UNASSIGNED: Vulnerable carotid plaque is closely associated with ischemic stroke. Contrast-enhanced ultrasound (CEUS) and high-resolution magnetic resonance imaging (HR-MRI) are two imaging modalities capable of assessing the vulnerability of carotid plaques. This systematic review aimed to compare the diagnostic performance of CEUS and HR-MRI in the evaluation of histologically defined vulnerable carotid plaques.
UNASSIGNED: A systematic literature search with predefined search terms was performed on PubMed, the Cochrane library, Embase, and Web of Science from January 2001 to December 2023. Studies that evaluated the diagnostic accuracy of vulnerable carotid plaques confirmed by histology with CEUS and/or HR-MRI were included. The pooled values were calculated using a random-effects meta-analysis to determine diagnostic power.
UNASSIGNED: This analysis included a total of 839 patients from 20 studies comprising 1,357 HR-MRI plaques and CEUS 504 plaques. With the reference to histological results, all nine CEUS studies focused on the detection of intraplaque neovascularization (IPN), and three studies also examined morphological changes or ulcerated plaques; meanwhile, among the HR-MRI studies, seven predominantly focused on identifying intraplaque hemorrhage (IPH) and three mainly examined lipid-rich necrotic cores (LRNCs). The pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, diagnostic odds ratio, and the area under the curve (AUC) for CEUS studies were 0.85 [95% confidence interval (CI): 0.81-0.89], 0.76 (95% CI: 0.69-0.83), 3.41 (95% CI: 1.68-6.94), 0.14 (95% CI: 0.05-0.38), 27.68 (95% CI: 5.78-132.62), and 0.89 [standard error (SE) 0.06], respectively; for HR-MRI, these values were 0.88 (95% CI: 0.85-0.90), 0.89 (95% CI: 0.86-0.92), 7.49 (95% CI: 3.28-17.09), 0.17 (95% CI: 0.12-0.24), 49.13 (95% CI: 23.87-101.11), and 0.94 (SE 0.01), respectively. The difference in AUC between the two modalities was not statistically significant (Z=0.82; P=0.68).
UNASSIGNED: CEUS and HR-MRI are valuable noninvasive diagnostic tools for identifying histologically confirmed vulnerable carotid plaques and demonstrate similar diagnostic performance. CEUS is more capable of detecting IPN and morphological changes, while HR-MRI is more suited to classifying IPH and LRNCs.

UNASSIGNED: The aim of this study is to investigate the correlation between the triglyceride-glucose-body mass index (TyG-BMI) and the characteristics of various carotid plaques in middle-aged and elderly patients with acute myocardial infarction (AMI).
UNASSIGNED: A retrospective study was conducted on 380 patients with AMI hospitalized in the Cardiology Department of Kaifeng Central Hospital. Based on carotid ultrasound results, patients were divided into the following two groups: the stable plaque group and the unstable plaque group. Additionally, a control group comprising 380 healthy individuals visiting the hospital\'s physical examination center during the same timeframe was established. Fasting venous blood samples were collected from all participants to measure blood glucose and triglyceride. The baseline TyG-BMI index was calculated using the formula Ln [fasting triglyceride (mg/dL)×fasting blood glucose (mg/dL)/2]×BMI. The correlation between different plaque groups and the TyG-BMI index was analyzed.
UNASSIGNED: The TyG-BMI index was significantly higher in the unstable plaque group compared to the stable plaque group, with values of 252.81±29.99 and 201.92±28.72, respectively (P = 0.034). Spearman\'s correlation analysis showed a positive correlation between the instability of carotid plaques and the TyG-BMI index in patients with AMI (r = 0.521, P = 0.003). Logistic regression analysis indicated that the TyG-BMI index was an important risk factor for unstable carotid plaques in patients with AMI (OR = 2.691, 95% CI: 1.169-4.123).
UNASSIGNED: The findings of this study suggest that an elevated TyG-BMI index significantly increases the risk of unstable carotid plaques in patients with AMI, making it an important risk factor for carotid plaque instability.

