivo Study by Vessel Wall Magnetic Resonance Imaging

Resistance Exercise Training as a New Trend in Alzheimer's Disease Research: From Molecular Mechanisms to Prevention

Alzheimer's disease is a pathology characterized by the progressive loss of neuronal connections, which leads to gray matter atrophy in the brain. Alzheimer's disease is the most prevalent type of dementia and has been classified into two types, early onset, which has been associated with genetic factors, and late onset, which has been associated with environmental factors. One of the greatest challenges regarding Alzheimer's disease is the high economic cost involved, which is why the number of studies aimed at prevention and treatment have increased. One possible approach is the use of resistance exercise training, given that it has been shown to have neuroprotective effects associated with Alzheimer's disease, such as increasing cortical and hippocampal volume, improving neuroplasticity, and promoting cognitive function throughout the life cycle. However, how resistance exercise training specifically prevents or ameliorates Alzheimer's disease has not been fully characterized. Therefore, the aim of this review was to identify the molecular basis by which resistance exercise training could prevent or treat Alzheimer's disease.

Hypertension and Mild Cognitive Impairment: State-of-the-Art Review

BACKGROUND

Mid-life hypertension is associated with cognitive decline and dementia in later life. Reducing high blood pressure (BP) with antihypertensive agents is a well-researched strategy to prevent dementia and mild cognitive impairment (MCI). However, there is still limited direct evidence to support the approach, and particularly for the treatment of the very old and those with existing MCI.

METHODS

This review presents an overview of the current evidence for the relationship between MCI and hypertension, and of the potential pathophysiological mechanisms related to cognitive decline and incidence dementia in relation to aging.

RESULTS

Although observational data are near consistent in showing an association between mid-life hypertension and MCI and/or dementia, the evidence in relation to hypertension in younger adults and the very old (age >80 years) is much more limited. Most of the commonly available antihypertensive agents appear to provide beneficial effects in reducing the risk dementia, but there is limited evidence to support such treatment in those with existing MCI.

CONCLUSIONS

Further studies are needed to determine the optimal levels of BP control across different age groups, especially in adults with MCI, and which class(es) of antihypertensive agents and duration of treatment best preserve cognitive function in those at risk of, or with established, MCI.

Segmentation of carotid artery vessel wall and diagnosis of carotid atherosclerosis on black blood magnetic resonance imaging with multi-task learning

BACKGROUND

Atherosclerotic cardiovascular disease is the leading cause of death worldwide. Early detection of carotid atherosclerosis can prevent the progression of cardiovascular disease. Many (semi-) automatic methods have been designed for the segmentation of carotid vessel wall and the diagnosis of carotid atherosclerosis (i.e., the lumen segmentation, the outer wall segmentation, and the carotid atherosclerosis diagnosis) on black blood magnetic resonance imaging (BB-MRI). However, most of these methods ignore the intrinsic correlation among different tasks on BB-MRI, leading to limited performance.

PURPOSE

Thus, we model the intrinsic correlation among the lumen segmentation, the outer wall segmentation, and the carotid atherosclerosis diagnosis tasks on BB-MRI by using the multi-task learning technique and propose a gated multi-task network (GMT-Net) to perform three related tasks in a neural network (i.e., carotid artery lumen segmentation, outer wall segmentation, and carotid atherosclerosis diagnosis).

METHODS

In the proposed method, the GMT-Net is composed of three modules, including the sharing module, the segmentation module, and the diagnosis module, which interact with each other to achieve better learning performance. At the same time, two new adaptive layers, namely, the gated exchange layer and the gated fusion layer, are presented to exchange and merge branch features.

RESULTS

The proposed method is applied to the CAREII dataset (i.e., 1057 scans) for the lumen segmentation, the outer wall segmentation, and the carotid atherosclerosis diagnosis. The proposed method can achieve promising segmentation performances (0.9677 Dice for the lumen and 0.9669 Dice for the outer wall) and better diagnosis accuracy of carotid atherosclerosis (0.9516 AUC and 0.9024 Accuracy) in the "CAREII test" dataset (i.e., 106 scans). The results show that the proposed method has statistically significant accuracy and efficiency.

CONCLUSIONS

Even without the intervention of reviewers required for the previous works, the proposed method automatically segments the lumen and outer wall together and diagnoses carotid atherosclerosis with high performance. The proposed method can be used in clinical trials to help radiologists get rid of tedious reading tasks, such as screening review to separate normal carotid arteries from atherosclerotic arteries and to outline vessel wall contours.

Thrombospondin-1 associated with carotid intima-media thickness among individuals with hypertension

In vivo and in vitro studies have demonstrated that thrombospondin-1 (TSP-1) is involved in atherosclerotic pathogenesis. However, the role of TSP-1 in clinical atherosclerosis remains unknown. This cross-sectional study investigated the relationship between TSP-1 and carotid intima-media thickness (IMT) and examined whether it interacts with conventional cardiovascular risk factors. A total of 587 participants were enrolled from February 2018 to December 2021. TSP-1 was dichotomized based on median value. Carotid IMT was measured bilaterally in each segment, and the average value was taken as the overall IMT variable. Analysis of covariance models were used to ascertain the main and interaction effects of cardiovascular risk factors and circulating TSP-1 levels on carotid IMT. Those with high TSP-1 (n = 294) had significantly higher carotid IMT than did those with low TSP-1 (n = 293; 0.74 ± 0.12 vs 0.72 ± 0.11 mm; p = 0.011). After the combined effects of TSP-1 and vascular risk factors on carotid IMT were evaluated, an interaction effect on IMT was observed between TSP-1 and hypertension (adjusted F = 8.760; p = 0.003). Stratification analysis revealed that individuals with hypertension and high TSP-1 had significantly higher IMT than did those with low TSP-1 (adjusted p = 0.007). However, this difference was not observed in normotensive individuals (adjusted p = 0.636). In conclusion, this is the first study to provide clinical data supporting the correlation between TSP-1 and atherosclerosis. TSP-1 may be a crucial marker of increased susceptibility to atherosclerosis in individuals with hypertension.

