Regression of Plaque Enhancement Within Symptomatic Middle Cerebral Artery Atherosclerosis: A High-Resolution MRI Study

Association of vulnerable plaques with white matter hyperintensities on high-resolution magnetic resonance imaging

Background

One of the widespread manifestations of cerebral small vessel disease (CSVD) of the brain parenchyma is white matter lesion, which appears as white matter hyperintensities (WMHs) on magnetic resonance imaging (MRI). Previous studies have illustrated that large artery atherosclerosis is related to CSVD, but the precise progress of pathogenesis remains unknown. High-resolution MRI (HR-MRI) has the ability to delineate intracranial vascular walls, enabling a thorough exploration of the structure and composition of unstable plaques. This study aimed to apply HR-MRI to characterize the wall changes and plaque characteristics of middle cerebral arteries in patients with WMHs and to investigate the correlation between plaque vulnerability parameters and different degrees of WMHs.

Methods

In this study, 138 patients with acute ischemic stroke at Harbin Medical University's First Clinical Hospital (May 2021 to October 2023) were cross-sectionally reviewed and underwent conventional brain and HR-MRI using T1-weighted 3D volumetric isotropic turbo spin echo acquisition (T1W-3D-VISTA) of the unilateral middle cerebral artery (MCA). According to Fazekas grade (0-6), the patients were divided into two groups: Fazekas score 0-2, no-or-mild WMHs; and Fazekas 3-6, moderate-to-severe WMHs. The intraplaque hemorrhage, plaque distribution, plaque enhancement, plaque load, remodeling pattern, and stenosis of the two groups were measured. Binary logistic regression analysis was conducted to evaluate the relationship between vulnerable plaques and WMHs.

Results

Of the participants who were initially considered for inclusion, 71 were deemed eligible, among whom 34 were placed in the no-or-mild WMH group and 37 in the moderate-to-severe WMH group. Between the two groups, there were significant differences in intraplaque hemorrhage (P=0.01), a wide distribution (P=0.02), and plaque enhancement (P=0.02). Univariate analysis showed that WMHs were associated with age [odds ratio (OR) =1.080; 95% confidence interval (CI): 1.020-1.144; P=0.008], hypertension (OR =3.500; 95% CI: 1.276-9.597; P=0.01), intraplaque hemorrhage (OR =3.955; 95% CI: 1.247-12.538; P=0.02), a wide distribution (OR =3.067; 95% CI: 1.159-8.115; P=0.02), and significant plaque enhancement (OR =4.372; 95% CI: 1.101-17.358; P=0.03); however, the multivariate results showed that the only independent factors associated with WMHs were age (OR =1.095; 95% CI: 1.019-1.176; P=0.01) and intraplaque hemorrhage (OR =5.88; 95% CI: 1.466-23.592; P=0.01).

Conclusions

Our findings suggest that age and intraplaque hemorrhage may be associated with more severe WMHs in patients with acute ischemic stroke, which may be helpful for further clinical examination and intervention treatment.

MR Vessel Wall Imaging for Atherosclerosis and Vasculitis

Conventional imaging modalities, such as computed tomography angiography, MR angiography, transcranial Doppler ultrasonography, and digital subtraction angiography, are utilized in evaluating intraluminal or intravascular pathology of the intracranial vessels. Limitations of luminal imaging techniques can lead to inaccurate diagnosis, evaluation, and risk stratification, as many cerebrovascular pathologies contain an extrinsic vessel wall component. Furthermore, vessel wall imaging can provide information regarding extent, treatment response, and biopsy targets for vasculitis cases. Overall, while vessel wall imaging can provide robust data regarding intracranial pathologies, further prospective, multicenter studies are required to improve diagnostic application and accuracy.

Association of plaque characteristics with long-term stroke recurrence in patients with intracranial atherosclerotic disease: a 3D high-resolution MRI-based cohort study

OBJECTIVES

To evaluate the predictive ability of plaque characteristics for long-term stroke recurrence among patients with symptomatic intracranial atherosclerotic disease (ICAD).

METHODS

This cohort study included 132 patients with acute ischemic stroke (AIS) attributed to ICAD who were recruited between July 2017 and December 2020 and followed until stroke recurrence or December 2021. Plaque surface irregularity, degree of stenosis, plaque burden, remodeling ratio, enhancement ratio, and intraplaque hemorrhage were assessed with 3-dimensional high-resolution magnetic resonance vessel wall imaging (3D HR-MRI). Data were analyzed using Cox models, receiver operating characteristic (ROC) curves, and Kaplan-Meier survival analysis.

