Evaluation of the stability of carotid atherosclerotic plaque with contrast-enhanced ultrasound

Investigating the Association of Carotid Atherosclerotic Plaque MRI Features and Silent Stroke After Carotid Endarterectomy

BACKGROUND

The predictive value of carotid plaque characteristics for silent stroke (SS) after carotid endarterectomy (CEA) is unclear.

OBJECTIVE

To investigate the associations between carotid plaque characteristics and postoperative SS in patients undergoing CEA.

STUDY TYPE

Prospective.

POPULATION

One hundred fifty-three patients (mean age: 65.4 ± 7.9 years; 126 males) with unilateral moderate-to-severe carotid stenosis (evaluated by CT angiography) referred for CEA.

FIELD STRENGTH/SEQUENCE

3 T, brain-MRI:T2-PROPELLER, T1-/T2-FLAIR, diffusion weighted imaging (DWI) and T2*, carotid-MRI:black-blood T1-/T2W, 3D TOF, Simultaneous Non-contrast Angiography intraplaque hemorrhage.

ASSESSMENT

Patients underwent carotid-MRI within 1-week before CEA, and brain-MRI within 48-hours pre-/post-CEA. The presence and size (volume, maximum-area-percentage) of carotid lipid-rich necrotic core (LRNC), intraplaque hemorrhage (Type-I/Type-II IPH) and calcification were evaluated on carotid-MR images. Postoperative SS was assessed from pre-/post-CEA brain DWI. Patients were divided into moderate-carotid-stenosis (50%-69%) and severe-carotid-stenosis (70%-99%) groups and the associations between carotid plaque characteristics and SS were analyzed.

STATISTICAL TESTS

Independent t test, Mann-Whitney U-test, chi-square test and logistic regressions (OR: odds ratio, CI: confidence interval). P value <0.05 was considered statistically significant.

RESULTS

SS was found in 8 (16.3%) of the 49 patients with moderate-carotid-stenosis and 21 (20.2%) of the 104 patients with severe-carotid-stenosis. In patients with severe-carotid-stenosis, those with SS had significantly higher IPH (66.7% vs. 39.8%) and Type-I IPH (66.7% vs. 38.6%) than those without. The presence of IPH (OR 3.030, 95% CI 1.106-8.305) and Type-I IPH (OR 3.187, 95% CI 1.162-8.745) was significantly associated with SS. After adjustment, the associations of SS with presence of IPH (OR 3.294, 95% CI 1.122-9.669) and Type-I IPH (OR 3.633, 95% CI 1.216-10.859) remained significant. Moreover, the volume of Type-II IPH (OR 1.014, 95% CI 1.001-1.028), and maximum-area-percentage of Type-II IPH (OR 1.070, 95% CI 1.002-1.142) and LRNC (OR 1.030, 95% CI 1.000-1.061) were significantly associated with SS after adjustment. No significant (P range: 0.203-0.980) associations were found between carotid plaque characteristics and SS in patients with moderate-carotid-stenosis.

DATA CONCLUSIONS

In patients with unilateral severe-carotid-stenosis, carotid vulnerable plaque MR features, particularly presence and size of IPH, might be effective predictors for SS after CEA.

EVIDENCE LEVEL

2 TECHNICAL EFFICACY: Stage 2.

Diagnostic Performance of Atherosclerotic Carotid Plaque Neovascularization with Contrast-Enhanced Ultrasound: A Meta-Analysis

Objectives

To evaluate the diagnostic performance of contrast-enhanced ultrasound (CEUS) for atherosclerotic carotid plaque neovascularization.

Methods

The electronic databases like PubMed, Embase, OVID, and Web of Science were used to search for the relevant studies, which are involved in the evaluation of the diagnostic parameters of QUS for atherosclerotic carotid plaque neovascularization. Review Manager 5.4 and Stata 14.0 were used to estimate the pooled diagnostic value of CEUS. Forest plots, sensitivity analysis, and Deeks' funnel plots were performed on the included studies.

