Collaterals at angiography and outcomes in the Interventional Management of Stroke (IMS) III trial

Trans-Clot MAP gradient: A novel innovative technique during thrombectomy for acute ischemic stroke with potential applications for assessing collateral circulation, determining clot etiology, informing device selection, and predicting first-pass success

Endovascular mechanical thrombectomy has significantly improved recovery in acute ischemic stroke (AIS). While traditional patient selection has relied on factors such as last known well and penumbra volume, emerging research highlights the importance of collateral circulation in influencing thrombectomy success. However, current methods to assess collateral circulation are often unreliable and lack standardization, limiting their integration into clinical decision-making and prompting the need for innovative approaches. This study introduces trans-clot manometry as a promising approach for quantitatively assessing collateral blood flow before thrombectomy. Two patients were included in this study: a 64-year-old female with a left M1 near-complete occlusion and an 81-year-old male with a left P1 occlusion. After receiving intravenous tenecteplase, each patient underwent emergent thrombectomy where intraoperative trans-clot manometry revealed significant trans-clot mean arterial pressure (MAP) gradients (66.7% for Patient 1 and 96.9% for Patient 2). Both patients had successful first-pass thrombectomy (Patient 1: TICI 3; Patient 2: TICI 3), with substantial clinical improvement (Patient 1: NIHSS 11 to 1; Patient 2: NIHSS 19 to 8). Intraoperative trans-clot manometry offers a simple yet powerful, objective, and generalizable measure of collateral circulation, applicable to a wide range of AIS cases regardless of clot location or vessel size. In addition, real-time correlations with heart-rate variability and radial artery pressures provide an intrinsic quality control, ensuring proper execution of the technique and accuracy of the resulting MAP gradient. Future research will focus on validating this approach, determining its generalizability, and establishing MAP gradient thresholds to enhance device selection and predict first-pass success.

MRI-based Quantitative Collateral Assessment in Acute Stroke : A Comparison with Single-phase CTA in Drip-and-ship Patients with Serial Imaging

PURPOSE

In acute ischemic stroke with large-vessel occlusion (LVO), collateral assessment with single-phase computed tomography angiography (CTA) might underestimate pial collateral supply in a considerable proportion of patients. We aimed to compare time-resolved magnetic resonance imaging (MRI)-based quantitative collateral mapping to conventional collateral imaging with CTA.

METHODS

This retrospective single-center study covering a period of 6 years (2012-2018) included drip-and-ship LVO patients who underwent MR imaging after initial imaging evaluation with CT. For MRI-based collateral assessment, T2*-weighted time series from perfusion-weighted imaging (PWI) were processed to compute a quantitative collateral vessel index (CVIPWI) based on the magnitude of signal variance across the entire acquisition time. CTA-based collateral scores (Tan and Maas) and CVIPWI were investigated in terms of inter-modality associations between collateral measures, as well as their relationships with stroke severity, infarct volume and early functional outcome.

RESULTS

The final analysis included n = 56 patients (n = 31 female, mean age 69.9 ± 14.21 years). No significant relationship was found between MR-based quantitative collateral supply (CVIPWI) and CT-based collateral scores (r = -0.00057, p = 0.502 and r = -0.124, p = 0.797). In contrast to CVIPWI, CTA-based collateral scores showed no significant relationship with clinical stroke severity and infarct volume. While MR-based CVIPWI was independently associated with favorable early functional outcome in multivariate analysis (OR 1.075, 95% CI 1.001-1.153, p = 0.046), CTA-based collateral scores were not significantly associated with outcome.

CONCLUSIONS

Since collateral scores based on single-phase CTA do not accurately reflect infarct progression and might underestimate pial collateralization in a relevant proportion of patients, they are not associated with early functional outcome in LVO patients. In contrast, CVIPWI represents a robust imaging parameter of collateral supply and is independently associated with functional outcome.

Rescue therapy of early neurological deterioration in lacunar stroke

BACKGROUND

Early neurological deterioration (END) occurs in many patients with acute ischemic stroke due to a variety of causes. Although pharmacologically induced hypertension (PIH) and anticoagulants have been investigated in several clinical trials for the treatment of END, the efficacy and safety of these treatments remain unclear. Here, we investigated whether PIH or anticoagulation is better as a rescue therapy for the progression of END in patients with lacunar stroke.

METHODS

This study included patients with lacunar stroke who received rescue therapy with END within 3 days of symptom onset between April 2014 and August 2021. In the PIH group, phenylephrine was administered intravenously for 24 h and slowly tapered when symptoms improved or after 5 days of PIH. In the anticoagulation group, argatroban was administered continuously intravenously for 2 days and twice daily for next 5 days. We compared END recovery, defined as improvement in NIHSS from baseline, excellent outcomes (0 or 1 mRS at 3 months), and safety profile.

RESULTS

Among the 4818 patients with the lacunar stroke, END occurred in 147 patients. Seventy-nine patients with END received PIH (46.9%) and 68 patients (46.3%) received anticoagulation therapy. There was no significant difference in age (P = 0.82) and sex (P = 0.87) between the two groups. Compared to the anticoagulation group, the PIH group had a higher incidence of END recovery (77.2% vs. 51.5%, P < 0.01) and excellent outcomes (34.2% vs. 16.2%, P = 0.04). PIH was associated with END (HR 2.49; 95% CI 1.06-5.81, P = 0.04). PIH remained associated with END recovery (adjusted HR 3.91; 95% CI 1.19-12.90, P = 0.02). Safety outcomes, like hemorrhagic conversion and mortality, were not significantly different between the two groups.

CONCLUSIONS

As a rescue therapy for the progression of END in lacunar stroke patients, PIH with phenylephrine was more effective with similar safety compared to anticoagulation with argatroban.

Flow restoration during mechanical thrombectomy for large vessel occlusion is associated with an immediate reduction of systemic blood pressure

INTRODUCTION

Managing blood pressure in patients with large vessel occlusion affects infarct size and clinical outcomes. We examined how restoring blood flow impacts systemic blood pressure during mechanical thrombectomy.

PATIENTS AND METHODS

Patients with large vessel occlusion in the anterior circulation undergoing mechanical thrombectomy between June 2016 and January 2018 were screened. We included those treated under local anesthesia or conscious sedation and analyzed standardized anesthesia protocols to assess systolic and diastolic blood pressure levels throughout the procedure. The primary outcome was the change of blood pressure, compared 5 min before versus 5 min after the last recanalization attempt. Successful reperfusion was defined as Thrombolysis in Cerebral Infarction score ⩾ 2b.

RESULTS

Of 134 patients, 117 (87%) achieved successful angiographic reperfusion, showing a notable systolic blood pressure drop 5 min after flow restoration (10.2 ± 14.6 vs 3.24 ± 8.65 mm Hg, p = 0.009). Successful angiographic reperfusion was a significant predictor for this decrease in multivariable logistic regression: OR = 1.34 (95% CI: 1.03-1.73, p = 0.0299). Among 66 patients not given circulation-affecting meds, a significant systolic pressure reduction was also observed (155 ± 17 mm Hg to 148 ± 17 mm Hg ; p < 0.001). No diastolic pressure changes were significant.

DISCUSSION AND CONCLUSIONS

Flow restoration was associated with an immediate reduction of systolic blood pressure values in patients undergoing mechanical recanalization under local anesthesia or conscious sedation. This suggests a complex interplay between endovascular stroke therapy and cardiovascular hemodynamics.

Relative Cerebral Blood Flow as an Indirect Imaging Surrogate in Patients With Anterior Circulation Large Vessel Occlusion and Association of Baseline Characteristics With Poor Collateral Status

BACKGROUND

In acute ischemic stroke (AIS), collateral status (CS) is an important predictor of favorable outcomes in patients with AIS. Among quantitative cerebral perfusion parameters, relative cerebral blood flow (rCBF) is considered an accurate perfusion-based indicator of CS. This study investigated the relationship between admission laboratory values, baseline characteristics, and CS as assessed by rCBF in patients with AIS-large vessel occlusion.

METHODS AND RESULTS

In this retrospective multicenter study, consecutive patients presenting with AIS secondary to anterior circulation large vessel occlusion who underwent pretreatment computed tomography perfusion were included. The computed tomography perfusion data processed by RAPID (IschemaView, Menlo Park, CA) generated the rCBF. Binary logistic regression models assessed the relationship between patients' baseline characteristics, admission laboratory values, and poor CS. The primary outcome measure was the presence of poor CS, which was defined as rCBF <38% at a lesion size ≥27 mL. Between January 2017 and September 2022, there were 221 consecutive patients with AIS-large vessel occlusion included in our study (mean age 67.0±15.8 years, 119 men [53.8%]). Logistic regression showed that male sex (odds ratio [OR], 2.98 [1.59-5.59]; P=0.001), chronic kidney disease (OR, 5.18 [2.44-11.0]; P<0.001), admission National Institutes of Health Stroke Scale score ≥12 (OR, 5.17 [2.36-11.36]; P<0.001), and systolic blood pressure <140 (OR, 2.00 [1.07-3.76]; P=0.030) were associated with poor CS.

CONCLUSIONS

Higher stroke severity on admission with National Institutes of Health Stroke Scale score ≥12, systolic blood pressure <140, chronic kidney disease, and male sex are statistically significantly associated with poor CS in patients with AIS due to anterior circulation large vessel occlusion as defined by rCBF <38%.

CT perfusion based rCBF <38% volume is independently and negatively associated with digital subtraction angiography collateral score in anterior circulation large vessel occlusions

BACKGROUND

Collateral status (CS) is an important biomarker of functional outcomes in patients with acute ischemic stroke secondary to large vessel occlusion (AIS-LVO). Pretreatment CT perfusion (CTP) parameters serve as reliable surrogates of collateral status (CS). In this study, we aim to assess the relationship between the relative cerebral blood flow less than 38% (rCBF <38%), with the reference standard American Society of Interventional and Therapeutic Neuroradiology (ASITN) collateral score (CS) on DSA.