BACKGROUND: To investigate the relationship between pericarotid fat density measured in carotid CTA and vulnerable carotid plaque.
METHODS: This retrospective study included 374 participants who underwent carotid CTA between June 1, 2021, and December 1, 2021 (234 males, median age 68 years [interquartile range: 61-75]). Two groups, symptomatic and asymptomatic, were defined based on either diffusion-weighted MRI or a clinical history of acute ischemia or TIA within 6 months before or after CTA. The relationship between pericarotid fat density and cerebrovascular ischemic events was assessed using receiver operating characteristic analysis and binary logistic regression analysis.
RESULTS: In the symptomatic group (n = 135), mean pericarotid fat density (-63.3 ± 21.7 vs. -81.7 ± 16.9 HU, respectively; p < 0.001) and median maximum plaque thickness (4 [interquartile range: 3-6] vs. 3.7 [interquartile range: 2.6-4.7] mm, respectively; p = 0.002) were higher, while plaque density (42.1 ± 19.6 vs. 50.6 ± 20.4 HU, respectively; p = 0.001) was lower compared to the asymptomatic group. Pericarotid fat density (OR: 1.038, 95% CI: 1.023-1.053, p < 0.001) was identified as an independent predictor for symptomatic patients. The optimal cut-off value for pericarotid fat density predicting symptomatic patients was estimated as -74 HU (area under the curve: 0.753, 95% CI:0.699-0.808, p < 0.001). Inter-reader agreement for pericarotid fat density was found to be almost perfect (intraclass correlation coefficient: 0.818, 95% CI: 0.770-0.856, p < 0.001).
CONCLUSIONS: Pericarotid fat density may serve as an imaging biomarker in predicting acute cerebrovascular ischemic events.

This study explored the impact of hypertension on atheroma plaque formation through a mechanobiological model. The model incorporates blood flow via the Navier-Stokes equation. Plasma flow through the endothelium is determined by Darcy\'s law and the Kedem-Katchalsky equations, which consider the three-pore model utilized for substance flow across the endothelium. The behaviour of these substances within the arterial wall is described by convection-diffusion-reaction equations, while the arterial wall itself is modelled as a hyperelastic material using Yeoh\'s model. To accurately evaluate hypertension\'s influence, adjustments were made to incorporate wall compression-induced wall compaction by radial compression. This compaction impacts three key variables of the transport phenomena: diffusion, porosity, and permeability. Based on the obtained findings, we can conclude that hypertension significantly augments plaque growth, leading to an over 400% increase in plaque thickness. This effect persists regardless of whether wall mechanics are considered. Tortuosity, arterial wall permeability, and porosity have minimal impact on atheroma plaque growth under normal arterial pressure. However, the atheroma plaque growth changes dramatically in hypertensive cases. In such scenarios, the collective influence of all factors-tortuosity, permeability, and porosity-results in nearly a 20% increase in plaque growth. This emphasizes the importance of considering wall compression due to hypertension in patient studies, where elevated blood pressure and high cholesterol levels commonly coexist.

Introduction: Blood flow produces fluid shear stress (SS), a frictional force parallel to the blood flow, on the endothelial cell (EC) layer of the lumen of the vessels. ECs themselves are sensitive to this frictional force in terms of directionality and intensity. The aim of this study was to determine the physiological shear stress value during the cardiac cycle and EC polarity and orientation from blood flow in healthy male and female mouse carotid artery. Methods: Experimentation is done on anesthetized male and female 8-week-old C5BL/6J mice. In vivo measurements of maximum blood velocity and vessel diameter in diastole and systole were performed on the right common carotid artery by Doppler ultrasound imaging. Blood viscosity (total and plasmatic) and hematocrit were determined on blood samples. For SS calculation, we developed a new method assuming heterogenous blood flow, i.e., a red cell central plug flow surrounded by a peripheral plasma sheath flow, and computing SS from vessel diameter and hemodynamical measurements (maximal blood velocity, hematocrit and plasmatic viscosity). Results: Results were compared with the classical method assuming a homogenous blood flow with constant apparent total blood viscosity. EC polarity and orientation were determined ex vivo on the carotid endothelium by confocal imaging after labeling of the EC nucleus and Golgi apparatus. Diastolic and systolic SS were 6 ± 2.5 Pa and 30 ± 6.5 Pa, respectively. Total blood and plasmatic viscosity was 4 ± 0.5 cP and 1.27 cP, respectively. ECs were polarized and significantly oriented against blood flow. No sex difference was identified.