Investigating the relationship between intracranial atherosclerotic plaque remodelling and diabetes using high-resolution vessel wall imaging

BACKGROUND

Intracranial atherosclerosis, a leading cause of stroke, involves arterial plaque formation. This study explores the link between plaque remodelling patterns and diabetes using high-resolution vessel wall imaging (HR-VWI).

AIM

To investigate the factors of intracranial atherosclerotic remodelling patterns and the relationship between intracranial atherosclerotic remodelling and diabetes mellitus using HR-VWI.

METHODS

Ninety-four patients diagnosed with middle cerebral artery or basilar artery atherosclerosis were enrolled. Their basic clinical data were collected, and HR-VWI was performed. The vascular area at the plaque (VAMLN) and normal reference vessel (VAreference) were delineated and measured using image postprocessing software, and the Remodelling index (RI) was calculated. According to the value of the RI, the patients were divided into a positive remodelling (PR) group, intermediate remodelling (IR) group, negative remodelling (NR) group, PR group and non-PR (N-PR) group.

RESULTS

The PR group exhibited a higher prevalence of diabetes and serum cholesterol levels than the IR and NR groups [45.2%, 4.54 (4.16, 5.93) vs 25%, 4.80 ± 1.22 and 16.4%, 4.14 (3.53, 4.75), respectively, P < 0.05]. The diabetes incidence was also significantly greater in the PR group than in the N-PR group (45.2% vs 17.5%, P < 0.05). Furthermore, the PR group displayed elevated serum triglyceride and cholesterol levels compared to the N-PR group [1.64 (1.23, 2.33) and 4.54 (4.16, 5.93) vs 4.54 (4.16, 5.93) and 4.24 (3.53, 4.89), P < 0.05]. Logistic regression analysis revealed diabetes mellitus as an independent influencing factor in plaque-PR [odds ratio (95% confidence interval): 3.718 (1.207-11.454), P < 0.05].

CONCLUSION

HR-VWI can clearly show the morphology and signal characteristics of intracranial vascular walls and plaques. Intracranial atherosclerotic plaques in diabetic patients are more likely to show PR, suggesting poor plaque stability and a greater risk of stroke.

Evaluation of atherosclerosis as a risk factor in COPD patients by measuring the carotid intima-media thickness

BACKGROUND

This study aimed to evaluate atherosclerosis as comorbidity by measuring the carotid (bulb and common carotid artery) Carotid intima-media thickness in COPD-diagnosed patients and to evaluate the relationship of atherosclerosis with the prevalence of COPD, hypoxemia and hypercapnia.

METHODS

This study was conducted out between January 2019-December 2019 consisting of a total of 140 participants (70 COPD-diagnosed patients-70 healthy individuals). The COPD-diagnosed patients have been planned according to the selection and diagnosis criteria as per the GOLD 2019 guide. It is planned to evaluate as per prospective matching case-control study of the carotid thickness, radial gas analysis, spirometric and demographic characteristics of COPD diagnosed patients and healthy individuals.

RESULTS

The average Carotid intima-media thickness in COPD patients was 0.8746±0.161 (p<0.05), and the thickness of the carotid bulb was 1.04±0.150 (p<0.05). In the control group, the average CCA intima-media thickness was 0.6650±0.139 (p<0.05), and the thickness of the carotid bulb was 0.8250±0.15(p<0.05) For the carotid thickness that has increased in COPD diagnosed patients a significant relationship is determined between hypoxemia (p<0.05) and hypercapnia(p<0.05). A significant relationship determined between CIMT and severity of COPD (p<0.05) The CIMT was high in COPD patients with hypoxemia and hypercapnia(p<0.05).

CONCLUSION

Significant difference was determined between the severity (grades) of COPD (mild, moderate, severe, very severe) in carotid thickness. Also, CIMT was found to be high in patients who is in the early phases of the prevalence of COPD. In COPD-diagnosed patients, it was determined that severity of COPD, hypoxemia, hypercapnia and age were determining factors of atherosclerosis.

Quantifying Carotid Stenosis: History, Current Applications, Limitations, and Potential: How Imaging Is Changing the Scenario

Carotid artery stenosis is a major cause of morbidity and mortality. The journey to understanding carotid disease has developed over time and radiology has a pivotal role in diagnosis, risk stratification and therapeutic management. This paper reviews the history of diagnostic imaging in carotid disease, its evolution towards its current applications in the clinical and research fields, and the potential of new technologies to aid clinicians in identifying the disease and tailoring medical and surgical treatment.

Tortuosity and Proximal-Specific Hemodynamics Associated with Plaque Location in the Carotid Bulb Stenosis

BACKGROUND

Atherosclerotic plaque locations in the carotid bulb increasingly have been found to be associated with patterns of ischemic lesions and plaque progression. However, the occurrence of carotid bulb plaque is a complex process. We aimed to investigate plaque characteristics and geometric and hemodynamic parameters among patients with body and apical plaques of the carotid bulb and to identify the mechanism of bulb plaque formation and location.

METHODS

Consecutive patients with single carotid bulb stenosis (50-99%) were enrolled retrospectively. Patients were divided into body and apical plaque groups based on plaque location. Plaque location and characteristics were identified and measured on high-resolution vessel wall magnetic resonance imaging. Geometric parameters were derived from time-of-flight magnetic resonance imaging. Computational fluid dynamics simulations were performed to quantify wall shear stress (WSS) and four associated WSS-based metrics on the plaque side, on the non-plaque side, and in different parts of the lesion. Plaque characteristics and geometric and hemodynamic parameters were compared, and their associations with the plaque location were determined.

