Combination of Plaque Characteristics, Pial Collaterals, and Hypertension Contributes to Misery Perfusion in Patients With Symptomatic Middle Cerebral Artery Stenosis

Advancements in imaging of intracranial atherosclerotic disease: beyond the arterial lumen to the vessel wall

Intracranial atherosclerotic disease (ICAD) significantly increases the risk of ischemic stroke. It involves the accumulation of plaque within arterial walls and narrowing or blockage of blood vessel lumens. Accurate imaging is crucial for the diagnosis and management of ICAD at both acute and chronic stages. However, imaging the small, tortuous intracranial arterial walls amidst complex structures is challenging. Clinicians have employed diverse approaches to improve imaging quality, with a particular emphasis on optimizing the acquisition of images using new techniques, enhancing spatial and temporal resolution of images, and refining post-processing techniques. ICAD imaging has evolved from depicting lumen stenosis to assessing blood flow reserve and identifying plaque components. Advanced techniques such as fractional flow reserve (FFR), high-resolution vessel wall magnetic resonance (VW-MR), optical coherence tomography (OCT), and radial wall strain (RWS) now allow direct visualization of flow impairment, vulnerable plaques, and blood flow strain to plaque, aiding in the selection of high-risk stroke patients for intervention. This article reviews the progression of imaging modalities from lumen stenosis to vessel wall pathology and compares their diagnostic value for risk stratification in ICAD patients.

Blood Pressure Control for Patients with Middle Cerebral Artery Severe Stenosis or Occlusion

Background

Chronic hypertension is an independent risk factor for ischemic stroke and worsens prognosis. However, the level of blood pressure control in hypertensive patients with severe intracranial stenosis is controversial.

Purpose

To investigate the effect of different levels of blood pressure on cerebral perfusion in patients with middle cerebral artery severe stenosis or occlusion.

Materials and methods

A total of 105 patients with isolated steno-occlusive middle cerebral artery (MCA) diagnosed by digital subtraction angiography (DSA) were enrolled, and PWI was compulsory. Relative risk factors were obtained by intergroup analysis in both hypertensive and non-hypertensive groups, and multivariable logistic regression was performed to determine whether hypertension was independently associated with PWI values. Next, the effects of different levels of blood pressure levels on cerebral perfusion as a whole and subgroup were further compared.

Results

The hypertension (HT) group (Am 1.04±0.05, Lm 1.07±0.06, Pm 1.07±0.05) demonstrated lower cerebral perfusion pressure at a larger rMTT (p=0.0001, 0.004, 0.006) than the nonhypertension (NHT) group (Am 1.01±0.21, Lm 1.04±0.04, Pm 1.04±0.04). After adjustment for age, diabetes, and fibrinogen (FIB), HT was independently associated with the rMTT of Am, Lm, and Pm (P=0.015, 0.001, 0.022). Significant differences were observed with HT+SBP<140 (p=0.035, 0.048, 0.049) and HT+DBP<80 (p=0.034, 0.045, 0.055) in rMTT compared with NHT.

Conclusion

Chronic hypertension might damage cerebral perfusion. Strictly control of blood pressure (<140/80mmHg) in hypertensive patients with intracranial artery stenosis will further reduce ipsilateral cerebral perfusion.

Comparative analysis of imaging features and stroke-related factors between posterior circulation atherosclerosis and intramural hematoma-type dissection

AIM

To compare the features detected by high resolution magnetic resonance vessel wall imaging (HR-VWI) between posterior circulation atherosclerosis and intramural hematoma (IMH)-type dissection, and to identify indicators related to cerebral ischemic events.

MATERIALS AND METHODS

Clinical and HR-VWI data of 55 patients with posterior circulation IMH-type dissection and 132 patients with posterior circulation atherosclerosis collected between October 2017 and October 2023 were analyzed retrospectively. Two radiologists independently extracted the imaging features. Multivariable logistic regression was used to identify factors independently associated with stroke.

