A Multicenter, Randomized, Controlled Study to Investigate Extending the Time for Thrombolysis in Emergency Neurological Deficits with Intra-Arterial Therapy (EXTEND-IA)

Whole Blood Viscosity and Cerebral Blood Flow in Acute Ischemic Stroke

Existing effective treatments for ischemic stroke restore blood supply to the ischemic region using thrombolysis or mechanical removal of clot. However, it is increasingly recognized that successful removal of occlusive thrombus from the large artery-recanalization, may not always be accompanied by successful restoration of blood flow to the downstream tissues-reperfusion. Ultimately, brain tissue survival depends on cerebral perfusion, and a functioning microcirculation. Because capillary diameter is often equal to or smaller than an erythrocyte, microcirculation is largely dependent on erythrocyte rheological (hemorheological) factors such as whole blood viscosity (WBV). Several studies in the past have demonstrated elevated WBV in stroke compared with healthy controls. Also, elevated WBV has shown to be an independent risk factor for stroke. Elevated WBV leads to endothelial dysfunction, decreases nitric oxide-dependent flow-mediated vasodilation, and promotes hemostatic alterations/thrombosis, all leading to microcirculation sludging. Compromised microcirculation further leads to decreased cerebral perfusion. Hence, modulating WBV through pharmacological agents might be beneficial to improve cerebral perfusion in stroke. This review discusses the effect of elevated WBV on endothelial function, hemostatic alterations, and thrombosis leading to reduced cerebral perfusion in stroke.

Ion Dyshomeostasis in the Early Hyperacute Phase after a Temporary Large-Vessel Occlusion Stroke

Element dysregulation is a pathophysiologic hallmark of ischemic stroke. Prior characterization of post-stroke element dysregulation in the photothrombotic model demonstrated significant element changes for ions that are essential for the function of the neurovascular unit. To characterize the dynamic changes during the early hyperacute phase (<6 h), we employed a temporary large-vessel occlusion stroke model. The middle cerebral artery was temporarily occluded for 30 min in male C57BL/6 mice, and coronal brain sections were prepared for histology and X-ray fluorescence microscopy from 5 to 120 min post-reperfusion. Ion dysregulation was already apparent by 5 min post-reperfusion, evidenced by reduced total potassium in the lesion. Later time points showed further dysregulation of phosphorus, calcium, copper, and zinc. By 60 min post-reperfusion, the central portion of the lesion showed pronounced element dysregulation and could be differentiated from a surrounding region of moderate dysregulation. Despite reperfusion, the lesion continued to expand dynamically with increasing severity of element dysregulation throughout the time course. Given that the earliest time point investigated already demonstrated signs of ion disruption, we anticipate such changes may be detectable even earlier. The profound ion dysregulation at the tissue level after reperfusion may contribute to hindering treatments aimed at functional recovery of the neurovascular unit.

Numerical Cincinnati Stroke Scale versus Stroke Severity Screening Tools for the Prehospital Determination of LVO

Background

Previous research demonstrated that the numerical Cincinnati Prehospital Stroke Scale (CPSS) identifies large vessel occlusion (LVO) at similar rates compared to a limited number of stroke severity screening tools. We aimed to compare numerical CPSS to additional stroke scales using a national EMS database.

Methods

Using the ESO Data Collaborative, the largest EMS database with hospital linked data, we retrospectively analyzed prehospital patient records for the year 2022. Stroke and LVO diagnoses were determined by ICD-10 codes from linked hospital discharge and emergency department records. Prehospital CPSS was compared to the Cincinnati Stroke Triage Assessment Tool (C-STAT), the Field Assessment Stroke Triage for Emergency Destination (FAST-ED), and the Balance Eyes Face Arm Speech Time (BE-FAST). The optimal prediction cut-points for LVO screening were determined by intersecting the sensitivity and specificity curves for each scale. To compare the discriminative abilities of each scale among those diagnosed with LVO, we used the area under the receiver operating curve (AUROC).

Results

We identified 17,442 prehospital records from 754 EMS agencies with ≥ 1 documented stroke scale of interest: 30.3% (n=5,278) had a hospital diagnosis of stroke, of which 71.6% (n=3,781) were ischemic; of those, 21.6% (n=817) were diagnosed with LVO. CPSS score ≥ 2 was found to be predictive of LVO with 76.9% sensitivity, 68.0% specificity, and AUROC 0.787 (95% CI 0.722-0.801). All other tools had similar predictive abilities, with sensitivity / specificity / AUROC of: C-STAT 62.5% / 76.5% / 0.727 (0.555-0.899); FAST-ED 61.4% / 76.1%/ 0.780 (0.725-0.836); BE-FAST 70.4% / 67.1% / 0.739 (0.697-0.788).

Conclusion

The less complex CPSS exhibited comparable performance to three frequently employed LVO detection tools. EMS agency leadership, medical directors, stroke system directors, and other stroke leaders may consider the complexity of stroke severity instruments and challenges with ensuring accurate recall and consistent application when selecting which instrument to implement. Use of the simpler CPSS may enhance compliance with the utilization of LVO screening instruments while maintaining the accuracy of prehospital LVO determination.

Safety and Efficacy of Aspiration Catheter CAT6 and 5 Fr Navien in the Endovascular Treatment of Acute Ischemic Stroke

BACKGROUND

Mechanical thrombectomy has become a key treatment option for acute ischemic stroke. This study compared the safety and efficacy of aspiration catheter CAT6 and 5 Fr Navien.

METHODS

Thrombectomy was performed in103 patients with the acute internal carotid artery, middle cerebral artery M1 or M2 occlusions, including the CAT6 group (n=53 with stent retriever and CAT6 aspiration) and the 5 Fr Navien group (n=50 with stent retriever and 5 Fr Navien aspiration) at the Advanced Stroke Center.

RESULTS

Overall, an aspiration catheter placement success rate was achieved in 93.2% of cases, 52 (98.11%) for CAT6, and 44 (88.00%) for 5 Fr Navien ( P =0.042). Overall, 17 cases (16.51%) required additional guidewire rates, 5.66% for CAT6, and 13.592% for 5 Fr Navien ( P =0.002). First-pass success rate (FPSR) was achieved in 38.84% of cases overall, a rate that did not differ significantly between catheters: 45.28% for CAT6; 32.00% for 5 Fr Navien ( P =0.167). Final thrombolysis in cerebral infarction 2b or 3 reperfusion was achieved in 91.26% of cases overall, 51 (96.23%) for CAT6, and 43 (86%) for 5 Fr Navien ( P =0.066). The participants had a mean number of passes for the index thrombus of 1.956 and a median procedure time of 65.82±21.8 minutes. There was no significant difference found in 90-day good outcome (mean 42.7%, modified Rankin Score 0 to 2) and 90-day mortality (17%) between CAT6 and 5 Fr Navien.

CONCLUSION

Aspiration catheter placement success rate and first-pass success rate seemed to be higher for CAT6 and, moreover, the rate of additional guidewires was lower.