METHODS

In this prospectively collected, retrospectively reviewed analysis, inclusion criteria were as follows: (a) CT angiography (CTA) confirmed anterior circulation large vessel occlusion from 9/1/2017 to 10/01/2023; (b) diagnostic CT perfusion; and (c) underwent mechanical thrombectomy with documented ASITN CS. The ratios of the CTP-derived CBF values were calculated by dividing the values of the ischemic lesion by the corresponding values of the contralateral normal region (which were defined as rCBF). Spearman's rank correlation and logistic regression analysis were performed to determine the relationship of rCBF <38% lesion volume with DSA ASITN CS. p ≤ .05 was considered significant.

RESULTS

In total, 223 patients [mean age: 67.77 ± 15.76 years, 56.1% (n = 125) female] met our inclusion criteria. Significant negative correlation was noted between rCBF <38% volume and DSA CS (ρ = -0.37, p < .001). On multivariate logistic regression analysis, rCBF <38% volume was found to be independently associated with worse ASITN CS (unadjusted OR: 3.03, 95% CI: 1.60-5.69, p < .001, and adjusted OR: 2.73, 95% CI: 1.34-5.50, p < .01).

CONCLUSION

Greater volume of tissue with rCBF <38% is independently associated with better DSA CS. rCBF <38% is a useful adjunct tool in collateralization-based prognostication. Future studies are needed to expand our understanding of the role of rCBF <38% within the decision-making in patients with AIS-LVO.

Cerebral collaterals are associated with pre-treatment brain-blood barrier permeability in acute ischemic stroke patients

INTRODUCTION

To investigate the relationship between collaterals and blood-brain barrier (BBB) permeability on pre-treatment MRI in a cohort of acute ischemic stroke (AIS) patients treated with thrombectomy.

METHODS

We conducted a retrospective analysis of the HIBISCUS-STROKE cohort, a single-center observational study that enrolled patients treated with thrombectomy from 2016 to 2022. Dynamic-susceptibility MRIs were post-processed to generate K2 maps with arrival-time correction, which were co-registered with apparent diffusion coefficient (ADC) maps. The 90th percentile of K2 was extracted from the infarct core-defined by an ADC ≤ 620 × 10-6 mm2/s with manual adjustments-and expressed as a percentage change compared to the contralateral white matter. Collaterals were assessed using pre-thrombectomy digital subtraction arteriography with an ASITN/SIR score < 3 defining poor collaterals.

RESULTS

Out of 249 enrolled, 101 (40.6%) were included (median age: 72.0 years, 52.5% of males, median NIHSS score at admission: 15.0). Patients with poor collaterals (n = 44) had worse NIHSS scores (median: 16.0 vs 13.0, p = 0.04), larger infarct core volumes (median: 43.7 mL vs 9.5 mL, p < 0.0001), and higher increases in K2 (median: 346.3% vs 152.7%, p = 0.003). They were less likely to achieve successful recanalization (21/44 vs 51/57, p < 0.0001) and experienced more frequent hemorrhagic transformation (16/44 vs 9/57, p = 0.03). On multiple variable analysis, poor collaterals were associated with larger infarct cores (odds ratio (OR) = 1.12, 95% confidence interval (CI): [1.07, 1.17], p < 0.0001) and higher increases in K2 (OR = 6.63, 95% CI: [2.19, 20.08], p = 0.001).

CONCLUSION

Poor collaterals are associated with larger infarct cores and increased BBB permeability at admission MRI.

CLINICAL RELEVANCE STATEMENT

Poor collaterals are associated with a larger infarct core and increased BBB permeability at admission MRI of AIS patients treated with thrombectomy. These findings may have translational interests for extending thrombolytic treatment eligibility and developing neuroprotective strategies.

KEY POINTS

In AIS, collaterals and BBB disruption have been both linked to hemorrhagic transformation. Poor collaterals were associated with larger ischemic cores and increased BBB permeability on pre-treatment MRI. These findings could contribute to hemorrhagic transformation risk stratification, thereby refining clinical decision-making for reperfusion therapies.

Differences in stroke clinical presentation among sexes

INTRODUCTION

There are sex-based differences in stroke epidemiology, treatment, and outcomes. In this manuscript, we discuss the differences that exist in the clinical presentation of acute stroke among sexes.

DISCUSSION

We present the differences in stroke presentation among sexes including age at the time of presentation, severity of stroke on presentation, and stroke type and location. We discuss the atypical clinical presentations, explore the radiographic findings on presentation (including location, infarct core volume, the impact of collateral circulation, hematoma location in intracranial hemorrhage), and discuss differences in time elapsed between symptom onset and management amongst sexes.

CONCLUSION

Differences exist in stroke clinical presentation amongst sexes. These disparities have public health implications, and as they become better understood, impact awareness campaigns in both the public and healthcare communities.

Communicating Arteries and Leptomeningeal Collaterals: A Synergistic but Independent Effect on Patient Outcomes after Stroke

The collateral system is a compensatory mechanism activated in the acute phase of an ischemic stroke. It increases brain perfusion to the hypoperfused area. Arteries of the Willis' circle supply antegrade blood flow, while pial (leptomeningeal) arteries direct blood via retrograde flow. The aim of our retrospective study was to investigate the relationship between both collateral systems, computed tomography perfusion (CTP) values, and functional outcomes in acute stroke patients. Overall, 158 patients with anterior circulation stroke who underwent mechanical thrombectomy were included in the study. We analyzed the presence of communicating arteries and leptomeningeal arteries on computed tomography angiography. Patients were divided into three groups according to their collateral status. The main outcomes were the rate of functional independence 3 months after stroke (modified Rankin scale score, mRS) and mortality rate. Our study suggests that the collateral status, as indicated by the three groups (unfavorable, intermediate, and favorable), is linked to CT perfusion parameters, potential recuperation ratio, and stroke outcomes. Patients with favorable collateral status exhibited smaller core infarct and penumbra volumes, higher mismatch ratios, better potential for recuperation, and improved functional outcomes compared to patients with unfavorable or intermediate collateral status.

Recanalization status and temporal evolution of early ischemic changes following stroke thrombectomy

INTRODUCTION

Present-day computer tomography (CT) scanners have excellent spatial resolution and signal-to-noise ratio and are instrumental detecting early ischemic changes (EIC) in brain. We assessed the temporal changes of EIC based on the recanalization status after thrombectomy.

PATIENTS AND METHODS

The cohort comprises consecutive patients with acute ischemic stroke in anterior circulation treated with thrombectomy in tertiary referral hospital. All baseline and follow-up scans were screened for any ischemic changes and further classified using Alberta Stroke Program Early CT Score (ASPECTS). Generalized linear mixed models were used to analyze the impact of recanalization status using modified Thrombolysis in Cerebral Infarction (mTICI) on temporal evolution of ischemic changes.

RESULTS

We included 614 patients with ICA, M1, or M2 occlusions. Median ASPECTS score was 9 (IQR 7-10) at baseline and 7 (5-8) at approximately 24 h. mTICI 3 was achieved in 207 (33.8%), 2B 241 (39.3%), 2A in 77 (12.6%), and 0-1 in 88 (14.3%) patients. Compared to patients with mTICI 3, those with mTICI 0-1 and 2A had less favorable temporal changes of ASPECTS (p < 0.001). Effect of recanalization was noted in the cortical regions of ICA/M1 patients, but not in their deep structures or patients with M2 occlusions. All ischemic changes detected at baseline were also present at all follow-up images, regardless of the recanalization status.

CONCLUSIONS

Temporal evolution of the ischemic changes and ASPECTS are related to the success of the recanalization therapy in cortical regions of ICA/M1 patients, but not in their deep brain structures or M2 patients. In none of the patients did EIC revert in any brain region after successful recanalization.

Cerebral microbleeds and risk of symptomatic hemorrhagic transformation following mechanical thrombectomy for large vessel ischemic stroke

BACKGROUND AND PURPOSE

In patients with acute ischemic stroke (AIS) treated with endovascular therapy (EVT), the association of pre-existing cerebral small vessel disease (cSVD) with symptomatic intracerebral hemorrhage (sICH) remains controversial. We tested the hypothesis that the presence of cerebral microbleeds (CMBs) and their burden would be associated with sICH after EVT of AIS.

METHODS

We conducted a retrospective study combining cohorts of patients that underwent EVT between January 1st 2015 and January 1st 2020. CMB presence, burden, and other cSVD markers were assessed on a pre-treatment MRI, evaluated independently by two observers. Primary outcome was the occurrence of sICH.

RESULTS

445 patients with pretreatment MRI were included, of which 70 (15.7%) demonstrated CMBs on baseline MRI. sICH occurred in 36 (7.6%) of all patients. Univariate analysis did not demonstrate an association between CMB and the occurrence of sICH (7.5% in CMB+ group vs 8.6% in CMB group, p = 0.805). In multivariable models, CMBs' presence was not significantly associated with increased odds for sICH (-aOR- 1.19; 95% CI [0.43-3.27], p = 0.73). Only ASPECTs (aOR 0.71 per point increase; 95% CI [0.60-0.85], p < 0.001) and collaterals status (aOR 0.22 for adequate versus poor collaterals; 95% CI [0.06-0.93], p 0.019) were independently associated with sICH.

CONCLUSION

CMB presence and burden is not associated with increased occurrence of sICH after EVT. This result incites not to exclude patients with CMBs from EVT. The risk of sICH after EVT in patients with more than10 CMBs will require further investigation.

REGISTRATION

Registration-URL: http://www.

CLINICALTRIALS

gov ; Unique identifier: NCT01062698.