RESULTS

Seventy patients were recruited (41 body plaques and 29 apical plaques). WSSplaque values were lower than WSSnon-plaque values for all plaques (median [interquartile range], 12.59 [9.83-22.14] vs. 17.27 [11.63-27.63] Pa, p = 0.001). In a multivariate binary logistic regression, the tortuosity of the stenosed region, the magnitudes of the mean relative residence time, and the minimum transverse WSS in the proximal part of the lesion were the key factors independently associated with plaque location (p = 0.022, 0.013, and 0.012, respectively).

CONCLUSIONS

Plaque formation was associated with the local flow pattern, and the tortuosity and proximal-specific hemodynamics were significantly associated with plaque location in the carotid bulb.

Identification of vulnerable carotid plaque with histologically validated CT-derived plaque maps

OBJECTIVES

Ruptured carotid plaque causes stroke, but differentiating rupture-prone necrotic core from fibrous tissue with CT is limited by overlap of X-ray attenuation. We investigated the ability of CT-derived plaque maps created from ratios of plaque/contrast attenuation to identify histologically proven vulnerable plaques.

METHODS

Seventy patients underwent carotid CT angiography and carotid endarterectomy. A derivation cohort of 20 patients had CT images matched with histology and carotid plaque components attenuation defined. In a validation cohort of 50 patients, CT-derived plaque maps were compared in 43 symptomatic vs 40 asymptomatic carotid plaques and accuracy detecting vulnerable plaques calculated.

RESULTS

In 250 plaque areas co-registered with histology, the median attenuation (HU) of necrotic core 43(26-63), fibrous plaque 127(110-162) and calcified plaque 964 (816-1207) created significantly different ratios of plaque/contrast attenuation. CT-derived plaque maps revealed symptomatic plaques had larger necrotic core than asymptomatic (13.5%(5.9-33.3) vs 7.4%(2.3-14.3), p = 0.004) with large necrotic core predicting symptoms (area under ROC curve 0.68, p = 0.004). Twenty-four of 47 carotid plaques were histologically classified as most vulnerable (Starry-Type VI). Plaque maps revealed Type VI plaques had a greater necrotic core volume than Type IV/V plaques and a necrotic core/fibrous plaque ratio >0.5 distinguished Type VI plaques with sensitivity 75.0% (55.1-88.0) and specificity of 39.1% (22.2-59.2).

CONCLUSIONS

Carotid plaque components can be differentiated by CT using a ratio of plaque/contrast attenuation. CT-derived plaque map volumes of necrotic core help distinguished the most vulnerable plaques.

ADVANCES IN KNOWLEDGE

CT-derived plaque maps based on plaque/contrast attenuation may provide new markers of carotid plaque vulnerability.

Pathophysiological Association of Alzheimer's Disease and Hypertension: A Clinical Concern for Elderly Population

Alzheimer's disease (AD), the most common cause of dementia and the fifth leading cause of death in the adult population has a complex pathophysiological link with hypertension (HTN). A growing volume of published literature on a parallel elevation of blood pressure (BP), amyloid plaques, and neurofibrillary tangles formation in post-middle of human brain cells has developed new, widely accepting foundations on this association. In particular, HTN in elderly life mediates cerebral blood flow dysfunction, neuronal dysfunction, and significant decline in cognitive impairment, primarily in the late-life populace, governing the onset of AD. Thus, HTN is an established risk factor for AD. Considering the impact of AD, 1.89 million deaths annually, and the failure of palliative therapies to cure AD, the scientific research community is looking to adopt integrated approaches to target early modified risk factors like HTN to reduce AD burden. The current review highlights the significance and impact of HTN-based prevention in lowering the AD burden in the elderly by providing a comprehensive overview of the physiological relationship between AD and HTN with an in-detail explanation of the role and applications of pathological biomarkers in this clinical association. The review will gain worth in presenting new insights and providing inclusive discussion on the correlation between HTN and cognitive impairment. It will increase across a wider scientific audience to expand understanding of this pathophysiological association.

Dilated hypertrophic phenotype of the carotid artery is associated with accelerated age-associated central arterial stiffening

Hypertrophic carotid geometric phenotypes (h-CGP) are predictors of incident cardiovascular disease (CVD). While arterial aging is hypothesized as a contributor to this associated risk, the association of CGPs with chronological age is not clear. In this manuscript we examine whether hypertrophic CGPs represent accelerated biological, rather than chronological, aging by examining their association with carotid-femoral pulse wave velocity (PWV), the hallmark of arterial aging. We analyzed data from 5516 participants of the SardiNIA study with a wide range of age at baseline (20-101 years), and a median follow-up time of 13 years (mean 11.5 years; maximum 17.9 years). Baseline CGPs were defined based on the common carotid lumen diameter, wall thickness, and their ratio. Subject-specific rates of change of PWV, blood pressure parameters, body mass index, glucose, and lipids were estimated using linear mixed effects models. Compared to those with typical(t-) CGP, those with dilated hypertrophy (dh-) CGP had a greater longitudinal increase in PWV; this increase was significantly greater among older individuals and men. The greater PWV longitudinal increase in dh-CGP remained significant after adjusting for baseline values and rates of change of covariates. Dilated hypertrophic CGP is independently associated with accelerated increase in age-associated arterial stiffening over time, with a strong association in men than in women. Future studies are needed to examine if this association mediates the increased risk for CVD observed in individuals with hypertrophic cardiac remodelling and the role of retarding it to reduce this risk. HIGHLIGHTS: • Individuals with dilated hypertrophic geometric phenotypes of the common carotid artery (increased age- and sex-specific wall thickness and lumen diameter) have greater future central arterial stiffening, independently of other determinants of arterial stiffening. • The dilated hypertrophic phenotype group has a greater age-specific arterial dilation, wall thickening, and stiffness (the arterial aging triad). This suggests that this phenotype is a form of accelerated aging that might explain the worse clinic outcomes observed in this group. • Understanding the natural history of the carotid geometric phenotype across the lifespan and the determinants of the deleterious progression towards the dilated hypertrophic phenotype are needed to develop interventions that reduce the adverse clinical outcomes associated with it.