Computed tomography perfusion stroke mimics on RAPID commercial software: A case-based review

Acute ischemic stroke (AIS) is a leading cause of morbidity worldwide and can present with nonspecific symptoms, making diagnosis difficult. Many neurologic diseases present similarly to stroke; stroke mimics account for up to half of all hospital admissions for stroke. Stroke therapies carry risk, so accurate diagnosis of AIS is crucial for prompt treatment and prevention of adverse outcomes for patients with stroke mimics. Computed tomography (CT) perfusion techniques have been used to distinguish between nonviable tissue and penumbra. RAPID is an operator-independent, automated CT perfusion imaging software that can aid clinicians in diagnosing strokes quickly and accurately. In this case-based review, we demonstrate the applications of RAPID in differentiating between strokes and stroke mimics.

Quantifying infarct core volume in ischemic stroke: What is the optimal threshold and parameters of computed tomography perfusion?

OBJECTIVE

Although computed tomography perfusion (CTP) is used to select and guide decision-making processes in patients with acute ischemic stroke, there is no clear standardization of the optimal threshold to predict ischemic core volume accurately. The infarct core volume with a relative cerebral blood flow(rCBF) threshold of < 30% is commonly used. We aimed to assess the volumetric agreement of the infarct core volume with different CTP parameters and thresholds using CTP software (RAPID, VITREA) and the infarct volume on diffusion-weighted imaging (DWI), with a short interval time (within 60 min) between CTP and follow-up DWI.

MATERIALS AND METHODS

This retrospective study included 42 acute ischemic stroke patients with occlusion of the large artery in the anterior circulation between April 2017-November 2020. RAPID identified infarct core as tissue rCBF < 20-38%. VITREA defined the infarct core as cerebral blood volume (CBV) < 26-56%. Olea Sphere was used to measure infarct core volume on DWI. The CTP-infarct core volume with different thresholds of perfusion parameters (CBF threshold vs CBV threshold) were compared with DWI-infarct core volumes.

RESULTS

The median time between CTP and DWI was 37.5min. The commonly used threshold of CBV< 41% (4.3 mL) resulted in lower median infarct core volume difference compared to the commonly used thresholds of rCBF < 30% (8.2mL). On the other hand, the optimal thresholds of CBV < 26% (-1.0mL; 95% CI, -53.9 to 58.1 mL; 0.945) resulted in the lowest median infarct core volume difference, narrowest limits of agreement, and largest interclass correlation coefficient compared with the optimal thresholds of rCBF < 38% (4.9 mL; 95% CI, -36.4 to 62.9 mL; 0.939).

CONCLUSION

Our study found that the both optimal and commonly used thresholds of CBV provided a more accurate prediction of the infarct core volume in patients with AIS than rCBF.

MRI for collateral assessment pre-thrombectomy and association with outcome: a systematic review and meta-analysis

PURPOSE

Various neuroimaging methods exist to assess the collateral circulation in stroke patients but much of the evidence is based on computed tomography. Our aim was to review the evidence for using magnetic resonance imaging for collateral status evaluation pre-thrombectomy and assess the impact of these methods on functional independence.

METHODS

We systematically reviewed EMBASE and MEDLINE for studies that evaluated baseline collaterals using MRI pre-thrombectomy and conducted a meta-analysis to express the relationship between good collaterals (defined variably as the presence [good] vs absence [poor] or quality [ordinal scores binarized as good-moderate vs poor] of collaterals) and functional independence (modified Rankin score mRS≤2) at 90 days. Outcome data were presented as relative risk (RR, 95% confidence interval, 95%CI). We assessed for study heterogeneity, publication bias, and conducted subgroup analyses of different MRI methods and affected arterial territories.

RESULTS

From 497 studies identified, we included 24 (1957 patients) for the qualitative synthesis, and 6 (479 patients) for the metanalysis. Good pre-thrombectomy collaterals were significantly associated with favorable outcome at 90 days (RR=1.91, 95%CI=1.36-2.68], p= 0.0002) with no difference between MRI methods and affected arterial territory subgroups. There was no evidence of statistical heterogeneity (I²=25%) among studies but there was evidence of publication bias.

CONCLUSION

In stroke patients treated with thrombectomy, good pre-treatment collaterals assessed using MRI are associated with double the rate of functional independence. However, we found evidence that relevant MR methods are heterogenous and under-reported. Greater standardization and clinical validation of MRI for collateral evaluation pre-thrombectomy are required.

Pictorial Review on Imaging Findings in Cerebral CTP in Patients with Acute Stroke and Its Mimics: A Primer for General Radiologists

The imaging evaluation of computed tomography (CT), CT angiography (CTA), and CT perfusion (CTP) is of crucial importance in the setting of each emergency department for suspected cerebrovascular impairment. A fast and clear assignment of characteristic imaging findings of acute stroke and its differential diagnoses is essential for every radiologist. Different entities can mimic clinical signs of an acute stroke, thus the knowledge and fast identification of stroke mimics is important. A fast and clear assignment is necessary for a correct diagnosis and a rapid initiation of appropriate therapy. This pictorial review describes the most common imaging findings in CTP with clinical signs for acute stroke or other acute neurological disorders. The knowledge of these pictograms is therefore essential and should also be addressed in training and further education of radiologists.

The Application of Software "Rapid Processing of Perfusion and Diffusion" in Acute Ischemic Stroke

In the event of an acute ischemic stroke, saving the penumbra is the most important aspect of early treatment. The rapid and accurate identification of ischemic penumbra plays a key role in its comprehensive treatment. At present, the identification method and evaluation standard of ischemic penumbra have not been unified. Numerous pieces of software identifying ischemic penumbra have been developed, such as rapid processing of perfusion and diffusion (RAPID), Sphere, Vitrea, and computed tomography perfusion+ (CTP+). The RAPID software, analyzing and integrating multi-mode image data (mainly based on perfusion weighted imaging (PWI) or computed tomography perfusion (CTP) images, shows good performance in identifying ischemic penumbra and has been utilized for the assessment of ischemic penumbra in many ischemic stroke clinical studies, achieving good outcomes and promoting the transition from "time window" to "tissue window" in the treatment of early stage AIS. To obtain a comprehensive understanding of the RAPID software and its accuracy in evaluating ischemic penumbra, this paper reviews the background and development of the RAPID software, summarizes the published acute cerebral infarction trials using the RAPID software, generalizes the threshold parameters in different time windows, and further discusses its application and limitations.