RESULTS

Of the 132 patients, during a median follow-up of 2.8 years, stroke recurrence occurred in 35 patients. The multivariable-adjusted hazard ratio (95% confidence interval) of stroke recurrence was 3.15 (1.34-7.42) per 10% increase in plaque burden and 2.17 (1.27-3.70) for enhancement ratio. The area under the curve (AUC) to predict stroke recurrence was 0.725 (95% CI 0.629-0.822) for plaque burden, 0.692 (95% CI 0.593-0.792) for enhancement ratio, and only 0.595 (95% CI 0.492-0.699) for the Essen stroke risk score. The Kaplan-Meier survival analysis further demonstrated significant differences in survival of free recurrent stroke between patients with plaque burden or enhancement ratio below and above the optimum cut-offs (both p < 0.001).

CONCLUSION

Higher plaque burden and enhancement ratio are independent risk factors for long-term stroke recurrence among patients with symptomatic ICAD, and valuable imaging markers for predicting and stratifying risk of stroke recurrence.

CLINICAL RELEVANCE STATEMENT

In patients with symptomatic ICAD, the results of this high-resolution magnetic resonance vessel wall imaging study have potential implications for optimal management of intracranial plaques and secondary prevention of stroke recurrence based on plaque burden and enhancement ratio.

KEY POINTS

• Identification of intracranial plaque characteristics responsible for stroke recurrence is essential to preventing stroke recurrence in patients with symptomatic intracranial atherosclerotic disease. • Higher plaque burden and enhancement ratio are independent risk factors for stroke recurrence. • Plaque burden and enhancement ratio are valuable imaging markers in the prediction and stratification of the risk of stroke recurrence.

Differences in intracranial atherosclerosis plaque between posterior circulation and anterior circulation on high-resolution magnetic resonance imaging: A systematic review and meta-analysis

OBJECTIVE

The clinical characteristics and mechanisms of stroke caused by anterior circulation atherosclerotic plaques (ACAPs) and posterior circulation atherosclerotic plaques (PCAPs) are distinct. We aimed to compare the differences in vulnerability, morphology, and distribution between ACAPs and PCAPs based on hign-resolution magnetic resonance imaging (HR-MRI).

MATERIALS AND METHODS

The PubMed, Embase, Cochrane Library, China National Knowledge Infrastructure (CNKI), and Wanfang database were retrieved from inception through May 2023. Meta-analysis was performed by R 4.2.1 software. The quality of the literature was assessed by the Agency for Healthcare Research and Quality (AHRQ). Subgroup analysis was conducted to explore the heterogeneity of the pooled results.

RESULTS

There were a total of 13 articles, including 1194 ACAPs and 1037 PCAPs. The pooled estimates demonstrated that the incidence of intraplaque hemorrhage in the PCAPs was higher (OR 1.72, 95%CI 1.35-2.18). The plaque length (SMD 0.23, 95%CI 0.06-0.39) and remodeling index (SMD 0.29, 95%CI 0.14-0.44) of PCAPs were larger than those in ACAPs. However, there were no evident differences in significant enhancement or stenosis degree between the two groups.

CONCLUSION

There were more unstable features in PCAPs, highlighting an elevated risk of recurrent ischemic stroke in the posterior circulation. Furthermore, PCAPs were prone to developing penetrating artery disease due to their wider distribution. Nevertheless, posterior circulation arteries exhibited a greater propensity for outward remodeling, which may lead treatment team to miss the optimal intervention stage by being overlooked on angiographic detection.

HDL subfractions determined by microfluidic chip electrophoresis predict the vulnerability of intracranial plaque: A HRMRI study

AIM

High-density lipoprotein (HDL) can be divided into several subfractions based on density, size and composition. Accumulative evidence strongly suggests that the subfractions of HDL have very different roles in the pathogenesis of atherosclerosis. The purpose of this study was to further delineate the relationship between HDL subfractions extracted by microfluidic chip electrophoresis and the vulnerability of plaques in patients with intracranial atherosclerosis with a high-resolution magnetic resonance imaging (HRMRI) study.

METHODS

We prospectively enrolled patients with single atherosclerotic plaque in the middle cerebral artery (MCA) or basilar artery (BA) between July 2020 and Dec 2022 and performed 3-tesla HRMRI on the relevant artery. The HDL cholesterol concentration and HDL subfractions (HDL-2a, HDL-2b and HDL-3) percentage were analyzed in serum samples from the same patients by electrophoresis on a microfluidics system.

RESULTS

A total of 81 MCA or BA plaques [38 (46.9%) symptomatic and 43 (53.1%) asymptomatic] in 81 patients were identified on HRMRI. Patients with symptomatic plaques had a significantly lower HDL-2b level than asymptomatic plaques [symptomatic vs. asymptomatic: 0.16 (0.10-0.18) vs. 0.27(0.21-0.34), p = 0.001]. After adjusting for demographics and vascular risk factors, logistic regression showed that HDL-2b was inversely associated with asymptomatic plaques (B = -0.04, P = 0.017). According to receiver operating characteristic (ROC) curve model analysis, the cutoff point of HDL-2b in predicting asymptomatic plaques was 0.21 mmol/L (Area under curve: 0.719, specificity: 73.7%, sensitivity: 72.1%). Furthermore, plaque enhancement on HRMRI (P < 0.001), positive remodeling (P < 0.001), plaque load (P < 0.001) and luminal stenosis (P < 0.001) were superior among patients with HDL-2b < 0.21 mmol/L.