暂无摘要。

UNASSIGNED: Ischemic stroke, which has a high incidence, disability, and mortality rate, is mainly caused by carotid atherosclerotic plaque. The difference in the geometric structures of the carotid arteries inevitably leads to the variability in the local hemodynamics, which plays a key role in the formation of carotid atherosclerosis. At present, the combined mechanisms of hemodynamic and geometric in the formation of carotid atherosclerotic plaque are not clear. Thus, this study characterized the geometric and hemodynamic characteristics of carotid atherosclerotic plaque formation using four-dimensional (4D) flow magnetic resonance imaging (MRI).
UNASSIGNED: Ultimately, 122 carotid arteries from 61 patients were examined in this study. According to the presence of plaques at the bifurcation of the carotid artery on cervical vascular ultrasound (US), carotid arteries were placed into a plaque group (N=69) and nonplaque group (N=53). The ratio of the maximum internal carotid artery (ICA) inner diameter to the maximum common carotid artery (CCA) inner diameter (ICA-CCA diameter ratio), bifurcation angle, and tortuosity were measured using neck three-dimensional time-of-flight magnetic resonance angiography (3D TOF-MRA). Meanwhile, 4D flow MRI was used to obtain the following hemodynamic parameters of the carotid arteries: volume flow rate, velocity, wall shear stress (WSS), and pressure gradient (PG). Independent sample t-tests were used to compare carotid artery geometry and hemodynamic changes between the plaque group and nonplaque group.
UNASSIGNED: The ICA-CCA diameter ratio between the plaque group and the nonplaque group was not significantly different (P=0.124), while there were significant differences in the bifurcation angle (P=0.005) and tortuosity (P=0.032). The bifurcation angle of the plaque group was greater than that of the nonplaque group (60.70°±20.75° vs. 49.32°±22.90°), and the tortuosity was smaller than that of the nonplaque group (1.07±0.04 vs. 1.09±0.05). There were no significant differences between the two groups in terms of volume flow rate (P=0.351) and the maximum value of velocity (velocitymax) (P=0.388), but the axial, circumferential, and 3D WSS values were all significantly different, including their mean values (all P values <0.001) and the maximum value of 3D WSS (P<0.001), with the mean axial, circumferential, 3D WSS values, along with the maximum 3D WSS value, being lower in the plaque group. The two groups also differed significantly in terms of maximum PG value (P=0.030) and mean PG value (P=0.026), with these values being greater in the nonplaque group than in the plaque group.
UNASSIGNED: A large bifurcation angle and a low tortuosity of the carotid artery are geometric risk factors for plaque formation in this area. Low WSS and low PG values are associated with carotid atherosclerotic plaque formation.