Hearing Impairment in Stroke Patients- Findings from a Pilot Study Conducted in India

Auditory processing difficulties and hearing loss have been reported among stroke survivors, but is largely neglected. Post-stroke hearing impairment may affect communication between stroke survivors and healthcare professionals, thereby restricting rehabilitation and long-term patient outcome. In this prospective pilot study, we sought to determine the prevalence and pattern of hearing loss in stroke patients when compared to age and sex matched controls. 50 consecutive patients with first-ever stroke, both hemorrhagic and ischemic, and a comparison cohort of 50 age and sex matched controls were assessed. Pure Tone Audiogram was performed in all patients within 15 days of stroke onset and mean hearing loss was determined. Mean audiometric threshold was significantly higher in both ears in stroke patients (mean 44.0 ± 12.1 dB) when compared to the control subjects (36.1 ± 11.4 dB; p = 0.001). After adjusting for Diabetes mellitus and hypertension, sensorineural hearing loss was more common and severe in stroke compared to controls (p < 0.005). Most of the strokes were ischemic and involved middle cerebral artery territory. A modest correlation between hearing threshold and stroke severity in both ears was seen (mean B 0.775, R² 0.54, CI 0.122-1.427, p = 0.020). Our pilot study shows significant hearing impairment in patients with stroke, compared to age and sex matched controls with similar prevalence of cardiovascular risk factors, interestingly seen in a predominantly anterior circulation stroke population. Undetected hearing loss may impact post stroke functional recovery. Hence, current rehabilitation guidelines should include auditory screening in all patients of stroke for detection of hearing loss.

Health outcomes after acute ischemic stroke:retrospective and survival analysis from Oman

BACKGROUND

Stroke mortality and related functional disability have been declining over the last two decades, but stroke continues to represent the second leading cause of cardiovascular death worldwide and the number one cause for acquired long-term disability.

OBJECTIVES

Assess short- and long-term health outcomes after acute ischemic stroke and analyze factors associated with poor survival and functional outcomes.

DESIGN

Retrospective and survival analysis SETTING: Inpatient unit at a tertiary care referral hospital.

PATIENTS AND METHODS

All patients admitted with acute ischemic stroke from 1 January 2017 to 31 August 2018 were included in the study. Functional status was assessed using the modified Rankin Scale (mRS). Other demographic and clinical variables were obtained from medical records. Data were analyzed by multivariable logistic regression, Cox proportional hazards, and the Kaplan-Meier method. Long-term follow-up data, including mortality and mRS was collected by follow-up phone call.

MAIN OUTCOME MEASURES

Functional dependency and factors associated with mortality.

SAMPLE SIZE AND CHARACTERISTICS

110 with mean age of 67.0 (14.7) years; 59 patients (53.6%) were males.

RESULTS

Hypertension (75.5%), diabetes mellitus (54.6%), and dyslipidemia (29.1%) were common. Sixty-five patients (59.1%) had mRS >2 upon discharge including 18 patients (16.4%) who died during the hospital stay. The cumulative mortality rate was 25.4% (28/110) at 12 months and 30.0% (33/110) at 24 months. Twenty-nine stroke survivors (29/70, 41.4%) remained physically dependent (mRS >2) at the end of follow-up. Old age, atrial fibrillation, history of prior stroke, chronic kidney disease, and peripheral arterial disease were associated with increased mortality and functional dependence.

CONCLUSIONS

Patients in Oman with acute ischemic stroke tend to have a high comorbidity burden, and their functional dependency and mortality are higher compared to patients from developed countries. Therefore, evidence-based measures such as establishing stroke units are essential to improve the health outcomes of patients with acute ischemic stroke.

LIMITATIONS

Retrospective at single center.

CONFLICT OF INTEREST

None.

Deep Learning Applications for Acute Stroke Management

Brain imaging is essential to the clinical care of patients with stroke, a leading cause of disability and death worldwide. Whereas advanced neuroimaging techniques offer opportunities for aiding acute stroke management, several factors, including time delays, inter-clinician variability, and lack of systemic conglomeration of clinical information, hinder their maximal utility. Recent advances in deep machine learning (DL) offer new strategies for harnessing computational medical image analysis to inform decision making in acute stroke. We examine the current state of the field for DL models in stroke triage. First, we provide a brief, clinical practice-focused primer on DL. Next, we examine real-world examples of DL applications in pixel-wise labeling, volumetric lesion segmentation, stroke detection, and prediction of tissue fate postintervention. We evaluate recent deployments of deep neural networks and their ability to automatically select relevant clinical features for acute decision making, reduce inter-rater variability, and boost reliability in rapid neuroimaging assessments, and integrate neuroimaging with electronic medical record (EMR) data in order to support clinicians in routine and triage stroke management. Ultimately, we aim to provide a framework for critically evaluating existing automated approaches, thus equipping clinicians with the ability to understand and potentially apply DL approaches in order to address challenges in clinical practice. ANN NEUROL 2022.

Factors affecting mechanical thrombectomy outcome in acute ischemic stroke patients: an Egyptian sample

Background

Stroke constitutes a major health problem worldwide, nowadays endovascular treatment is considered to be a standard of care in acute ischemic stroke patients with large vessel occlusion, accurate prediction of outcome of thrombectomy is essential for health care providers, patients and families. We studied different clinical and radiological variables that could predict functional outcome in stroke patients after thrombectomy. Thirty-four consecutive ischemic stroke patients were included, received intravenous tissue plasminogen activator (iv-tpa), then mechanical thrombectomy was done. Patients were clinically assessed at admission with National Institute of Health Stroke Scale (NIHSS) then evaluated by the Alberta Stroke Program early computerized tomography (CT) score (ASPECTS), clot burden scale (CBS) and collateral score (CS) in multiphase computerized tomography angiography (CTA) then good and poor outcomes at 3 months were defined by Modified Rankin Scale (MRS) of 0–2 and 3–6 points, respectively.

Results

Factors associated with good outcome (MRS 0–2) were lower admission NIHSS score (p < 0.037), small infarct core aspects ≥ 6 (p < 0.001), low clot burden (CBS 7–10) (p = 0.046) good collaterals (2–3) (p = 0.038) and absence of post-procedure hemorrhage (p < 0.0005).

Conclusions

Low admission NIHSS score, absence of post-procedure hemorrhage, small infarct core, low clot burden and good collaterals are reliable factors for good clinical outcome.

Primer reporte de inmaduros de Cryptocephalus Geoffroy, 1762 (Coleoptera: Chrysomelidae) de Brasil con notas de su bioecología sobre Wedelia goyazensis Gardner (Asteraceae) y síntesis de los registros de presencia del género en territorio brasileño

Cryptocephalus Geoffroy, 1762 es reconocido por su distribución cosmopolita y gran riqueza, con al menos 1700 especies descritas. Sin embargo, falta información para Brasil: (1) no hay registro de inmaduros; y (2) no se conoce casi nada sobre la biología de este género. En este trabajo se documentan por primera vez las etapas inmaduras de Cryptocephalus de Brasil y se presentan algunas notas sobre su bioecología en la planta huésped. Además, se recopilan sus registros en territorio brasileño a partir de la bibliografía.