CONCLUSIONS

Our data showed that serum HDL-2b levels may serve as a biomarker for predicting vulnerability in intracranial atherosclerotic plaques.

A Non-Linear Role of Hyperlipidemia on Progression of Intracranial Atherosclerotic Plaques and Acute Downstream Ischemic Events

AIM

Intracranial atherosclerotic stenosis (ICAS) is the leading cause of ischemic stroke worldwide. Hyperlipidemia is a major contributor to atherosclerosis. However, the effect of hyperlipidemia on the evolution of intracranial atherosclerotic plaques and downstream ischemic episodes remains unclear. In this study, we aimed to assess the radiological features of ICAS plaques and to explore the relationship between hyperlipidemia and plaque progression.

METHODS

We included people with ICAS (≥50% stenosis) undergoing high-resolution magnetic resonance imaging. The culprit plaque was defined as the sole, or in case of multiple stenosis, the narrowest plaque on the intracranial artery responsible for acute ischemic stroke. Demographic, clinical data, plaque features on MRI, and lipid parameters were compared between culprit and non-culprit plaques. Plaque enhancement was graded as Grade 0, 1 and 2 by comparing to the adjacent normal vessel wall and pituitary funnel after contrast enhancement on T1-weighted sequences.

RESULTS

162 patients were included (mean age 57.7±12.1 years, male 61.6%), 110 of whom were identified as culprit plaque with an ipsilateral acute stroke. High-grade enhancement was the most prominent MRI feature of the culpable plaque (Grade-2: OR 6.539, 95%CI 1.706-23.707, p=0.006). LDL cholesterol was significantly associated with overall acute ischemic stroke caused by culprit plaque. After stratification by enhancement grading LDL was independently associated with ischemic events in Grade-1 enhancement plaques (OR 6.778, 95%CI 2.122-21.649, p=0.001). In patients with Grade-2 enhancement plaques, however, LDL was not associated with ischemic event; in contrast, Neutrophil/Lymphocyte ratio was independently associated with ischemic events caused by Grade-2 enhancement plaques (OR 2.188, 95%CI 1.209-3.961, p=0.010).

CONCLUSIONS

LDL was related with ischemia events in intermediate stage of intracranial atherosclerotic plaque progression, an excellent period for intensive lipid-lowering treatment. In advanced stage, inflammatory agents maybe the main contributor to ischemic events.

Predicting acute ischemic stroke using the revised Framingham stroke risk profile and multimodal magnetic resonance imaging

Background and purpose

Patients with transient ischemic attacks (TIA) have a significant risk of developing acute ischemic strokes (AIS), emphasizing the critical need for hierarchical management. This study aims to develop a clinical-imaging model utilizing multimodal magnetic resonance imaging (mMRI) and the revised Framingham Stroke Risk Profile (FSRP) to predict AIS and achieve early secondary prevention.

Methods

mMRI scans were conducted on patients with symptomatic intracranial atherosclerotic disease (ICAD) to assess vascular wall features and cerebral perfusion parameters. Based on diffusion-weighted imaging (DWI), patients were divided into two groups: TIA and AIS. Clinical data were evaluated to calculate the FSRP score. Differences in clinical and imaging characteristics between the groups were analyzed, and a predictive model for AIS probability in patients with ICAD was established.

Results

A total of 112 TIA and AIS patients were included in the study. The results showed that the AIS group had higher proportions of FSRP-high risk, hyperhomocysteinemia, and higher value of low-density lipoprotein (LDL), standardized plaque index (SQI), and enhancement rate (ER) compared to the TIA group (p < 0.05). Mean transit time (MTT) and time to peak (TTP) in the lesion area were significantly longer in the AIS group (p < 0.05). Multivariate analysis identified FSRP-high risk (p = 0.027) and high ER (p = 0.046) as independent risk factors for AIS. The combined clinical and mMRI model produced an area under the curve (AUC) of 0.791 in receiver operating characteristic (ROC) analysis. The constructed nomogram model combining clinical and mMRI features demonstrated favorable clinical net benefits.

Conclusion

FSRP-high risk and high ER were confirmed as independent risk factors for AIS. The combined prediction model utilizing clinical and imaging markers effectively predicts stroke risk in symptomatic ICAD patients.

Multimodal MRI study of the relationship between plaque characteristics and hypoperfusion in patients with transient ischemic attack

Objective

Transient ischemic attack is a significant risk factor for acute cerebral infarction. Previous studies have demonstrated that hypoperfusion in patients with transient ischemic attack was associated with the recurrence of transient ischemic attack, stroke, and persistent worsening of neurological symptoms. Moreover, transient ischemic attack patients classified as high-risk group according to the ABCD2 score have a higher incidence of stroke. Therefore, the objective of this study was to investigate the plaque characteristics of transient ischemic attack patients with concomitant cerebral hypoperfusion using multimodal MRI, as well as hemodynamic changes in the high-risk group with transient ischemic attack patients.

