Large Culprit Plaque and More Intracranial Plaques Are Associated with Recurrent Stroke: A Case-Control Study Using Vessel Wall Imaging

The relationship between intracranial atherosclerosis and white matter hyperintensity in ischemic stroke patients: a retrospective cross-sectional study using high-resolution magnetic resonance vessel wall imaging

Background

Both intracranial atherosclerosis and white matter hyperintensity (WMH) are prevalent among the stroke population. However, the relationship between intracranial atherosclerosis and WMH has not been fully elucidated. Therefore, the aim of this study was to investigate the relationship between the characteristics of intracranial atherosclerotic plaques and the severity of WMH in patients with ischemic stroke using high-resolution magnetic resonance vessel wall imaging.

Methods

Patients hospitalized with ischemic stroke and concurrent intracranial atherosclerosis at Beijing Tsinghua Changgung Hospital, a tertiary comprehensive stroke center, who underwent high-resolution magnetic resonance vessel wall imaging and conventional brain magnetic resonance imaging were continuously recruited from January 2018 to December 2018. Both intracranial plaque characteristics (plaque number, maximum wall thickness, luminal stenosis, T1 hyperintensity, and plaque length) and WMH severity (Fazekas score and volume) were evaluated. Spearman correlation or point-biserial correlation analysis was used to determine the association between clinical characteristics and WMH volume. The independent association between intracranial plaque characteristics and the severity as well as WMH score was analyzed using logistic regression. The associations of intracranial plaque characteristics with total white matter hyperintensity (TWMH) volume, periventricular white matter hyperintensity (PWMH) volume and deep white matter hyperintensity (DWMH) volume were determined using multilevel mixed-effects linear regression.

Results

A total of 159 subjects (mean age: 64.0±12.5 years; 103 males) were included into analysis. Spearman correlation analysis indicated that age was associated with TWMH volume (r=0.529, P<0.001), PWMH volume (r=0.523, P<0.001) and DWMH volume (r=0.515, P<0.001). Point-biserial correlation analysis indicated that smoking (r=-0.183, P=0.021) and hypertension (r=0.159, P=0.045) were associated with DWMH volume. After adjusting for confounding factors, logistic regression analysis showed plaque number was significantly associated with the presence of severe WMH [odds ratio (OR), 1.590; 95% CI, 1.241-2.035, P<0.001], PWMH score of 3 (OR, 1.726; 95% CI, 1.074-2.775, P=0.024), and DWMH score of 2 (OR, 1.561; 95% CI, 1.150-2.118, P=0.004). Intracranial artery luminal stenosis was associated with presence of severe WMH (OR, 1.032; 95% CI, 1.002-1.064, P=0.039) and PWMH score of 2 (OR, 1.057; 95% CI, 1.008-1.109, P=0.023). Multilevel mixed-effects linear regression analysis showed that plaque number was associated with DWMH volume (β=0.128; 95% CI, 0.016-0.240; P=0.026) after adjusted for age and sex.

Conclusions

In ischemic stroke patients, intracranial atherosclerotic plaque characteristics as measured by plaque number and luminal stenosis were associated with WMH burden.

Application of high-resolution MRI in evaluating statin efficacy on symptomatic intracranial atherosclerosis

OBJECTIVES

To investigate the efficacy of statins on symptomatic intracranial atherosclerotic plaques using high-resolution 3.0 T MR vessel wall imaging (HR-MRI).

METHODS

Patients with symptomatic intracranial atherosclerotic plaques (cerebral ischemic events within the last three months) confirmed by HR-MRI from July 2017 to August 2022 were retrospectively included in this study. The enrolled patients started statin therapy at baseline. All the patients underwent the follow-up HR-MRI examination after statin therapy for at least 3 months. A paired sample t-test and Wilcoxon rank sum test were used to evaluate the changes in plaque characteristics after statin therapy. Multivariate linear regression was further used to investigate the clinical factors associated with statin efficacy.

RESULTS

A total of 48 patients (37 males; overall mean age = 60.2 ± 11.7 years) were included in this study. The follow-up time was 7.0 (5.6-12.0) months. In patients treated with statins for > 6 months (n = 31), plaque length, wall thickness, plaque burden, luminal stenosis and plaque enhancement were significantly reduced. Similar results were found in patients with good lipid control (n = 21). Younger age, lower BMI and hypertension were associated with decreased plaque burden. Lower BMI, hypertension and longer duration of statin therapy were associated with decreased plaque enhancement. Younger age and hypertension were associated with decreased luminal stenosis (all p < 0.05).