RESULTS

Compared with patients with atherosclerosis, those with IMH-type dissection were younger, with a lower prevalence of diabetes and hypertriglyceridemia, lower hypertension grade, enhanced grade, remodeling index (RI), vertebrobasilar artery/brainstem ratio, and prevalence of nonsmooth surface, and higher prevalence of intraluminal thrombus (ILT), lumen (LA), wall area (WA), and total vessel area (TVA). In patients with stroke, those with IMH-type dissection were younger, with a lower prevalence of diabetes, and degree of hypertension, and higher RI, WA, TVA, and the prevalence of ILT. Multivariable logistic regression showed that RI (odds ratio [OR], 0.37; 95% CI, 0.17-0.77) and normalized wall index (NWI) (OR, 39.02; 95% CI, 2.19-695.35) were risk factors for stroke in patients with dissection, and LA (OR, 1.52; 95% CI, 1.12-2.06) and NWI (OR, 60.84; 95% CI 3.70-998.06) were risk factors for atherosclerotic stroke.

CONCLUSION

Patients with posterior circulation IMH-type dissection had greater potential for positive remodeling than those with atherosclerosis. The arterial remodeling capacity was closely related to stroke risk.

The prevalence and prognosis of asymptomatic intracranial atherosclerosis in a community-based population: Results based on high-resolution magnetic resonance imaging

BACKGROUND AND PURPOSE

Intracranial atherosclerotic disease (ICAD) is a major cause of ischemic stroke in China, but the prevalence and prognosis of asymptomatic ICAD detected using high-resolution magnetic resonance imaging (HR-MRI) is largely unknown. The aim of this study was to investigate the prevalence and prognosis in order to guide neurologists in interpreting ICAD detected on HR-MRI.

METHODS

We included stroke-free participants from a community-based prospective cohort (Shunyi study participants) who underwent HR-MRI between July 2014 and April 2016. The participants were divided into two groups: those with or without ICAD (ICAD+ and ICAD- , respectively). ICAD included intracranial artery stenosis and non-stenotic plaque. The primary outcome was ischemic stroke. Cox proportional hazard models were used to evaluate the association between ICAD and event outcomes.

RESULTS

A total of 1060 stroke-free participants evaluated by HR-MRI were included from the Shunyi study. The median age at HR-MRI was 56 years and 64.7% were female. The ICAD prevalence was 36.3% (n = 385). The ICAD+ group was older and had more cerebrovascular risk factors. The rates of ischemic stroke in the ICAD- and ICAD+ groups were 1.3% (n = 9) and 5.2% (n = 20), respectively, with a median follow-up time of 54 months. ICAD was associated with an increased risk of ischemic stroke in the unadjusted and adjusted Cox models, with hazard ratios of 4.12 (95% confidence interval [CI] 1.87-9.05) and 2.50 (95% CI 1.05-5.94), respectively. The greatest risk of an event outcome was observed in participants with ≥70% stenosis or occlusion. The features of high-risk plaques were also identified.

CONCLUSIONS

We found that ICAD detected using HR-MRI increases the long-term risk of a first-ever ischemic stroke in a stroke-free population, suggesting that the current primary prevention protocol of stroke awaits further optimization.

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.

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.

The relationship between neutrophil-to-lymphocyte ratio and cerebral collateral circulation in patients with symptomatic severe intracranial artery stenosis or occlusion

BACKGROUND

The neutrophil/lymphocyte ratio (NLR) has been considered a prognostic indicator for determining the systemic inflammatory response and atherosclerosis. We aimed to determine the relationship between NLR and the development of cerebral collateral circulation in patients with symptomatic severe stenosis or occlusion of intracranial arteries.

METHODS

All patients underwent digital subtraction angiography (DSA) within 14 days of admission and were divided into a group with good collateral circulation (77 patients) and a group with poor collateral circulation (86 patients) according to the DSA collateral compensation grading method. Apo B, total cholesterol, LDL, and Neutrophil count in the poor side branch group were significantly higher than in the good side branch group. Multifactorial analysis showed that high NLR levels were a valid predictor of poor collateral circulation in patients with symptomatic severe intracranial artery stenosis or occlusion. Spearman correlation analysis showed that the size of the collateral branch score was negatively correlated with NLR (r = -0.509, P < 0.001) and cholesterol content (r = -0.249, P = 0.002). NLR predicted poor collateral circulation with an AUC of 0.620 (sensitivity 66.7 %, specificity 61.3 %, 95 % CI = 0.517-0.723,P < 0.05).

CONCLUSION

We demonstrate a correlation between NLR levels and the development of collateral circulation in the brain in patients with symptomatic severe stenosis or occlusion of the intracranial arteries.

Plaque characteristics after endovascular treatment in patients with intracranial atherosclerotic disease

BACKGROUND

Endovascular treatment (EVT) is an alternative option for symptomatic intracranial atherosclerotic disease (ICAD). However, the effect of EVT treatment on ICAD plaques is still unclear. This study describes the ICAD plaque characteristics after EVT treatment and analyzes the effect of different EVT treatments on plaque characteristics.