Challenges and Pitfalls in CT-Angiography Evaluation of Carotid Bulb Stenosis: Is It Time for a Reappraisal?

We aimed to perform an anatomical evaluation of the carotid bulb using CT-angiography, implement a new reliable index for carotid stenosis quantification and to assess the accuracy of relationship between NASCET and ECST methods in a large adult population. The cross-sectional areas of the healthy carotid at five levels were measured by two experienced radiologists. A regression analysis was performed in order to quantify the relationship between the areas of the carotid bulb at different carotid bulbar level. A new index (Regression indeX, RegX) for carotid stenosis quantification was proposed. Five different stenoses with different grade in three bulbar locations were simulated for all patients for a total of 1365 stenoses and were used for a direct comparison of the RegX, NASCET, and ECST methods. The results of this study demonstrated that the RegX index provided a consistent and accurate measure of carotid stenosis through the application of the ECST method, avoiding the limitations of NASCET method. Furthermore, our results strongly depart from the consolidated relationships between NASCET and ECST values used in clinical practice and reported in extensive medical literature. In particular, we highlighted that a major misdiagnosis in patient selection for CEA could be introduced because of the large underestimation of real stenosis degree provided by the NASCET method. A reappraisal of carotid stenosis patients' work-up is evoked by the effectiveness of state-of-the-art noninvasive contemporary carotid imaging.

Identification Markers of Carotid Vulnerable Plaques: An Update

Vulnerable plaques have been a hot topic in the field of stroke and carotid atherosclerosis. Currently, risk stratification and intervention of carotid plaques are guided by the degree of luminal stenosis. Recently, it has been recognized that the vulnerability of plaques may contribute to the risk of stroke. Some classical interventions, such as carotid endarterectomy, significantly reduce the risk of stroke in symptomatic patients with severe carotid stenosis, while for asymptomatic patients, clinically silent plaques with rupture tendency may expose them to the risk of cerebrovascular events. Early identification of vulnerable plaques contributes to lowering the risk of cerebrovascular events. Previously, the identification of vulnerable plaques was commonly based on imaging technologies at the macroscopic level. Recently, some microscopic molecules pertaining to vulnerable plaques have emerged, and could be potential biomarkers or therapeutic targets. This review aimed to update the previous summarization of vulnerable plaques and identify vulnerable plaques at the microscopic and macroscopic levels.

Imaging Approaches to the Diagnosis of Vascular Diseases

PURPOSE OF REVIEW

Vascular imaging is a complex field including numerous modalities and imaging markers. This review is focused on important and recent findings in atherosclerotic carotid artery plaque imaging with an emphasis on developments in magnetic resonance imaging (MRI) and computed tomography (CT).

RECENT FINDINGS

Recent evidence shows that carotid plaque characteristics and not only established measures of carotid plaque burden and stenosis are associated independently with cardiovascular outcomes. On carotid MRI, the presence of a lipid-rich necrotic core (LRNC) has been associated with incident cardiovascular disease (CVD) events independent of wall thickness, a traditional measure of plaque burden. On carotid MRI, intraplaque hemorrhage (IPH) presence has been identified as an independent predictor of stroke. The presence of a fissured carotid fibrous cap has been associated with contrast enhancement on CT angiography imaging. Carotid artery plaque characteristics have been associated with incident CVD events, and advanced plaque imaging techniques may gain additional prominence in the clinical treatment decision process.

Risk factors for changes in carotid intima media thickness and plaque over 5 years in women with systemic lupus erythematosus

Objective

To investigate the occurrence of and risk factors for progression of carotid intima media thickness (IMT) and plaque in women with and without SLE.

Methods

A cohort of 149 women with SLE and 126 controls participated in SOLVABLE (Study of Lupus Vascular and Bone Long-term Endpoints). Demographics, cardiovascular and SLE factors, and laboratory assessments were collected at baseline. Carotid IMT and plaque were measured using B-mode ultrasound at baseline and at 5-year follow-up. Regression models were used to identify predictors of progression in carotid IMT and plaque; multivariate models were adjusted for age, hypertension and total cholesterol to high-density lipoprotein ratio.

Results

The mean±SD follow-up time was 5.35±0.60 years in cases and 5.62±0.66 years in controls. The mean IMT change per year was 0.008±0.015 mm in cases and 0.005±0.019 mm in controls (p=0.24). At follow-up, 31.5% of cases and 15% of controls had plaque progression, with a relative risk for plaque progression of 2.09 (95% CI 1.30 to 3.37). In SLE cases, higher fasting glucose and lower fibrinogen were associated with IMT progression after adjustment. Larger waist circumference and non-use of hydroxychloroquine were associated with plaque progression after adjustment.

Conclusion

Potential modifiable risk factors for carotid IMT and plaque progression in women with SLE were identified, suggesting that monitoring of glucose and waist circumference and use of hydroxychloroquine may be beneficial.

Atherosclerotic Burden and Remodeling Patterns of the Popliteal Artery as Detected in the Magnetic Resonance Imaging Osteoarthritis Initiative Data Set

Background

An artificial intelligence vessel segmentation tool, Fully Automated and Robust Analysis Technique for Popliteal Artery Evaluation (FRAPPE), was used to analyze a large databank of popliteal arteries imaged through the OAI (Osteoarthritis Initiative) to study the impact of atherosclerosis risk factors on vessel dimensions and characterize remodeling patterns.

