Perfusion and plaque evaluation to predict recurrent stroke in symptomatic middle cerebral artery stenosis

Association between high-resolution magnetic resonance vessel wall imaging characteristics and recurrent stroke in patients with intracranial atherosclerotic steno-occlusive disease: A prospective multicenter study

BACKGROUND

High-resolution magnetic resonance vessel wall imaging (HRMR-VWI) is a promising technique for identifying intracranial vulnerable plaques beyond lumen narrowing. However, the association between HRMR-VWI characteristics and recurrent stroke remains uncertain.

AIMS

This study aimed to investigate the association between HRMR-VWI characteristics and recurrent ipsilateral stroke in patients with symptomatic intracranial atherosclerotic steno-occlusive disease (ICAS).

METHODS

This multicenter, observational study recruited first-ever acute ischemic stroke patients attributed to ICAS (>50% stenosis or occlusion) within 7 days after onset. Participants were assessed by multiparametric magnetic resonance imaging (MRI) including diffusion-weighted imaging, three-dimension time-of-flight magnetic resonance angiography, and three-dimensional T1-weighted HRMR-VWI. The patients were recommended to receive best medical therapy and were systematically followed up for 12 months. The association between HRMR-VWI characteristics and the time to recurrent ipsilateral stroke was investigated by univariable and multivariable analysis.

RESULTS

Two hundred and fifty-five consecutive patients were enrolled from 15 centers. The cumulative 12 month ipsilateral recurrence incidence was 4.1% (95% confidence interval (CI): 1.6-6.6%). Patients with recurrent ipsilateral stroke exhibited higher rates of intraplaque hemorrhage (IPH) (30.0% vs 6.5%) and eccentric plaque (90.0% vs 48.2%), and lower occurrence of occlusive thrombus (10.0% vs 23.7%). Plaque length (5.69 ± 2.21 mm vs 6.67 ± 4.16 mm), plaque burden (78.40 ± 7.37% vs 78.22 ± 8.32%), degree of stenosis (60.25 ± 18.95% vs 67.50% ± 22.09%) and remodeling index (1.07 ± 0.27 vs 1.03 ± 0.35) on HRMR-VWI did not differ between patients with and without recurrent ipsilateral stroke. In the multivariable Cox regression analysis, IPH (hazard ratio: 6.64, 95% CI: 1.23-35.8, p = 0.028) was significantly associated with recurrent ipsilateral stroke after adjustment.Conclusions:Our results suggest intraplaque hemorrhage (IPH) is significantly associated with recurrent ipsilateral stroke and has potential value in the selection of patients for aggressive treatment strategies.

DATA ACCESS STATEMENT

Data from this study are available and can be accessed upon request.

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.

A novel method of carotid artery wall imaging: black-blood CT

OBJECTIVES

To evaluate the application of black-blood CT (BBCT) in carotid artery wall imaging and its accuracy in disclosing stenosis rate and plaque burden of carotid artery.

METHODS

A total of 110 patients underwent contrast-enhanced CT scan with two phases, and BBCT images were obtained using contrast-enhancement (CE)-boost technology. Two radiologists independently scored subjective image quality on black-blood computerized tomography (BBCT) images using a 4-point scale and then further analyzed plaque types. The artery stenosis rate on BBCT was measured and compared with CTA. The plaque burden on BBCT was compared with that on high-resolution intracranial vessel wall MR imaging (VW-MR imaging). The kappa value and intraclass correlation coefficient (ICC) were used for consistency analysis. The diagnostic accuracy of BBCT for stenosis rate and plaque burden greater than 50% was evaluated by AUC.

RESULTS

The subjective image quality scores of BBCT had good consistency between the two readers (ICC = 0.836, p < 0.001). BBCT and CTA had a good consistency in the identification of stenosis rate (p < 0.001). There was good consistency between BBCT and VW-MR in diagnosis of plaque burden (p < 0.001). As for plaque burden over 50%, BBCT had good sensitivity (93.10%) and specificity (73.33%), with an AUC of 0.950 (95%CI 0.838-0.993). Compared with CTA, BBCT had higher consistency with VW-MR in disclosing low-density plaques and mixed plaques (ICC = 0.931 vs 0.858, p < 0.001).

CONCLUSIONS

BBCT can not only display the carotid artery wall clearly but also accurately diagnose the stenosis rate and plaque burden of carotid artery.

CLINICAL RELEVANCE STATEMENT

Black-blood CT, as a novel imaging technology, can assist clinicians and radiologists in better visualizing the structure of the vessel wall and plaques, especially for patients with contraindication to MRI.

KEY POINTS

• Black-blood CT can clearly visualize the carotid artery wall and plaque burden. • Black-blood CT is superior to conventional CTA with more accurate diagnosis of the carotid stenosis rate and plaque burden features.