Materials and methods

A total of 151 patients with transient ischemic attack were prospectively recruited for this study. All enrolled patients underwent multimodal MRI, including DWI, TOF-MRA, HR-VWI, and DSC-PWI. Finally, 56 patients met the inclusion criteria. Based on DSC-PWI images, patients were divided into two groups: hypoperfusion (n = 41) and non-hypoperfusion (n = 15). Clinical baseline characteristics and plaque characteristics were analyzed between the two groups. Furthermore, within the hypoperfusion group, patients were further classified into low-risk (n = 11) and high-risk (n = 30) subgroups based on the ABCD2 score. Hemodynamic differences between these subgroups were also analyzed.

Results

Compared with the non-hypoperfusion group, the hypoperfusion group had a significantly higher prevalence of hypertension (68.3% vs. 33.3%, p = 0.019) and hyperhomocysteinemia (65.9% vs. 33.3%, p = 0.029). Moreover, the hypoperfusion group exhibited more significant luminal stenosis degree [41.79 ± 31.36 vs. 17.62± 13.62, p = 0.006] and greater NWI (57.1%± 20.47% vs. 40.21%± 21.56%, p = 0.009) compared to the non-hypoperfusion group. In addition, the high-risk group identified by the ABCD2 score had a higher rMTT [117.6(109.31-128.14) vs. 108.36(100.67-119.92), p = 0.037].

Conclusion

Transient ischemic attack patients with hypoperfusion exhibited a higher prevalence of hypertension and hyperhomocysteinemia, as well as higher luminal stenosis degree, and greater NWI. Furthermore, Transient ischemic attack patients in the high-risk group demonstrated higher MTT.

Refined imaging features of culprit plaques improve the prediction of recurrence in intracranial atherosclerotic stroke within the middle cerebral artery territory

Recurrence is a significant adverse outcome of ischemic stroke (IS), particularly in cases of intracranial arteriosclerosis (ICAS). In this study, we investigated the impact of imaging features of culprit plaque using high-resolution magnetic resonance vessel wall imaging (HR-MR-VWI) on the prediction of IS recurrence. A total of 86 patients diagnosed with ICAS-related IS within the middle cerebral artery (MCA) territory were included, of which 23.25% experienced recurrent IS within one year. Our findings revealed significant differences between the recurrence and non-recurrence groups in terms of age (p = 0.007), diabetes mellitus (p = 0.031), hyperhomocysteinemia (p = 0.021), artery-artery embolism (AAE) infarction (p = 0.019), prominent enhancement (p = 0.013), and surface irregularity of the culprit plaque (p = 0.009). Age (HR = 1.063, p = 0.005), AAE infarction (HR = 5.708, p = 0.008), and prominent enhancement of the culprit plaque (HR = 4.105, p = 0.025) were identified as independent risk factors for stroke recurrence. The areas under the receiver operating characteristic curve (AUCs) for predicting IS recurrence using clinical factors, conventional imaging findings, HR-MR-VWI plaque features, and a combination of clinical and conventional imaging models were 0.728, 0.645, 0.705, and 0.814, respectively. Notably, the combination model demonstrated superior predictive performance with an AUC of 0.870. Similarly, AUC of combination model for predicting IS recurrence in validation cohort which enrolled another 37 patients was 0.865. In conclusion, the presence of obvious enhancement in culprit plaque on HR-MR-VWI is a valuable factor in predicting IS recurrence in ICAS-related strokes within the MCA territory. Furthermore, our combination model, incorporating plaque features, exhibited improved prediction accuracy.

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.

The fibrinogen-to-albumin ratio is associated with intracranial atherosclerosis plaque enhancement on contrast-enhanced high-resolution magnetic resonance imaging

Background

Contrast-enhanced high-resolution magnetic resonance imaging (CE-HR-MRI) is a useful imaging modality to assess vulnerable plaques in intracranial atherosclerotic stenosis (ICAS) patients. We studied the relationship between the fibrinogen-to-albumin ratio (FAR) and plaque enhancement in patients with ICAS.

Methods

We retrospectively enrolled consecutive ICAS patients who had undergone CE-HR-MRI. The degree of plaque enhancement on CE-HR-MRI was evaluated both qualitatively and quantitatively. Enrolled patients were classified into no enhancement, mild enhancement, and obvious enhancement groups. An independent association of the FAR with plaque enhancement was identified by multivariate logistic regression and receiver operating characteristic (ROC) curve analyses.

Results

Of the 69 enrolled patients, 40 (58%) were classified into the no/mild enhancement group, and 29 (42%) into the obvious enhancement group. The obvious enhancement group had a significantly higher FAR than the no/mild enhancement group (7.36 vs. 6.05, p = 0.001). After adjusting for potential confounders, the FAR was still significantly independently associated with obvious plaque enhancement in multiple regression analysis (odds ratio: 1.399, 95% confidence interval [CI]: 1.080-1.813; p = 0.011). ROC curve analysis revealed that FAR >6.37 predicted obvious plaque enhancement with 75.86% sensitivity and 67.50% specificity (area under the ROC curve = 0.726, 95% CI: 0.606-0.827, p < 0.001).