Methods and Results

Magnetic resonance images from 4668 subjects contributing 9189 popliteal arteries were analyzed using FRAPPE. Age ranged from 45 to 79 years (median, 61), and 58% were women. Mean lumen diameter, mean outer wall diameter, and mean wall thickness (MWT) were measured per artery. Their median values were 5.8 mm (interquartile range, 5.2–6.5 mm), 7.3 mm (interquartile range, 6.7–8.1 mm), and 0.78 mm (interquartile range, 0.73–0.84 mm) respectively. MWT was associated with multiple cardiovascular risk factors, with age (4.2% increase in MWT per 10‐year increase in age; 95% CI, 3.9%–4.5%) and sex (8.6% higher MWT in men than women; 95% CI, 7.7%–9.3%) being predominant. On average, lumen and outer wall diameters increased with increasing MWT until the thickness was 0.92 mm for men and 0.84 mm for women. After this point, lumen diameter decreased steadily, more rapidly in men than women (−7.9% versus −6.1% per 25% increase in MWT; P<0.001), with little change in outer wall diameter.

Conclusions

FRAPPE has enabled the analysis of the large OAI knee magnetic resonance imaging data set, successfully showing that popliteal atherosclerosis is predominantly associated with age and sex. The average vessel remodeling pattern consisted of an early phase of compensatory enlargement, followed by a negative remodeling, which is more pronounced in men.

Abdominal visceral adipose tissue over the menopause transition and carotid atherosclerosis: the SWAN heart study

OBJECTIVES

To characterize abdominal visceral adipose tissue (VAT) trajectory relative to the final menstrual period (FMP), and to test whether menopause-related VAT accumulation is associated with greater average, common carotid artery intima-media thickness (cIMT) and/or internal carotid artery intima-media thickness (ICA-IMT).

METHODS

Participants were 362 women (at baseline: age was (mean ± SD) 51.1 ± 2.8 y; 61% White, 39% Black) with no cardiovascular disease from the Study of Women's Health Across the Nation Heart study. Women had up to two measurements of VAT and cIMT over time. Splines revealed a nonlinear trajectory of VAT with two inflection points demarcating three time segments: segment 1: >2 years before FMP; segment 2: 2 years before FMP to FMP; and segment 3: after FMP. Piecewise-linear random-effects models estimated changes in VAT. Random-effects models tested associations of menopause-related VAT with each cIMT measure separately. Estimates were adjusted for age at FMP, body mass index, and sociodemographic, lifestyle, and cardiovascular disease risk factors.

RESULTS

VAT increased significantly by 8.2% (95% CI: 4.1%-12.5%) and 5.8% (3.7%-7.9%) per year in segments 2 and 3, respectively, with no significant change in VAT within segment 1. VAT predicted greater ICA-IMT in segment 2, such that a 20% greater VAT was associated with a 2.0% (0.8%-3.1%) greater ICA-IMT. VAT was not an independent predictor of ICA-IMT in the other segments or of the other cIMT measures after adjusting for covariates.

CONCLUSIONS

Women experience an accelerated increase in VAT starting 2 years before menopause. This menopause-related increase in VAT is associated with greater risk of subclinical atherosclerosis in the internal carotid artery.

Snoring severity is associated with carotid vascular remodeling in young adults with overweight and obesity

BACKGROUND

Snoring is often used as a surrogate measure for obstructive sleep apnea (OSA), a sleep disorder associated with cardiovascular disease (CVD) risk. Whether snoring is linked to CVD independent of OSA remains unclear. We aimed to explore the snoring and subclinical CVD association in adults with and without OSA.

METHODS

We conducted a cross-sectional study in 122 overweight/obese participants (24% male; mean age 40.1 years) attending the 24-month follow-up visit of a lifestyle intervention. Using home-based objective measures of sleep-disordered breathing, we stratified participants into 3 snoring/OSA categories using the snoring index (SI), a measure of snoring vibration, and oxygen desaturation index (ODI): (1) OSA (ODI ≥ 5), (2) non-OSA heavy snorer (ODI <5, above-median SI), and (3) non-OSA low snorer (ODI <5, below-median SI). Vascular measures including pulse wave velocity ([PWV]; carotid-femoral [cf], femoral-ankle [fa], brachial-ankle [ba]), carotid intima-media thickness (IMT), and carotid interadventitial diameter (IAD) were compared across snoring/OSA categories. Linear regressions assessed the association between snoring and subclinical CVD independent of traditional CVD risk factors.

RESULTS

Compared to non-OSA low snorers, common carotid IMT and IAD were higher in non-OSA heavy snorers, and faPWV, IMT, and IAD were higher among those with OSA. The difference between non-OSA heavy snorers and low snorers persisted after adjusting for age, race, sex, blood pressure, body mass index, lipids, and insulin resistance (P < .05 for IMT and IAD).

CONCLUSIONS

In overweight/obese young to middle-aged adults, objectively measured snoring was related to vascular remodeling in those without OSA. Snoring may contribute to CVD risk but warrants further examination in larger prospective cohorts.