Examining the Role of Cerebral Embolic Protection Devices in Preventing Postoperative Stroke in Patients with a History of Stroke or Transient Ischemic: Insights from the National Inpatient Sample

Cerebral embolic protection devices (CEPD) during transcatheter aortic valve replacement (TAVR) have been shown to lower the risk of stroke during the procedure. However, their long-term and clinical effects on neuro-cognition are unknown. Therefore, we hypothesized the benefit of CEPD in TAVR patients with a prior history of stroke or transient ischemic attack (TIA). National Inpatient Sample (2019) and International Classification of Diseases, 10th Revision codes were used to identify patients undergoing TAVR with prior stroke or TIA. Propensity-matched analysis was performed to adjust for baseline characteristics and comorbidities. Primary outcome measures were postoperative stroke and all-cause mortality. Length of stay and hospital cost were secondary outcomes. Of 8450 unmatched TAVR patients with prior stroke or TIA in 2019, 1095 (13%) utilized CEPD. After propensity matching previous myocardial infarction (MI), coronary artery bypass grafting, and drug abuse were higher in the TAVR-only cohort. Postoperative stroke rate (1.4% vs 2.2%; P = 0.081) and odds [adjusted odds ratio (aOR), 0.48; 95% confidence interval (CI), 0.11-2.17; P = 0.341] were lower in the CEPD group. There was no difference in all-cause in-hospital mortality between the 2 groups (0.9% vs 1.0%). Length of stay (3 vs 2 days, P <0.001) and hospital expenditure ($172,711 vs $162,284; P = 0.002) were higher for the TAVR-only cohort. CEPD in TAVR patients with prior stroke or TIA did not show statistically significant postoperative stroke benefits. However, further larger-scale prospective studies are needed to evaluate the long-term neurocognitive benefits of CEPD in these patients. As the use of TAVR continues to expand, optimizing peri-procedural strategies such as the use of CEPD remains a critical area of research to improve patient outcomes.

Evaluating Middle Cerebral Artery Plaque Characteristics and Lenticulostriate Artery Morphology Associated With Subcortical Infarctions at 7T MRI

BACKGROUND

Lenticulostriate artery (LSA) obstruction is a potential cause of subcortical infarcts. However, MRI LSA evaluation at 3T is challenging.

PURPOSE

To investigate middle cerebral artery (MCA) plaque characteristics and LSA morphology associated with subcortical infarctions in LSA territories using 7-T vessel wall MRI (VW-MRI) and time-of-flight MR angiography (TOF-MRA).

STUDY TYPE

Prospective.

POPULATION

Sixty patients with 80 MCA atherosclerotic plaques (37 culprit and 43 non-culprit).

FIELD STRENGTH/SEQUENCE

7-T with 3D TOF-MRA and T1-weighted 3D sampling perfection with application-optimized contrast using different flip angle evolutions (SPACE) sequences.

ASSESSMENT

Plaque distribution (superior, inferior, ventral, or dorsal walls), LSA origin involvement, LSA morphology (numbers of stems, branches, and length), and plaque characteristics (normalized wall index, maximal wall thickness, plaque length, remodeling index, intraplaque hemorrhage, and plaque surface morphology (regular or irregular)) were assessed.

STATISTICAL TESTS

Least absolute shrinkage and selection operator regression, generalized estimating equations regression, receiver operating characteristic curve, independent t-test, Mann-Whitney U test, Chi-square test, Fisher's exact test, and intra-class coefficient. A P value <0.05 was considered statistically significant.

RESULTS

Plaque irregular surface, superior wall plaque, longer plaque length, LSA origin involvement, fewer LSA stems, and shorter total and average lengths of LSAs were significantly associated with culprit plaques. Multivariable logistic analysis confirmed that LSA origin involvement (OR, 28.51; 95% CI, 6.34-181.02) and plaque irregular surface (OR, 8.32; 95% CI, 1.41-64.73) were independent predictors in differentiating culprit from non-culprit plaques. A combination of LSA origin involvement and plaque irregular surface (area under curve = 0.92; [95% CI, 0.86-0.98]) showed good performance in identifying culprit plaques, with sensitivity and specificity of 86.5% and 86.0%, respectively.

DATA CONCLUSION

7-T VW-MRI and TOF-MRA can demonstrate plaque involvement with LSA origins. MCA plaque characteristics derived from 7-T VW-MRI showed good diagnostic accuracy in determining the occurrence of subcortical infarctions.

