Prominent Hypointense Vessel Sign on Susceptibility-Weighted Imaging Is Associated with Clinical Outcome in Acute Ischaemic Stroke

SWI brush sign of cerebral parenchymal veins in central nervous system diseases

Brush sign (BS) was first reported as prominent hypointensity of deep medullary veins and subependymal veins on T2*-weighted images at 3 T MRI in patients with acute stroke in the territory of the middle cerebral artery. Subsequently, BS in central nervous system (CNS) diseases such as moyamoya disease, cerebral venous thrombosis, and Sturge-Weber syndrome was also described on susceptibility-weighted imaging (SWI), and the clinical implications of BS were discussed. The purpose of this review is to demonstrate BS on SWI in various CNS diseases and its mechanisms in the above-mentioned diseases. We also explain the clinical implications of this finding in each disease.

Association of intravascular enhancement sign on 3D-T1W TSE with collateral status in middle cerebral artery occlusion stroke

OBJECTIVE

The significance of the intravascular enhancement sign (IVES) on high-resolution magnetic resonance vascular wall imaging (HR-VWI) remains unclear. This study aimed to investigate the correlation between the IVES and collateral assessment derived from digital subtraction angiography (DSA).

METHOD

A total of 75 patients with occlusion of the first segment of the middle cerebral artery (MCA) who underwent HR-VWI and DSA examinations at our research institution between November 2016 and February 2023 were included. The number of vessels with IVES, IVES-Alberta Stroke Program Early Computed Tomography Score (ASPECTS), American Society of Interventional and Therapeutic Neuroradiology/Society of Interventional Radiology (ASITN/SIR) collateral grade, and DSA collateral blood flow grade were retrospectively evaluated. Correlations between these indicators were assessed using Spearman's correlation.

RESULTS

Interrater agreement was good for the assessment of HR-VWI and DSA indicators. After adjustments for age, degree of wall enhancement, and hypertension, a multivariable ordinal logistic regression model identified both the number of IVES vessels (OR = 1.37; 95%CI [1.06-1.78]; P = 0.017) and IVES-ASPECTS (OR = 2.00; 95%CI [1.03-3.87]; P = 0.041) as independent predictors of ischemic stroke. In the patient group with acute ischemic stroke, we found weak correlations between the number of IVES vessels and the ASITN/SIR collateral grade (rho = -0.35; P = 0.002) and between the IVES-ASPECTS and ASITN/SIR collateral grade (rho = -0.27; P = 0.02). Moreover, there were strong correlations between the number of IVES vessels and the DSA collateral blood flow grade (rho = -0.74; P < 0.001) and between the IVES-ASPECTS and the DSA collateral blood flow grade (rho = -0.65; P < 0.001). The number of IVES vessels correlated strongly with the IVES-ASPECTS (rho = 0.92, P < 0.001).

CONCLUSION

We find that the IVES is closely associated with sluggish collateral blood flow, which further confirms the hemodynamic mechanism underlying the IVES in MCA occlusion.

Negative susceptibility vessel sign might be predictive of complete reperfusion in patients with acute basilar artery occlusion managed with thrombectomy

OBJECTIVES

Negative susceptibility vessel sign (SVS) on pre-thrombectomy MRI has been linked to fibrin-rich thrombus and difficult retrieval in anterior ischemic stroke. However, its impact in posterior circulation-large vessel occlusion stroke (PC-LVOS) has not yet been elucidated. We aim to investigate the relationship of SVS parameters with stroke subtypes and their influence on angiographic and functional outcomes.

METHODS

Prospective thrombectomy registries at two-comprehensive stroke centers were retrospectively reviewed between January 2015 and December 2019 for consecutive MRI-selected patients with PC-LVOS. Two groups were assigned by two independent readers, based on the presence or absence of the SVS (SVS +, SVS -) on MRI-GRE sequence. Multivariate logistic regression analysis was utilized to study primarily the impact of the SVS on the rate of complete recanalization (defined as mTICI 2c/3) at the final series following endovascular thrombectomy (EVT) and whether or not it might influence the efficacy of the frontline EVT strategy. Secondarily, we studied whether the absence of the SVS was predictive of the rate of 90-day functional independence (defined as mRS score < 2). Lastly, both qualitative (SVS +, SVS-) and quantitative (SVS length and diameter) parameters of the SVS were analyzed in association with the puncture to recanalization interval and various stroke etiological subtypes based on TOAST criteria.