A real-time patient-specific treatment strategy for enhanced external counterpulsation

Diastolic/systolic blood pressure ratio (D/S) ≥ 1.2 is the gold standard of enhanced external counterpulsation (EECP) treatment, but it does not show a clear clinical correspondence with the configuration of the EECP mode. As such, a single target results in different treatment effects in different individuals. The local haemodynamic effect (wall shear stress, WSS) of EECP on vascular endothelial cells is conducive to promote the growth of collateral circulation vessels and restore the blood supply distal to the stenosis lesion. Considering the haemodynamic effects of WSS on human arteries, this study developed a real-time patient-specific treatment strategy of EECP for patients with cardio-cerebrovascular diseases. Based on patient-specific haemodynamic data from 113 individuals, an optimization algorithm was developed to achieve the individualization of a 0D lumped-parameter model of the human circulatory system, thereby simulating the patient-specific global haemodynamic effects. 0D/3D coupled cardio-cerebrovascular models of two subjects were established to simulate the local WSS. We then established statistical models to evaluate clinically unmeasurable WSS based on measurable global haemodynamic indicators. With the aim of attaining appropriate area- and time-averaged WSS (ATAWSS, 4-7 Pa), as evaluated by global haemodynamic indicators, a closed-loop feedback tuning method was developed to provide patient-specific EECP treatment strategies. Results showed that for clinical data collected from 113 individuals, the individualized 0D model can accurately simulate patient-specific global haemodynamic effects (average error <5%). Based on two subjects, the statistical models can be used to evaluate local ATAWSS (error <6%) for coronary arteries and for cerebral arteries. An EECP mode planned by the patient-specific treatment strategy can promote an appropriate ATAWSS within a 16 s calculation time. The real-time patient-specific treatment strategy of EECP is expected to improve the long-term outcome for each patient and have potential clinical significance.

A comprehensive review for artificial intelligence on neuroimaging in rehabilitation of ischemic stroke

Stroke is the second leading cause of death worldwide, with ischemic stroke accounting for a significant proportion of morbidity and mortality among stroke patients. Ischemic stroke often causes disability and cognitive impairment in patients, which seriously affects the quality of life of patients. Therefore, how to predict the recovery of patients can provide support for clinical intervention in advance and improve the enthusiasm of patients for rehabilitation treatment. With the popularization of imaging technology, the diagnosis and treatment of ischemic stroke patients are often accompanied by a large number of imaging data. Through machine learning and Deep Learning, information from imaging data can be used more effectively. In this review, we discuss recent advances in neuroimaging, machine learning, and Deep Learning in the rehabilitation of ischemic stroke.

The collateral map: prediction of lesion growth and penumbra after acute anterior circulation ischemic stroke

OBJECTIVES

This study evaluated the collateral map's ability to predict lesion growth and penumbra after acute anterior circulation ischemic strokes.

METHODS

This was a retrospective analysis of selected data from a prospectively collected database. The lesion growth ratio was the ratio of the follow-up lesion volume to the baseline lesion volume on diffusion-weighted imaging (DWI). The time-to-maximum (Tmax)/DWI ratio was the ratio of the baseline Tmax  > 6 s volume to the baseline lesion volume. The collateral ratio was the ratio of the hypoperfused lesion volume of the phase_FU (phase with the hypoperfused lesions most approximate to the follow-up DWI lesion) to the hypoperfused lesion volume of the phase_baseline of the collateral map. Multiple logistic regression analyses were conducted to identify independent predictors of lesion growth. The concordance correlation coefficients of Tmax/DWI ratio and collateral ratio for lesion growth ratio were analyzed.

RESULTS

Fifty-two patients, including twenty-six males (mean age, 74 years), were included. Intermediate (OR, 1234.5; p < 0.001) and poor collateral perfusion grades (OR, 664.7; p = 0.006) were independently associated with lesion growth. Phase_FUs were immediately preceded phases of the phase_baselines in intermediate or poor collateral perfusion grades. The concordance correlation coefficients of the Tmax/DWI ratio and collateral ratio for the lesion growth ratio were 0.28 (95% CI, 0.17-0.38) and 0.88 (95% CI, 0.82-0.92), respectively.

CONCLUSION

Precise prediction of lesion growth and penumbra can be possible using collateral maps, allowing for personalized application of recanalization treatments. Further studies are needed to generalize the findings of this study.

CLINICAL RELEVANCE STATEMENT

Precise prediction of lesion growth and penumbra can be possible using collateral maps, allowing for personalized application of recanalization treatments.

KEY POINTS

• Cell viability in cerebral ischemia due to proximal arterial steno-occlusion mainly depends on the collateral circulation. • The collateral map shows salvageable brain extent, which can survive by recanalization treatments after acute anterior circulation ischemic stroke. • Precise estimation of salvageable brain makes it possible to make patient-specific treatment decision.

Prognostic value of CBV index in patients with acute ischemic stroke treated with endovascular thrombectomy in late therapeutic window

Purpose

To evaluate the prognostic value of the cerebral blood volume (CBV) index for 90-day functional outcomes in patients with acute ischemic stroke (AIS) treated within a late therapeutic window.

Methods

We retrospectively reviewed patients who underwent pre-treatment computed tomography perfusion (CTP) and endovascular thrombectomy (EVT) for large-vessel occlusion (LVO) of the anterior circulation within the late therapeutic window between January 2021 and February 2023. Clinical data, the Alberta Stroke Program Early Computed Tomography Score (ASPECTS) based on unenhanced computed tomography (CT), and perfusion parameters, including ischemic core, hypoperfusion volume, mismatch volume between the core and penumbra, and CBV index, were assessed and compared between patients who achieved favorable outcomes (defined as a modified Rankin Scale score of 0-2).

Results

Of the 118 patients, 56 (47.5%) had favorable outcomes. In the univariate analysis, age, National Institutes of Health Stroke Scale (NIHSS) score at admission, ASPECTS score, CBV index, and ischemic core volume were significantly associated with functional outcomes (P < 0.05). In multivariate analyses, age (odds ratio [OR], 1.060; 95% confidence interval [CI] 1.013-1.110, P = 0.012), NIHSS score at admission (OR, 1.126; 95% CI 1.031-1.229, P = 0.009), and CBV index (OR, 0.001; 95% CI 0.000-0.240, P = 0.014) were independent predictors of a 90-day favorable outcome.

Conclusion

A high CBV index was independently associated with favorable outcomes in patients who underwent mechanical thrombectomy within the late therapeutic window. In addition, a higher CBV index reflects improved blood flow and favorable digital subtraction angiography collateral status.

Impact of Collateral Circulation on Futile Endovascular Thrombectomy in Acute Anterior Circulation Ischemic Stroke

OBJECTIVE

Collateral circulation is associated with the differential treatment effect of endovascular thrombectomy (EVT) in acute ischemic stroke. We aimed to verify the ability of the collateral map to predict futile EVT in patients with acute anterior circulation ischemic stroke.

METHODS

This secondary analysis of a prospective observational study included data from participants underwent EVT for acute ischemic stroke due to occlusion of the internal carotid artery and/or the middle cerebral artery within 8 hours of symptom onset. Multiple logistic regression analyses were conducted to identify independent predictors of futile recanalization (modified Rankin scale score at 90 days of 4-6 despite of successful reperfusion).

RESULTS

In a total of 214 participants, older age (odds ratio [OR], 2.40; 95% confidence interval [CI], 1.56 to 3.67; p<0.001), higher baseline National Institutes of Health Stroke Scale (NIHSS) scores (OR, 1.12; 95% CI, 1.04 to 1.21; p=0.004), very poor collateral perfusion grade (OR, 35.09; 95% CI, 3.50 to 351.33; p=0.002), longer door-to-puncture time (OR, 1.08; 95% CI, 1.02 to 1.14; p=0.009), and failed reperfusion (OR, 3.73; 95% CI, 1.30 to 10.76; p=0.015) were associated with unfavorable functional outcomes. In 184 participants who achieved successful reperfusion, older age (OR, 2.30; 95% CI, 1.44 to 3.67; p<0.001), higher baseline NIHSS scores (OR, 1.12; 95% CI, 1.03 to 1.22; p=0.006), very poor collateral perfusion grade (OR, 4.96; 95% CI, 1.42 to 17.37; p=0.012), and longer door-to-reperfusion time (OR, 1.09; 95% CI, 1.03 to 1.15; p=0.003) were associated with unfavorable functional outcomes.

CONCLUSION

The assessment of collateral perfusion status using the collateral map can predict futile EVT, which may help select ineligible patients for EVT, thereby potentially reducing the rate of futile EVT.

Drivers of Chronic Pathology Following Ischemic Stroke: A Descriptive Review

Stroke is the third leading cause of death and long-term disability in the world. Considered largely a disease of aging, its global economic and healthcare burden is expected to rise as more people survive into advanced age. With recent advances in acute stroke management, including the expansion of time windows for treatment with intravenous thrombolysis and mechanical thrombectomy, we are likely to see an increase in survival rates. It is therefore critically important to understand the complete pathophysiology of ischemic stroke, both in the acute and subacute stages and during the chronic phase in the months and years following an ischemic event. One of the most clinically relevant aspects of the chronic sequelae of stroke is its extended negative effect on cognition. Cognitive impairment may be related to the deterioration and dysfunctional reorganization of white matter seen at later timepoints after stroke, as well as ongoing progressive neurodegeneration. The vasculature of the brain also undergoes significant insult and remodeling following stroke, undergoing changes which may further contribute to chronic stroke pathology. While inflammation and the immune response are well established drivers of acute stroke pathology, the chronicity and functional role of innate and adaptive immune responses in the post-ischemic brain and in the peripheral environment remain largely uncharacterized. In this review, we summarize the current literature on post-stroke injury progression, its chronic pathological features, and the putative secondary injury mechanisms underlying the development of cognitive impairment and dementia. We present findings from clinical and experimental studies and discuss the long-term effects of ischemic stroke on both brain anatomy and functional outcome. Identifying mechanisms that occur months to years after injury could lead to treatment strategies in the chronic phase of stroke to help mitigate stroke-associated cognitive decline in patients.