EVIDENCE LEVEL

2 TECHNICAL EFFICACY: Stage 3.

Cerebral haemodynamics in symptomatic intracranial atherosclerotic disease: a narrative review of the assessment methods and clinical implications

Intracranial atherosclerotic disease (ICAD) is a common cause of ischaemic stroke and transient ischaemic attack (TIA) with a high recurrence rate. It is often referred to as intracranial atherosclerotic stenosis (ICAS), when the plaque has caused significant narrowing of the vessel lumen. The lesion is usually considered 'symptomatic ICAD/ICAS' (sICAD/sICAS) when it has caused an ischaemic stroke or TIA. The severity of luminal stenosis has long been established as a prognostic factor for stroke relapse in sICAS. Yet, accumulating studies have also reported the important roles of plaque vulnerability, cerebral haemodynamics, collateral circulation, cerebral autoregulation and other factors in altering the stroke risks across patients with sICAS. In this review article, we focus on cerebral haemodynamics in sICAS. We reviewed imaging modalities/methods in assessing cerebral haemodynamics, the haemodynamic metrics provided by these methods and application of these methods in research and clinical practice. More importantly, we reviewed the significance of these haemodynamic features in governing the risk of stroke recurrence in sICAS. We also discussed other clinical implications of these haemodynamic features in sICAS, such as the associations with collateral recruitment and evolution of the lesion under medical treatment, and indications for more individualised blood pressure management for secondary stroke prevention. We then put forward some knowledge gaps and future directions on these topics.

Plaque enhancement predicts recurrence in acute ischemic stroke patients with large artery intracranial atherosclerosis

BACKGROUND

The association between the degree of plaque enhancement and ischemic brain stroke recurrence remains unclear. We aimed to establish models to predict plaque enhancement and stroke recurrence.

METHODS

Seventy-eight participants with acute ischemic brain stroke due to intracranial arterial stenosis were recruited and divided into high enhancement (HE) and non-HE groups. The relationship between imaging characteristics (degree of stenosis, minimal lumen area, intraplaque hemorrhage, and plaque burden) and the degree of plaque contrast enhancement was analyzed. Inflammatory cytokine expression was examined by flow cytometry. Independent predictors of stroke recurrence were investigated via multivariate Cox proportional hazards regression analysis. Nomogram was used to construct a prediction model. Harrell's concordance indices (c-indices) and calibration curves were used to assess the discrimination of the nomogram. A risk prediction nomogram for prognosis was constructed.

RESULTS

Thirty-three participants were assigned to the HE group and 45 to the non-HE group. The degree of stenosis and plaque burden in the HE group was higher than that in the non-HE group (P<0.05). Multiple linear regression analysis showed the degree of stenosis was associated with HE (β=0.513; P=0.000). After adjusting for confounding factors, age (HR=1.115; 95%CI=1.034-1.203, P=0.005) and HE plaques (HR=10.457; 95%CI=1.176-93.018; P=0.035) were independent risk factors of stroke recurrence, whereas cytokine levels were not statistically significant between two group.

CONCLUSIONS

HE of intracranial atherosclerosis plaques is an independent factor for ischemic brain stroke recurrence.

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.

Effect of arteriosclerotic intracranial arterial vessel wall enhancement on downstream collateral flow

BACKGROUND

The effect of arteriosclerotic intracranial arterial vessel wall enhancement (IAVWE) on downstream collateral flow found in vessel wall imaging (VWI) is not clear. Regardless of the mechanism underlying IAVWE on VWI, damage to the patient's nervous system caused by IAVWE is likely achieved by affecting downstream cerebral blood flow. The present study aimed to investigate the effect of arteriosclerotic IAVWE on downstream collateral flow.

METHODS

The present study recruited 63 consecutive patients at the Second Hospital of Hebei Medical University from January 2021 to November 2021 with underlying atherosclerotic diseases and unilateral middle cerebral artery (MCA) M1-segment stenosis who underwent an magnetic resonance scan within 3 days of symptom onset. The patients were divided into 4 groups according to IAVWE and the stenosis ratio (Group 1, n = 17; Group 2, n = 19; Group 3, n = 13; Group 4, n = 14), and downstream collateral flow was analyzed using three-dimensional pseudocontinuous arterial spin labeling (3D-pCASL) and RAPID software. The National Institutes of Health Stroke Scale (NIHSS) scores of the patients were also recorded. Two-factor multivariate analysis of variance using Pillai's trace was used as the main statistical method.

RESULTS

No statistically significant difference was found in baseline demographic characteristics among the groups. IAVWE, but not the stenosis ratio, had a statistically significant significance on the late-arriving retrograde flow proportion (LARFP), hypoperfusion intensity ratio (HIR), and NIHSS scores ( F = 20.941, P <0.001, Pillai's trace statistic = 0.567). The between-subject effects test showed that IAVWE had a significant effect on the three dependent variables: LARFP ( R2 = 0.088, F = 10.899, P = 0.002), HIR ( R2 = 0.234, F = 29.354, P <0.001), and NIHSS ( R2 = 114.339, F = 33.338, P <0.001).

CONCLUSIONS

Arteriosclerotic IAVWE significantly reduced downstream collateral flow and affected relevant neurological deficits. It was an independent factor affecting downstream collateral flow and NIHSS scores, which should be a focus of future studies.

TRIAL REGISTRATION

ChiCTR.org.cn, ChiCTR2100053661.

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.