RESULTS

Among 1823 patients, 116 were qualified for final analysis (median age, 68 (59-75) years; male, 65%); SVS was detected in 62.9% (73/116) of cases. SVS length was an independent predictor of procedural duration (p = .01) whilst two-layered SVS was inversely associated with the atherosclerosis etiological subtype (aOR = 0.27, 95% CI 0.08-0.89; p = .03). Successful recanalization was achieved in 82% (60/73) vs. 86% (37/43), p = .80 of patients with SVS (+, -) respectively. Only in SVS (+), stentriever (RR 0.59 (0.4-0.88), p = .009), and contact-aspiration (RR 0.82 (0.7-0.96), p = .01) achieved a lower rate of successful recanalization compared to combined technique. SVS (-) was significantly associated with a higher rate of mTICI 2c/3 (aOR = 4.444; 95% CI 1.466-13.473; p = .008) and showed an indirect effect of 9% towards functional independence mediated by mTICI 2c/3.

CONCLUSION

SVS parameters in PC-LVOS might predict stroke subtype and indirectly influence the functional outcome by virtue of complete recanalization.

KEY POINTS

• Negative susceptibility vessel sign (SVS) in patients with basilar occlusion independently predict complete recanalization that indirectly instigated a 3-month favorable outcome following thrombectomy. • The longer the SVS, the higher likelihood of large artery atherosclerosis and the longer the thrombectomy procedure. • Two-layered SVS might be negatively associated with the presence of atherosclerosis, yet already-known limitations of TOAST classification and the absence of pathological analysis should be taken into consideration.

Brush sign and collateral supply as potential markers of large infarct growth after successful thrombectomy

OBJECTIVES

To investigate the relationships between brush sign and cerebral collateral status on infarct growth after successful thrombectomy.

METHODS

HIBISCUS-STROKE cohort includes acute ischemic stroke patients treated with thrombectomy after MRI triage and undergoing a day-6 MRI including FLAIR images to quantify final infarct volume (FIV). Successful reperfusion was defined as a modified thrombolysis in cerebral infarction score  ≥ 2B. Infarct growth was calculated by subtracting FIV from baseline ischemic core after co-registration and considered large (LIG) when  > 11.6 mL. Brush sign was assessed on T2*-weighted-imaging and collaterals were assessed using the hypoperfusion intensity ratio, which is the volume of Time-To-Tmax (Tmax)  ≥ 10 s divided by the volume of Tmax  ≥  6 s. Good collaterals were defined by a hypoperfusion intensity ratio  < 0.4.

RESULTS

One hundred and twenty-nine patients were included, of whom 45 (34.9%) had a brush sign and 63 (48.8%) good collaterals. Brush sign was associated with greater infarct growth (p = 0.01) and larger FIV (p = 0.02). Good collaterals were associated with a smaller baseline ischemic core (p < 0.001), larger penumbra (p = 0.04), and smaller FIV (p < 0.001). Collateral status was not significantly associated with brush sign (p = 0.20) or with infarct growth (p = 0.67). Twenty-eight (22.5%) patients experienced LIG. Univariate regressions indicated that brush sign (odds ratio (OR) = 4.8; 95% confidence interval (CI): [1.9;13.3]; p = 0.004) and hemorrhagic transformation (OR = 1.7; 95%CI: [1.2;2.6]; p = 0.04) were predictive of LIG. In multivariate regression, only the brush sign remained predictive of LIG (OR = 5.2; 95%CI: [1.8-16.6], p = 0.006).

CONCLUSIONS

Brush sign is a predictor of LIG after successful thrombectomy and cerebral collateral status is not.

KEY POINTS

• Few predictors of ischemic growth are known in ischemic stroke patients achieving successful mechanical thrombectomy. • Our results suggest that the brush sign-a surrogate marker of severe hypoperfusion-is independently associated with large ischemic growth (> 11.6 mL) after successful thrombectomy whereas cerebral collateral status does not.

The prominent hypointense vessel sign on susceptibility-weighted imaging (SWI) as a potential imaging biomarker for poor clinical outcome in acute ischemic stroke (AIS)

Susceptibility-weighted imaging (SWI) is a relatively new magnetic resonance imaging (MRI) technique used in the workup and diagnosis of brain pathologies. In the context of acute ischemic stroke (AIS), it is increasingly becoming useful in the diagnosis, treatment, and further management of these patients. An elderly man with metabolic syndrome presented to us with an acute onset of right sided body weakness and aphasia. Urgent imaging via MRI noted a left middle cerebral artery (MCA) occlusion. Diffusion-weighted imaging (DWI)/fluid attenuated inversion recovery (FLAIR) mismatch was noted with an acute infarct involving the left MCA territory; hence, treatment with intravenous (IV) thrombolysis was administered. On SWI, the prominent hypointense vessel sign was noted. Recanalization of the occluded left MCA was seen on diagnostic cerebral angiography post IV thrombolysis, however, the patient was noted to have early neurological deterioration (END) and poor early stage clinical outcome, despite repeat MRI showing recanalization of the left MCA occlusion and reversal of the prominent hypointense vessel sign on SWI. Presence of the prominent hypointense vessel sign on SWI in AIS patients is associated with poor clinical outcome, unsuccessful recanalization rates, END, poor early stage clinical outcome, and infarct core progression. Some studies have shown an association between this imaging sign and poor collateral circulation status. Therefore, this imaging sign could potentially prove to be a useful imaging biomarker. However, more studies are needed to validate this theory.