Results

Ten studies eventually met the final inclusion criteria. For diagnostic performance, CUES showed that the pooled values of sensitivity, specificity, positive likelihood odds ratios, negative likelihood odds ratios, and diagnostic odds ratios were 0.83 (95% CI 0.78-0.86), 0.77 (95% CI 0.68-0.84), 3.61 (95% CI 2.59-5.03), 0.23 (95% CI 0.18-0.28), and 16.02 (95% CI 10.02-25.60), respectively. The estimate of the area under curve (AUC) was 0.85 (95% CI 0.82-0.88).

Conclusion

Our research supported that CEUS had high sensitivity and specificity in the diagnosis of atherosclerotic carotid plaque neovascularization. More high-quality prospective multicenter studies focusing on the accuracy of CEUS for carotid atherosclerotic plaque should be performed to verify our conclusions.

Consistency of superb microvascular imaging and contrast-enhanced ultrasonography in detection of intraplaque neovascularization: A meta-analysis

This meta-analysis assesses the consistency of superb microvascular imaging (SMI) and contrast-enhanced ultrasonography (CEUS) in detecting intraplaque neovascularization (IPN). We searched PubMed, Web of Science, the Cochrane Library, and CBM databases. A meta-analysis was conducted using STATA version 15.1 software. We calculated the pooled Kappa index. Ten studies that met all of the inclusion criteria were included in this meta-analysis. A total of 608 carotid plaques were assessed through both SMI and CEUS. The pooled summary Kappa index was 0.743 (95% confidence interval (CI) = 0.696–0.790) with statistical significance (z = 31.14, P < 0.01). We found no evidence of publication bias (t = −1.21, P = 0.261). Our meta-analysis indicates that SMI and CEUS display a good consistency in detecting the IPN of carotid plaque; that is, SMI ultrasound may be a promising alternative to CEUS for detecting the IPN of carotid plaque.

Contrast-Enhanced Ultrasound to Assess Carotid Intraplaque Neovascularization

Contrast-enhanced ultrasound (CEUS) is increasingly being used to identify patients with carotid plaques that are vulnerable to rupture, so-called vulnerable atherosclerotic plaques, by assessment of intraplaque neovascularization. A complete overview of the strengths and limitations of carotid CEUS is currently not available. The aim of this systematic review was to provide a complete overview of existing publications on the role of CEUS in assessment of carotid intraplaque neovascularization. The systematic review of the literature yielded 52 studies including a total of 4660 patients (mean age: 66 y, 71% male) who underwent CEUS for the assessment of intraplaque neovascularization. The majority of the patients (76%) were asymptomatic and had no history of transient ischemic attack (TIA) or stroke. The assessment of intraplaque neovascularization was mostly performed using a visual scoring system; several studies used time-intensity curves or dedicated quantification software to optimize analysis. In 17 studies CEUS was performed in patients before carotid surgery (endarterectomy), allowing a comparison of pre-operative CEUS findings with histologic analysis of the tissue sample that is removed from the carotid artery. In a total of 576 patients, the CEUS findings were compared with histopathological analysis of the plaque after surgery. In 16 of the 17 studies, contrast enhancement was found to correlate with the presence and degree of intraplaque neovascularization on histology. Plaques with a larger amount of contrast enhancement had significantly increased density of microvessels in the corresponding region on histology. In conclusion, CEUS is a readily available imaging modality for the assessment of patients with carotid atherosclerosis, providing information on atherosclerotic plaques, such as ulceration and intraplaque neovascularization, which may be clinically relevant. The ultimate clinical goal is the early identification of carotid atherosclerosis to start early preventive therapy and prevent clinical complications such as TIA and stroke.