Arterial Spin Labeling-Based MRI Estimation of Penumbral Tissue in Acute Ischemic Stroke

BACKGROUND

Arterial spin labeling (ASL) has shown potential for the assessment of penumbral tissue in patients with acute ischemic stroke (AIS). The postlabeling delay (PLD) parameter is sensitive to arterial transit delays and influences cerebral blood flow measurements.

PURPOSE

To assess the impact of ASL acquisition at different PLDs for penumbral tissue quantification and to compare their performance regarding assisting patient selection for endovascular treatment with dynamic susceptibility contrast MRI (DSC-MRI) as the reference method.

STUDY TYPE

Retrospective.

POPULATION

A total of 53 patients (59.98 ± 12.60 years, 32% women) with AIS caused by internal carotid or middle cerebral artery occlusion.

FIELD STRENGTH/SEQUENCE

A 3-T, three-dimensional pseudo-continuous ASL with fast-spin echo readout.

ASSESSMENT

Hypoperfusion volume was measured using DSC-MRI and ASL with PLDs of 1.500 msec and 2.500 msec, respectively. Eligibility for endovascular treatment was retrospectively determined according to the imaging criteria of the Endovascular Therapy Following Imaging Evaluation for Ischemic Stroke trial (DEFUSE 3).

STATISTICAL TESTS

Kruskal-Wallis tests, Bland-Altman plots, Cohen's kappa, and receiver operating characteristic analyses were used. The threshold for statistical significance was set at P ˂ 0.05.

RESULTS

Hypoperfusion volume for ASL with a PLD of 1.500 msec was significantly larger than that for DSC-MRI, while the hypoperfusion volume for a PLD of 2.500 msec was not significantly different from that of DSC-MRI (P = 0.435). Bland-Altman plots showed that the mean volumetric error between the hypoperfusion volume measured by DSC-MRI and ASL with PLDs of 1.500/2.500 msec was -107.0 mL vs. 4.49 mL. Cohen's kappa was 0.679 vs. 0.773 for DSC-MRI and ASL, respectively, with a PLD of 1.500/2.500 msec. The sensitivity and specificity for ASL with a PLD of 1.500/2.500 msec in identifying patients eligible for treatment were 89.74% vs. 97.44% and 92.86% vs. 64.29%, respectively.

DATA CONCLUSION

In AIS, PLDs for ASL acquisition may have a considerable impact on the quantification of the hypoperfusion volume.

EVIDENCE LEVEL

3 TECHNICAL EFFICACY: Stage 2.

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.

Association of fluid-attenuated inversion recovery vascular hyperintensity with ischaemic events in internal carotid artery or middle cerebral artery occlusion

BACKGROUND AND PURPOSE

Individuals with intracranial artery occlusion have high rates of ischaemic events and recurrence. It has been challenging to identify patients who had high-risk stroke using a simple, valid and non-invasive screening approach. This study aimed to investigate whether fluid-attenuated inversion recovery (FLAIR) vascular hyperintensity (FVH), a specific imaging sign on the FLAIR sequence, could be a predictor of ischaemic events in a population with internal carotid artery (ICA) or middle cerebral artery (MCA) occlusion.

METHODS

We retrospectively analysed 147 patients (mean 60.43±12.83 years) with 149 lesions, including 37 asymptomatic and 112 symptomatic cases of ICA or MCA occlusion. Symptomatic occlusion was considered if ischaemic events were present in the relevant territory within 90 days. FVH Alberta Stroke Program Early Computed Tomography Score (FVH-ASPECTS: 0-7, with 0 indicating absence of FVH and 7 suggesting prominent FVH) and collateral circulation grade were assessed for each participant. Multivariable logistic regression analysis was performed to detect independent markers associated with symptomatic status.

RESULTS

A lower FVH-ASPECTS was associated with a more favourable collateral circulation grade (rho=-0.464, p<0.0001). The FVH-ASPECTS was significantly lower in the asymptomatic occlusion group than in the symptomatic occlusion group (p<0.0001). FVH-ASPECTS (Odd ratio, 2.973; 95% confidence interval, 1.849 to 4.781; p<0.0001) was independently associated with symptomatic status after adjustment for age, sex, lesion location and collateral circulation grade in the multivariate logistic regression. The area under the curve was 0.861 for the use of FVH-ASPECTS to identify symptomatic occlusion.

CONCLUSIONS

The ability to discriminate symptomatic from asymptomatic occlusion suggests that FVH may be a predictor of stroke. As a simple imaging sign, FVH may serve as a surrogate for haemodynamic impairments and can be used to identify high-risk stroke cases early in ICA or MCA occlusion.