Automated Artery Localization and Vessel Wall Segmentation using Tracklet Refinement and Polar Conversion

Quantitative analysis of blood vessel wall structures is important to study atherosclerotic diseases and assess cardiovascular event risks. To achieve this, accurate identification of vessel luminal and outer wall contours is needed. Computer-assisted tools exist, but manual preprocessing steps, such as region of interest identification and/or boundary initialization, are still needed. In addition, prior knowledge of the ring shape of vessel walls has not been fully explored in designing segmentation methods. In this work, a fully automated artery localization and vessel wall segmentation system is proposed. A tracklet refinement algorithm was adapted to robustly identify the artery of interest from a neural network-based artery centerline identification architecture. Image patches were extracted from the centerlines and converted in a polar coordinate system for vessel wall segmentation. The segmentation method used 3D polar information and overcame problems such as contour discontinuity, complex vessel geometry, and interference from neighboring vessels. Verified by a large (>32000 images) carotid artery dataset collected from multiple sites, the proposed system was shown to better automatically segment the vessel wall than traditional vessel wall segmentation methods or standard convolutional neural network approaches. In addition, a segmentation uncertainty score was estimated to effectively identify slices likely to have errors and prompt manual confirmation of the segmentation. This robust vessel wall segmentation system has applications in different vascular beds and will facilitate vessel wall feature extraction and cardiovascular risk assessment.

Recent Advances in Vascular Imaging

Recent advances in vascular imaging have enabled us to uncover the underlying mechanisms of vascular diseases both ex vivo and in vivo. In the past decade, efforts have been made to establish various methodologies for evaluation of atherosclerotic plaque progression and vascular inflammatory changes in addition to biomarkers and clinical manifestations. Several recent publications in Arteriosclerosis, Thrombosis, and Vascular Biology highlighted the essential roles of in vivo and ex vivo vascular imaging, including magnetic resonance image, computed tomography, positron emission tomography/scintigraphy, ultrasonography, intravascular ultrasound, and most recently, optical coherence tomography, all of which can be used in bench and clinical studies at relative ease. With new methods proposed in several landmark studies, these clinically available imaging modalities will be used in the near future. Moreover, future development of intravascular imaging modalities, such as optical coherence tomography-intravascular ultrasound, optical coherence tomography-near-infrared autofluorescence, polarized-sensitive optical coherence tomography, and micro-optical coherence tomography, are anticipated for better management of patients with cardiovascular disease. In this review article, we will overview recent advances in vascular imaging and ongoing works for future developments.

Association Between Carotid Bifurcation Geometry and Atherosclerotic Plaque Vulnerability: A Chinese Atherosclerosis Risk Evaluation Study

OBJECTIVE

Carotid bifurcation geometry has been believed to be a risk factor for the initiation of atherosclerosis because of its influence on hemodynamics. However, the relationships between carotid bifurcation geometry and plaque vulnerability are not fully understood. This study aimed to determine the association between carotid bifurcation geometry and plaque vulnerability using magnetic resonance vessel wall imaging. Approach and Results: A total of 501 carotid arteries with nonstenotic atherosclerosis were included from the cross-sectional, multicenter CARE II study (Chinese Atherosclerosis Risk Evaluation). Four standardized carotid bifurcation geometric parameters (bifurcation angle, internal carotid artery planarity, luminal expansion FlareA, and tortuosity Tort2D) were derived from time-of-flight magnetic resonance angiography. Presence of vulnerable plaque, which was characterized by intraplaque hemorrhage, large lipid-rich necrotic core, or disrupted luminal surface, was determined based on multicontrast carotid magnetic resonance vessel wall images. Vulnerable plaques (N=43) were found to occur at more distal locations (ie, near the level of flow divider) than stable plaques (N=458). Multivariable logistic regression showed that the luminal expansion FlareA (odds ratio, 0.45 [95% CI, 0.25-0.81]; P=0.008) was associated with plaque vulnerability after adjustment for age, sex, maximum wall thickness, plaque location, and other geometric parameters.

CONCLUSIONS

Smaller luminal expansion at carotid bifurcation is associated with vulnerable plaque. The finding needs to be verified with longitudinal studies and the underlying mechanism should be further explored with hemodynamics measurement in the future.

Beyond plaque: A pictorial review of non-atherosclerotic abnormalities of extracranial carotid arteries

The common carotid artery (CCA) and extracranial internal carotid artery are subject to a wide variety of non-atheromatous pathologies. These entities are often overshadowed in both research and clinical realms by atherosclerotic disease. Nevertheless, non-atherosclerotic disease of the carotid arteries may have profound, even devastating, neurologic consequences. Hence, this review will cover both common and uncommon forms of extracranial carotid artery pathologies in a pictorial format, in order to aid the diagnostician in identifying and differentiating such pathologies.

Segment-specific progression of carotid artery atherosclerosis: a magnetic resonance vessel wall imaging study

PURPOSE

This study aimed to investigate the segment-specific progression of atherosclerotic carotid plaques using serial multi-contrast magnetic resonance (MR) imaging.

METHODS

Symptomatic patients with carotid 30-70% stenosis were recruited and underwent carotid MR vessel wall imaging at baseline and follow-up time point (≥ 6 months after baseline). The location of plaques was determined according to the maximum wall thickness located above or below carotid bifurcation. The baseline and changing characteristics of carotid plaques were compared between plaques above and below carotid bifurcation, and the risk factors for segment-specific plaque progression were analyzed with logistic regression.

RESULTS

Ninety-six carotid plaques from 73 patients (mean age 66.5 ± 11.4 years old) were eligible for statistical analysis. Compared with plaques located below carotid bifurcation, those above bifurcation had significantly greater stenosis at baseline (57.2 ± 13.0% vs. 50.4 ± 13.5%, p = 0.016, adjusted p = 0.005) and greater progression rate of carotid wall volume (35.2 ± 68.8 mm³/year vs. 4.2 ± 65.0 mm³/year, p = 0.026, adjusted p = 0.005) before and after adjusting for all clinical risk factors and baseline stenosis and wall volume of carotid arteries. Logistic regression showed that the related risk factors were age, hypertension, and smoke for the progression of plaques located above the bifurcation and age for plaques below the bifurcation, respectively.

CONCLUSION

Plaques located above the bifurcation of carotid arteries had greater annual progression and correlated with more cardiovascular risk factors compared with those located below the bifurcation.