Common scale minimal sufficient balance: An improved method for covariate-adaptive randomization based on the Wilcoxon-Mann-Whitney odds ratio statistic

Minimal sufficient balance (MSB) is a recently suggested method for adaptively controlling covariate imbalance in randomized controlled trials in a manner which reduces the impact on randomness of allocation over other approaches by only intervening when the imbalance is sufficiently significant. Despite its improvements, the approach is unable to consider the relative clinical importance or magnitude of imbalance in each covariate weight, and ignores any imbalance which is not statistically significant, even when these imbalances may collectively justify intervention. We propose the common scale MSB (CS‐MSB) method which addresses these limitations, and present simulation studies comparing our proposed method to MSB. We demonstrate that CS‐MSB requires less intervention than MSB to achieve the same level of covariate balance, and does not adversely impact either statistical power or Type‐I error.

Comparison of Two Automated Computed Tomography Perfusion Applications to Predict the Final Infarct Volume After Thrombolysis in Cerebral Infarction 3 Recanalization

BACKGROUND AND PURPOSE

Several automated computed tomography perfusion software applications have been developed to provide support in the definition of ischemic core and penumbra in acute ischemic stroke. However, the degree of interchangeability between software packages is not yet clear. Our study aimed to evaluate 2 commonly used automated perfusion software applications (Syngo.via and RAPID) for the indication of ischemic core with respect to the follow-up infarct volume (FIV) after successful recanalization and with consideration of the clinical impact.

METHODS

Retrospectively, 154 patients with large vessel occlusion of the middle cerebral artery or the internal carotid artery, who underwent endovascular therapy with a consequent Thrombolysis in Cerebral Infarction 3 result within 2 hours after computed tomography perfusion, were included. Computed tomography perfusion core volumes were assessed with both software applications with different thresholds for relative cerebral blood flow (rCBF). The results were compared with the FIV on computed tomography within 24 to 36 hours after recanalization. Bland-Altman was applied to display the levels of agreement and to evaluate systematic differences.

RESULTS

Highest correlation between ischemic core volume and FIV without significant differences was found at a threshold of rCBF<38% for the RAPID software (r=0.89, P<0.001) and rCBF<25% for the Syngo software (r=0.87, P<0.001). Bland-Altman analysis revealed best agreement in these settings. In the vendor default settings (rCBF<30% for RAPID and rCBF<20% for Syngo) correlation between ischemic core volume and FIV was also high (RAPID: r=0.88, Syngo: r=0.86, P<0.001), but mean differences were significant (P<0.001). The risk of critical overestimation of the FIV was higher with rCBF<38% (RAPID) and rCBF<25% (Syngo) than in the default settings.

CONCLUSIONS

By adjusting the rCBF thresholds, comparable results with reliable information on the FIV after complete recanalization can be obtained both with the RAPID and Syngo software. Keeping the software specific default settings means being more inclusive in patient selection, but forgo the highest possible accuracy in the estimation of the FIV.

Topographic Evolution of Anterior Cerebral Artery Infarction and Its Impact on Motor Impairment

INTRODUCTION

Motor deficit is common following anterior cerebral artery (ACA) stroke. This study aimed to determine the impact on the motor outcome, given the location of descending corticofugal fiber tracts (from the primary motor cortex [M1], dorsal and ventral premotor area [PMdv], and supplementary motor area [SMA]) and the regional variations in collateral support of the ACA territory.

METHODS

Patients with ACA vessel occlusion were included. Disruption to corticofugal fibers was inferred by overlap of tracts with a lesion on computed tomography perfusion at the onset and on magnetic resonance imaging (MRI) poststroke. The motor outcome was defined by dichotomized and combined National Institute of Health Stroke Scale (NIHSS) sub-scores for the arm and leg. Multivariate hierarchical partitioning was used to analyze the proportional contribution of the corticofugal fibers to the motor outcome.

RESULTS

Forty-seven patients with a median age of 77.5 (interquartile range 68.0-84.5) years were studied. At the stroke onset, 96% of patients showed evidence of motor deficit on the NIHSS, and the proportional contribution of the corticofugal fibers to motor deficit was M1-33%, SMA-33%, and PMdv-33%. By day 7, motor deficit was present in <50% of patients and contribution of M1 fiber tracts to the motor deficit was reduced (M1-10.2%, SMA-61.0%, PMdv-28.8%). We confirmed our findings using publicly available high-resolution templates created from Human Connectome Project data. This also showed a reduction in involvement of M1 fiber tracts on initial perfusion imaging (33%) compared to MRI at a median time of 7 days poststroke (11%).

CONCLUSION

Improvements in the motor outcome seen in ACA stroke may be due to the relative sparing of M1 fiber tracts from infarction. This may occur as a consequence of the posterior location of M1 fiber tracts and the evolving topography of ACA stroke due to the compensatory capacity of leptomeningeal anastomoses.

Fully Automated and Real-Time Volumetric Measurement of Infarct Core and Penumbra in Diffusion- and Perfusion-Weighted MRI of Patients with Hyper-Acute Stroke

Multimodal magnetic resonance imaging (MRI) has emerged as a promising tool for diagnosing ischemic stroke and for determining treatment strategies in the acute phase. The detection and quantification of the penumbra and the infarct core regions aid the assessment of the potential risks and benefits of thrombolysis by providing information on salvageable tissue or ischemic lesion age. In this study, we proposed a fully automated and real-time algorithm to compute parameter maps of perfusion-weighted images (PWIs) and to identify an infarct core from diffusion-weighted images (DWIs). DWI and PWI were obtained using a 1.5 Tesla MRI scanner for 15 patients with acute ischemic stroke. Parameter maps of PWI were computed using restricted gamma-variate curve fitting and Fourier-based deconvolution. The ischemic penumbra was identified using time-to-maximum (T_max) > 6 s as the mutual optimal threshold, while the infarct core was segmented using an adaptive thresholding on DWI. When the penumbra on PWI was compared with that generated using commercial software Pearson's linear correlation coefficient between penumbra volumes was 0.601 (p = 0.030), and the Dice coefficient was 0.51 ± 0.15. The infarct core on DWI was compared with the manually segmented gold standard. Dice coefficient between the manually drawn and automated segmented infarct cores was 0.62 ± 0.18. The processing times for PWI and DWI were 222.9 ± 16.4 and 53.4 ± 4.8 s, respectively. In conclusion, we demonstrate a fully automated and real-time algorithm to segment the penumbra and the infarct core regions based on PWI and DWI.

Comparison of the Solitaire and Trevo Stents for Endovascular Treatment of Acute Ischemic Stroke: A Single.Center Experience

Aims

Limited studies have compared the effectiveness of Solitaire and Trevo stentrievers for endovascular thrombectomy to achieve recanalization and improve functional outcomes of patients with acute ischemic stroke. Therefore, we compared the safety and efficacy of the two stents during endovascular thrombectomy for patients with acute ischemic stroke.