The role of asymmetrical prominent veins sign in early neurological deterioration of acute ischemic stroke patients

Background and purpose

Asymmetrical prominent veins sign (APVS) often appears on susceptibility-weighted angiography (SWAN) images in patients with acute stroke. Early neurological deterioration (END) is highly correlated with survival prognosis in patients with ischemic stroke. This study sought to explore the relationship between APVS and END in patients with acute stroke.

Methods

The subjects retrospectively enrolled in this study were patients with acute ischemic stroke in the middle cerebral artery supply area. All patients underwent head MRI, including the SWAN sequence, within 7 days of stroke symptom onset. END was defined as clinical deterioration or recurrence within 72 h after ischemic stroke. The volume of infarction on diffusion-weighted imaging was measured. Univariate and multivariate analyses were used to analyze the relationship between APVS and END. Spearman correlation between APVS grades and infarct volume, white matter hyperintensity (WMH) volume, and offending vessel were also analyzed.

Results

A total of 157 patients with middle cerebral artery infarct between September 2018 and April 2020 were included in the study. APVS appeared on MRI in 84 of 157 patients, and 34 of 157 patients were diagnosed with END. In patients with END, the proportion of severe APVS was higher than in patients without END (P = 0.001, x² = 14.659). Patients with END were older and had a larger volume of infarct and WMH than patients without END (all P < 0.05). After adjustments were made for related risk factors of END, the severity of APVS was still related to END (OR = 2.56, 95% CI, 1.38–4.75; P for trend = 0.003). Spearman correlation showed that APVS grades were positively related to infarct volume (r = 0.289, P < 0.001) and 3-month modified Rankin Scale score (r = 0.203, P = 0.011) and negatively related to offending vessels (r = −0.170, P = 0.034).

Conclusion

APVS may be an important predictor of END in patients with acute ischemic stroke.

Does the Brush-Sign Reflect Collateral Status and DWI-ASPECTS in Large Vessel Occlusion?

Introduction

The relevance of the brush-sign remained poorly documented in large vessel occlusion (LVO). We aimed to assess the relationship between the brush-sign and collateral status and its potential impact on baseline diffusion-weighted imaging–Alberta Stroke Program Early Computed Tomography Score (DWI-ASPECTS) in acute ischemic stroke (AIS) patients eligible to mechanical thrombectomy (MT).

Methods

Consecutive patients admitted in the Lyon Stroke Center with anterior circulation AIS due to intracranial internal carotid artery (ICA) and/or M1 or M2 segment of the middle cerebral artery (MCA) occlusion eligible for MT were included. The brush-sign was assessed on T2-gradient-echo MRI. Collateral status was assessed on digital subtraction angiography according to the American Society of Interventional and Therapeutic Neuroradiology/Society of Interventional Radiology (ASITN/SIR) score.

Results

In this study, 504 patients were included, among which 171 (33.9%) patients had a brush-sign. Patients with a brush-sign more frequently had a poor collateral status [72 (42.1%) vs. 103 (30.9%); p = 0.017]. In univariable analysis, a DWI-ASPECTS < 7 was associated with a brush sign. Following multivariable analysis, the brush-sign no longer affected DWI-ASPECTS < 7 while the latter remained associated with younger age [odds ratio (OR) 0.97, 95% CI.96–0.99], male sex (OR 1.79, 95% CI 1.08–2.99), a higher National Institutes of Health Stroke Scale (NIHSS) score (OR 1.16, 95% CI 1.1–1.21), a poor collateral status (OR 9.35, 95% CI 5.59-16.02), MCA segment (OR 2.54, 95% CI 1.25–5.38), and intracranial ICA (OR 3.01, 95% CI 1.16–8) occlusion.

Conclusions and Relevance

The brush-sign may be a marker of poor collateral status but did not independently predict a lower DWI-ASPECTS.

Clinical Trial Registration

ClinicalTrials.gov, identifier: NCT04620642.