Promising Cerebral Blood Flow Enhancers in Acute Ischemic Stroke

Ischemic stroke presents a major global economic and public health burden. Although recent advances in available endovascular therapies show improved functional outcome, a good number of stroke patients are either ineligible or do not have access to these treatments. Also, robust collateral flow during acute ischemic stroke independently predicts the success of endovascular therapies and the outcome of stroke. Hence, adjunctive therapies for cerebral blood flow (CBF) enhancement are urgently needed. A very clear overview of the pial collaterals and the role of genetics are presented in this review. We review available evidence and advancement for potential therapies aimed at improving CBF during acute ischemic stroke. We identified heme-free soluble guanylate cyclase activators; Sanguinate, remote ischemic perconditioning; Fasudil, S1P agonists; and stimulation of the sphenopalatine ganglion as promising potential CBF-enhancing therapeutics requiring further investigation. Additionally, we outline and discuss the critical steps required to advance research strategies for clinically translatable CBF-enhancing agents in the context of acute ischemic stroke models.

Motor rehabilitation after stroke: European Stroke Organisation (ESO) consensus-based definition and guiding framework

PURPOSE

To propose a consensus-based definition and framework for motor rehabilitation after stroke.

METHODS

An expert European working group reviewed the literature, attaining internal consensus after external feedback.

FINDINGS

Motor rehabilitation is defined as a process that engages people with stroke to benefit their motor function, activity capacity and performance in daily life. It is necessary for people with residual motor disability whose goal is to enhance their functioning, independence and participation. Motor rehabilitation operates through learning- and use-dependent mechanisms. The trajectory of motor recovery varies across patients and stages of recovery. Early behavioral restitution of motor function depends on spontaneous biological mechanisms. Further improvements in activities of daily living are achieved by compensations. Motor rehabilitation is guided by regular assessment of motor function and activity using consensus-based measures, including patient-reported outcomes. Results are discussed with the patient and their carers to set personal goals. During motor rehabilitation patients learn to optimize and adapt their motor, sensory and cognitive functioning through appropriately dosed repetitive, goal-oriented, progressive, task- and context-specific training. Motor rehabilitation supports people with stroke to maximize health, well-being and quality of life. The framework describes the International Classification of Functioning, Disability and Health in the context of stroke, describes neurobiological mechanisms of behavioral restitution and compensation, and summarizes recommendations for clinical assessment, prediction tools, and motor interventions with strong recommendations from clinical practice guidelines (2016-2022).

CONCLUSIONS

This definition and framework may guide clinical educators, inform clinicians on current recommendations and guidelines, and identify gaps in the evidence base.

Interaction of heart failure and stroke: A clinical consensus statement of the ESC Council on Stroke, the Heart Failure Association (HFA) and the ESC Working Group on Thrombosis

Heart failure (HF) is a major disease in our society that often presents with multiple comorbidities with mutual interaction and aggravation. The comorbidity of HF and stroke is a high risk condition that requires particular attention to ensure early detection of complications, efficient diagnostic workup, close monitoring, and consequent treatment of the patient. The bi-directional interaction between the heart and the brain is inherent in the pathophysiology of HF where HF may be causal for acute cerebral injury, and - in turn - acute cerebral injury may induce or aggravate HF via imbalanced neural and neurovegetative control of cardiovascular regulation. The present document represents the consensus view of the ESC Council on Stroke, the Heart Failure Association and the ESC Working Group on Thrombosis to summarize current insights on pathophysiological interactions of the heart and the brain in the comorbidity of HF and stroke. Principal aspects of diagnostic workup, pathophysiological mechanisms, complications, clinical management in acute conditions and in long-term care of patients with the comorbidity are presented and state-of-the-art clinical management and current evidence from clinical trials is discussed. Beside the physicians perspective, also the patients values and preferences are taken into account. Interdisciplinary cooperation of cardiologists, stroke specialists, other specialists and primary care physicians is pivotal to ensure optimal treatment in acute events and in continued long-term treatment of these patients. Key consensus statements are presented in a concise overview on mechanistic insights, diagnostic workup, prevention and treatment to inform clinical acute and continued care of patients with the comorbidity of HF and stroke.

Intravenous thrombolysis prior to endovascular thrombectomy in elderly stroke patients: An analysis of the National Inpatient Sample database

BACKGROUND

The effectiveness of intravenous thrombolysis (IVT) prior to endovascular thrombectomy (EVT), also termed bridging thrombolysis, remains uncertain, and there is limited data on its use for elderly patients who may be more prone to hemorrhagic complications.

METHODS

This was a large-scale cross-sectional study of the 2016-2020 National Inpatient Sample (NIS) database. Adult EVT patients presenting directly to thrombectomy centers without prior treatment were identified. Patient demographics, stroke risk factors, stroke etiology, medical comorbidities, and IVT treatment were recorded. Outcomes of interest include in-hospital mortality, rates of discharge to home, and hemorrhagic complications. Multivariable logistic regression models were used to account for possible confounders.

RESULTS

35,735 EVT patients presenting directly to thrombectomy centers without prior thrombolytic treatment were identified. 32.5% (11,630 patients) were treated with bridging thrombolysis. Overall, bridging thrombolysis was significantly associated with lower rates of in-hospital mortality (8.8% vs. 11.2%, p < 0.001) and higher rates of discharge to home (38.0% vs. 28.7%, p < 0.001). IVT's association with lower odds of in-hospital mortality was significantly attenuated with increasing age (interaction p = 0.038), and there was no significant association between IVT treatment with in-hospital mortality for patients 80 years or older (OR 0.99 [95%CI 0.72-1.35], p = 0.94). Similarly, older age significantly amplifies the hemorrhagic risk associated with bridging thrombolysis (interaction p = 0.006). When considering only patients without hemorrhagic complications, age does not significantly modulate IVT's association with patient outcomes.

CONCLUSIONS

Bridging thrombolysis may be associated with better outcomes; however, its benefit may be diminished among elderly patients due to higher rates of hemorrhagic complications.

The Presence of Communicating Arteries in the Circle of Willis Is Associated with Higher Rate of Functional Recovery after Anterior Circulation Ischemic Stroke

Acute ischemic stroke (AIS) is the world's second leading cause of mortality. An established method for treating stroke patients in acute settings is endovascular therapy (EVT). However, the correlation of the successful endovascular treatment of AIS with the presence of communicating arteries in the circle of Willis needs to be proven. Our study examined clinical and radiological data of 158 consecutive patients treated with mechanical thrombectomy (MT) at our comprehensive stroke center. We analyzed their CT angiograms and digital subtraction angiography (DSA) to assess anatomical variants of Willis' circle and formed two groups-collateral-negative and collateral-positive group. The first group included patients with aplasia of both anterior (ACoA) and posterior communicating Artery (PCoA). The second group included patients that have at least one communicating artery (either anterior or posterior). We evaluated their reperfusion outcomes and functional recovery three months later. Our results showed that patients with communicating arteries had smaller areas of infarction on post-interventional CT and higher rates of functional recovery (Modified Rankin Score). The ACoA had a higher impact on early and late outcomes, confirmed by lower control CT scores and more favorable functional recovery. Therefore, anatomic variants of Willis' circle should be considered as a significant prognostic factor in AIS.

Efficacy and safety of bridging therapy versus direct thrombectomy for tandem lesions in acute stroke: A systematic review and meta-analysis

BACKGROUND

Current studies have concluded that MT (Mechanical Thrombectomy) is safe and effective for tandem lesions (TL). However, The benefit of bridging therapy for TL is controversial.

OBJECTIVE

To compare efficacy and safety between bridging therapy and direct thrombectomy of tandem lesions.

METHOD

We conducted a systematic review and meta-analysis of studies comparing bridging therapy versus direct thrombectomy among TL patients with regards to symptomatic intracerebral hemorrhage(sICH), Parenchymal hemorrhage (PH), 3-month mortality, modified Rankin Scale (mRS) score within 3 months, successful reperfusion, and excellent reperfusion. The meta-analysis of proportions was conducted with a common effects model.

RESULT

Five studies (n = 1198 patients) were identified for the systematic review. For safety outcomes, the bridging group had no significant difference in the rate of symptomatic intracranial hemorrhage (OR = 0.78, 95% CI = 0.49-1.25, P = 0.31) and the rate of PH (OR = 0.67, 95% CI = 0.39-1.13, P = 0.13) but significantly lower rate of 3-month mortality (OR = 0.53, 95% CI = 0.37-0.75, P = 0.0004) compared to the direct thrombectomy group. In terms of efficacy outcomes, the bridging therapy group had a significantly higher rate of 3- month good functional outcome (mRS 0-2) (OR = 1.76, 95% CI = 1.38-2.24, P < 0.00001) and successful recanalization (OR = 1.69, 95% CI = 1.27-2.25, P = 0.0003) but no significant difference in the rate of excellent recanalization(OR = 1.21, 95% CI = 0.91-1.59, P = 0.19) in patients with TL compared to direct thrombectomy group.

CONCLUSION

Bridging therapy is effective in improving the 3-month functional prognosis and increasing the rate of arterial recanalization without increasing the risk of intracranial hemorrhage in patients with TL compared to direct thrombectomy. A large multicentre clinical RCT is expected, as are advanced intravenous thrombolysis and endovascular thrombectomy techniques.

Hypersensitive MR angiography based on interlocking stratagem for diagnosis of cardiac-cerebral vascular diseases

Magnetic resonance (MR) angiography is one of the main diagnostic approaches for cardiac-cerebral vascular diseases. Nevertheless, the non-contrast-enhanced MR angiography suffers from its intrinsic problems derived from the blood flow-dependency, while the clinical Gd-chelating contrast agents are limited by their rapid vascular extravasation. Herein, we report a hypersensitive MR angiography strategy based on interlocking stratagem of zwitterionic Gd-chelate contrast agents (PAA-Gd). The longitudinal molar relaxivity of PAA-Gd was 4.6-times higher than that of individual Gd-chelates as well as appropriate blood half-life (73.8 min) and low immunogenicity, enabling sophisticated micro-vessels angiography with a resolution at the order of hundred micrometers. A series of animal models of cardiac-cerebrovascular diseases have been built for imaging studies on a 7.0 T MRI scanner, while the clinical translation potential of PAA-Gd has been evaluated on swine on a 3.0 T clinical MRI scanner. The current studies offer a promising strategy for precise diagnosis of vascular diseases.