Materials and Methods

This study included 130 patients who underwent endovascular thrombectomy using either the Trevo (n = 51) or the Solitaire (n = 79) stent for anterior circulation acute ischemic stroke. Recanalization was classified using thrombolysis in cerebral infarction (TICI) grading. Efficacy and safety of the devices during endovascular thrombectomy were analyzed by evaluating the rate of good recanalization after the first pass, clot retrieval rate, final recanalization grade, use of rescue treatment, recanalization time, and hemorrhagic and thromboembolic complications.

Results

Overall, good recanalization (TICI grades 2b and 3) was achieved (Solitaire: n = 57, 72.2%; Trevo: n = 46, 90.2%) (P = 0.01). The rate of good recanalization after the first pass and clot retrieval rate were similar between groups; however, the use of rescue treatment was more frequent in the Solitaire group. Recanalization time was shorter in the Trevo group. The good clinical outcome rate was higher in the Trevo group but not statistically significantly. The rates of symptomatic hemorrhage and thromboembolism were not significantly different between groups.

Conclusion

The Trevo stent achieved more successful recanalization with less need for rescue treatment and less time for recanalization than the Solitaire stent. There was no statistically significant difference in the clinical outcomes.

Agreement and Accuracy of Ischemic Core Volume Evaluated by Three CT Perfusion Software Packages in Acute Ischemic Stroke

PURPOSE

To compare the ischemic core volume estimated by CT Perfusion 4D and Vue PACS with that estimated by RAPID software in acute ischemic stroke (AIS).

MATERIALS AND METHODS

CT perfusion data from AIS patients were retrospectively post-processed with RAPID, CT Perfusion 4D and Vue PACS software. The Vue PACS application included three different settings: method A (Circular Singular Value Decomposition), method B (Oscillating index Singular Value Decomposition) and method C (Standard Singular Value Decomposition). Bland-Altman analysis, intraclass correlation coefficients (ICCs) and Kappa analysis were used to evaluate concordance between estimated ischemic core values. Final infarct volume (FIV) was measured by follow-up non-contrast CT or MRI 5-7 days after mechanical thrombectomy (MT) in patients with successful recanalization.

RESULTS

A total of 82 patients were included in the study. Concordance with RAPID ranged from good (method B: ICC 0.780; method C: ICC 0.852) to excellent (CT perfusion 4D: ICC 0.950; method A: ICC 0.954). The limits of agreement (-32.3, 41.8 mL) were the narrowest with method A. For detecting core volumes ≤ 70 ml, method A and CT perfusion 4D showed almost perfect concordance with RAPID (CT perfusion 4D, kappa=0.87; method A, kappa=0.87), whereas methods B and C showed substantial concordance with RAPID (method B, kappa=0.77; method C, kappa =0.73). Thirty-two patients had good reperfusion after MT. RAPID showed the highest accuracy for predicting FIV, followed by method A.

CONCLUSION

CT perfusion 4D and Vue PACS method A showed excellent concordance with RAPID for quantifying ischemic core volume, which can be considered as alternatives in selecting patients for MT in clinical practice.

A nephroprotective iodinated contrast agent with cardioprotective properties: A pilot study

BACKGROUND AND PURPOSE

Evaluation and treatment of acute ischemic syndromes, in the heart and brain, require vessel visualization by iodinated X-ray contrast agents. However, these contrast agents can induce injury, in both the kidneys and target organs themselves. Sulfobutylether beta cyclodextrin (SBECD) added to iohexol (SBECD-iohexol) (Captisol Enabled-iohexol, Ligand Pharmaceuticals, Inc, San Diego, CA) is currently in clinical trials in cardiovascular procedures, to determine its relative renal safety in high-risk patients. Preclinical studies showed that SBECD-iohexol reduced contrast-induced acute kidney injury in rodent models by blocking apoptosis. The current study was undertaken to determine whether SBECD-iohexol is also cardioprotective, in the male rat ischemia-reperfusion model, compared to iohexol alone.

METHODS

After anesthesia, the left coronary artery was ligated for 30 min and the ligation released and reperfusion followed for 2 h prior to sacrifice. Groups 1-4 were injected in the tail vein 10 min prior to ischemia with: (1) vehicle; (2) iohexol; (3) SBECD; and (4) SBECD-iohexol. Infarct size, hemodynamics, and serum markers were measured.

RESULTS

An eight-fold increase in serum creatine kinase in the iohexol-alone group was observed, compared with no increase in the SBECD-iohexol group. The mean arterial pressure and rate pressure product were depressed in the iohexol-alone group, but not in the SBECD-iohexol group, or controls. No difference in infarct size or serum creatinine among the groups was observed.

CONCLUSION

The results of this study suggest that SBECD-iohexol is superior to iohexol alone, for both the preservation of cardiomyocyte integrity and preservation of myocardial function in myocardial ischemia.

POSITIVE: Perfusion imaging selection of ischemic stroke patients for endovascular therapy

BACKGROUND

The PerfusiOn imaging Selection of Ischemic sTroke patIents for endoVascular thErapy (POSITIVE) trial was designed to evaluate functional outcome in patients with emergent large vessel occlusion (ELVO) presenting within 0-12 hours with pre-specified bifurcated arms of early and late window presentation, who were selected for endovascular thrombectomy with non-vendor specific commercially available perfusion imaging software. Recent trials demonstrating the benefit of thrombectomy up to 16-24 hours following ELVO removed equipoise to randomize late window ELVO patients and therefore the trial was halted.

METHODS

Up to 200 patients were to be enrolled in this FDA-cleared, prospective, randomized, multicenter international trial to compare thrombectomy and best medical management in patients with ELVO ineligible for or refractory to treatment with IV tissue plasminogen activator (IV-tPA) selected with perfusion imaging and presenting within 0-12 hours of last seen normal. The primary outcome was 90-day clinical outcome as measured by the raw modified Rankin Scale (mRS) with scores 5 and 6 collapsed (mRS shift analysis).

RESULTS

The POSITIVE trial suspended enrollment with the release of results from the DAWN trial and was stopped after the release of the DEFUSE 3 trial results. Thirty-three patients were enrolled (21 for medical management and 12 for thrombectomy). Twelve of the 33 patients were enrolled in the 6-12 hour cohort. Despite the early cessation, the primary outcome demonstrated statistically significant superior clinical outcomes for patients treated with thrombectomy (P=0.0060). The overall proportion of patients achieving an mRS score of 0-2 was 75% in the thrombectomy cohort and 43% in the medical management cohort (OR 4.00, 95% CI 0.84 to 19.2).

CONCLUSION

POSITIVE supports the already established practice of delayed thrombectomy for appropriately selected patients presenting within 0-12 hours selected by perfusion imaging from any vendor. The results of the POSITIVE trial are consistent with other thrombectomy trials. The statistically significant effect on functional improvement, despite the small number of patients, reinforces the robust benefits of thrombectomy.

CLINICAL TRIAL REGISTRATION

NCT01852201.