METHOD

From 2017 January to 2022 January, ICAD patients who underwent endovascular treatment and had follow-up high-resolution magnetic resonance image (HRMRI) were enrolled in the study. Multiple plaque characteristics, including plaque enhancement, plaque burden, were measured based on preoperative, and follow-up HRMRI. Plaque characteristics and postoperative plaque changes were analyzed between different treatment groups.

RESULT

Finally, 50 intracranial atherosclerotic plaques in 45 patients were included. Including 28 male patients and 17 female, media age 63.0 years old. Among 50 plaques, 41 received percutaneous angioplasty (including 22 plain balloons and 19 drug-coated balloons (DCB)) and the other 9 underwent stenting. Stenosis rate, plaque burden and eccentricity index at the lesion site were significantly decreased after EVT compared with preoperative periods (p <0.001). And only the DCB group showed a significant reduction in plaque enhancement at follow-up (p < 0.001). No significant preoperative and postoperative changes in other plaque characteristics were found.

CONCLUSION

EVT treatment could compromise the characteristics of intracranial periarterial atherosclerotic plaques, and DCB treatment may result in a reduction in plaque enhancement after treatment.

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.

High-Risk Intracranial Atherosclerotic Stenosis Despite Aggressive Medical Treatment: Protocol for a Prospective Nested Case-Control Study

Introduction

Intracranial atherosclerotic disease (ICAD) is one of the most important etiologies of ischemic stroke, especially in Asia. Although medical treatment was recommended as the first-line therapy for ICAD, the recurrent stroke rate was still high in severe stenosis of ICAD despite aggressive medical treatment. Traditionally, the degree of luminal stenosis is used as the principal index for stroke risk stratification in patients with ICAD, while recent evidence suggested that symptomatic atherosclerotic plaques were characterized by plaque features and hemodynamics. This prospective, longitudinal, and nested case-control study aims to identify multimodal imaging predictors of high-risk patients with ICAD refractory to medical treatment and explore a refined risk stratification model based on the above multimodal imaging predictors.

Methods

This prospective, longitudinal, and nested case-control study includes 400 symptomatic patients with ICAD with 50–99% of stenosis treated with aggressive medical therapy. All patients who meet the eligibility criteria are assessed by multimodal imaging examination from three aspects, including lumen stenosis, plaque characteristics, and hemodynamic features. The enrolled patients receive aggressive medical management, including antiplatelet therapy and cardiovascular risk control. The primary outcome is ischemic stroke or death attributable to the lesion of the target vessel within 1 year. The secondary endpoints are (1) any stroke or death; (2) all-cause mortality; (3) any stroke out of the territory of the responsible lesion; (4) functional outcome with the modified Rankin Scale (mRS).

Ethics and Dissemination

This study has been approved by the ethics committee of our center ([2021]083) and has been prospectively registered (Registration No: ChiCTR2100048832). Study findings will be disseminated through peer-reviewed publications and presentations at scientific meetings.

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

BACKGROUND AND PURPOSE

Intracranial atherosclerotic plaque features are potential factors associated with recurrent stroke, but previous studies only focused on a single lesion, and few studies investigated them with perfusion impairment. This study aimed to investigate the association among whole-brain plaque features, perfusion deficit, and stroke recurrence.

MATERIALS AND METHODS

Patients with ischemic stroke due to intracranial atherosclerosis were retrospectively collected and categorized into first-time and recurrent-stroke groups. Patients underwent high-resolution vessel wall imaging and DSC-PWI. Intracranial plaque number, culprit plaque features (such as plaque volume/burden, degree of stenosis, enhancement ratio), and perfusion deficit variables were recorded. Logistic regression analyses were performed to determine the independent factors associated with recurrent stroke.

RESULTS

One hundred seventy-five patients (mean age, 59 [SD, 12] years; 115 men) were included. Compared with the first-time stroke group (n = 100), the recurrent-stroke group (n = 75) had a larger culprit volume (P = .006) and showed more intracranial plaques (P < .001) and more enhanced plaques (P = .003). After we adjusted for other factors, culprit plaque volume (OR, 1.16 per 10-mm³ increase; 95% CI, 1.03-1.30; P = .015) and total plaque number (OR, 1.31; 95% CI, 1.13-1.52; P < .001) were independently associated with recurrent stroke. Combining these factors increased the area under the curve to 0.71.