Collateral-Core Ratio as a Novel Predictor of Clinical Outcomes in Acute Ischemic Stroke

The interaction effect between collateral circulation and ischemic core size on stroke outcomes has been highlighted in acute ischemic stroke (AIS). However, biomarkers that assess the magnitude of this interaction are still lacking. We aimed to present a new imaging marker, the collateral-core ratio (CCR), to quantify the interaction effect between these factors and evaluate its ability to predict functional outcomes using machine learning (ML) in AIS. Patients with AIS caused by anterior circulation large vessel occlusion (LVO) were recruited from a prospective multicenter study. CCR was calculated as collateral perfusion volume/ischemic core volume. Functional outcomes were assessed using the modified Rankin Scale (mRS) at 90 days. An ML model was built and tested with a tenfold cross-validation using nine clinical and four imaging variables with mRS score 3-6 as unfavorable outcomes. Among 129 patients, CCR was identified as the most important variable. The prediction model incorporating clinical factors, ischemic core volume, collateral perfusion volume, and CCR showed better discriminatory power in predicting unfavorable outcomes than the model without CCR (mean C index 0.853 ± 0.108 versus 0.793 ± 0.133, P = 0.70; mean net reclassification index 52.7% ± 32.7%, P < 0.05). When patients were divided into two groups based on their CCR value with a threshold of 0.73, unfavorable outcomes were significantly more prevalent in patients with CCR ≤ 0.73 than in those with CCR > 0.73. CCR is a robust predictor of functional outcomes, as identified by ML, in patients with acute LVO. The prediction model that incorporated CCR improved the model's ability to identify unfavorable outcomes. ClinicalTrials.gov Identifier: NCT02580097.

Altered Cerebral Blood Flow in the Progression of Chronic Kidney Disease

Background: In chronic kidney disease (CKD), cognitive impairment is a definite complication. However, the mechanisms of how CKD leads to cognitive impairment are not clearly known. Methods: Cerebral blood flow (CBF) information was collected from 37 patients with CKD (18 in stage 3; 19 in stage 4) and 31 healthy controls (HCs). For CKD patients, we also obtained laboratory results as well as neuropsychological tests. We conducted brain perfusion imaging studies using arterial spin labeling and calculated the relationship between regional CBF changes and various clinical indicators and neuropsychological tests. We also generated receiver operator characteristic (ROC) curves to explore whether CBF value changes in certain brain regions can be used to identify CKD. Results: Compared with HCs, CBF decreased in the right insula and increased in the left hippocampus in the CKD4 group; through partial correlation analysis, we found that CBF in the right insula was negatively correlated with the number connection test A (NCT-A) (r = −0.544, p = 0.024); CBF in the left hippocampus was positively correlated with blood urea nitrogen (r = 0.649, p = 0.005) and negatively correlated with serum calcium level (r = −0.646, p = 0.005). By comparing the ROC curve area, it demonstrated that altered CBF values in the right insula (AUC = 0.861, p < 0.01) and left hippocampus (AUC = 0.862, p < 0.01) have a good ability to identify CKD. Conclusions: Our study found that CBF alterations in the left hippocampus and the right insula brain of adult patients with stage 4 CKD were correlated with disease severity or laboratory indicators. These findings provide further insight into the relationship between altered cerebral perfusion and cognitive impairment in patients with non-end-stage CKD as well as, additional information the underlying neuropathophysiological mechanisms.

Association of periprocedural perfusion non-improvement with recurrent stroke after endovascular treatment for Intracranial Atherosclerotic Stenosis

Background

Predictors of recurrent stroke after endovascular treatment for symptomatic intracranial atherosclerotic stenosis (ICAS) remain uncertain.

Objectives

Among baseline characteristics, lesion features, and cerebral perfusion changes, we try to explore which factors are associated with the risk of recurrent stroke in symptomatic ICAS after endovascular treatment.

Design

Consecutive patients with symptomatic ICAS of 70-99% receiving endovascular treatment were enrolled. All patients underwent whole-brain computer tomography perfusion (CTP) within 3 days before and 3 days after the endovascular treatment. Baseline characteristics, lesion features, and cerebral perfusion changes were collected.

Methods

Cerebral perfusion changes were evaluated with RAPID software and calculated as preprocedural cerebral blood flow (CBF) < 30%, time to maximum of the residue function (Tmax) > 6 s, and Tmax > 4 s volumes minus postprocedural. Cerebral perfusion changes were divided into periprocedural perfusion improvement (>0 ml) and non-improvement (⩽ 0 ml). Recurrent stroke within 180 days was collected. The Cox proportional hazards analysis analyses were performed to evaluate factors associated with recurrent stroke.

Results

From March 2021 to December 2021, 107 patients with symptomatic ICAS were enrolled. Of the 107 enrolled patients, 30 (28.0%) patients underwent balloon angioplasty alone and 77 patients (72.0%) underwent stenting. The perioperative complications occurred in three patients. Among CBF < 30%, Tmax > 6 s, and Tmax > 4 s volumes, Tmax > 4 s volume was available to evaluate cerebral perfusion changes. Periprocedural perfusion improvement was found in 77 patients (72.0%) and non-improvement in 30 patients (28.0%). Nine patients (8.4%) suffered from recurrent stroke in 180-day follow-up. In Cox proportional hazards analysis adjusted for age and sex, perfusion non-improvement was associated with recurrent stroke [hazards ratio (HR): 4.472; 95% CI: 1.069-18.718; p = 0.040].