Absent Contrast Filling of Ipsilateral Superficial Middle Cerebral Vein Predicts Midline Shift in Acute Middle Cerebral Artery Occlusion

Background and purpose: Midline shift is a life-threatening complication of acute large artery occlusion (LAO). The value of superficial middle cerebral vein (SMCV) for predicting midline shift is currently unclear for patients with acute LAO.

Methods: Consecutive acute LAO (middle cerebral artery M1 ± intracranial internal carotid artery) patients between March 2018 and May 2019 were included. Absent filling of ipsilateral cortical vein (marked as SMCV–) was defined as no contrast filling into the vein across the whole venous phase of four-dimensional computed tomography (CT) angiography derived from CT perfusion in the ischemic hemisphere.

Results: In the total of 81 patients, 31 (38.4%) were identified as SMCV–. SMCV– independently predicted midline shift, with sensitivity of 87.5% and specificity of 82.5%. Receiver operating characteristic analysis showed that including SMCV– as a predictor in addition to baseline ischemic core volume significantly increased the area under the curve in predicting midline shift (SMCV– with baseline ischemic core volume vs. baseline ischemic core volume: AUC = 0.903 vs. 0.841, Z = 2.451, P = 0.014).

Conclusion: In acute LAO patients, the presence of SMCV– was a sensitive and specific imaging marker for midline shift. SMCV– had supplementary value to baseline ischemic core volume in predicting midline shift.

A pilot protocol and review of triple neuroprotection with targeted hypothermia, controlled induced hypertension, and barbiturate infusion during emergency carotid endarterectomy for acute stroke after failed tPA or beyond 24-hour window of opportunity

An alternative to tissue plasminogen activator (tPA) failure has been a daunting challenge in ischemic stroke management. As tPA is time-dependent, delays can occur in definitive treatment while passively waiting to observe a clinical response to intravenous thrombolysis. Until today, uncertainty exists in the management strategy of wake-up stroke patients or those presenting beyond the therapeutic tPA window. Clinical dilemmas in these situations can prolong the transitional period of inertia, resulting in an adverse neurological outcome. We propose and review an innovative approach called triple neuro-protection (TNP), which encompasses three technical domains-targeted hypothermia, systemic induced hypertension, and barbiturates infusion, to protect the brain during carotid endarterectomy after failed tPA and/or beyond the 24-hour therapeutic mechanical thrombectomy window. This proposal assimilates discussion on the clinical evidence of the individual domains of TNP with our own clinical experience with TNP. Our first TNP was successfully employed in a 55-year-old man in 2015 while performing emergency carotid endarterectomy after he was referred to us 72 hours post tPA failure. The patient had a successful clinical outcome despite being in therapeutic inertia with 90–99% ipsilateral carotid stenosis and contralateral occlusion on presentation. In the last five years, we have safely used TNP in 25 selected cases with favourable clinical outcomes.

Absent filling of the superficial middle cerebral vein is associated with reperfusion but not parenchymal hematoma in stroke patients undergoing thrombectomy: an observational study

Background

Parenchymal hematoma (PH) is the most feared complication of reperfusion therapy after stroke. The opacification of the superficial middle cerebral vein (SMCV) on computed tomography perfusion (CTP) has been associated with poor functional outcomes after stroke, while its association with PH has not been verified for acute stroke patients undergoing thrombectomy.

Methods

Consecutive patients with acute anterior large artery occlusion (LAO) who received thrombectomy were retrospectively enrolled between May 2018 and May 2019. Absent filing of the SMCV (SMCV−) on CTP-derived CT angiography was defined as no contrast filling of the SMCV across the whole venous phase in the ischemic hemisphere, while SMCV+ was defined as the presence of contrast filling of the SMCV at any time point of the venous phase.

Results

A total of 52 patients were enrolled in the study, and 15 patients (28.8%) developed a PH within 48 hours after thrombectomy. SMCV− was not associated with PH in both the univariate and multivariate logistic regression analyses (all P>0.05), but was an independent risk factor for reperfusion [modified thrombolysis in cerebral infarction score of 2b-3; odds ratio (OR) =0.172, 95% confidence interval (CI): 0.031–0.960, P=0.045]. Reperfusion was associated with a reduced risk of PH (OR =0.110, 95% CI: 0.013–0.913, P=0.041). However, in a subgroup analysis of patients who had reperfusion, the SMCV− group had a higher rate of PH than the SMCV+ group (40.0% vs. 13.8%, P=0.049).

Conclusions

In patients who received thrombectomy, SMCV− did not predict PH, but was a risk factor for reperfusion. Although reperfusion was a protective factor for PH, the SMCV− group was still at a higher risk of PH compared with the SMCV+ group when reperfusion was successfully achieved.

Safety of Triple Neuroprotection with Targeted Hypothermia, Controlled Induced Hypertension, and Barbiturate Infusion during Emergency Carotid Endarterectomy for Acute Stroke after Missing the 24 Hours Window Opportunity

BACKGROUND

The aim of this study is to establish the initial safety of triple neuroprotection (TNP) in an acute stroke setting in patients presenting outside the window for systemic tissue plasminogen activator (tPA).

METHODS

Over 12,000 patients were referred to our vascular services with carotid artery disease, of whom 832 had carotid intervention with a stroke rate of 0.72%. Of these, 25 patients presented (3%), between March 2015 and 2019, with acute dense stroke. These patients had either failed tPA or passed the recommended timing for acute stroke intervention. Fifteen (60%) had hemi-neglect with evidence of acute infarct on magnetic resonance imaging of the brain and a Rankin score of 4 or 5. Ninety-six percent had an 80-99% stenosis on the symptomatic side. Mean ABCD3-I score was 11.35. All patients underwent emergency carotid endarterectomy (CEA) with therapeutically induced hypothermia (32-34°C), targeted hypertension (systolic blood pressure 180-200 mm Hg), and brain suppression with barbiturate.

RESULTS

There were no cases of myocardial infarction, death, cranial nerve injury, wound hematoma, or procedural bleeding. Mean hospital stay was 8.4 (±9.5) days. All cases had resolution of neurological symptoms, except 3 who had failed previous thrombolysis. Eighty percent had a postoperative Rankin score of 0 on discharge and 88% of patients were discharged home with 3 requiring rehabilitation.

CONCLUSIONS

Positive neurological outcomes and no serious adverse events were observed using TNP during emergency CEA in patients with acute brain injury. We recommend TNP for patients who are at an increased risk of stroke perioperatively, or who have already suffered from an acute stroke beyond the recommended window of 24 hr. Certainly, the positive outcomes are not likely reproducible outside of high-volume units and patients requiring this surgery should be transferred to experienced surgeons in appropriate tertiary referral centers.

CT Imaging of Acute Ischemic Stroke [Formula: see text]

Although acute ischemic stroke remains one of the most common causes of death and disability worldwide, it is a potentially treatable condition if appropriately managed in a timely manner. The goals of acute stroke imaging include establishing a diagnosis as fast as possible with (1) accurate infarct quantification, (2) intracranial and cervical vasculature assessment, and (3) brain perfusion analysis for detection of infarct core and potentially salvageable penumbra allowing optimal patient selection for appropriate therapy. Given the extensive number of images generated from acute stroke imaging studies and as "time is brain," this article aims to highlight a logical approach for the radiologist in acute stroke computed tomography imaging in order to accurately interpret and communicate results in a timely manner.