UNASSIGNED: Atherosclerosis of the carotid artery is a major risk factor for stroke. Quantitative assessment of the carotid vessel wall can be based on cross-sections of three-dimensional (3D) black-blood magnetic resonance imaging (MRI). To increase reproducibility, a reliable automatic segmentation in these cross-sections is essential.
UNASSIGNED: We propose an automatic segmentation of the carotid artery in cross-sections perpendicular to the centerline to make the segmentation invariant to the image plane orientation and allow a correct assessment of the vessel wall thickness (VWT). We trained a residual U-Net on eight sparsely sampled cross-sections per carotid artery and evaluated if the model can segment areas that are not represented in the training data. We used 218 MRI datasets of 121 subjects that show hypertension and plaque in the ICA or CCA measuring ≥ 1.5    mm in ultrasound.
UNASSIGNED: The model achieves a high mean Dice coefficient of 0.948/0.859 for the vessel\'s lumen/wall, a low mean Hausdorff distance of 0.417 / 0.660    mm , and a low mean average contour distance of 0.094 / 0.119    mm on the test set. The model reaches similar results for regions of the carotid artery that are not incorporated in the training set and on MRI of young, healthy subjects. The model also achieves a low median Hausdorff distance of 0.437 / 0.552    mm on the 2021 Carotid Artery Vessel Wall Segmentation Challenge test set.
UNASSIGNED: The proposed method can reduce the effort for carotid artery vessel wall assessment. Together with human supervision, it can be used for clinical applications, as it allows a reliable measurement of the VWT for different patient demographics and MRI acquisition settings.

Recognizing the significance of drug carriers in the treatment of atherosclerotic plaque is crucial in light of the worldwide repercussions of ischemic stroke. Conservative methodologies, specifically targeted drug delivery, present encouraging substitutes that mitigate the hazards linked to invasive procedures. With the intention of illuminating their considerable significance and prospective benefits, this study examines the impact of the geometry and dimensions of drug-loaded nano-microcarriers on atherosclerotic plaque. The research utilizes a finite element approach to simulate the motion and fluid dynamics of nano-microcarriers loaded with drugs within the carotid arteries. Carriers are available in a variety of shapes and sizes to accommodate patient-specific geometries, pulsatile fluid flow, and non-Newtonian blood properties. Optimization of drug delivery is achieved through the examination of carrier interaction with the inner wall. The results demonstrated that the interaction data between particles and the inner wall of atherosclerotic plaques exhibits micro- and nanoscale patterns that are distinct. Symmetric plaques demonstrate that nanoparticles with a 0.4 shape factor and diameters below 200 nm show the highest interaction rate. Conversely, larger particles (200 and 500 nm) with shape factors of 1 demonstrate comparatively elevated interaction rates. The optimal shape factor for drug-loaded microparticles has been determined to be one, and the number of interactions increases as the diameter of the nanoparticles increases, with a significant increase observed at a shape factor of one. Asymmetric plaques exhibit the maximum interaction rates among particles that have a shape factor of 0.4 and have diameters smaller than 500 µm. The findings establish a foundation for novel therapeutic strategies, establishing nano-microparticles as auspicious contenders for accurate and efficacious drug delivery systems that inhibit plaque proliferation.

OBJECTIVE: Intraplaque neovessels (INVs) are considered important contributors to carotid plaque vulnerability. The purpose of this study was to examine whether differences in INV distribution affect plaque vulnerability.
METHODS: The study cohort comprised 110 patients with significant stenosis of the carotid artery who had undergone carotid endarterectomy. The distribution of INVs within carotid plaques was assessed by immunohistochemical studies using anti-CD-34 antibody as a marker for endothelial cells. First, we divided the patients into M group and S group depending on the numbers of INVs in middle and shoulder region. Next, we categorized carotid plaques into four categories according to the distributions of INVs: Shoulder, Middle, Mixed, and Scarce. We then compared total area of intraplaque hemorrhage, cholesterol, and calcification, width of thinnest fibrous cap, and number of INVs between the four categories of plaque.
RESULTS: The area of intraplaque hemorrhage was significantly larger in the M group than in the S group (P = 0.011). Meanwhile, symptomatic carotid stenosis was significantly more frequently associated with the Middle and Mixed than the Shoulder and Scarce categories (P < 0.01). The area of intraplaque hemorrhage was significantly different between the four groups (P = 0.022). Rupture of the fibrous cap was more frequently detected in the Middle and Mixed than the other categories (P = 0.002).
CONCLUSIONS: INVs in the middle region of carotid plaques are strongly associated with symptomatic carotid stenosis, intraplaque hemorrhage, and rupture of the fibrous cap. Our findings indicate that the distribution of INVs may affect plaque vulnerability.