CONCLUSIONS

Large culprit plaque and more intracranial plaques were independently associated with recurrent stroke. Performing whole-brain vessel wall imaging may help identify patients with a higher risk of recurrent stroke.

Leptomeningeal collateral activation indicates severely impaired cerebrovascular reserve capacity in patients with symptomatic unilateral carotid artery occlusion

For patients with symptomatic unilateral internal carotid artery (ICA) occlusion, impaired cerebrovascular reactivity (CVR) indicates increased stroke risk. Here, the role of collateral activation remains a matter of debate, whereas angio-anatomical collateral abundancy does not necessarily imply sufficient compensatory flow provided. We aimed to further elucidate the role of collateral activation in the presence of impaired CVR. From a prospective database, 62 patients with symptomatic unilateral ICA occlusion underwent blood oxygenation-level dependent (BOLD) fMRI CVR imaging and a transcranial Doppler (TCD) investigation for primary and secondary collateral activation. Descriptive statistic and multivariate analysis were used to evaluate the relationship between BOLD-CVR values and collateral activation. Patients with activated secondary collaterals exhibited more impaired BOLD-CVR values of the ipsilateral hemisphere (p = 0.02). Specifically, activation of leptomeningeal collaterals showed severely impaired ipsilateral hemisphere BOLD-CVR values when compared to activation of ophthalmic collaterals (0.05 ± 0.09 vs. 0.12 ± 0.04, p = 0.005). Moreover, the prediction analysis showed leptomeningeal collateral activation as a strong independent predictor for ipsilateral hemispheric BOLD-CVR. In our study, ipsilateral leptomeningeal collateral activation is the sole collateral pathway associated with severely impaired BOLD-CVR in patients with symptomatic unilateral ICA occlusion.

Advances in imaging acute ischemic stroke: evaluation before thrombectomy

Recent advances in neuroimaging have demonstrated significant assessment benefits and appropriate triage of patients based on specific clinical and radiological features in the acute stroke setting. Endovascular thrombectomy is arguably the most important aspect of acute stroke management with an extended time window. Imaging-based physiological information may potentially shift the treatment paradigm from a rigid time-based model to a more flexible and individualized, tissue-based approach, increasing the proportion of patients amenable to treatment. Various imaging modalities are routinely used in the diagnosis and management of acute ischemic stroke, including multimodal computed tomography (CT) and magnetic resonance imaging (MRI). Therefore, these imaging methods should provide information beyond the presence or absence of intracranial hemorrhage as well as the presence and extent of the ischemic core, collateral circulation and penumbra in patients with neurological symptoms. Target mismatch may optimize selection of patients with late or unknown symptom onset who would potentially be eligible for revascularization therapy. The purpose of this study was to provide a comprehensive review of the current evidence about efficacy and theoretical basis of present imaging modalities, and explores future directions for imaging in the management of acute ischemic stroke.

DSC perfusion-based collateral imaging and quantitative T2 mapping to assess regional recruitment of leptomeningeal collaterals and microstructural cortical tissue damage in unilateral steno-occlusive vasculopathy

Leptomeningeal collateral supply is considered pivotal in steno-occlusive vasculopathy to prevent chronic microstructural ischaemic tissue damage. The aim of this study was to assess the alleged protective role of leptomeningeal collaterals in patients with unilateral high-grade steno-occlusive vasculopathy using quantitative (q)T2 mapping and perfusion-weighted imaging (PWI)-based collateral abundance. High-resolution qT2 was used to estimate microstructural damage of the segmented normal-appearing cortex. Volumetric abundance of collaterals was assessed based on PWI source data. The ratio relative cerebral blood flow/relative cerebral blood volume (rCBF/rCBV) as a surrogate of relative cerebral perfusion pressure (rCPP) was used to investigate the intravascular hemodynamic competency of pial collateral vessels and the hemodynamic state of brain parenchyma. Within the dependent vascular territory with increased cortical qT2 values (P = 0.0001) compared to the contralateral side, parenchymal rCPP was decreased (P = 0.0001) and correlated negatively with increase of qT2 (P  < 0.05). Furthermore, volumetric abundance of adjacent leptomeningeal collaterals was significantly increased (P < 0.01) and negatively correlated with changes of parenchymal rCPP (P = 0.01). Microstructural cortical damage is closely related to restrictions of antegrade blood flow despite increased pial collateral vessel abundance. Therefore, increased leptomeningeal collateral supply cannot necessarily be regarded as a sign of effective compensation in patients with high-grade steno-occlusive vasculopathy.