Mechanical thrombectomy in patients with heart failure: the Italian registry of Endovascular Treatment in Acute Stroke

BACKGROUND

Heart failure (HF) is the second most important cardiac risk factor for stroke after atrial fibrillation (AF). Few data are available on mechanical thrombectomy (MT) in acute ischemic stroke (AIS) patients with HF.

METHODS

The source of data is the multicentre Italian Registry of Endovascular Treatment in Acute Stroke (IRETAS). All AIS patients ≥ 18 years receiving MT were categorised in two groups: HF and no-HF. Baseline clinical and neuroradiological findings on admission were analysed.

RESULTS

Of 8924 patients, 642 (7.2%) had HF. Compared to the no-HF group, HF patients had higher prevalence of cardiovascular risk factors. Rate of complete recanalisation (TICI 2b-3) was 76.9% in HF vs 78.1% in no-HF group (p = 0.481). Rate of symptomatic intracerebral haemorrhage at 24-h non-contrast computed tomography (NCCT) was 7.6% in HF vs 8.3% in no-HF patients (p = 0.520). At 3 months, 36.4% of HF patients and 48.2% of no-HF patients (p < 0.001) had mRS 0-2, and mortality was, respectively, 30.7% and 18.5% (p < 0.001). In multivariate logistic regression, HF was independently associated with mortality at 3 months (OR 1.53, 1.24-1.88 95% CI, p < 0.001). In multivariate ordinal regression, HF patients had a probability of transitioning to a higher mRS level of 1.23 (1.05-1.44 95% CI, p = 0.012). The propensity score analysis of two groups matched for age, sex, and NIHSS at admission yielded the same results.

CONCLUSION

MT is safe and effective in HF patients with AIS. Patients with HF and AIS suffered from higher 3-month mortality and unfavourable outcome regardless of acute treatments.

Exploring sex differences for acute ischemic stroke clinical, imaging and thrombus characteristics in the INTERRSeCT study

Women, especially following menopause, are known to have worse outcomes following acute ischemic stroke. One primary postulated biological mechanism for worse outcomes in older women is a reduction in the vasculoprotective effects of estrogen. Using the INTERRseCT cohort, a multicentre international observational cohort studying recanalization in acute ischemic stroke, we explored the effects of sex, and modifying effects of age, on neuroradiological predictors of recanalization including robustness of leptomeningeal collaterals, thrombus burden and thrombus permeability. Ordinal regression analyses were used to examine the relationship between sex and each of the neuroradiological markers. Further, we explored both multiplicative and additive interactions between age and sex. All patients (n = 575) from INTERRseCT were included. Mean age was 70.2 years (SD: 13.1) and 48.5% were women. In the unadjusted model, female sex was associated with better collaterals (OR 1.37, 95% CIs: 1.01-1.85), however this relationship was not significant after adjusting for age and relevant comorbidities. There were no significant interactions between age and sex. In a large prospective international cohort, we found no association between sex and radiological predictors of recanalization including leptomeningeal collaterals, thrombus permeability and thrombus burden.

Prognostic Neuroimaging Biomarkers in Acute Vascular Brain Injury and Traumatic Brain Injury

Prognostic imaging biomarkers after acute brain injury inform treatment decisions, track the progression of intracranial injury, and can be used in shared decision-making processes with families. Herein, key established biomarkers and prognostic scoring systems are surveyed in the literature, and their applications in clinical practice and clinical trials are discussed. Biomarkers in acute ischemic stroke include computed tomography (CT) hypodensity scoring, diffusion-weighted lesion volume, and core infarct size on perfusion imaging. Intracerebral hemorrhage biomarkers include hemorrhage volume, expansion, and location. Aneurysmal subarachnoid biomarkers include hemorrhage grading, presence of diffusion-restricting lesions, and acute hydrocephalus. Traumatic brain injury CT scoring systems, contusion expansion, and diffuse axonal injury grading are reviewed. Emerging biomarkers including white matter disease scoring, diffusion tensor imaging, and the automated calculation of scoring systems and volumetrics are discussed.

Impaired post-stroke collateral circulation in sickle cell anemia mice

Patients with sickle cell anemia (SCA) have a high incidence of ischemic stroke, but are usually excluded from thrombolytic therapy due to concerns for cerebral hemorrhage. Maladaptation to cerebral ischemia may also contribute to the stroke propensity in SCA. Here we compared post-stroke cortical collateral circulation in transgenic sickle (SS) mice, bone marrow grafting-derived SS-chimera, and wildtype (AA) controls, because collateral circulation is a critical factor for cell survival within the ischemic penumbra. Further, it has been shown that SS mice develop poorer neo-collateral perfusion after limb ischemia. We used the middle cerebral artery (MCA)-targeted photothrombosis model in this study, since it is better tolerated by SS mice and creates a clear infarct core versus peri-infarct area. Compared to AA mice, SS mice showed enlarged infarction and lesser endothelial proliferation after photothrombosis. SS-chimera showed anemia, hypoxia-induced erythrocyte sickling, and attenuated recovery of blood flow in the ipsilateral cortex after photothrombosis. In AA chimera, cerebral blood flow in the border area between MCA and the anterior cerebral artery (ACA) and posterior cerebral artery (PCA) trees improved from 44% of contralateral level after stroke to 78% at 7 d recovery. In contrast, blood flow in the MCA-ACA and MCA-PCA border areas only increased from 35 to 43% at 7 d post-stroke in SS chimera. These findings suggest deficits of post-stroke collateral circulation in SCA. Better understanding of the underpinnings may suggest novel stroke therapies for SCA patients.

Ipsilateral and contralateral carotid stenosis contribute to the outcome of reperfusion treatment for ischemic stroke

Introduction

Ipsilateral and contralateral carotid stenosis (ICS, CCS) influence acute ischemic stroke (AIS) severity and prognosis. Few data are available about their impact on reperfusion therapies efficacy. Aim of this study was to evaluate the impact of ICS and CCS on the effect of intravenous thrombolysis (IT), mechanical thrombectomy (MT) or both and of antiplatelet therapy (AT).

Methods

We enrolled all the consecutive patients admitted for AIS to our stroke unit and submitted to IT, MT, IT+MT, or AT. We established the presence of a significant ICS or CCS (≥70%) by ultrasound examination or brain angio-CT, or MRI. Clinical and instrumental information were collected; delta National Institutes of Health Stroke Scale (NIHSS) from pre-treatment to patients' discharge was employed as the main outcome measure.

Results

In total, 460 subjects were enrolled, 86 with ICS and 38 with CCS. We observed a significant linear trend of delta (NIHSS) between carotid stenosis categories for patients undergoing IT (p = 0.011), MT (p = 0.046), and MT+IT (p = 0.040), but no significant trend among subjects receiving no reperfusion treatments was observed (p = 0.174).

Discussion

According to our findings, ICS and CCS negatively influence AIS patients' outcome treated by interventional therapies. ICS might exert an unfavorable effect both by cerebral hypoperfusion and by continuous microembolization toward ischemic area, while CCS is probable involved in reducing the collateral circles effectiveness. The importance of early carotid stenosis detection and treatment should then be reevaluated not only to manage the prevention approaches but also to obtain insights about post-stroke treatment strategies efficacy.

Vascular hyperintensities on baseline FLAIR images are associated with functional outcome in stroke patients with successful recanalization after mechanical thrombectomy

PURPOSE

The purpose of this study was to assess the prognostic value of vascular hyperintensities on FLAIR images (VHF) at admission MRI in patients with acute ischemic stroke (AIS) achieving successful recanalization after mechanical thrombectomy.

MATERIALS AND METHODS

Patients with AIS treated by mechanical thrombectomy following admission MRI from the single-center HIBISCUS-STROKE cohort were assessed for eligibility. VHF were categorized using a four-scale classification and were considered poor when grade < 3 (i.e., absence of distal VHF). Recanalization was considered successful when modified thrombolysis in cerebral infarction score was ≥ 2B Functional outcome was considered poor if modified Rankin scale (mRS) at three months was > 2. Univariable and multiple variable logistic regressions were performed to identify factors associated with poor functional outcome despite successful recanalization.

RESULTS

A total of 108 patients were included. There were 65 men and 43 women with a median age of 70.5 years (interquartile range: 55.0, 81.0; age range: 22.0-93.0 years). Among them, 39 subjects (36.1%) had poor functional outcome at three months. Univariable logistic regressions indicated that poorly extended VHF (VHF grade < 3) were associated with a poor functional outcome (P = 0.008) as well as age, hypertension and diabetes, baseline National Institute of Health Stroke Scale (NIHSS) score, pre-stroke mRS, lack of intravenous thrombolysis, cerebral microangiopathy and the presence of microbleeds. Multivariable analysis confirmed that poor VHF status was independently associated with a poor functional outcome (odds ratio [OR], 4.26; 95% confidence interval [CI]: 1.55-12.99; P = 0.007) in combination with hypertension (OR, 1.25; 95% CI: 0.87-1.85; P = 0.02), baseline NIHSS score (OR, 1.09; 95% CI: 1.04-1.20; P = 0.03), pre-stroke mRS (OR, 2.05; 95% CI: 1.07-4.61; P = 0.05) and lack of intravenous thrombolysis (OR, 0.23; 95% CI: 0.08-0.61; P = 0.004).

CONCLUSION

Poorly extended VHF (grade <3) at admission MRI are associated with a poor functional outcome at three months despite successful recanalization by mechanical thrombectomy.

Pivotal role of multiphase computed tomography angiography for collateral assessment in patients with acute ischemic stroke

The cerebral collateral circulation is the main compensatory mechanism that maintains the ischemic penumbra viable, the tissue at risk for infarction that can be saved if blood flow is restored by reperfusion therapies. In clinical practice, the extent of collateral vessels recruited after vessel occlusion can be easily assessed with computed tomography angiography (CTA) using two different techniques: single-phase CTA (sCTA) and multi-phase CTA (mCTA). Both these methodologies have demonstrated a high prognostic predictive value for prognosis due to the strong association between the presence of good collaterals and favorable radiological and clinical outcomes in patients with acute ischemic stroke (AIS). However, mCTA seems to be superior to sCTA in the evaluation of collaterals and a promising tool for identifying AIS patients who can benefit from reperfusion therapies. In particular, it has recently been proposed the use of mCTA eligibility criteria has been recently proposed for the selection of AIS patients suitable for endovascular treatment instead of the current accepted criteria based on CT perfusion. In this review, we analyzed the characteristics, advantages and disadvantages of sCTA and mCTA to better understand their fields of application and the potential of mCTA in becoming the method of choice to assess collateral extent in AIS patients.