Cerebral Blood Flow Response to Simulated Hypovolemia in Essential Hypertension: A Magnetic Resonance Imaging Study

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Hypertension is associated with raised cerebral vascular resistance and cerebrovascular remodeling. It is currently unclear whether the cerebral circulation can maintain cerebral blood flow (CBF) during reductions in cardiac output (CO) in hypertensive patients thereby avoiding hypoperfusion of the brain. We hypothesized that hypertension would impair the ability to effectively regulate CBF during simulated hypovolemia. In the present study, 39 participants (13 normotensive, 13 controlled, and 13 uncontrolled hypertensives; mean age±SD, 55±10 years) underwent lower body negative pressure (LBNP) at −20, −40, and −50 mmHg to decrease central blood volume. Phase-contrast MR angiography was used to measure flow in the basilar and internal carotid arteries, as well as the ascending aorta. CBF and CO decreased during LBNP (P<0.0001). Heart rate increased during LBNP, reaching significance at −50 mmHg (P<0.0001). There was no change in mean arterial pressure during LBNP (P=0.3). All participants showed similar reductions in CBF (P=0.3, between groups) and CO (P=0.7, between groups) during LBNP. There was no difference in resting CBF between the groups (P=0.36). In summary, during reductions in CO induced by hypovolemic stress, mean arterial pressure is maintained but CBF declines indicating that CBF is dependent on CO in middle-aged normotensive and hypertensive volunteers. Hypertension is not associated with impairments in the CBF response to reduced CO.

Four Different Carotid Atherosclerotic Behaviors Based on Luminal Stenosis and Plaque Characteristics in Symptomatic Patients: An in Vivo Study

Correct stratification of ischemic stroke risk allows for the proper treatment of carotid atherosclerotic disease. We seek to differentiate plaque types based on stenosis level and plaque morphology. The Chinese Atherosclerosis Risk Evaluation (CARE-II) study is a cross-sectional, observational, multicenter study to assess carotid atherosclerotic plaques in symptomatic subjects using vessel wall magnetic resonance imaging. Plaque morphology and presence of plaque components were reviewed using multi-contrast magnetic resonance imaging. The carotid arteries were divided into four groups based on stenosis level and plaque components. Out of 1072 ischemic stroke subjects, 452 ipsilateral side carotid arteries were included. Significant stenosis (SS) (≥50% stenosis) with high-risk plaque (HRP) features was present in 37 arteries (8.2%), SS(+)/HRP(-) in 29 arteries (6.4%), SS(-)/HRP(+) in 57 arteries (12.6%), and SS(-)/HRP(-) in 329 arteries (72.8%). The prevalence of SS(-)/HRP(+) arteries in this cohort was substantial and had greater wall thickness than the SS(+)/HRP(-) group. These arteries may be misclassified for carotid revascularization by current guidelines based on the degree of luminal stenosis only. These findings have implications for further studies to assess stroke risk using vessel wall imaging.

Neurovascular and Cognitive Dysfunction in Hypertension

Hypertension has emerged as a leading cause of age-related cognitive impairment. Long known to be associated with dementia caused by vascular factors, hypertension has more recently been linked also to Alzheimer disease-the major cause of dementia in older people. Thus, although midlife hypertension is a risk factor for late-life dementia, hypertension may also promote the neurodegenerative pathology underlying Alzheimer disease. The mechanistic bases of these harmful effects remain to be established. Hypertension is well known to alter in the structure and function of cerebral blood vessels, but how these cerebrovascular effects lead to cognitive impairment and promote Alzheimer disease pathology is not well understood. Furthermore, critical questions also concern whether treatment of hypertension prevents cognitive impairment, the blood pressure threshold for treatment, and the antihypertensive agents to be used. Recent advances in neurovascular biology, epidemiology, brain imaging, and biomarker development have started to provide new insights into these critical issues. In this review, we will examine the progress made to date, and, after a critical evaluation of the evidence, we will highlight questions still outstanding and seek to provide a path forward for future studies.

Longitudinal study of carotid artery bifurcation geometry using magnetic resonance angiography

BACKGROUND AND PURPOSE

Carotid artery geometry has been suggested as a risk factor for atherosclerotic carotid disease. Although normal aging and disease development can both lead to geometric changes in the arteries, the exact nature of this phenomenon remains elusive. The aim of our study was to investigate carotid artery geometric changes in a longitudinal study.

MATERIAL AND METHODS

We conducted a retrospective study of 114 subjects who underwent carotid contrast-enhanced magnetic resonance angiography at our clinic at baseline (2005 to 2007) and after 10 years. The right (Rev#2-1) carotid arteries were segmented using semi-automated methods to obtain various measurements of carotid artery geometry. For each patient, these parameters were assessed at both time points, including bifurcation angle, internal carotid artery angle, vessel diameter, and circumference.

RESULTS

The median age for the total patient population (n = 114) at baseline was 59.06 ± 10.40 years. Mean time interval between baseline magnetic resonance angiography and magnetic resonance angiography after 10 years of these patients was 129.18 ± 7.77 months. For the whole group, there was a significant increase in the bifurcation angle (p < 0.05) over a 10-year period. A significant increase was also noted in the diameter and circumference of the common carotid artery (p < 0.05). However, the other vessel diameters and circumferences (bulb carotid, internal carotid) as well as the internal carotid angle did not significantly change (p ≥ 0.05).

CONCLUSION

The diameter and circumference of the common carotid artery and bifurcation angle significantly increased over a decade of life.

Longitudinal study of carotid artery bifurcation geometry using magnetic resonance angiography

OBJECTIVES

Geometry of carotid artery has been known as a risk factor for atherosclerotic carotid disease. Though aging and disease progression can both attribute to geometric changes in the arteries, the exact nature of this phenomenon remains elusive. The aim of our study was to investigate carotid artery geometric changes in a longitudinal study.