Plaque characteristics and hemodynamics contribute to neurological impairment in patients with ischemic stroke and transient ischemic attack

OBJECTIVES

We aimed to investigate differential characteristics of plaque in the middle cerebral artery (MCA) and hemodynamics in patients with ischemic stroke and transient ischemic attack (TIA), and to develop a predictive model for the presence of ischemic stroke and neurological impairment.

METHODS

Sixty-seven patients with acute ischemic events in MCA territory who underwent high-resolution vessel wall imaging between September 2016 and August 2018 were reviewed retrospectively. Patients were assigned to either the stroke group or TIA group, according to diffusion-weighted imaging and neurological examination. Plaque characteristics and anterograde score (AnS) were calculated. Tmax > 6.0-s volume was acquired by RApid Processing of perfusIon and Diffusion software. Multivariate logistic regression analysis and multiple linear regression analysis were performed to establish a predictive model for irreversible infarction occurrence and clinical severity.

RESULTS

Forty-five patients were assigned to the stroke group, and 22 were assigned to the TIA group. Plaque length, intraplaque hemorrhage (IPH), enhancement, AnS, and Tmax > 6.0-s volumes were significantly different between the two groups (p < 0.05). IPH and AnS were independent predictors for patients with stroke (p = 0.020 and 0.034, respectively). Tmax > 6.0-s volume, IPH, hypertension, and AnS were associated with high National Institutes of Health Stroke Scale (NIHSS) scores (all p < 0.05, R = 0.725, and adjusted R² = 0.494).

CONCLUSIONS

IPH and AnS are useful in predicting stroke occurrence. Tmax > 6.0-s volume, IPH, hypertension, and AnS are associated with neurological impairment of the patients.

KEY POINTS

• Ischemic stroke and TIA patients have different plaque characteristics and hemodynamics. • Intraplaque hemorrhage and anterograde score have high diagnostic efficiency for ischemic stroke. • The combination of Tmax > 6.0-s volume, intraplaque hemorrhage, hypertension, and anterograde score can predict the National Institutes of Health Stroke Scale scores of patients.

Plaque characteristics of middle cerebral artery assessed using strategically acquired gradient echo (STAGE) and vessel wall MR contribute to misery downstream perfusion in patients with intracranial atherosclerosis

OBJECTIVES

To assess plaque vulnerability of the middle cerebral artery (MCA) using strategically acquired gradient echo (STAGE) versus high-resolution vessel wall MRI (hr-vwMRI), and explore the relationship between plaque characteristics and misery downstream perfusion.

METHODS

Ninety-one patients with single MCA atherosclerotic plaques underwent STAGE and hr-vwMRI were categorized into a group with misery perfusion and a group without based on the Alberta Stroke Program Early CT score (MTT-ASPECTS) with a threshold of 6. Plaque characteristics including inner lumen area (IWA), susceptibility, presence of hyperintensity within plaque (HIP), surface irregularity, stenosis degree, remodeling index, lipid ratio, and enhancement grade were compared between the two groups. The vulnerability of each plaque was retrospectively assessed on both STAGE and hr-vwMRI according to the combination of plaque features. Logistic regression analysis and ROC curve were performed to evaluate the effect of plaque characteristics on the presence of misery perfusion.

RESULTS

Taking hr-vwMRI as the reference, STAGE showed good efficiency in detecting vulnerable plaques. Patients with misery perfusion had less IWA, higher stenosis degree, more irregular surface and HIP, higher enhancement grade, and susceptibility (p < 0.01 for all). Higher susceptibility and stenosis degree were independent predictors for the occurrence of misery perfusion (p = 0.025, p = 0.048). The AUC was 0.900 for the combination of the two variables.

CONCLUSION

STAGE shows good efficiency to assess MCA plaque vulnerability versus hr-vwMRI. Plaque susceptibility evaluated using STAGE provides incremental value to predict misery perfusion combined with hr-vwMRI plaque features.

KEY POINTS

• STAGE has good efficiency in evaluating MCA plaque vulnerability versus hr-vwMRI. • Higher plaque susceptibility assessed using STAGE and higher grade luminal stenosis based on hr-vwMRI attribute to misery downstream perfusion. • STAGE provides incremental value on the understanding of plaque vulnerability in addition to conventional hr-vwMRI.