Conclusion

The FAR can serve as an independent predictor of the degree of plaque enhancement on CE-HR-MRI in patients with ICAS. Also, as an inflammatory marker, the FAR has potential as a serological biomarker of intracranial atherosclerotic plaque vulnerability.

Vessel Wall Imaging in Cryptogenic Stroke

Cryptogenic strokes are symptomatic cerebral ischemic infarcts without a clear etiology identified following standard diagnostic evaluation and currently account for 10% to 40% of stroke cases. Continued research is needed to identify and bridge gaps in knowledge of this stroke grouping. Vessel wall imaging has increasingly shown its utility in the diagnosis and characterization of various vasculopathies. Initial promising evidence suggests rational use of vessel wall imaging in stroke workup may unravel pathologies that otherwise would have been occult and further improve our understanding of underlying disease processes that can translate into improved patient outcomes and secondary stroke prevention.

Identifying vulnerable plaques: A 3D carotid plaque radiomics model based on HRMRI

Background

Identification of vulnerable carotid plaque is important for the treatment and prevention of stroke. In previous studies, plaque vulnerability was assessed qualitatively. We aimed to develop a 3D carotid plaque radiomics model based on high-resolution magnetic resonance imaging (HRMRI) to quantitatively identify vulnerable plaques.

Methods

Ninety patients with carotid atherosclerosis who underwent HRMRI were randomized into training and test cohorts. Using the radiological characteristics of carotid plaques, a traditional model was constructed. A 3D carotid plaque radiomics model was constructed using the radiomics features of 3D T₁-SPACE and its contrast-enhanced sequences. A combined model was constructed using radiological and radiomics characteristics. Nomogram was generated based on the combined models, and ROC curves were utilized to assess the performance of each model.

Results

48 patients (53.33%) were symptomatic and 42 (46.67%) were asymptomatic. The traditional model was constructed using intraplaque hemorrhage, plaque enhancement, wall remodeling pattern, and lumen stenosis, and it provided an area under the curve (AUC) of 0.816 vs. 0.778 in the training and testing sets. In the two cohorts, the 3D carotid plaque radiomics model and the combined model had an AUC of 0.915 vs. 0.835 and 0.957 vs. 0.864, respectively. In the training set, both the radiomics model and the combination model outperformed the traditional model, but there was no significant difference between the radiomics model and the combined model.

Conclusions

HRMRI-based 3D carotid radiomics models can improve the precision of detecting vulnerable carotid plaques, consequently improving risk classification and clinical decision-making in patients with carotid stenosis.

The lymphocyte-to-monocyte ratio predicts intracranial atherosclerotic stenosis plaque instability

Background and purpose

Gadolinium enhancement on high-resolution vessel wall imaging (HR-VWI) is an imaging marker of intracranial atherosclerotic stenosis (ICAS) plaque instability. This study aimed to evaluate the relationships between hematological inflammatory indicators and the enhancement of ICAS plaques and to search for hematological indicators that can predict ICAS plaque instability.

Methods

Consecutive adult patients diagnosed with ICAS from April 2018 to December 2021 were recruited retrospectively, and every patient underwent HR-VWI. Plaque enhancement was measured qualitatively and quantitatively. The plaque-to-pituitary stalk contrast ratio (CR) indicated the degree of plaque enhancement. Clinical and laboratory data, including the lymphocyte-to-monocyte ratio (LMR), neutrophil-to-lymphocyte ratio (NLR), and systemic immune inflammation index (SII), were recorded. The hematological inflammatory indicators were compared between ICAS patients with and without plaque enhancement and between patients with and without symptomatic plaque. The hematological inflammatory indicators and the CR were compared using linear regression. Furthermore, receiver operating characteristic curve analysis was performed to assess the discriminative abilities of the inflammatory indicators to predict plaque instability.

Results

Fifty-nine patients were included. The NLR, SII and LMR were significantly correlated with plaque enhancement. The LMR was independently associated with plaque enhancement, and a linear negative correlation was observed between the LMR and CR (R = 0.716, P < 0.001). The NLR, LMR, plaque enhancement and CR were significantly associated with symptomatic ICAS, and the LMR and plaque enhancement were independent risk factors for symptomatic ICAS. The optimal cutoff value of the admission LMR to distinguish symptomatic plaque from asymptomatic plaque was 4.0 (80.0% sensitivity and 70.6% specificity).

Conclusion

The LMR was independently associated with ICAS plaque enhancement and showed a linear negative correlation with CR. The LMR and plaque enhancement were independent risk factors for symptomatic ICAS. An LMR ≤ 4.0 may predict ICAS plaque instability.