METHODS

We conducted a retrospective study of 114 subjects who underwent carotid contrast-enhanced magnetic resonance angiography at our clinic at baseline (2005 to 2007) and after 10 years. The right carotid arteries were segmented using semi-automated methods to obtain various measurements of carotid artery geometry. For each patient, these parameters were assessed at both time points, including bifurcation angle, internal carotid artery angle, vessel diameter, and circumference.

RESULTS

The median age for the total patient population ( n = 114) at baseline was 59.06 ± 10.40 years. Mean time interval between baseline magnetic resonance angiography and magnetic resonance angiography after 10 years of these patients was 129.18 ± 7.77 months. For the whole group, there was a significant increase in the bifurcation angle ( p < 0.05) over a 10-year period. A significant increase was also noted in the diameter and circumference of the common carotid artery ( p < 0.05). However, the other vessel diameters and circumferences (bulb carotid, internal carotid) as well as the internal carotid angle did not significantly change ( p ≥ 0.05).

CONCLUSIONS

The diameter and circumference of the common carotid artery and bifurcation angle significantly increased over a decade of life.

Shape and Location of Carotid Atherosclerotic Plaque and Intraplaque Hemorrhage: A High-resolution Magnetic Resonance Imaging Study

Aim: The present study aimed to investigate the association between shape and location of atherosclerotic plaques and intraplaque hemorrhage (IPH) in carotid arteries using magnetic resonance (MR) imaging.

Methods: Overall, 114 symptomatic patients (mean age: 64.9±10.9 years; 81 males) who underwent MR imaging and had advanced carotid plaques were included in analysis. IPH presence and carotid plaque shape and location (below and above bifurcation) were evaluated. The plaque shape was defined as follows: type-I: the arc-length of plaque is greater in the upstream; type-II: the arc-length of plaque in downstream and upstream is equal; and type-III: the arc-length of plaque is greater in downstream. The plaque shape and location were compared between plaques with and without IPH and their associations with IPH were determined.

Results: Of 181detectedplaques, 57 (31.5%) had IPH. Compared with plaques without IPH, those with IPH had higher incidence of the plaque shape of type-I (66.7% vs. 32.2%, P<0.001), lower incidence of plaque shape of type-III (24.6% vs. 50.0%, P=0.001), and were more likely located above carotid bifurcation (71.9% vs. 48.4%, P=0.003). The plaque shape of type-I (OR, 4.01; 95%CI, 1.36–11.83; P=0.012) and location above bifurcation (OR, 3.21; 95%CI, 1.07–9.61; P=0.037) of carotid plaques were significantly associated with IPH after adjusting for confounder factors.

Conclusions: Carotid plaque shape and location are significantly associated with the occurrence of IPH. Our findings could provide new insights for the pathogenesis of IPH and vulnerably plaques.

Comparison of two different measurement methods in evaluating basilar atherosclerotic plaque using high-resolution MRI at 3 tesla

Background

To compare the Self-referenced and Referenced measurement methods in assessing basilar artery (BA) atherosclerotic plaque employing dark blood high-resolution MRI at 3 Tesla.

Methods

Forty patients with > 20% stenosis as identified by conventional MRA were recruited and evaluated on a 3 Tesla MRI system. The outer wall, inner wall and lumen areas of maximal lumen narrowing site and the outer wall and lumen areas of sites that were proximal and distal to the maximal lumen narrowing site were manually traced. Plaque area (PA), stenosis rate (SR) and percent plaque burden (PPB) were calculated using the Self-referenced and Referenced measurement methods, respectively. To assess intra-observer reproducibility, BA plaque was measured twice with a 2-week interval in between measurements.

Results

Thirty-seven patients were included in the final analysis. There were no significant differences in PA, SR and PPB measurements between the two methods. The intra-class coefficients and coefficient of variations (CV) ranged from 0.976 to 0.990 and from 3.73 to 5.61% for the Self-referenced method and ranged from 0.928 to 0.971 and from 4.64 to 9.95% for the Referenced method, respectively. Both methods are effective in the evaluation of BA plaque. However, the CVs of the Self-referenced method is lower than the Referenced measurement method. Moreover, Bland-Altman plots showed that the Self-referenced method has a narrower interval than the Referenced measurement method.

Conclusions

The Self-referenced method is better and more convenient for evaluating BA plaque, and it may serve as a promising method for evaluation of basilar atherosclerotic plaque.

Segment-specific associations between local haemodynamic and imaging markers of early atherosclerosis at the carotid artery: an in vivo human study

Low and oscillatory wall shear stress (WSS) has long been hypothesized as a risk factor for atherosclerosis; however, evidence has been inferred primarily from model and post-mortem studies, or clinical studies of patients with already-developed plaques. This study aimed to identify associations between local haemodynamic and imaging markers of early atherosclerosis. Comprehensive magnetic resonance imaging allowed quantification of contrast enhancement (CE) (a marker of endothelial dysfunction) and vessel wall thickness at two distinct segments: the internal carotid artery bulb and the common carotid artery (CCA). Strict criteria were applied to a large dataset to exclude inward remodelling, resulting in 41 cases for which personalized computational fluid dynamic simulations were performed. After controlling for cardiovascular risk factors, bulb wall thickening was found to be weakly, but not significantly, associated with oscillatory WSS. CE at the bulb was significantly associated with low WSS (p < 0.001) and low flow helicity (p < 0.05). No significant associations were found for the CCA segment. Local haemodynamics at the bulb were significantly correlated with blood flow rates and heart rates, but not carotid bifurcation geometry (flare and curvature). Therefore low, but not oscillatory, WSS is an early independent marker of atherosclerotic changes preceding intimal thickening at the carotid bulb.