Clinical Implications of Prominent Cortical Vessels on Susceptibility-Weighted Imaging in Acute Ischemic Stroke Patients Treated with Recanalization Therapy

Prominent cortical vessels on susceptibility-weighted imaging (PCV–SWI) correlate with poor leptomeningeal collaterals. However, little is known about PCV–SWI in recanalization therapy-treated patients with anterior circulation large vessel occlusions (LVO). We investigated PCV–SWI-based assessment of leptomeningeal collaterals and outcome predictions in 100 such patients in an observational study. We assessed PCV–SWI using the Alberta Stroke Program Early CT Score and evaluated leptomeningeal collaterals on multiphase CT angiography (mCTA). Predictive abilities were analyzed using multivariable logistic regression and area of receiver operating curves (AUCs). The extent of PCV–SWI correlated with leptomeningeal collaterals on mCTA (Spearman test, r = 0.77; p < 0.001); their presence was associated with worse functional outcomes and a lower successful recanalization rate (adjusted odds ratios = 0.24 and 0.23, 95% CIs = 0.08–0.65 and 0.08–0.65, respectively). The presence of PCV–SWI predicted outcomes better than good collaterals on mCTA did (C-statistic = 0.84 vs. 0.80; 3-month modified Rankin Scale (mRS) 0–2 = 0.75 vs. 0.67 for successful recanalization). Comparison of AUCs showed that they had similar abilities for predicting outcomes (p = 0.68 for 3-month mRS 0–2; p = 0.23 for successful recanalization). These results suggest that PCV–SWI is a useful feature for assessing leptomeningeal collaterals in acute ischemic stroke patients with anterior circulation LVO and predicting outcomes after recanalization therapy.

The Influence of Cerebral Arterial Circle on Prominent Hypointense Vessel Signs in Patients With Internal Carotid Artery Occlusion

Background and Purpose

Previous studies on the presence of asymmetrical prominent cortical and medullary vessel signs (APCV/APMV) and collateral circulation in patients with internal carotid artery occlusion internal carotid artery occlusion (ICAO) are rare, and the conclusions are inconsistent. Our study aimed to investigate the relationship between the presence of APCV/APMV and collateral circulation in patients with ICAO.

Methods

Patients with acute ischemic stroke with ICAO were recruited in this study. All 74 patients were divided into two groups depending on the presence of APCV and APMV. The status of the cerebral arterial circle (CAC) was graded as poor or good. The poor CAC was defined as MCA was invisible. Severe stroke was defined as cerebral watershed infarction (CWI) or territorial infarction (TI). Clinical and radiological markers were compared between these two groups. Logistic regression was used to investigate the association between the APCV/APMV and clinical and radiological markers.

Results

A total of 74 patients with ICAO were enrolled. Forty-three patients (58.1%) presented with an APCV and APMV was found in 35 (47.2%) patients. Compared with patients with non-APCV, patients with APCV had a more severe stroke (P = 0.038) and had a significantly higher incidence of poor CAC (P = 0.022) than those with APCV. Patients with APMV had a more severe stroke (P = 0.001). Logistic regression showed that poor CAC was independently associated with APCV and severe stroke were independently associated with APMV.

Conclusions

Our study demonstrates that poor CAC was independently associated with the presence of the APCV in patients with ICAO. Severe stroke was independently associated with the APMV.

Changes of prominent vessel sign and susceptibility vessel sign in acute ischemic stroke patients with and without successful recanalization: a study based on susceptibility weighted images

OBJECTIVES

To investigate the changes of prominent vessel sign (PVS) and susceptibility vessel sign (SVS) in acute ischemic stroke (AIS) patients with successful and non-successful vascular recanalization treatment, and to study the associations between the susceptibility-weighted imaging (SWI) findings and early clinical and imaging prognosis.

METHODS

Thirty-five patients with the acute MCA territory infarction were retrospectively included and classified into Group_re (n = 25) and Group_non (n = 10) according to the success of vascular recanalization. NIHSS was used for clinical assessment. PVS and DWI were analyzed using ASPECT scores. Baseline, post-treatment, the changes of PVS and SVS, and SVS length were recorded and compared between two groups. Correlation analysis was performed between SWI factors and early post-treatment clinical and imaging factors.

RESULTS

The mean PVS_pre value was 5.20 ± 1.76 and PVS_post was 8.20 ± 1.86. PVS_pre and PVS_post showed statistical significance between Group_re and Group_non (both p < 0.001). A significant difference wasfound in SVS_post(+) (p < 0.001), SVS_post-pre(+) (p = 0.001), SVS_post-pre length (p = 0.036) and SVSpost length (p = 0.001) between the two groups.  A positive correlation was found between PVS_pre and DWI_post (p < 0.001, r = 0.564). There were positive correlations between PVS-DWI mismatch and NIHSS_post in Group_re (p = 0.042, r = 0.410) and in Group_non (p = 0.006, r = 0.789).