Automated LVO detection and collateral scoring on CTA using a 3D self-configuring object detection network: a multi-center study

The use of deep learning (DL) techniques for automated diagnosis of large vessel occlusion (LVO) and collateral scoring on computed tomography angiography (CTA) is gaining attention. In this study, a state-of-the-art self-configuring object detection network called nnDetection was used to detect LVO and assess collateralization on CTA scans using a multi-task 3D object detection approach. The model was trained on single-phase CTA scans of 2425 patients at five centers, and its performance was evaluated on an external test set of 345 patients from another center. Ground-truth labels for the presence of LVO and collateral scores were provided by three radiologists. The nnDetection model achieved a diagnostic accuracy of 98.26% (95% CI 96.25-99.36%) in identifying LVO, correctly classifying 339 out of 345 CTA scans in the external test set. The DL-based collateral scores had a kappa of 0.80, indicating good agreement with the consensus of the radiologists. These results demonstrate that the self-configuring 3D nnDetection model can accurately detect LVO on single-phase CTA scans and provide semi-quantitative collateral scores, offering a comprehensive approach for automated stroke diagnostics in patients with LVO.

Evaluation of Collateral Circulation in Patients with Acute Ischemic Stroke

The cerebral collateral circulation is an increasingly important consideration in the management of acute ischemic stroke and is a key determinant of outcomes. Growing evidence has demonstrated that better collaterals can predict the rate of infarct progression, degree of recanalization, the likelihood of hemorrhagic transformation and various therapeutic opportunities. Collaterals can also identify those unlikely to respond to reperfusion therapies, helping to optimize resources. More randomized trials are needed to evaluate the risks and benefits of endovascular reperfusion with consideration of collateral status. This reviews our current understanding of the pathophysiologic mechanisms, effect on outcomes and strategies for improvement of the collateral system.

Under (back) pressure: Better collateral flow may facilitate clot removal in ischemic stroke: A systematic review and meta-analysis

BACKGROUND

Collateral status may facilitate clot removal and affect rates of successful reperfusion following endovascular therapy (EVT) for acute ischemic stroke (AIS).

METHODS

Following the PRISMA guidelines, a systematic literature review of the English language literature was conducted using PubMed, Scopus, Web of Science, and Embase. Papers which focused on collateral status and patients treated with EVT for AIS were included in our analysis. Outcomes of interest included collateral score grading, rates of successful reperfusion defined as thrombolysis in cerebral infarction (TICI) score 2b-3 and onset to revascularization time. We calculated pooled odds ratio (OR) or mean difference (MD) and their corresponding 95% confidence intervals (CI) based on collateral status.

RESULTS

16 studies, with 6073 patients, were included in our analysis. Among the included studies, there were six different collateral grading scales, which were dichotomized into "good to moderate" and "poor" collaterals. Odds of successful reperfusion were significantly higher among patients with good to moderate collateral circulation compared to those with poor collaterals (OR =  1.61; 95% CI = 1.24 to 2.09; P-value < 0.001); however, there was heterogeneity among included studies (I2= 5 4%; P-value = 0.008). Onset to revascularization time was comparable between patients with good to moderate collateral circulation compared to those with poor collaterals (MD = 3.91 min; 95% CI = -8.71 to 16.53; P-value = 0.544); however, there was heterogeneity among included studies (I2= 60%; P-value = 0.014).

CONCLUSIONS

The presence of good collaterals may increase the odds of achieving successful reperfusion following EVT for AIS. Improved collateral flow was associated with improved angiographic outcomes, although future work is needed to determine if a causal relationship exists.

Prognostic significance of blood pressure parameters after mechanical thrombectomy according to collateral status

BACKGROUND

Mechanical thrombectomy (MT) has been proven as an effective and safe therapy for patients with acute ischemic stroke from large vessel occlusion. However, there is still a controversial topic about post-procedural management including blood pressure (BP).

METHODS

A total of 294 patients who received MT in Second Affiliated Hospital of Soochow University from April 2017 to September 2021 were included consecutively. The association of blood pressure parameters (BPV and hypotension time) with poor functional outcome was evaluated using logistic regression models. Meanwhile, the effects of BP parameters on mortality was analyzed using cox proportional hazards regression models. Furthermore, the corresponding multiplicative term was added to the above models to study the interaction between BP parameters and CS.

RESULTS

Two hundred ninety four patients were included finally. The mean age was 65.5 years. At the 3-month follow-up, 187(61.5%) had poor functional outcome and 70(23.0%) died. Regardless of the CS, BP CV is positively associated with poor outcome. Hypotension time was negatively associated with poor outcome. We conducted a subgroup analysis according to CS. BPV was significantly associated with mortality at 3-month and displayed a trend toward poor outcome for patients with poor CS only. The interaction between SBP CV and CS with respect to mortality after adjusting for confounding factors was statistically significant (P for interaction = 0.025) and the interaction between MAP CV and CS with respect to mortality after multivariate adjustment was also statistically significant (P for interaction = 0.005).

CONCLUSION

In MT-treated stroke patients, higher BPV in the first 72 h is significantly associated with poor functional outcome and mortality at 3-month regardless of CS. This association was also found for hypotension time. Further analysis showed CS modified the association between BPV and clinical prognosis. BPV displayed a trend toward poor outcome for patients with poor CS.

Ischemic Lesion Growth in Patients with a Persistent Target Mismatch After Large Vessel Occlusion

BACKGROUND

Failure to reperfuse a cerebral occlusion resulting in a persistent penumbral pattern has not been fully described.

METHODS

We retrospectively reviewed patients with anterior large vessel occlusion who did not receive reperfusion, and underwent repeated perfusion imaging, with baseline imaging < 6 h after onset and follow-up scans from 16-168 h. A persistent target mismatch (PTM) was defined as core volume of < 100 mL, mismatch ratio > 1.2, and mismatch volume > 10 mL on follow-up imaging. Patients were divided into PTM or non-PTM groups. Ischemic core and penumbral volumes were compared between baseline and follow-up imaging between the two groups, and collateral flow status assessed using CT perfusion collateral index.

RESULTS

A total of 25 patients (14 PTM and 11 non-PTM) were enrolled in the study. Median core volumes increased slightly in the PTM group, from 22 to 36 ml. There was a much greater increase in the non-PTM group, from 57 to 190 ml. Penumbral volumes were stable in the PTM group from a median of 79 ml at baseline to 88 ml at follow-up, whereas penumbra was reduced in the non-PTM group, from 120 to 0 ml. Collateral flow status was also better in the PTM group and the median collateral index was 33% compared with 44% in the non-PTM group (p = 0.043).

CONCLUSION

Multiple patients were identified with limited core growth and large penumbra (persistent target mismatch) > 16 h after stroke onset, likely due to more favorable collateral flow.

Risk factors of unexplained early neurological deterioration after treatment for ischemic stroke due to large vessel occlusion: a post hoc analysis of the HERMES study

BACKGROUND

Early neurological deterioration (END) after endovascular treatment (EVT) in patients with anterior circulation acute ischemic stroke (AIS) is associated with poor outcome. END may remain unexplained by parenchymal hemorrhage (UnEND). We aim to analyze the risk factors of UnEND in the medical management (MM) and EVT arms of the HERMES study.

METHODS

We conducted a post-hoc analysis of anterior AIS patients who underwent EVT for proximal anterior occlusions. Risk factors of UnEND, defined as a worsening of ≥4 points between baseline National Institutes of Health Stroke Scale (NIHSS) and NIHSS at 24 hours without hemorrhage, were compared between both arms using mixed logistic regression models adjusted for baseline characteristics. An interaction analysis between the EVT and MM arms for risk factors of UnEND was conducted.

RESULTS

Among 1723 patients assessable for UnEND, 160 patients experienced an UnEND (9.3%), including 9.1% (78/854) in the EVT arm and 9.4% (82/869) in the MM arm. There was no significant difference in the incidence of UnEND between the two study arms. In the EVT population, independent risk factors of UnEND were lower baseline NIHSS, higher baseline glucose, and lower collateral grade. In the MM population, the only independent predictor of UnEND was higher baseline glucose. However, we did not demonstrate an interaction between EVT and MM for baseline factors as risk factors of UnEND. UnEND was, similarly in both treatment groups, a significant predictor of unfavorable outcome in both the EVT (p<0.001) and MM (p<0.001) arms.

CONCLUSIONS

UnEND is not an uncommon event, with a similar rate which ever treatment arm is considered. In the clinical scenario of AIS due to large vessel occlusion, no patient-related factor seems to increase the risk for UnEND when treated by EVT compared with MM.

The prognostic value of caveolin-1 levels in ischemic stroke patients after mechanical thrombectomy

BACKGROUND AND PURPOSE

The impact of serum caveolin-1 (Cav-1) on clinical outcomes in patients after mechanical thrombectomy (MT) is unclear. We aimed to investigate the association between serum cav-1 levels and the 3-month functional outcome.

METHODS

We prospectively enrolled and analyzed patients with an anterior circulation large vessel occlusion who underwent MT. Serum cav-1 concentrations were tested after admission. The primary outcome was a 90-day modified Rankin Scale score of 3-6.

RESULTS

Of the 237 recruited patients (mean age, 69.7 ± 12.1 years; 152 male), 131 (55.3%) experienced a 90-day poor outcome. After adjustment for demographic characteristics and other covariates, patients with higher serum Cav-1 levels had a reduced risk of poor outcome at 3 months (Per 1-standard deviation increase; odd ratios [OR], 0.59; 95% confidence interval [CI], 0.39 - 0.89, P = 0.013). Elevated Cav-1 concentrations (Per 1-standard deviation increase; OR, 0.59; 95% CI, 0.40 - 0.88, P = 0.011) were significantly associated with a favorable shift in modified Rankin Scale score distribution. Similar results were confirmed when the Cav-1 levels were analyzed as a categorical variable. Furthermore, the restricted cubic spline showed a linear association between Cav-1 levels and 90-day poor outcome (P = 0.032 for linearity).