Conclusion

In patients with symptomatic ICAS treated with endovascular treatment, recurrent stroke may be related to periprocedural cerebral perfusion non-improvement.

Registration

http://www.chictr.org.cn. Unique identifier: ChiCTR2100052925.

Evaluation of postcontrast images of intracranial tumors at 7T and 3T MRI: An intra-individual comparison study

AIM

This study aimed to evaluate the diagnostic value of ultrahigh-field magnetic resonance imaging (MRI) for brain tumors in clinical practice.

METHODS

Thirty patients with brain tumors underwent 7- and 3-T MRI. The performance and diagnostic confidence of 7- and 3-T MRI in the visualization of tumor details such as internal structure and feeding artery were evaluated by radiologists. Contrast-enhanced region performance and tumor detail diagnostic confidence score (DCS) were calculated and compared between 7 and 3T using Wilcoxon rank sum test.

RESULTS

In 19 with obvious enhancement and 11 cases without obvious enhancement, 7- and 3-T MRI showed similar performance. The tumors' internal structure and feeding artery were more clearly depicted by 7-T MRI (62.2% and 54.4%, respectively) than by 3-T MRI (2.2% and 6.7%, respectively). Furthermore, the mean DCSs of both internal structure and feeding artery were higher at 7T than at 3T (internal structure: 16.29 ± 9.67 vs. -5.79 ± 4.12, p = 0.028; feeding artery: 21.96 ± 6.93 vs. 4.46 ± 7.07, p = 0.028). The DCS was more significantly improved in the senior radiologist group.

CONCLUSION

Better visualization of brain tumor details and higher tumor detail diagnostic confidence can be obtained with 7-T MRI.

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.

Disparate trends of atherosclerotic plaque evolution in stroke patients under 18-month follow-up: a 3D whole-brain magnetic resonance vessel wall imaging study

PURPOSE

The trend of atherosclerotic plaque feature evolution is unclear in stroke patients with and without recurrence. We aimed to use three-dimensional whole-brain magnetic resonance vessel wall imaging to quantify the morphological changes of causative lesions during medical therapy in patients with symptomatic intracranial atherosclerotic disease.

METHODS

Patients with acute ischemic stroke attributed to intracranial atherosclerotic disease were retrospectively enrolled if they underwent both baseline and follow-up magnetic resonance vessel wall imaging. The morphological features of the causative plaque, including plaque volume, peak normalized wall index, maximum wall thickness, degree of stenosis, pre-contrast plaque-wall contrast ratio, and post-contrast plaque enhancement ratio, were quantified and compared between the non-recurrent and recurrent groups (defined as the recurrence of a vascular event within 18 months of stroke).

RESULTS

Twenty-nine patients were included in the final analysis. No significant differences were found in plaque features in the baseline scan between the non-recurrent (n = 22) and recurrent groups (n = 7). The changes in maximum wall thickness (-13.32% vs. 8.93%, P = 0.026), plaque-wall contrast ratio (-0.82% vs. 3.42%, P = 0.005) and plaque enhancement ratio (-11.03% vs. 9.75%, P = 0.019) were significantly different between the non-recurrent and recurrent groups. Univariable logistic regression showed that the increase in plaque-wall contrast ratio (odds ratio 3.22, 95% confidence interval 1.55-9.98, P = 0.003) was related to stroke recurrence.

CONCLUSION

Morphological changes of plaque features on magnetic resonance vessel wall imaging demonstrated distinct trends in symptomatic intracranial atherosclerotic disease patients with and without stroke recurrence.

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.

Applying Machine Learning to Carotid Sonographic Features for Recurrent Stroke in Patients With Acute Stroke

BACKGROUND

Although carotid sonographic features have been used as predictors of recurrent stroke, few large-scale studies have explored the use of machine learning analysis of carotid sonographic features for the prediction of recurrent stroke.

METHODS

We retrospectively collected electronic medical records of enrolled patients from the data warehouse of China Medical University Hospital, a tertiary medical center in central Taiwan, from January 2012 to November 2018. We included patients who underwent a documented carotid ultrasound within 30 days of experiencing an acute first stroke during the study period. We classified these participants into two groups: those with non-recurrent stroke (those who has not been diagnosed with acute stroke again during the study period) and those with recurrent stoke (those who has been diagnosed with acute stroke during the study period). A total of 1,235 carotid sonographic parameters were analyzed. Data on the patients' demographic characteristics and comorbidities were also collected. Python 3.7 was used as the programming language, and the scikit-learn toolkit was used to complete the derivation and verification of the machine learning methods.