CONCLUSIONS

PVS and SVS changes are influenced by the success of vascular recanalization. However, the changes are unrelated to either early clinical or imaging outcomes in AIS patients. PVS-DWI mismatch can be taken as an imaging biomarker for early clinical outcomes, both for patients with or without successful vascular recanalization.

Prominent hypointense vessel on susceptibility-weighted images accompanying hyperacute and acute large infarction

BACKGROUND

Multiple prominent hypointense vessels on susceptibility-weighted image (SWI) have been found in the ischemic territory of patients with acute ischemic stroke. SWI is suitable for venous imaging.

PURPOSE

To evaluate the conditions of prominent hypointense vessel (PHV) in hyperacute and acute cerebral infarctions using susceptibility-weighted image (SWI).

MATERIALS AND METHODS

Magnetic resonance images, including SWI, of 284 patients with acute infarction were evaluated. Based on lesion size, the infarction was classified as a small (< 3 cm) or a large (> 3 cm) infarction. Stage of infarction was classified as hyperacute (< 6 h) or acute (> 6 h, < 1 week) on the basis of the onset of stroke. The site of infarction was categorised as a deep grey matter or a mixed (cortical and/or deep grey matter) infarction. The venous structures were analysed qualitatively for the calibre difference between ipsilateral and contralateral hemispheres. We quantitatively analysed the relationship between the size of areas with PHV on SWI and the abnormalities on MR angiography, apparent diffusion coefficient value, and signal intensity on T2WI in the 271 patients.

RESULTS

PHV over the infarction site was observed in 54.1% (137/253) of the large infarctions, and 19.3% (6/31) of the small infarctions on SWI. PHV was demonstrated in 63.1% (118/187) of mixed infarctions and 25.8% (25/97) of deep grey matter infarctions, and 59.2% (58/98) in hyperacute and 45.7% (85/186) of acute infarctions. The presence of PHV was statistically significant in the size and region of cerebral infarction (p < 0.05), and was not significant in the stage of infarction (p = 0.137). Quantitative analysis revealed significant differences in the MRA abnormalities and ADC values in the PHV ( +) group (p < 0.05) and no significant difference in the T2WI SI ratio in the PHV ( +) group (p = 0.086), compared with PHV (-) group.

CONCLUSION

PHV on SWI was more prominent at the portions with the large and mixed infarctions. PHV was observed both in hyperacute and acute infarction.

Factors associated with prominent vessel sign on susceptibility-weighted imaging in acute ischemic stroke

The prominent vessel sign (PVS) on susceptibility-weighted imaging (SWI) is not displayed in all cases of acute ischemia. We aimed to investigate the factors associated with the presence of PVS in stroke patients. Consecutive ischemic stroke patients admitted within 24 h from symptom onset underwent emergency multimodal MRI at admission. Associated factors for the presence of PVS were analyzed using univariate analyses and multivariable logistic regression analyses. A total of 218 patients were enrolled. The occurrence rate of PVS was 55.5%. Univariate analyses showed significant differences between PVS-positive group and PVS-negative group in age, history of coronary heart disease, baseline NIHSS scores, total cholesterol, hemoglobin, anterior circulation infarct, large vessel occlusion, and cardioembolism. Multivariable logistic regression analyses revealed that the independent factors associated with PVS were anterior circulation infarct (odds ratio [OR] 13.7; 95% confidence interval [CI] 3.5–53.3), large vessel occlusion (OR 123.3; 95% CI 33.7–451.5), and cardioembolism (OR 5.6; 95% CI 2.1–15.3). Anterior circulation infarct, large vessel occlusion, and cardioembolism are independently associated with the presence of PVS on SWI.

Susceptibility-weighted Imaging: Technical Essentials and Clinical Neurologic Applications

Susceptibility-weighted imaging (SWI) evolved from simple two-dimensional T2*-weighted sequences to three-dimensional sequences with improved spatial resolution and enhanced susceptibility contrast. SWI is an MRI sequence sensitive to compounds that distort the local magnetic field (eg, calcium and iron), in which the phase information can differentiate. But the term SWI is colloquially used to denote high-spatial-resolution susceptibility-enhanced sequences across different MRI vendors and sequences even when phase information is not used. The imaging appearance of SWI and related sequences strongly depends on the acquisition technique. Initially, SWI and related sequences were mostly used to improve the depiction of findings already known from standard two-dimensional T2*-weighted neuroimaging: more microbleeds in patients who are aging or with dementia or mild brain trauma; increased conspicuity of superficial siderosis in Alzheimer disease and amyloid angiopathy; and iron deposition in neurodegenerative diseases or abnormal vascular structures, such as capillary telangiectasia. But SWI also helps to identify findings not visible on standard T2*-weighted images: the nigrosome 1 in Parkinson disease and dementia with Lewy bodies, the central vein and peripheral rim signs in multiple sclerosis, the peripheral rim sign in abscesses, arterial signal loss related to thrombus, asymmetrically prominent cortical veins in stroke, and intratumoral susceptibility signals in brain neoplasms.