CONCLUSION

HR-MRI can effectively evaluate plaques changes after statin therapy. Statins can reduce plaque burden and stabilize plaques. The effect of statin may have a relationship with age, BMI, hypertension, and duration of statin therapy.

CLINICAL RELEVANCE STATEMENT

High-resolution MRI can be applied to evaluate the efficacy of statins on symptomatic intracranial atherosclerotic plaques. Long-term statin use and well-controlled blood lipid levels can help reduce plaque burden and stabilize plaques.

KEY POINTS

High-resolution MRI provides great help evaluating the changes of plaque characteristics after statin therapy. Efficacy of statins is associated with duration of use, controlled lipid levels, and clinical factors. High-resolution MRI can serve as an effective method for following-up symptomatic intracranial atherosclerosis.

Delayed Enhancement of Intracranial Atherosclerotic Plaque Can Better Differentiate Culprit Lesions: A Multiphase Contrast-Enhanced Vessel Wall MRI Study

BACKGROUND AND PURPOSE

Intracranial plaque enhancement (IPE) identified by contrast-enhanced vessel wall MR imaging (VW-MR imaging) is an emerging marker of plaque instability related to stroke risk, but there was no standardized timing for postcontrast acquisition. We aim to explore the optimal postcontrast timing by using multiphase contrast-enhanced VW-MR imaging and to test its performance in differentiating culprit and nonculprit lesions.

MATERIALS AND METHODS

Patients with acute ischemic stroke due to intracranial plaque were prospectively recruited to undergo VW-MR imaging with 1 precontrast phase and 4 consecutive postcontrast phases (9 minutes and 13 seconds for each phase). The signal intensity (SI) values of the CSF and intracranial plaque were measured on 1 precontrast and 4 postcontrast phases to determine the intracranial plaque enhancement index (PEI). The dynamic changes of the PEI were compared between culprit and nonculprit plaques on the postcontrast acquisitions.

RESULTS

Thirty patients with acute stroke (aged 59 ± 10 years, 18 [60%] men) with 113 intracranial plaques were included. The average PEI of all intracranial plaques significantly increased (up to 14%) over the 4 phases. There was significantly increased PEI over the 4 phases for culprit plaques (an average increase of 23%), but this was not observed for nonculprit plaques. For differentiating culprit and nonculprit plaques, we observed that the performance of IPE in the second postcontrast phase (cutoff = 0.83, AUC = 0.829 [0.746-0.893]) exhibited superior accuracy when compared with PEI in the first postcontrast phase (cutoff = 0.48; AUC = 0.768 [0.680-0.843]) (P = .022).

CONCLUSIONS

A 9-minute delay of postcontrast acquisition can maximize plaque enhancement and better differentiate between culprit and nonculprit plaques. In addition, culprit and nonculprit plaques have different enhancement temporal patterns, which should be evaluated in future studies.

Association of culprit plaque enhancement ratio, hypoperfusion and HbA1c with recurrent ischemic stroke in patients with atherosclerotic stenosis of the middle cerebral artery

PURPOSE

To investigate the differences in intracranial culprit plaque characteristics of the middle cerebral artery (MCA), collateral circulation and hypoperfusion in patients with and without recurrent ischemic stroke and to identify the association with the recurrent ischemic cerebrovascular events.

METHOD

Eighty-six patients with acute/subacute ischemic stroke caused by atherosclerotic plaques of the MCA were retrospectively enrolled and grouped into patients with recurrence (n = 36) and without recurrence (n = 50). All patients underwent high-resolution vessel wall imaging and dynamic susceptibility contrast-enhanced perfusion weighted imaging. The differences in culprit plaque characteristics, collateral circulation and hypoperfusion in the territory of the stenotic MCA were assessed between the two groups. The relationship between plaque characteristics and hypoperfusion was evaluated. The independent factors of recurrent ischemic stroke were identified by logistic regression analyses.