Ischemic stroke and cerebral venous sinus thrombosis in pregnancy

Maternal ischemic stroke and cerebral venous sinus thrombosis (CVST) are dreaded complications of pregnancy and major contributors to maternal disability and mortality. This chapter summarizes the incidence and risk factors for maternal arterial ischemic stroke (AIS) and CVST and discusses the pathophysiology of maternal AIS and CVST. The diagnosis, treatment, and secondary preventive strategies for maternal stroke are also reviewed. Special populations at high risk of maternal stroke, including women with moyamoya disease, sickle cell disease, HIV, thrombophilia, and genetic cerebrovascular disorders, are highlighted.

Temporal evolution and spatial distribution of quantitative T2 MRI following acute ischemia reperfusion injury

Background

Determining mechanisms of secondary stroke injury related to cerebral blood flow and the severity of microvascular injury contributing to edema and blood-brain barrier breakdown will be critical for the development of adjuvant therapies for revascularization treatment.

Aim

To characterize the heterogeneity of the ischemic lesion using quantitative T2 imaging along with diffusion-weighted magnetic resonance imaging (DWI) within five hours of treatment.

Methods

Quantitative T2 magnetic resonance imaging was acquired within 5 h (baseline) and at 24 h (follow-up) of stroke treatment in 29 patients. Dynamic contrast enhanced permeability imaging was performed at baseline in a subgroup of patients. Absolute volume change and lesion percent change was determined for the quantitative T2, DWI, and absolute volume change sequences. A Gaussian process with RRELIEFF feature selection algorithm was used for prediction of relative quantitative T2 and DWI lesion growth, baseline and follow-up quantitative T2/DWI lesion ratios, and also NIHSS at 24 h and change in NIHSS from admission to 24 h.

Results

In n = 27 patients, median (interquartile range) lesion percent change was 114.8% (48.9%, 259.1%) for quantitative T2, 48.2% (−12.6%, 179.6%) for absolute volume change, and 62.7% (26.3%, 230.9%) for DWI, respectively. Our model, consisting of baseline NIHSS, CT ASPECTS, and systolic blood pressure, showed a strong correlation with quantitative T2 percent change (cross correlation R2 = 0.80). There was a strong predictive ability for quantitative T2/DWI lesion ratio at 24 h using baseline NIHSS and last seen normal to 24 h magnetic resonance imaging time (cross correlation R2 = 0.93). Baseline dynamic contrast enhanced permeability was moderately correlated to the baseline quantitative T2 values (rho = 0.38).

Conclusion

Quantitative T2 imaging provides critical information for development of therapeutic approaches that could ameliorate microvascular damage during ischemia reperfusion.

Predictive value of the THRIVE score for outcome in patients with acute basilar artery occlusion treated with thrombectomy

BACKGROUND AND PURPOSE

A higher Totaled Health Risks in Vascular Events (THRIVE) score has been shown to predict poor functional outcome in patients with acute ischemic stroke (AIS) and anterior circulation large vessel occlusions undergoing thrombectomy treatment. We attempted to evaluate the value of the THRIVE score in predicting the outcome of thrombectomy treatment in AIS patients with basilar artery occlusion (BAO).

METHODS

A total of 68 AIS patients with BAO who underwent thrombectomy treatment from May 2014 to August 2018 were included in the present study. Multivariable logistic regression was performed to determine the predictive value of the THRIVE score for poor functional outcome (defined as modified Rankin Scale score ≥ 3), all-cause mortality, and hemorrhage transformation (HT) at 3 months.

RESULTS

A total of 42 (61.8%) participants experienced poor functional outcomes, 25 (36.8%) patients died from all causes, and 21 (30.9%) patients had HT during the 3-month follow-up. Multivariable logistic regression showed that a higher THRIVE score was significantly associated with poor functional outcome (odds ratio [OR] 5.86, 95% confidence interval [CI], 2.28-14.91, p < .001) as well as all-cause mortality (OR 2.40, 95% CI, 1.32-4.34, p = .004) but not HT (p = .607). The C-statistic of the THRIVE score was significantly larger than that of the NIHSS score for predicting poor functional outcome (AUC = 0.913; cutoff > 5; sensitivity, 88.5%; specificity, 83.3%, p = .007) and all-cause mortality (AUC = 0.768; cutoff > 5; sensitivity, 92.0%; specificity, 65.1%, p = .018).

CONCLUSIONS

A high THRIVE score was independently associated with an increased risk of poor functional outcome and all-cause mortality in AIS patients with BAO who underwent thrombectomy treatment. Moreover, the THRIVE score appeared to be a better predictor of clinical outcome than the NIHSS score.

Identification of Corticospinal Tract Lesion for Predicting Outcome in Small Perfusion Stroke

Background and Purpose- Whether patients with small perfusion lesions benefit from thrombolysis remains an uncertainty. We assessed acute ischemic stroke patients with a total perfusion lesion of <15 mL and tested the hypothesis the pattern of corticospinal tract (CST) involvement might predict outcome in thrombolysis-eligible patients. Methods- We used a prospectively collected cohort of acute ischemic stroke patients being assessed for thrombolysis at 7 centers. Three neurologists categorized the presence of hypoperfusion and infarction within CST. Excellent outcome was defined as 90-day modified Rankin Scale score 0 to 1. Results- Of 2654 patients, 407 had a perfusion lesion <15 mL and were clinically eligible for thrombolysis (243 being treated). Median National Institutes of Health Stroke Scale was 5.0, and 312 (76.7%) patients achieved excellent outcome. Alteplase treatment was an independent unfavorable factor for excellent outcome (alteplase-treated 72.0% versus untreated 83.5%; odds ratio, 0.541; P=0.025). For patients with CST hypoperfusion without CST infarction, alteplase treatment was an independent favorable factor for excellent outcome (alteplase-treated 75.6% versus untreated 47.1%; odds ratio, 4.096; P=0.045). Among patients with CST infarction, alteplase treatment was an independent unfavorable factor for excellent outcome (alteplase-treated 30.6% versus untreated 88.9%; odds ratio, 0.002; P=0.003). Among patients without either CST hypoperfusion or CST infarction, alteplase treatment was not an independent influencing factor for excellent outcome (alteplase-treated 80.1% versus untreated 87.7%; P=0.258). Conclusions- Only patients with CST hypoperfusion without CST infarction among eligible acute ischemic stroke patients with small perfusion lesions could benefit from thrombolysis, which needs to be confirmed in future prospective studies. Patient selection, including an assessment of lesion location rather than purely lesion volume, may be ideal.