Are prominent medullary veins better than prominent cortical veins as predictors of early clinical outcome in patients with acute ischemic stroke?

PURPOSE

The prominent vessel sign (PVS) on susceptibility-weighted imaging (SWI) can be dichotomized into prominent cortical veins (PCV) and prominent medullary veins (PMV). This study was designed to compare the predictive value of PCV and PMV in the evaluation of the severity of acute ischemic stroke (AIS) in patients within the reperfusion window.

METHODS

Forty-seven consecutive patients with AIS within the middle cerebral artery territory were recruited. Magnetic resonance imaging was performed within 8 hours of symptom onset and at 7 days after stroke onset. Infarct volume was measured, and the early clinical outcome at 7 days was assessed using the modified Rankin Scale. PVS was dichotomized into cases with both PCV and PMV and cases with only PCV according to location.

RESULTS

Patients with both PCV and PMV (n=32) had higher admission National Institutes of Health Stroke Scale scores (p = 0.020), larger infarct volumes at baseline (p = 0.026) and 7 days (p = 0.007), and larger infarct growth at 7 days (p = 0.050) than those with PCV only. Multivariate regression analysis showed that both the time of onset at baseline (p = 0.013) and infarct growth at 7 days (p = 0.014) could independently predict poor early clinical outcome.

CONCLUSION

PMV may predict poor early clinical outcome in AIS patients, and reperfusion therapy may, therefore, be required more urgently in patients with PMV.

Effect of Oxygen Extraction (Brush-Sign) on Baseline Core Infarct Depends on Collaterals (HIR)

Objectives: Baseline-core-infarct volume is a critical factor in patient selection and outcome in acute ischemic stroke (AIS) before mechanical thrombectomy (MT). We determined whether oxygen extraction efficiency and arterial collaterals, two different physiologic components of the cerebral ischemic cascade, interacted to modulate baseline-core-infarct volume in patients with AIS-LVO undergoing MT triage.

Methods: Between January 2015 and March 2018, consecutive patients with an AIS and M1 occlusion considered for MT with a baseline MRI and perfusion-imaging were included. Variables such as baseline-core-infarct volume [mL], arterial collaterals (HIR: TMax > 10 s volume/TMax > 6 s), high oxygen extraction (HOE, presence of the brush-sign on T2^*) were assessed. A linear-regression was used to test the interaction of HOE and HIR with baseline-core-infarct volume, after including potential confounding variables.

Results: We included 103 patients. Median age was 70 (58–78), and 63% were female. Median baseline-core-infarct volume was 32 ml (IQR 8–74.5). Seventy six patients (74%) had HOE. In a multivariate analysis both favorable HIR collaterals (p = 0.02) and HOE (p = 0.038) were associated with lower baseline-core-infarct volume. However, HOE significantly interacted with HIR (p = 0.01) to predict baseline-core-infarct volume, favorable collaterals (low HIR) with HOE was associated with small baseline-core-infarct whereas patients with poor collaterals (high HIR) and HOE had large baseline-core-infarct.

Conclusion: While HOE under effective collateral blood-flow has the lowest baseline-core-infarct volume of all patients, the protective effect of HOE reverses under poor collateral blood-flow and may be a maladaptive response to ischemic stroke as measured by core infarctions in AIS-LVO patients undergoing MT triage.

The Prognostic Impact of Susceptibility-Weighted Imaging Prominent Veins in Acute Ischemic Stroke: A Systematic Review and Meta-Analysis

PURPOSE

We aimed to determine the prognostic impact of prominent veins (PVS) after an acute ischemic stroke identified on susceptibility-weighted imaging (PVS-SWI).

METHODS

We searched for studies published in PubMed, Embase, Cochrane Library and Chinese Biomedical Literature Database. Poor functional prognosis, early neurological deterioration, and hemorrhagic transformation were evaluated. Risk ratios (RR) were pooled implementing a random effect model. We performed a subgroup analysis by treatment, location (cortical/medullary) and a sensitivity analysis by follow-up time.

RESULTS

Sixteen studies were included (a total of 1605 patients) in the quantitative meta-analysis. PVS-SWI were related with a poor functional outcome (RR 1.62, 95% CI 1.25 to 2.10), especially in the patients receiving thrombolysis (RR 2.19, 95% CI 1.53 to 3.15) and an augmented risk of early neurological damage (RR 2.85, 95% CI 2.31 to 3.51). Both cortical and medullary prominent veins were accompanied by a poor functional outcome (RR 1.82, 95% CI 1.30 to 2.56/RR 2.59, 95% CI 1.98 to 3.38). PVS-SWI were not associated with poor functional outcomes when patients were treated conservatively (RR 1.35, 95% CI 0.82 to 2.22), or with an increased risk of hemorrhagic transformation (RR 0.97, 95% CI 0.64 to 1.47).