CONCLUSIONS

Increased serum Cav-1 levels were associated with improved prognosis at 3 months in ischemic stroke patients after MT, suggesting that Cav-1 may be a potential prognostic biomarker for ischemic stroke after reperfusion therapy.

The impact of leptomeningeal collaterals in acute ischemic stroke: a systematic review and meta-analysis

OBJECTIVES

Leptomeningeal collaterals provide an alternate pathway to maintain cerebral blood flow in stroke to prevent ischemia, but their role in predicting the outcome is still unclear. So, our study aims at assessing the significance of collateral blood flow (CBF) in acute stroke.

METHODS

Electronic databases were searched under different MeSH terms from January 2000 to February 2019. Studies were included if there was available data on good and poor CBF in acute ischemic stroke (AIS). The clinical outcomes included were modified Rankin scale (mRS), recanalization, mortality, and symptomatic intracranial hemorrhage (sICH) at 90 days. Data was analyzed using a random-effect model.

RESULTS

A total of 47 studies with 8194 patients were included. Pooled meta-analysis revealed that there exist twofold higher likelihood of favorable clinical outcome (mRS ≤ 2) at 90 days with good CBF compared with poor CBF (RR: 2.27; 95% CI: 1.94-2.65; p < 0.00001) irrespective of the thrombolytic therapy [RR with IVT: 2.90; 95% CI: 2.14-3.94; p < 0.00001, and RR with IAT/EVT: 1.99; 95% CI: 1.55-2.55; p < 0.00001]. Moreover, there exists onefold higher probability of successful recanalization with good CBF (RR: 1.31; 95% CI: 1.15-1.49; p < 0.00001). However, there was 54% and 64% lower risk of sICH and mortality respectively in patients with good CBF in AIS (p < 0.00001).

CONCLUSIONS

The relative risk of favorable clinical outcome is more in patients with good pretreatment CBF. This could be explained due to better chances of recanalization combined with a lesser risk of intracerebral hemorrhage with good CBF status.

Prognostic accuracy and impact of cerebral collateral status on clinical and safety outcomes in acute ischemic stroke patients receiving reperfusion therapy: a systematic meta-analysis

BACKGROUND

Cerebral collateral status has a potential role in mediating postreperfusion clinical and safety outcomes in acute ischemic stroke (AIS).

PURPOSE

To investigate the prognostic accuracy and impact of collateral status on clinical and safety outcomes in patients with AIS receiving reperfusion therapy.

MATERIAL AND METHODS

Studies with AIS patients treated with reperfusion therapy, collateral status assessed using Tan, ASITN/SIR, or similar collateral grading methods and data stratified according to collateral status were included. Relevant data on clinical outcomes, such as functional outcome at 90 days, mortality at 90 days, angiographic reperfusion, symptomatic intracerebral hemorrhage (sICH) and hemorrhagic transformation (HT), were collated and analyzed.

RESULTS

A meta-analysis of 18 studies involving 4132 patients with AIS was conducted. Good collateral status was significantly associated with angiographic reperfusion (odds ratio [OR]=1.97, 95% confidence interval [CI]=1.38-2.80; P < 0.0001), sICH (OR=0.67, 95% CI=0.46-0.99; P = 0.042), and 90-day functional outcome (OR=3.05, 95% CI=1.78-5.24; P < 0.0001). However, its association with HT (OR=0.76, 95% CI=0.38-1.51; P = 0.425) and three-month mortality (OR=0.53, 95% CI=0.17-1.69; P = 0.280) did not reach statistical significance. The prognostic accuracy of collaterals for predicting angiographic reperfusion, HT, functional outcome (at 90 days), and mortality (at 90 days) were 63%, 49%, 66%, and 48%, respectively.

CONCLUSION

Cerebral collaterals are significantly associated with clinical and safety outcomes, albeit with a prognostic accuracy range of 48%-66%; thus, evaluation of their patency is a useful prognostic tool in patients with AIS receiving reperfusion therapy.

Therapeutic Induction of Collateral Flow

Therapeutic induction of collateral flow as a means to salvage tissue and improve outcome from acute ischemic stroke is a promising approach in the era in which endovascular therapy is no longer time-dependent but collateral-dependent. The importance of collateral flow enhancement as a therapeutic for acute ischemic stroke extends beyond those patients with large amounts of salvageable tissue. It also has the potential to extend the time window for reperfusion therapies in patients who are ineligible for endovascular thrombectomy. In addition, collateral enhancement may be an important adjuvant to neuroprotective agents by providing a more robust vascular route for which treatments can gain access to at risk tissue. However, our understanding of collateral hemodynamics, including under comorbid conditions that are highly prevalent in the stroke population, has hindered the efficacy of collateral flow augmentation for improving stroke outcome in the clinical setting. This review will discuss our current understanding of pial collateral function and hemodynamics, including vasoactivity that is critical for enhancing penumbral perfusion. In addition, mechanisms by which collateral flow can be increased during acute ischemic stroke to limit ischemic injury, that may be different depending on the state of the brain and vasculature prior to stroke, will also be reviewed.

Collateral Status and Outcomes after Thrombectomy

Endovascular treatment (EVT) using novel mechanical thrombectomy devices has been the gold standard for patients with acute ischemic stroke caused by large vessel occlusion. Selection criteria of randomized control trials commonly include baseline infarct volume with or without penumbra evaluation. Although the collateral status has been studied and is known to modify imaging results and clinical course, it has not been commonly used for trials. Many post hoc studies, however, revealed that collateral status can help predict infarct growth, recanalization success, decreased hemorrhagic transformation after EVT, and extension of the therapeutic time window for revascularization. Here, we systematically review the recent literature and summarized the outcomes of EVT according to the collateral status of patients with acute ischemic stroke caused by large vessel occlusion. The studies reviewed indicate that pretreatment collateral circulation is associated with both clinical and imaging outcomes after EVT in patients with acute ischemic stroke due to large vessel occlusion although most patients were already selected by other imaging or clinical criteria. However, treatment decisions using information on patients' collateral status have not progressed in clinical practice. Further randomized trials are needed to evaluate the risks and benefits of EVT in consideration of collateral status.

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.

Time dependency of automated collateral scores in computed tomography angiography and computed tomography perfusion images in patients with intracranial arterial occlusion

PURPOSE

The assessment of collateral status may depend on the timing of image acquisition. The purpose of this study is to investigate whether there are optimal time points in CT Perfusion (CTP) for collateral status assessment, and compare collaterals scores at these time points with collateral scores from multiphase CT angiography (mCTA).

METHODS

Patients with an acute intracranial occlusion who underwent baseline non-contrast CT, mCTA and CT perfusion were selected. Collateral status was assessed using an automatically computed Collateral Ratio (CR) score in mCTA, and predefined time points in CTP acquisition. CRs extracted from CTP were correlated with CRs from mCTA. In addition, all CRs were related to baseline National Institutes of Health Stroke Scale (NIHSS) and Alberta Stoke Program Early CT Score (ASPECTS) with linear regression analysis to find the optimal CR.

RESULTS

In total 58 subjects (median age 74 years; interquartile range 61-83 years; 33 male) were included. When comparing the CRs from the CTP vs. mCTA acquisition, the strongest correlations were found between CR from baseline mCTA and the CR at the maximal intensity projection of time-resolved CTP (r = 0.81) and the CR at the peak of arterial enhancement point (r = 0.78). Baseline mCTA-derived CR had the highest correlation with ASPECTS (β = 0.36 (95%CI 0.11, 0.61)) and NIHSS (β = - 0.48 (95%CI - 0.72, - 0.16)).

CONCLUSION

Collateral status assessment strongly depends on the timing of acquisition. Collateral scores obtained from mCTA imaging is close to the optimal collateral score obtained from CTP imaging.

Efficacy and safety of endovascular treatment in patients older than 90 with acute ischemic stroke: A retrospective cohort study

Background

Endovascular treatment (EVT) for acute ischemic stroke (AIS) with large vessel occlusion (LVO) is the standard of care treatment today. Although elderly patients comprise the majority of stroke patients, octogenarians and non-agenarians are often poorly represented or even excluded in clinical trials. We looked at the safety and efficacy of EVT for AIS with LVO in patients over 90 (Non-agenarians), in comparison to patients aged 80-89 (Octogenarians) and to patients younger than 80 years (<80yrs).

Methods

A retrospective analysis of patients who underwent EVT in a single stroke center during 2015-2019. Patients were divided into three subgroups based on their age: Non-agenarians, Octogenarians, and patients <80 yrs. The groups were compared based on baseline characteristics and stroke variables. In addition, we compared clinical and radiological outcomes including functional outcomes measured by the modified ranking scale (mRS) at day 90, symptomatic intracranial hemorrhage (sICH), and mortality.

Results

Three hundred and forty seven patients were included, 20 (5.7%) of them were non-agenarians, 96 (27.7%) were octogenarians and 231 (66.6%) were <80 yrs. No statistically significant differences were found between groups regarding baseline characteristics, cardiovascular risk factors, stroke variables, or successful revascularization rates. Puncture to recanalization time intervals showed an age-related non-significant increase between the groups with a median time of 67.8, 51.6, and 40.2 min of the non-agenarian, octogenarian, and <80 yrs groups, respectively (p-value = 0.3). Favorable outcome (mRS 0-2) was 15% in non-agenarians vs. 13.54% in octogenarians (p-value = 1) and 40.2% in <80 yrs. sICH occurred among 5% of non-agenarians, compared to 4% among octogenarians (p-value = 1) and 2.6% in <80 yrs. The mortality rate at 3 months was significantly higher (55%) in non-agenarians compared to octogenarians (28%) (p-value = 0.03) and to <80 yrs (19.48%).