The MRI enhancement ratio and plaque steepness may be more accurate for predicting recurrent ischemic cerebrovascular events in patients with intracranial atherosclerosis

OBJECTIVES

To assess the complementary value of high-resolution multi-contrast MRI (hrMRI) in identifying symptomatic patients with intracranial atherosclerosis (ICAS) who are likely to experience recurrent ischemic cerebrovascular events.

METHODS

In this retrospective cohort study, eighty patients with acute ischemic events attributed to ICAS who underwent hrMRI examination between January 2015 and January 2019 were included. Median follow-up for all patients was 30 months (range: 1 to 52 months) and recurrent ischemic cerebrovascular events were recorded. Cox regression analysis and time-dependent ROC were performed to quantify the association between the plaque characteristics and recurrent events.

RESULTS

During the follow-up, 14 patients experienced recurrent ischemic cerebrovascular events. Young males and those with diabetes and poor medication persistence were more likely to experience recurrent events. ICAS in patients with recurrence had significantly higher enhancement ratio and steepness which is defined as the ratio between the plaque height and length than those without (p < 0.001 and p = 0.015, respectively). After adjustment of clinical factors, enhancement ratio (HR, 13.13 [95% CI, 3.58-48.20], p < 0.001) and plaque steepness (HR, 110.27 [95% CI, 4.75-2560.91], p = 0.003) were independent imaging biomarkers associated with recurrent events. Time-dependent ROC indicated that integrated high enhancement ratio and steepness into clinical risk factors improved discrimination power with the ROC increased from 0.79 to 0.94 (p = 0.008).

CONCLUSIONS

The enhancement ratio and plaque steepness improved the accuracy over traditional clinical risk factors in predicting recurrent ischemic cerebrovascular events for patients with ICAS.

KEY POINTS

• High-resolution magnetic resonance imaging helps clinicians to evaluate high-risk Intracranial plaque. • The higher enhancement ratio and plaque steepness (= height/length) were the primary biomarkers associated with future ischemic cerebrovascular events. • High-resolution magnetic resonance imaging combined with clinical characteristics showed a higher accuracy for the prediction of recurrent events in patients with intracranial atherosclerosis.

Follow-up assessment of atherosclerotic plaques in acute ischemic stroke patients using high-resolution vessel wall MR imaging

PURPOSE

Data on evolution of intracranial plaques in acute ischemic stroke patients after receiving medical therapy is still limited. We aimed to investigate the plaque features associated with culprit lesions and to explore the plaque longitudinal changes during treatment using high-resolution vessel wall MR imaging (VW-MRI).

METHODS

Twenty-three patients (16 men; mean age, 51.4 years ± 11.1) with acute ischemic stroke underwent 3-T VW-MRI for intracranial atherosclerosis and were taken follow-up assessments. Each identified plaque was retrospectively classified as culprit, probably culprit, or nonculprit. Plaque features were analyzed at both baseline and follow-up and were compared using paired t-test, paired Wilcoxon test, or McNemar's test.

RESULTS

A total of 87 intracranial plaques were identified (23 [26.4%] culprit, 10 [11.5%] probably culprit, and 54 [62.1%] nonculprit plaques). The median time interval between initial and follow-up MRI scans was 8.0 months. In the multiple ordinal logistic regression analysis, plaque contrast ratio (CR) (OR, 1.037; 95% CI, 1.013-1.062; P = 0.002) and surface irregularity (OR, 4.768; 95% CI, 1.064-21.349; P = 0.041) were independently associated with culprit plaques. During follow-up, plaque length, maximum thickness, normalized wall index (NWI), stenosis degree, and CR significantly decreased (all P-values < 0.05) in the culprit plaque group. The plaque NWI and CR dropped in the probably culprit plaques (P = 0.041, 0.026, respectively). In the nonculprit plaque group, only plaque NWI and stenosis degree showed significant decrement (P = 0.017, 0.037, respectively).

CONCLUSION

Follow-up VW-MRI may contribute to plaque risk stratification and may provide valuable insights into the evolution of different plaques in vivo.

Symptomatic plaque enhancement is associated with early-onset post-stroke depression

BACKGROUND

The association between imaging features closely associated with symptomatic intracranial atherosclerotic plaques and early-onset post-stroke depression (PSD) is currently unclear.

MATERIALS AND METHODS

76 ischemic stroke patients who underwent high-resolution vessel wall magnetic resonance imaging (HR-VWI) were divided into PSD and non-PSD groups according to their DSM-V diagnoses and HAMD-17 scores at 14 days after onset. Clinical data and the imaging features associated with symptomatic plaques (including the enhancement index (EI), remodeling index, and plaque surface irregularity) were compared between groups. Multifactorial logistic regression analysis was used to find independent predictors of early-onset PSD. Spearman rank correlation analysis explores the association between clinical data, symptomatic plaque imaging features, and HAMD-17 in patients.