CONCLUSION

PVS-SWI were related to a poor functional prognosis and an increased risk of early neurological damage. In patients treated conservatively, PVS-SWI were not accompanied by a poor prognosis. PVS-SWI were not associated with an augmented risk of hemorrhagic transformation.

Interactive effect of susceptibility-diffusion mismatch and recanalization status on clinical outcome in large vessel occlusion stroke

OBJECTIVE

To investigate the interactive effect of susceptibility-diffusion mismatch and recanalization status on clinical outcome in patients with acute ischemic stroke due to large vessel occlusion.

METHODS

In this prospective study, consecutive ischemic stroke patients admitted within 24 h from symptom onset underwent emergency multimodal MRI at admission, including diffusion-weighted imaging (DWI), susceptibility-weighted imaging (SWI), and time-of-flight magnetic resonance angiography (TOF-MRA). Patients with large vessel occlusion within the anterior circulation were recruited. Follow-up MRI was performed within 24 h after recanalization therapy (intravenous thrombolysis, endovascular therapy, or both). Multivariable logistic regression analysis was performed to estimate the interaction between SWI-DWI mismatch score and recanalization status on clinical outcome.

RESULTS

A total of 90 patients were enrolled. A multiplicative interaction between SWI-DWI mismatch score and recanalization status on clinical outcome was observed (P=0.037). The interaction term "SWI-DWI mismatch score × successful recanalization" was significantly associated with favorable outcome (modified Rankin Scale score of 0-2 at 90 days; adjusted odds ratio [aOR], 2.162; 95% confidence interval [CI], 1.046-4.468). Stratified analysis showed that the likelihood of favorable outcome increased with the increase of SWI-DWI mismatch score in the successful recanalization group (OR, 2.140; 95% CI, 1.376-3.326), while there was no significant relationship between SWI-DWI mismatch score and clinical outcome in the unsuccessful recanalization group (OR, 1.212; 95% CI, 0.933-1.574).

CONCLUSIONS

The effects of SWI-DWI mismatch and recanalization status on clinical outcome were realized through their interaction. In anterior circulation stroke due to large vessel occlusion, patients with both high SWI-DWI mismatch scores and successful recanalization were more likely to achieve a favorable outcome, while patients with unsuccessful recanalization, or with successful recanalization but low SWI-DWI mismatch scores, were less likely to have a good prognosis.

Asymmetrical cortical vessel sign predicts prognosis after acute ischemic stroke

INTRODUCTION

To assess whether the asymmetrical cortical vessel sign (ACVS) on susceptibility-weighted imaging (SWI) could predict 90-day poor outcomes in anterior circulation acute ischemic stroke (AIS) patients treated with recombinant tissue plasminogen activator (r-tPA).

METHODS

Clinical data of consecutive patients with anterior circulation AIS treated with r-tPA were retrospectively analyzed. Clinical variables included age, sex, vascular risk factors, NIHSS score, onset to treatment time, and initial hematologic and neuroimaging findings. Follow-up was performed 90 days after onset. Poor outcome was defined as a modified Rankin scale (mRS) ≥3 at 90 days.

RESULTS

A total of 145 patients were included, 35 (24.1%) patients presented with ACVS (≥Grade 1) on SWI. Fifty-three (36.6%) patients had a poor outcome at 90 days. ACVS (≥Grade 1) occurred in 21 (39.6%) patients with poor outcome compared with 14 (15.2%) patients with favorable outcome (p = .001). Univariate analysis indicated that age, NIHSS score on admission, previous stroke, hemorrhagic transformation, severe intracranial large artery stenosis or occlusion (SILASO), and ACVS were associated with 90-day poor outcome (p < .05). Since SILASO and ACVS were highly correlated and ACVS had different grades, we used three logistic regression models. Results from the three models showed that ACVS was associated with 90-day poor outcome.

CONCLUSIONS

In r-tPA-treated patients with anterior circulation AIS, ACVS might be a helpful neuroimaging predictor for poor outcome at 90 days.

Multiple hypointense vessels on susceptibility-weighted imaging predict early neurological deterioration in acute ischaemic stroke patients with severe intracranial large artery stenosis or occlusion receiving intravenous thrombolysis

Background and purpose

Early neurological deterioration (END) is a common feature in patients with acute ischaemic stroke (AIS) receiving thrombolysis. This study aimed to investigate whether the presence of multiple hypointense vessels (MHVs) on susceptibility-weighted imaging (SWI) could predict END in patients with the anterior circulation AIS treated with recombinant tissue plasminogen activator (r-tPA).