RESULTS

In total, 2,411 patients were enrolled in this study, of whom 1,896 and 515 had non-recurrent and recurrent stroke, respectively. After extraction, 43 features of carotid sonography (36 carotid sonographic parameters and seven transcranial color Doppler sonographic parameter) were analyzed. For predicting recurrent stroke, CatBoost achieved the highest area under the curve (0.844, CIs 95% 0.824-0.868), followed by the Light Gradient Boosting Machine (0.832, CIs 95% 0.813-0.851), random forest (0.819, CIs 95% 0.802-0.846), support-vector machine (0.759, CIs 95% 0.739-0.781), logistic regression (0.781, CIs 95% 0.764-0.800), and decision tree (0.735, CIs 95% 0.717-0.755) models.

CONCLUSION

When using the CatBoost model, the top three features for predicting recurrent stroke were determined to be the use of anticoagulation medications, the use of NSAID medications, and the resistive index of the left subclavian artery. The CatBoost model demonstrated efficiency and achieved optimal performance in the predictive classification of non-recurrent and recurrent stroke.

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.

Early Neurological Deterioration and Hypoperfusion Volume Ratio on Arterial Spin Labeling in Patients with Acute Ischemic Stroke

BACKGROUND

Arterial spin labeling (ASL) is a magnetic resonance imaging (MRI) technique used to quantify cerebral blood perfusion by labeling blood water as it flows throughout the brain. Hypoperfusion volume ratio (HVR) can be calculated using proportional hypoperfusion volume on ASL-based cerebral blood flow (CBF). This study aimed to explore the relation between HVR and early neurological deterioration (END) in AIS patients.

SUBJECTS AND METHODS

Patients with AIS were recruited consecutively, and ASL and regular MRI scans were performed. HVR was calculated from 1.5 and 2.5s post labeling delay (PLD) ASL-CBF maps. END was defined as ≥2 points increment of NIHSS within 72 hours of stroke onset. Univariate and multivariate analysis were used to evaluate the relation between HVR and END. Receiver operating characteristic (ROC) curves were used to determine the ability of HVR in predicting END.

RESULTS

Of the 52 enrolled patients, 18 (34.5%) were determined with END. In patients with END, the median hypoperfusion volume was 20 mL [Inter Quartile Range)IQR, 6-72.5 mL] at 1.5s PLD, and 11.2 mL (IQR, 5.3-26 mL) at 2.5s PLD; Sixteen (88.9%) patients had HVR ≥50%, and 13 (72.2%) patients hypoperfusion volume at 2.5s PLD ASL were greater than diffusion-weighted imaging (DWI) infarct volume. In patients without END, median hypoperfusion volume was 7 mL (IQR, 4-30 mL) at 1.5s PLD, and 4 mL (IQR, 1.5-8.5 mL) at 2.5s; Eleven (32.4%) patients had HVR ≥50%, and 10 (29.4%) patients hypoperfusion volume at 2.5s PLD ASL were greater than DWI infarct volume. The proportion of HVR ≥50% and hypoperfusion volume >DWI infarct volume were more frequent in patients with END than patients without (all P<0.001). After adjusted for age, admission NIHSS, proportion of hypoperfusion volume > DWI infarct and arterial transit artifact (ATA) by logistic regression analysis, HVR ≥50% (OR=13.1, P=0.003) was an independent risk factor for END. ROC analysis demonstrated that the HVR could predict END with an area under the curve of 0.794 (P=0.001).

CONCLUSIONS

HVR obtained from the 1.5 and 2.5s PLD ASL may be a useful predictor of END in AIS. The value of HVR may be a marker for hemodynamic impairments.

Risk Factors of Hypoperfusion on MRI of Ischemic Stroke Patients Within 7 Days of Onset

Objective: Hypoperfusion is an important factor determining the prognosis of ischemic stroke patients. The present study aimed to investigate possible predictors of hypoperfusion on MRI of ischemic stroke patients within 7 days of stroke onset.

Methods: Ischemic stroke patients, admitted to the comprehensive Stroke Center of Shanghai Fourth People's Hospital affiliated to Tongji University within 7 days of onset between January 2016 and June 2017, were recruited to the present study. Magnetic resonance imaging (MRI), including both diffusion-weighted imaging (DWI) and perfusion-weighted imaging (PWI), was performed within 7 days of the symptom onset. Time to maximum of the residue function (T_max) maps were automatically evaluated using the RAPID software. The volume of hypoperfusion was measured outside the infarct area based on ADC < 620 × 10⁻⁶ mm²/s. The 90 d mRS score was assessed through either clinic visits or telephone calls. Multivariate step-wise analysis was used to assess the correlation between MR findings and clinical variables, including the demographic information, cardio-metabolic characteristics, and functional outcomes.