RESULTS

The sample comprised 36 patients with early-onset PSD. The symptomatic plaque EI and infarct volume were significantly higher in depressed patients than in patients without depression (P < 0.05). Multivariate logistic regression showed that symptomatic plaque EI could be used as an independent predictor of early-onset PSD after correcting for the confounding factor of infarct volume (OR = 1.034, 95% CI:1.014-1.055, P = 0.001). In the total sample, symptomatic plaque EI, infarct volume, and HAMD-17 had a significant positive correlation with each other (P < 0.05).

LIMITATIONS

This study focused only on the patients' symptomatic plaques and did not monitor patients' systemic inflammation levels at the time of HR-VWI.

CONCLUSIONS

The degree of symptomatic plaque enhancement is an independent predictive imaging marker of early-onset PSD and can be used the early diagnosis of early-onset PSD.

Intracranial Arterial Calcification and Intracranial Atherosclerosis: Close but Different

Background and Purpose

Intracranial arterial calcification (IAC) may be present in the intimal or medial arterial layer. This study aimed to elucidate the link between the calcification and atherosclerotic disease in the intracranial vasculature.

Methods

Consecutive patients with acute ischemic stroke were included. Bilateral intracranial segment of the internal carotid artery, M1 segment of the middle cerebral artery, intracranial segment of the vertebral artery, and the basilar artery were visualized by the multi-detector computed tomography (CT) and vessel-wall magnetic resonance imaging (vwMRI) within 14 days after stroke onset. IAC was into the intimal or medial pattern. Subsequently, on the vwMRI, we assessed the luminal stenosis, eccentricity, plaque burden, and intraplaque hemorrhage (IPH) as markers of atherosclerosis at each IAC site.

Results

Among 69 patients with stroke, IAC was identified in 35% of (161/483) artery segments, of which 61.5% were predominantly intimal calcification and 38.5% were predominantly medial calcification. About 79.8% of intimal calcifications and 64.5% of medial calcifications co-existed with atherosclerotic plaques. Intimal calcification was associated with luminal stenosis (p = 0.003) caused by atherosclerotic lesions. Compared with the medial IAC, intimal IAC was more often accompanied by eccentric plaques (p = 0.02), larger plaque burden (p = 0.001), and IPH (p = 0.001).

Conclusion

Our multimodal imaging-based comparison study on intracranial arteriosclerosis demonstrated that intimal IAC, compared with medial IAC, was more often accompanied by the luminal stenosis, larger plaque burden, eccentricity, and IPH, providing strong evidence for clinical evaluation on the mechanism, risk, and prognosis of ischemic stroke.

Vertebrobasilar Junction Angle Over 90°: A Potential Imaging Marker Associated With Vertebrobasilar Atherosclerosis

Objective: Whether the cerebral vascular variations play an important role in the progression of intracranial atherosclerosis is yet largely unclear. We aimed to investigate the relationship between the magnitude of the vertebrobasilar junction (VBJ) angle and the imaging features of vertebrobasilar artery atherosclerosis.

Methods: Adult patients with acute ischemic stroke or transient ischemic attack undergoing a 3.0-tesla vessel wall magnetic resonance imaging (VW-MRI) scanning were consecutively included. Imaging features of vertebrobasilar artery atherosclerosis were assessed on the reconstructed short axis of VW-MRI at the most stenotic site. The VBJ angle degree was measured on magnetic resonance angiography and classified into the angle ≥90° or <90°.

Results: Among 68 patients (mean age = 63.5 ± 9.4 years old; 63.2% were male) with vertebrobasilar atherosclerosis, 33 had a VBJ angle ≥90° and 35 had a VBJ angle <90°. Compared to the vertebrobasilar plaques with VBJ angle <90°, those with VBJ angle ≥90° had a heavier plaque burden (84.35 vs. 70.58%, p < 0.001) and higher prevalence of intraplaque hemorrhage (17.1 vs. 3.3%, p = 0.01). In the regression analyses, the VBJ angle ≥90° was also robustly associated with plaque burden (odds ratio, 1.11; 95% confidential interval, 1.043–1.18; p = 0.001) and intraplaque hemorrhage (odds ratio, 5.776; 95% confidential interval, 1.095–30.46; p = 0.039) of vertebrobasilar atherosclerosis.

Conclusion: The VBJ angle over 90° might aggravate the vessel wall condition of the atherosclerotic vertebrobasilar arteries, which might serve as a potential risk factor for vertebrobasilar atherosclerosis.

Characteristics of symptomatic plaque on high-resolution magnetic resonance imaging and its relationship with the occurrence and recurrence of ischemic stroke

BACKGROUND

Atherosclerosis is the most common cause of ischemia stroke. Computed tomographic angiography (CTA) and digital subtraction angiography (DSA) are used to evaluate the degree of lumen stenosis. However, these examinations are invasive and can only reveal mild to moderate stenosis. High-resolution magnetic resonance imaging (HRMRI) seems a more intuitive way to show the pathological changes of vascular wall. Hence, we conducted a systematic retrospective study to determine the characteristics of symptomatic plaques in patients with intracranial atherosclerosis on HRMRI and their association with the occurrence and recurrence of ischemic stroke events.