RESULTS

Higher HbA1c, culprit plaque enhancement grade, culprit plaque enhancement ratio, and lower time to peak map based on the Alberta Stroke Program Early CT score (TTP-ASPECTS) were observed in the recurrence group(all p < 0.050). Both plaque enhancement grade and enhancement ratio were significantly associated with TTP-ASPECTS (p = 0.030 and 0.039, respectively). HbA1c, culprit plaque enhancement ratio and TTP-ASPECTS were independent factors of the recurrence of ischemic stroke (all p < 0.050). The area under the curve of the combination including the above factors (AUC = 0.819) was significantly higher than that of any variable alone after adjustment (all p < 0.050).

CONCLUSIONS

Culprit plaque enhancement ratio, TTP-ASPECTS and HbA1c were independent factors of recurrent ischemic stroke. Their combination improved the accuracy in identifying the risk of recurrent ischemic stroke.

Correlation of the middle cerebral artery atherosclerotic plaque characteristics with ischemic stroke recurrence: a vessel wall magnetic resonance imaging study

This study aims to analyze the imaging features of atherosclerotic plaques in the middle cerebral artery (MCA) of patients with recurrent ischemic stroke using vessel wall magnetic resonance imaging (VWMRI) and investigate the correlation between these imaging features and the recurrence of ischemic stroke. Consecutive patients with ischemic stroke caused by atherosclerotic stenosis of the MCA were collected. The patients were divided into recurrent and non-recurrent ischemic stroke groups. We obtained VWMRI images of MCA plaques using 3.0T MRI by black-blood sequences, and the differences in VWMRI characteristics and clinical information between the two groups were compared. A binary Logistic regression model was used to analyze the VWMRI characteristics and clinical information related to ischemic stroke recurrence. 179 patients were collected from August 2018 to May 2020, and 81 patients were included in the study. The recurrent ischemic stroke group patients had a higher stenosis rate (0.69 vs 0.64). Meanwhile, the rate of centripetal wall thickening was significantly higher in patients with recurrent ischemic stroke (33.3% vs 11.7%). Binary Logistic regression analysis showed that sex (P=0.036, OR:2.983, CI:1.075-8.279), stenosis rate (P=0.038, OR:148.565, CI:1.331-16583.631), and vessel wall thickening pattern (P=0.012, OR:0.171, CI:0.043-0.678) were related to ischemic stroke recurrence. The patients with ischemic stroke caused by atherosclerotic stenosis of MCA, female patients, and those with concentric wall thickening and a high degree of stenosis have a higher risk of recurrence. Our results suggest that VWMRI is a valuable tool for predicting the risk of ischemic stroke recurrence in patients with MCA plaques.

Qualitative and quantitative plaque enhancement on high-resolution vessel wall imaging predicts symptomatic intracranial atherosclerotic stenosis

BACKGROUND AND PURPOSE

Intracranial atherosclerotic stenosis (ICAS) is a major cause of ischemic stroke (IS), and high-resolution vessel wall imaging (HR-VWI) can be used to assess the plaque characteristics of ICAS. This study aimed to qualitatively and quantitatively assess plaque enhancement of ICAS and to investigate the relationship between plaque enhancement, plaque morphological features, and IS.

METHODS

Data from adult patients with ICAS from April 2018 to July 2022 were retrospectively collected, and all patients underwent HR-VWI examination. Plaque enhancement was qualitatively and quantitatively assessed, and the plaque-to-pituitary stalk contrast ratio (CR) indicated the degree of plaque enhancement. Plaque characteristics, such as plaque burden and area, were quantitatively measured using HR-VWI. Furthermore, receiver-operating characteristic (ROC) analysis was performed to assess the ability of CR to discriminate plaque enhancement. The patients were divided into a symptomatic ICAS group and an asymptomatic ICAS group according to the clinical and imaging characteristics. Univariate and multivariate analyses were performed to investigate which factors were significantly associated with plaque enhancement and symptomatic ICAS. The plaque burden and CR were compared using linear regression.

RESULTS

A total of 91 patients with ICAS were enrolled in this study. ICAS plaque burden was significantly associated with plaque enhancement (p = .037), and plaque burden was linearly positively correlated with CR (R = 0.357, p = .001). ROC analysis showed that the cutoff value of CR for plaque enhancement was 0.56 (specificity of 81.8%). Both plaque enhancement and plaque burden were significantly associated with symptomatic ICAS, and only plaque enhancement was an independent risk factor after multivariate analysis.

CONCLUSION

Plaque burden was an independent risk factor for plaque enhancement and showed a linear positive correlation with CR. The cutoff value of CR for plaque enhancement was 0.56, and CR ≥ 0.56 was significantly associated with symptomatic ICAS, which was independently associated with plaque enhancement.