Results: Among 635 patients admitted due to acute ischemic stroke within 7 days of onset, 241 met the inclusion criteria. Hypoperfusion volume of 38 ml was the best cut-off value for predicting poor prognosis of patients with cerebral infarction (90 d-mRS score ≥ 2). The incidences of MR perfusion T_max > 4–6 s maps with a volume of 0–38 mL or >38 mL were 51.9% (125/241) and 48.1% (116/241), respectively. Prior stroke and vascular stenosis (≥70%) were associated with MR hypoperfusion. Multivariate step-wise analysis showed that prior stroke and vascular stenosis (≥70%) were risk factors of T_max > 4–6 s maps, and the odds ratios (OR) were 3.418 (adjusted OR 95% CI: 1.537–7.600), and 2.265 (adjusted OR, 95% CI: 1.199–4.278), respectively.

Conclusion: Our results suggest that prior stroke and vascular stenosis (≥70%) are strong predictors of hypoperfusion in patients with acute ischemic stroke within 7 days of stroke onset.

Quantitative and Qualitative Analysis of Atherosclerotic Stenosis in the Middle Cerebral Artery Using High-Resolution Magnetic Resonance Imaging

PURPOSE

We analyzed and compared the imaging characteristics of the vessel wall of the middle cerebral artery (MCA) in symptomatic and asymptomatic patients using a 3.0-T high-resolution magnetic resonance imaging (HR-MRI) protocol, including a 3-dimensional T1-sampling perfection with application-optimized contrasts using different flip angle evolutions sequence.

METHODS

Fifty-three patients with atherosclerotic stenosis of the MCA underwent 3.0-T HR-MRI examinations. The characteristics of atherosclerotic plaques in 53 patients (28 symptomatic, 25 asymptomatic) were analyzed, including plaque distribution and signal intensity. Plaque burden (PB), stenosis degree, and the remodeling index were measured and compared between symptomatic and asymptomatic patients.

RESULTS

The PB of the symptomatic group was significantly higher than that of the asymptomatic group (P = .006), and moderate-severe stenosis was more common (P = .01). The remodeling index of the symptomatic group was also lower (P = .015) and negative remodeling (NR) was more common (P = .043). Binary logistic regression analysis showed that stenosis degree was a risk factor in symptomatic patients (odds ratio = 135, P = .023).

CONCLUSION

There is a trend that some characteristics of plaques and vessels, including the moderate-severe stenosis, larger PB, and NR, were observed more frequently among patients with symptomatic atherosclerotic stenosis of the MCA than among asymptomatic patients.

Imaging of intracranial atherosclerotic plaques using 3.0 T and 7.0 T magnetic resonance imaging-current trends and future perspectives

Intracranial atherosclerotic disease (ICAD) is one of the most common causes of ischemic stroke and carries a relatively high risk of stroke recurrence. Advances in high-resolution magnetic resonance imaging (HRMRI) techniques of intracranial arteries now have made it possible to directly visualize atherosclerotic plaque itself, allowing detailed assessments of plaque morphology and components. Currently available intracranial HRMRI could be performed with 2-dimensional (2D) and 3D acquisitions, and multicontrast weightings in clinically reasonable scan times. Until now, HRMRI research of ICAD has focused on the identification of plaque vulnerability, and the relationship between plaque characteristics and ischemic stroke. HRMRI at ultra-high-field strength (7.0 T) holds promise in better visualizing intracranial vessel walls, as well as identifying early lesions and total burden of ICAD. As a result, intracranial HRMRI provides great insights into pathology of intracranial atherosclerotic plaques, stroke mechanisms, and future stroke risk. In this article, we will review the technical implementation, preclinical research, clinical applications, and future directions of HRMRI for the evaluation of ICAD at 3.0 T and 7.0 T.

Hypoperfusion Distal to Anterior Circulation Intracranial Atherosclerosis is Associated with Recurrent Stroke

BACKGROUND AND PURPOSE

In patients with symptomatic vertebrobasilar intracranial atherosclerotic disease (ICAD), impaired distal flow predicts recurrent stroke, but limited data exist on the association between perfusion status and recurrent stroke in anterior circulation ICAD.

METHODS

This is a retrospective study of patients hospitalized for symptomatic ICAD with 50-99% stenosis of the intracranial carotid or middle cerebral artery. The primary outcome is recurrent symptomatic ischemic stroke in the territory of the artery with ≥50% stenosis within 90 days. The primary predictor is distal hypoperfusion on magnetic resonance (MR) or computed tomography (CT) perfusion, defined as a ≥15 mL volume of territory of the symptomatic artery with Tmax >6 seconds.

RESULTS

Fifty patients met inclusion criteria, including 15 (30%) with recurrent stroke and 15 (30%) with distal hypoperfusion. Distal hypoperfusion was present in 10 of 15 (66.7%) with recurrent stroke versus 5 of 35 (14.3%) without recurrent stroke (P < .001). The hazard ratio for recurrent stroke in patients with distal hypoperfusion was 6.80 (95% confidence interval [CI] 2.31-20.0).

CONCLUSION

Distal hypoperfusion in acutely symptomatic ICAD with 50-99% stenosis is associated with stroke recurrence. Distal hypoperfusion could be used to enrich future trials of secondary stroke prevention in ICAD patients.