METHODS

The PubMed database was searched for relevant studies reported from January 31, 2010, to October 31, 2020.

RESULTS

We selected 14 clinical outcome studies. We found that plaque enhancement and positive remodeling on HRMRI indicate symptomatic plaques. Besides, intraplaque hemorrhage and positive remodeling index are closely related to the occurrence of stroke. However, it is still controversial whether the initial enhancement of plaque and the occurrence and recurrence of stroke are related. There is also no significant correlation between vascular stenosis and symptomatic plaque or the occurrence and recurrence of ischemic stroke.

CONCLUSION

High-resolution magnetic resonance imaging can be used as an assessment tool to predict the risk of stroke onset and recurrence in patients with atherosclerosis, but further research is also needed.

Gadolinium enhancement of atherosclerotic plaque in the intracranial artery

Background: Gadolinium enhancement on high resolution magnetic resonance imaging (HR-MRI) has been considered a sign of instability and inflammation of intracranial atherosclerotic plaques. Our research objective was to explore the relationship between the extent of plaque enhancement (PE), the degree of intracranial artery stenosis, and acute ischemic stroke events.Methods: HR-MRI was performed in 91 patients with intracranial vascular stenosis to determine the existence and intensity of PE.Results: Among 91 patients enrolled in the trial, there were 43 patients in the acute/subacute group (≤1 month from ischemic stroke event), 15 patients in the chronic group (>1 month from ischemic stroke event), and 33 patients in the non-culprit plaques group (no ischemic stroke event). A total of 105 intracranial atherosclerotic plaques were detected in 91 patients. 14 (13.3%) were mild-stenosis plaques, 22 (21.0%) were moderate-stenosis plaques, and 69 (65.7%) were severe-stenosis plaques. There were 12 (11.4%), 18 (17.1%), and 75 (71.4%) plaques in the non-enhanced plaque group, the mild-enhancement group, and the significant-enhancement group, respectively. The degree of PE among the acute/subacute group, the chronic group, and the non-culprit plaque group had a significant difference (P = 0.005). Enhanced plaques were more often observed in culprit plaques (acute/subacute group and chronic group) than non-culprit plaques (96.7% vs 77.3%). Non-enhanced plaques were more often observed in non-culprit plaques than culprit plaques (acute/subacute group and chronic group) (22.7% vs 3.3%). And 36.6% of the enhanced plaques were non-culprit plaques. After performing univariate and multivariate logistic regression analysis, the results showed that strong plaque enhancement (P = 0.025, odds ratio [OR] 3.700, 95% confidence interval [95% CI] 1.182-11.583) and severe stenosis (P = 0.008, OR 4.393, 95%CI 1.481-13.030) were significantly associated with acute ischemic events.Conclusion: Enhanced plaques were more often observed in culprit plaques, and non-enhanced plaques were more often observed in non-culprit plaques. Moreover, significant plaque enhancement and severe ICAS were closely associated with acute ischemic events.

Understanding the Clinical Implications of Intracranial Arterial Calcification Using Brain CT and Vessel Wall Imaging

Background and Purpose: Intracranial arterial calcification (IAC) has been the focus of much attention by clinicians and researchers as an indicator of intracranial atherosclerosis, but correlations of IAC patterns (intimal or medial) with the presence of atherosclerotic plaques and plaque stability are still a matter of debate. Our study aimed to assess the associations of IAC patterns identified on computed tomography (CT) with the presence of plaque detected on vessel wall magnetic resonance imaging and plaque stability. Materials and Methods: Patients with stroke or transient ischemic attack and intracranial artery stenosis were recruited. IAC was detected and localized (intima or media) on non-contrast CT images. Intracranial atherosclerotic plaques were identified using vessel wall magnetic resonance imaging and matched to corresponding CT images. Associations between IAC patterns and culprit atherosclerotic plaques were assessed by using multivariate regression. Results: Seventy-five patients (mean age, 63.4 ± 11.6 years; males, 46) were included. Two hundred and twenty-one segments with IAC were identified on CT in 66 patients, including 86 (38.9%) predominantly intimal calcifications and 135 (61.1%) predominantly medial calcifications. A total of 72.0% of intimal calcifications coexisted with atherosclerotic plaques, whereas only 10.2% of medial calcifications coexisted with plaques. Intimal calcification was more commonly shown in non-culprit plaques than culprit plaques (25.9 vs. 9.4%, P = 0.008). The multivariate mixed logistic regression adjusted for the degree of stenosis showed that intimal calcification was significantly associated with non-culprit plaques (OR, 2.971; 95% CI, 1.036-8.517; P = 0.043). Conclusion: Our findings suggest that intimal calcification may indicate the existence of a stable form of atherosclerotic plaque, but plaques can exist in the absence of intimal calcification especially in the middle cerebral artery.