Incremental value of enhanced plaque length for identifying intracranial atherosclerotic culprit plaques: a high-resolution magnetic resonance imaging study

OBJECTIVES

Besides plaque enhancement grade, the incremental value of enhancement-related high-resolution MRI features in defining culprit plaques needs further evaluation. This study was focused on assessing whether plaque enhancement features contribute to culprit plaque identification and further risk stratification.

METHODS

We retrospectively studied patients who experienced an acute ischaemic stroke and transient ischaemic attack due to intracranial atherosclerosis from 2016 to 2022. The enhancement features included enhancement grade, enhanced length, and enhancement quadrant. Associations between plaque enhancement features and culprit plaques, as well as diagnostic value, were investigated using logistic regression and receiver operating characteristic analyses.

RESULTS

Overall, 287 plaques were identified, of which 231 (80.5%) and 56 (19.5%) were classified as culprit and non-culprit plaques, respectively. Comparison of the pre- and post-enhancement images revealed enhanced length longer than the plaque length in 46.32% of the culprit plaques. Multivariate logistic regression showed that enhanced length longer than plaque length (OR 6.77; 95% CI 2.47-18.51) and grade II enhancement (OR 7.00; 95% CI 1.69-28.93) were independently associated with culprit plaques. The area under the curve value for the combination of stenosis and plaque enhancement grade for the diagnosis of culprit plaques was 0.787, which increased significantly to 0.825 on the addition of enhanced length longer than the plaque length (p = 0.026 for DeLong's test).

CONCLUSIONS

Enhanced length longer than the plaque length and grade II enhancement were independently associated with culprit plaques. The combination of the enhanced plaque features resulted in better culprit plaque identification.

The incomplete circle of Willis is associated with vulnerable intracranial plaque features and acute ischemic stroke

BACKGROUND

The circle of Willis (CoW) plays a significant role in intracranial atherosclerosis (ICAS). This study investigated the relationship between different types of CoW, atherosclerosis plaque features, and acute ischemic stroke (AIS).

METHODS

We investigated 97 participants with AIS or transient ischemic attacks (TIA) underwent pre- and post-contrast 3T vessel wall cardiovascular magnetic resonance within 7 days of the onset of symptoms. The culprit plaque characteristics (including enhancement grade, enhancement ratio, high signal in T1, irregularity of plaque surface, and normalized wall index), and vessel remodeling (including arterial remodeling ratio and positive remodeling) for lesions were evaluated. The anatomic structures of the anterior and the posterior sections of the CoW (A-CoW and P-CoW) were also evaluated. The plaque features were compared among them. The plaque features were also compared between AIS and TIA patients. Finally, univariate and multivariate regression analysis was performed to evaluate the independent risk factors for AIS.

RESULT

Patients with incomplete A-CoW showed a higher plaque enhancement ratio (P = 0.002), enhancement grade (P = 0.01), and normalized wall index (NWI) (P = 0.018) compared with the patients with complete A-CoW. A higher proportion of patients with incomplete symptomatic P-CoW demonstrated more culprit plaques with high T1 signals (HT1S) compared with those with complete P-CoW (P = 0.013). Incomplete A-CoW was associated with a higher enhancement grade of the culprit plaques [odds ratio (OR):3.84; 95% CI: 1.36-10.88, P = 0.011], after adjusting for clinical risk factors such as age, sex, smoking, hypertension, hyperlipemia, and diabetes mellitus. Incomplete symptomatic P-CoW was associated with a higher probability of HT1S (OR:3.88; 95% CI: 1.12-13.47, P = 0.033), after adjusting for clinical risk factors such as age, sex, smoking, hypertension, hyperlipemia, and diabetes mellitus. Furthermore, an irregularity of the plaque surface (OR: 6.24; 95% CI: 2.25-17.37, P < 0.001), and incomplete symptomatic P-CoW (OR: 8.03, 95% CI: 2.43-26.55, P = 0.001) were independently associated with AIS.

CONCLUSIONS

This study demonstrated that incomplete A-CoW was associated with enhancement grade of the culprit plaque, and incomplete symptomatic side P-CoW was associated with the presence of HT1S of culprit plaque. Furthermore, an irregularity of plaque surface and incomplete symptomatic side P-CoW were associated with AIS.