Methods

This was a retrospective study focusing on AIS patients suffering from symptomatic stenosis or occlusion of the middle cerebral artery or internal carotid artery with r-tPA treatment. We collected clinical variables and initial haematological and neuroimaging findings. MHVs were measured on SWI performed after intravenous thrombosis and were defined as the presence of a greater number of veins or veins of a larger diameter with greater signal loss on SWI than those of the contralesional haemisphere. The degree of hyperintensity of MHVs was classified into four grades: none, subtle, moderate and extensive. END was defined as an increase in the National Institutes of Health Stroke Scale score by 2 points during the first 48 hours after the onset of symptoms. Multivariate logistic regressions were conducted to investigate the predictors of END.

Results

The study included 61 patients (51 males and 10 females) with a mean age of 62.4±12.6 years. Thirty-five (57.4%) patients presented with MHVs: 8 (13.1%) were graded as subtle MHVs, while 23 (37.7%) and 4 (6.6%) were graded as moderate or extensive MHVs, respectively. Twenty patients (32.8%) presented with END. Logistic regression analysis showed that compared with patients without MHVs, moderate MHVs (adjusted OR 5.446, 95% CI 1.360 to 21.800; p=0.017) and extensive MHVs (adjusted OR 15.240, 95% CI 1.200 to 193.544; p=0.036) were significantly associated with END.

Conclusions

MHVs might be a useful predictor of END in AIS patients with symptomatic large artery stenosis or occlusion after r-tPA treatment.

An analysis of the risk of perioperative ischemic stroke in patients undergoing non-cardiovascular and non-neurological surgeries

Objectives: This study aimed to assess the preoperative risk factor for perioperative ischemic stroke (PIS) in patients undergoing non-cardiovascular and non-neurological surgeries.Methods: Patients were retrospectively enrolled and grouped into two groups at a ratio of 1:2 according to their PIS status, i.e. patients with PIS in disease group, and patients without PIS in control group. Univariate analysis and multivariate logistic regression analysis were performed on admission laboratory test indices and preoperative risk factors for stroke. The pooled cohort equation (PCE), Essen Stroke Risk Score (ESRS), and Stroke Prognostic Instrument II (SPI-II) were used to separately assess the risk of stroke in patients with or without a history of stroke.Results: There were significant differences between the two groups in the levels of high-density lipoprotein cholesterol (HDL-C), prealbumin, renal insufficiency, dyslipidemia, coronary heart disease, anemia, and hemoglobin; the incidence of electrolyte disturbance; and previous histories of smoking, drinking, and stroke. Multivariate logistic regression analysis showed that renal insufficiency, histories of smoking and stroke, and decreased HDL-C can increase the risk of PIS. There were no significant differences between the disease group and the control group in ESRS or SPI-II score in patients with stroke history. There was a significant difference between the two groups in the risk of PIS evaluated by PCE in patients without stroke history.Conclusions: History of stroke and smoking, renal insufficiency, and low HDL-C are independent risk factors for PIS. It is feasible to assess the risk of stroke in preoperative patients using PCE in clinical practice.

Characteristic Signs on T2*-Based Imaging and Their Relationship with Results of Reperfusion Therapy for Acute Ischemic Stroke: A Systematic Review and Evidence to Date

PURPOSE

Characteristic signs - the susceptibility vessel sign (SVS) and the prominent hypointense vessel sign (PHVS) - on T2*-based magnetic resonance imaging (T2*MRI) can be seen for acute ischemic stroke with large artery occlusion. In this study, we investigated the evidence to support our hypothesis that these findings may help to predict outcomes after reperfusion therapy.

MATERIALS AND METHODS

We searched for papers describing SVS and PHVS in patients treated with reperfusion therapy for acute ischemic stroke, and their functional/radiologic outcomes were systematically reviewed.

RESULTS

Nine studies on the SVS and six studies on the PHVS were included. The pooled odds ratio (OR) of recanalization after intravenous thrombolysis or mechanical thrombectomy was not significantly different with the presence of SVS (OR, 0.615; 95% confidence interval [CI], 0.335-1.131 and OR, 0.993; 95% CI, 0.629-1.567). The OR of favorable functional outcome after reperfusion therapy in terms of the presence of PHVS varied (0.083 to 1.831) by study.

CONCLUSION

Our meta-analysis of the published data showed that a SVS was not a predictive factor for recanalization after reperfusion therapy for acute ischemic stroke. Currently, the data available on T2*MRI are too limited to warrant reperfusion therapy in routine practice. More data are needed from studies with randomized treatment allocation to determine the role of T2*MRI.