Prospective Study About the Relationship Between CEUS of Carotid Intraplaque Neovascularization and Ischemic Stroke in TIA Patients

Objective: To evaluate the relationship between contrast-enhanced ultrasonography (CEUS) of carotid intraplaque neovascularization and ischemic stroke in transient ischemic attack (TIA) patients. Methods: A total of 112 TIA patients were selected for the study. Routine carotid ultrasonic examination was performed for all the patients. CEUS was carried out for consecutive patients with plaque thicker than 2.5 mm in carotid bifurcation and follow-up for at least 24 months. The number of patients with incurrence of ischemic stroke or recurrence of TIA was obtained during the follow-up period. To detect the risk factors for incurrence of ischemic stroke or recurrence of TIA in 24 months, multivariate logistic regression analyses were performed for all the risk factors in all the selected patients. Results: Ninety-one patients underwent CEUS and were followed up at least 24 months. There were statistical differences between recurrent and non-recurrent groups about hypertension, diabetes, hyperlipemia, smoking history, family history of stroke, medication compliance, two-dimensional ultrasound, and CEUS (P < 0.05). The higher CEUS intensity in the carotid plaque was, the higher was the possibility of ischemic stroke or recurrent TIA. Multivariate logistic regression analysis showed that the CEUS characteristics of carotid plaque such as linear enhancement or diffuse enhancement were independent risk factors for ischemic stroke or recurrent TIA in TIA patients (P < 0.05). Conclusion: For carotid plaques, CEUS could evaluate the infusion mode, which could reflect the neovascularization in plaques. CEUS could predict the incurrence of ischemic stroke or recurrence of TIA in TIA patients, which is useful information when making a clinical decision.

Carotid artery imaging: The study of intra-plaque vascularization and hemorrhage in the era of the "vulnerable" plaque

Intraplaque hemorrhage (IPH) is one of the main factors involved in atherosclerotic plaque (AP) instability. Its recognition is crucial for the correct staging and management of patients with carotid artery plaques to limit ischemic stroke. Imaging plays a crucial role in identifying IPH, even if the great variability of intraplaque vascularization and the limitations of our current imaging technologies make it difficult. The intent of this review is to give a general overview of the main features of intraplaque vascularization and IPH on Ultrasound (US), Computed Tomography (CT), Magnetic Resonance (MR) and Nuclear Medicine, and a brief description on the future prospectives.

Plaque Characteristics of Patients with Symptomatic Mild Carotid Artery Stenosis

BACKGROUND

Carotid revascularization may be considered for severe stenosis, but its use for symptomatic mild stenosis (<50%) with vulnerable plaque or ulcer remains uncertain. The characteristics of patients with symptomatic mild stenosis who underwent revascularization are reviewed.

METHODS

The subjects of this study were 18 patients with symptomatic mild stenosis (<50%) on angiography from among 175 patients who underwent revascularization in our department. The plaques were evaluated by black-blood magnetic resonance imaging (BB-MRI) and ultrasonography (US) and classified into 2 types: type 1 (n = 15), a lesion with an ulcer or mobile plaque or thrombosis on angiography or US; and type 2 (n = 3), a lesion without any of the above. Fourteen patients underwent carotid endarterectomy (CEA), and 4 patients underwent carotid artery stenting.

RESULTS

The stenosis on angiography was 27.2% ± 10.7 (5%-41%), and the area carotid artery stenosis rate on US was 69.8 ± 14.5% (44.5%-97%). The stenosis rate of these 2 methods was not at all correlated. In type 1 plaque that underwent CEA, 10 of 11 patients had vulnerable plaque by histopathology, and 1 patient had thrombus on the plaque by operative findings. In type 2 plaque that underwent CEA, all patients had vulnerable plaque by histopathology. During the follow-up period, none of the patients had restenosis or stroke.

CONCLUSIONS

The findings of US and BB-MRI in patients with symptomatic mild stenosis (<50%) on angiography are important for determining treatment. If BB-MRI or US shows the findings of vulnerable plaque in mild stenosis, surgical treatment may be considered for these patients.