Conclusion

EVT in nonagenarians demonstrated a high rate of successful revascularization, whilst also showing an increased rate of sICH when compared to octogenarians. Mortality rates showed an age-related correlation. Although further studies are needed to clarify the patient selection algorithm and identify sub-groups of elderly patients that could benefit from EVT, we showed that some patients do benefit from EVT therefore exclusion should not be based on age alone.

Multicentre registration of wake-up stroke in China (MCRWUSC): a protocol for a prospective, multicentre, registry-based cohort study

INTRODUCTION

Wake-up stroke (WUS) is a type of acute ischaemic stroke (AIS) that occurs during sleep with unknown time of symptom onset. The best treatment is usually not suitable for WUS, as thrombolysis is usually provided to patients who had a symptomatic AIS within a definite 4.5 hours, and WUS remains a therapeutic quandary. Efforts to explore the onset time characteristics of patients who had a WUS and the risk factors affecting poor prognosis support a role for providing new insights by performing multicentre cohort study.

METHODS AND ANALYSIS

This multicentre, nationwide prospective registry will include 21 comprehensive stroke centres, with a goal of recruiting 550 patients who had a WUS in China. In this study, clinical data including patient's clinical characteristics, stroke onset time, imaging findings, therapeutic interventions and prognosis (the National Institutes of Health Stroke Scale Score and the modified Rankin Scale Score at different time points) will be used to develop prediction models for stroke onset time and prognostic evaluation using the fast-processing of ischemic stroke software. The purpose of this study is to identify risk factors influencing prognosis, to investigate the relationship between the time when the symptoms are found and the actual onset time and to establish an artificial intelligence-based model to predict the prognosis of patients who had a WUS.

ETHICS AND DISSEMINATION

This study is approved by the ethics committee of Shanghai Pudong Hospital (Shanghai, China) and rest of all participating centres. The findings will be disseminated through peer-reviewed publications and conference presentations.

PROSPERO REGISTRATION NUMBER

ChiCTR2100049133.

Correlation of Collateral Scores Derived from Whole-Brain Time-Resolved Flat Panel Detector Imaging in Acute Ischemic Stroke

BACKGROUND AND PURPOSE

Flat panel detector CT imaging allows simultaneous acquisition of multiphase flat panel CTA and flat panel CTP imaging directly in the angio suite. We compared collateral assessment derived from multiphase flat panel CTA and flat panel CTP with collateral assessment derived from DSA as the gold-standard.

MATERIALS AND METHODS

We performed a retrospective analysis of patients with occlusion of the first or second segment of the MCA who underwent pre-interventional flat panel detector CT. The hypoperfusion intensity ratio as a correlate of collateral status was calculated from flat panel CTP (time-to-maximum > 10 seconds volume/time-to-maximum > 6 seconds volume). Intraclass correlation coefficients were calculated for interrater reliability for the Calgary/Menon score for multiphase flat panel CTA and for the American Society of Interventional and Therapeutic Neuroradiology/Society of Interventional Radiology (ASITN/SIR) score for DSA collateral scores. Correlations of the hypoperfusion intensity ratio, multiphase flat panel CTA score, and the ASITN/SIR score were calculated using the Spearman correlation.

RESULTS

From November 2019 to February 2020, thirty patients were included. Moderate interrater reliability was achieved for the ASITN/SIR DSA score (0.68; 95% CI, 0.50-0.82) as well as for the Calgary/Menon multiphase flat panel CTA score (0.53; 95% CI, 0.29-0.72). We found a strong correlation between the ASITN/SIR DSA and Calgary/Menon multiphase flat panel CTA score (ρ = 0.54, P = .002) and between the hypoperfusion intensity ratio and the Calgary/Menon multiphase flat panel CTA score (ρ = -0.57, P < .001). The correlation was moderate between the hypoperfusion intensity ratio and the ASITN/SIR DSA score (ρ = -0.49, P = .006). The infarct core volume correlated strongly with the Calgary/Menon multiphase flat panel CTA score (ρ = -0.66, P < .001) and the hypoperfusion intensity ratio (ρ = 0.76, P < .001) and correlated moderately with the ASITN/SIR DSA score (ρ = -0.46, P = .01).

CONCLUSIONS

The Calgary/Menon multiphase flat panel CTA score and the hypoperfusion intensity ratio correlated with each other and with the ASITN/SIR DSA score as the gold-standard. In our cohort, the collateral scoring derived from flat panel detector CT was clinically reliable.

A 3D Multi-task Regression and Ordinal Regression Deep Neural Network for Collateral Imaging from Dynamic Susceptibility Contrast-Enhanced MR perfusion in Acute Ischemic Stroke

BACKGROUND AND OBJECTIVE

Cerebral collaterals have been identified as one of the primary determinants for treatment options in acute ischemic stroke. Several works have been proposed, but these have not been adopted for a routine clinical usage due to their manual and heuristic nature as well as inconsistency and instability of the assessment. Herein, we present an advanced deep learning-based method that can automatically generate a multiphase collateral imaging (collateral map) derived from dynamic susceptibility contrast-enhanced MR perfusion (DSC-MRP) in an accurate and robust manner.

METHODS

We develop a 3D multi-task regression and ordinal regression deep neural network for generating collateral maps from DSC-MRP, which formulates the prediction of collateral maps as both a regression task and an ordinal regression task. For an ordinal regression task, we introduce a spacing-decreasing discretization (SDD) strategy to represent the intensity of the collateral status on a discrete, ordinal scale. We also devise loss functions to achieve effective and efficient multi-task learning.

RESULTS

We systematically evaluated the performance of the proposed network using DSC-MRP from 802 patients. On average, the proposed network achieved ≥0.900 squared correlation coefficient (R-Squared), ≥0.916 Tanimoto measure (TM), ≥0.0913 structural similarity index measure (SSIM), and ≤0.564 × 10^-1 mean absolute error (MAE), outperforming eight competing models that have been recently developed in medical imaging and computer vision. We also found that the proposed network could provide an improved contrast between the low and high intensity regions in the collateral maps, which is a key to an accurate evaluation of the collateral status.

CONCLUSIONS

The experimental results demonstrate that the proposed network is able to generate collateral maps with high accuracy, facilitating a timely and prompt assessment of the collateral status in clinlcs. The future study will entail the optimization of the proposed network and its clinical evalution in a prospective manner.

Association between Early Ischemic Changes and Collaterals in Acute Stroke: A Retrospective Study

BACKGROUND AND PURPOSE

The quality of leptomeningeal collaterals may influence the speed of infarct progression in acute stroke. Our main objective was to evaluate the association of leptomeningeal collateral score and its interaction with time with ischemic changes on CT in patients with acute stroke.

MATERIALS AND METHODS

Adult patients with acute stroke symptoms and anterior circulation large-vessel occlusion on CTA from 2015 to 2019 were included. Routinely performed NCCT and multiphase CTA were reviewed to assess ASPECTS and the leptomeningeal collateral score. We built multivariate regression models to assess the association between leptomeningeal collateral score and its interaction with time and ASPECTS. Performance measures to predict poor ASPECTS at different time thresholds (identified with receiver operating characteristic curve analysis) were estimated in a subgroup of patients with poor leptomeningeal collateral scores.

RESULTS

Leptomeningeal collateral scores 0-1 were associated with lower ASPECTS, and the model with dichotomized and trichotomized leptomeningeal collateral score showed a significant multiplicative interaction between time and the leptomeningeal collateral score. The negative predictive value for poor ASPECTS was >0.9 for at least the first 3 hours from stroke onset to imaging, and the positive predictive value was <0.5 for every time threshold tested in the subgroup of patients with leptomeningeal collateral scores 0-3.

CONCLUSIONS

Poor (0-1) leptomeningeal collateral scores were associated with lower ASPECTS, and an increase in time has a multiplicative interaction with the leptomeningeal collateral score on ASPECTS.

Evaluation of collateral status and outcome in patients with middle cerebral artery stenosis in late time window by CT perfusion imaging

Objectives

Collateral status (CS) is a crucial determinant of outcome in patients with ischemic stroke. We aimed to test whether the cerebral blood volume (CBV) and cerebral blood flow (CBF) based on computed tomography perfusion (CTP) measurements can quantitatively evaluate CS and explore the predictive ability of CTP parameters in determining clinical outcomes in patients with MCA severe stenosis or occlusion presenting beyond 24 h.

Materials and methods

In this retrospective study, data obtained from September 2018 to March 2022 in consecutive stroke patients caused by isolated middle cerebral artery severe stenosis or occlusion were reviewed within 24–72 h after onset. Correlation between the collateral score systems assessed with CT angiography (CTA) and CTP parameters was calculated using the Spearman correlation. The optimal threshold of the CBV ratio for predicting a good outcome was determined using receiver operating characteristic curve (ROC) analysis.

Results

A total of 69 patients met inclusion criteria. Both the CBV ratio and the CBF ratio had significant correlation with collateral score systems assessed with CTA [CBV ratio and Tan score: rs = 0.702, P &lt; 0.0001; CBV ratio and regional leptomeningeal collateral (rLMC) score: rs = 0.705, P &lt; 0.0001; CBV ratio and Miteff score: rs = 0.625, P &lt; 0.0001. CBF ratio and Tan score: rs= 0.671, P &lt; 0.0001; CBF ratio and rLMC score: rs = 0.715, P &lt; 0.0001; CBF ratio and Miteff score: rs = 0.535, P &lt; 0.0001]. ROC analysis revealed the CBV ratio performed better than the qualitative collateral assessments and the CBF ratio in the prediction of a favorable 90-day modified Rankin scale score. The CBV ratio was a useful parameter that predicted a good functional outcome [area under the curve (AUC), 0.922; 95% CI, 0.862 ± 0.982].

Conclusions

In late time window stroke patients, the CBV and CBF ratio on CTP may be valuable parameters for quantitatively revealing the collateral status after stroke. In addition, the CBV ratio was the predictor of clinical outcomes in patients with MCA severe stenosis or occlusion.