Intracranial atherosclerotic plaque enhancement and long-term risk of future strokes: A prospective, longitudinal study

BACKGROUND AND PURPOSE

The prognostic significance of postcontrast enhancement of intracranial atheromatous plaque is uncertain. Prospective, long-term follow-up studies in Caucasians, using a multicenter design, are lacking. We aimed to evaluate whether this radiological sign predicts long-term new stroke in symptomatic and asymptomatic intracranial atherosclerotic disease (ICAD) patients.

METHODS

This was a prospective, observational, longitudinal, multicenter study. We included a symptomatic and an asymptomatic cohort of ICAD patients that underwent 3T MRI including high-resolution sequences focused on the atheromatous plaque. We evaluated grade of stenosis, plaque characteristics, and gadolinium enhancement ratio (postcontrast plaque signal/postcontrast corpus callosum signal). The occurrence of new events was evaluated at 3, 6, 9, and 12 months and annually thereafter. The association between plaque characteristics and new stroke was studied using Cox multiple regression survival analysis and Kaplan-Meier curves.

RESULTS

Forty-eight symptomatic and 13 asymptomatic patients were included. During 56.3 ± 16.9 months, 11 patients (18%) suffered a new event (seven ischemic, two hemorrhagic, and two transient ischemic attacks). A receiver operating characteristic curve identified an enhancement ratio of >1.77 to predict a new event. In a multivariable Cox regression, postcontrast enhancement ratio >1.77 (hazard ratio [HR]= 3.632; 95% confidence interval [CI], 1.082-12.101) and cerebral microbleeds (HR = 5.244; 95% CI, 1.476-18.629) were independent predictors of future strokes. Patients with a plaque enhancement ratio >1.77 had a lower survival free of events (p < .05).

CONCLUSIONS

High intracranial postcontrast enhancement is a long-term predictor of new stroke in ICAD patients. Further studies are needed to elucidate whether postcontrast enhancement reflects inflammatory activity of intracranial atheromatous plaque.

Characteristics of culprit intracranial plaque without substantial stenosis in ischemic stroke using three-dimensional high-resolution vessel wall magnetic resonance imaging

Background and aims

We aim to analyze the difference in quantitative features between culprit and non-culprit intracranial plaque without substantial stenosis using three-dimensional high-resolution vessel wall MRI (3D hr-vw-MRI).

Methods

The patients with cerebral ischemic symptoms of the unilateral anterior circulation were recruited who had non-stenotic intracranial atherosclerosis (<50%) confirmed by computed tomographic angiographic (CTA) or magnetic resonance angiography (MRA). All patients underwent 3D hr-vw MRI within 1 month after symptom onset. 3D hr-vw-MRI characteristics, including wall thickness, plaque burden, enhancement ratio, plaque volume and intraplaque hemorrhage, and histogram features were analyzed based on T2-, precontrast T1-, and post-contrast T1-weighted images. Univariate and multivariate logistic regression analysis were used to identify key determinates differentiating culprit and non-culprit plaques and to calculate the odds ratios (ORs) with 95% confidence intervals (CIs).

Results

A total of 150 plaques were identified, of which 133 plaques (97 culprit and 36 non-culprit) were in the middle cerebral artery, three plaques (all culprit) were in the anterior cerebral artery (ACA) and 14 (11 culprit and three non-culprit) were in the internal carotid artery (ICA). Of all the quantitative parameters analyzed, plaque volume, maximum wall thickness, minimum wall thickness, plaque burden, enhancement ratio, coefficient of variation of the most stenotic site, enhancement ratio of whole culprit plaque in culprit plaques were significantly higher than those in non-culprit plaques. Multivariate logistic regression analysis found that plaque volume [OR, 1.527 (95% CI, 1.231-1.894); P < 0.001] and enhancement ratio of whole plaque [OR, 1.095 (95% CI, 1.021-1.175); P = 0.011] were significantly associated with culprit plaque. The combination of the two features obtained a better diagnostic efficacy for culprit plaque with sensitivity and specificity (0.910 and 0.897, respectively) than each of the two parameters alone.

Conclusion

3D hr-vw MRI features of intracranial atherosclerotic plaques provided potential values over prediction of ischemic stroke patients with non-stenotic arteries. The plaque volume and enhancement ratio of whole plaque of stenosis site were found to be effective predictive parameters.