Relationship between CT angiography-derived collateral status and CT perfusion-derived tissue viability

AIM

To explore the relationship between computed tomography (CT) angiography (CTA)-derived collateral status and CT perfusion (CTP)-derived tissue viability.

MATERIALS AND METHODS

Patients having middle cerebral artery (MCA) M1/M2 segment and/or internal carotid artery (ICA) occlusion and within 12 hours of onset were included. Collateral was graded from 0 to 3 on maximum intensity projection (MIP) images of CTA. The area with relative cerebral blood flow (rCBF) <30% or time-to-maximum (Tmax) >10 or >12 or >14 seconds was defined as the infarct core, and Tmax >6 seconds as the penumbra. Kruskal-Wallis and Spearman's correlation tests were performed to assess the correlation between collateral grade and infarct size or mismatch ratio.

RESULTS

Eighty-three patients were enrolled and 52 of them met the inclusion criteria. Infarct size defined by rCBF <30% or Tmax >10 or >12 or >14 seconds and mismatch ratios were significantly different among the four groups. The correlation between collateral grades and infarct core using rCBF <30% (ρ=-0.814, p<0.01) was better than that defined by Tmax >10s, >12s or >14s. Mismatch ratio for the infarct core defined by rCBF <30% (ρ=0.945, p<0.01) had the best correlation with collateral grades.

CONCLUSION

Patients with good collaterals show a smaller infarct core and higher mismatch ratio. Infarct size defined by rCBF <30% and mismatch ratio defined by rCBF <30% and Tmax >6 seconds appear to be more correlated with collaterals in AIS patients.

Early hemodynamic predictors of good outcome and reperfusion injury after endovascular treatment

Objective

To find early hemodynamic predictors of outcome and reperfusion injury in patients with acute ischemic stroke due to anterior circulation large artery occlusion (LAO) after endovascular treatment (EVT).

Methods

Serial transcranial color-coded sonography examinations assessed the vessel status and cerebral hemodynamics of 185 (109 [58.9%] men, mean age 69.5 ± 12.3 years) consecutive patients with acute anterior circulation LAO soon after, at 48 hours after, and 1 week after EVT.

Results

Successful recanalization (odds ratio [OR] 0.25, 95% confidence interval [CI] 0.11–0.61) and normal peak systolic velocity (PSV) ratio (PSV of recanalized middle cerebral artery/PSV of contralateral middle cerebral artery) at 48 hours (OR 0.22, 95% CI 0.15–0.64) and after 1 week (OR 0.11, 95% CI 0.07–0.31) from EVT were independent predictors of good outcome at 3 months. Thrombectomy failure (OR 10.22, 95% CI 1.47–45.53) and pathologic PSV ratio at 1 week from EVT (OR 15.23, 95% CI 4.54–46.72) were associated with a worse 90-day outcome. Patients who subsequently developed postinterventional intracranial hemorrhage (ICH) showed a higher mean PSV ratio (3.5 ± 0.2 vs 2.4 ± 0.1, p < 0.0001) soon after successful recanalization. In multivariate analysis, early PSV ratio was independently associated with postprocedural ICH (OR 8.474, 95% CI 3.066–45.122, p < 0.01]. At 1 week from EVT, 15 of 21 (71.4%) patients with ICH who resumed normal PSV values had a better 90-day outcome (modified Rankin Scale score 0–2: 40% vs 0%).

Conclusion

Post-EVT ultrasound monitoring of stroke patients might be an effective bedside method for assessing treatment efficacy, shedding light on outcome variability and identifying patients at increased risk of ICH.

Low thalamostriate venous quantitative susceptibility measurements correlate with higher presenting NIH stroke scale score in emergent large vessel occlusion stroke

Objective

Hyperacute stroke affects various patient subgroups who may benefit from different management strategies. Magnetic resonance imaging (MRI) quantitative susceptibility mapping (QSM) is a recent MRI technique for measuring deoxyhemoglobin levels. The results of QSM thus have the potential to act as a quantitative biomarker for predicting the success of endovascular interventions.

Methods

Twenty-five patients with M1 occlusions were evaluated retrospectively. QSM measurements were obtained based on susceptibility-weighted imaging sequences from the most prominent veins in each of the four standard regions of interest: the cortical and thalamostriate veins ipsilateral and contralateral to the side of the stroke. The results were analyzed using Wilcoxon’s signed rank test and compared with presenting National Institutes of Health stroke scale (NIHSS) score.

Results

Cortical veins ipsilateral to the stroke showed the greatest elevation in susceptibility compared with all other vein groups. Both ipsilateral and contralateral thalamostriate vein susceptibilities showed strong inverse correlation with presenting NIHSS score.

Conclusion

Thalamostriate vein susceptibility shows a strong inverse correlation with presenting NIHSS in adult patients with hyperacute stroke who are selected for endovascular intervention by advanced imaging.

Hypoperfusion in lenticulostriate arteries territory related to unexplained early neurological deterioration after intravenous thrombolysis

BACKGROUND

Early neurological deterioration occurs in approximately 10% acute ischemic stroke patients after thrombolysis. Over half of the early neurological deterioration occurred without known causes and is called unexplained early neurological deterioration.

AIMS

We aimed to explore the development of early neurological deterioration at 24 h after thrombolysis, and whether it could be predicted by the presence of baseline hypoperfusion in lenticulostriate arteries territory in acute ischemic stroke patients.

METHODS

We retrospectively reviewed our prospectively collected database of acute ischemic stroke patients in the unilateral middle cerebral artery territory who had baseline perfusion image and received thrombolysis. Unexplained early neurological deterioration was defined as ≥ 2 points increase of National Institutes of Health Stroke Scale (NIHSS) from baseline to 24 h, without known causes. Hypoperfusion lesions in different territories were identified on perfusion maps.

RESULTS

A total of 306 patients were included in analysis. Patients with pure lenticulostriate arteries hypoperfusion (defined as the presence of hypoperfusion in lenticulostriate artery territory, but not in middle cerebral artery terminal branch territory) were more likely to have unexplained early neurological deterioration than others (27.6% vs. 6.1%; OR, 5.974; p = 0.001), after adjusting for age, baseline NIHSS and onset to treatment time.

CONCLUSIONS

Patients presenting hypoperfusion in pure lenticulostriate arteries territory were easier to experience unexplained early neurological deterioration.

An acute stroke CT imaging algorithm incorporating automated perfusion analysis

In this paper, we propose a CT imaging algorithm for patients presenting with suspected acute stroke that incorporates automated CT perfusion (CTP) imaging. The algorithm details evaluation of the non-contrast CT (NCCT) for hemorrhage and acute ischemia, calculation of ASPECTS, with performance and interpretation of CTP if appropriate. In particular, we consider the key steps in expeditious interpretation of non-contrast CT and CT angiography in the context of suspected acute ischemic stroke. Given the recent expansion of the "imaging based" treatment window for thrombectomy from 6 to 24 h in the 2018 American Heart Association stroke guidelines, we consider the key criteria in the decision to perform CT perfusion and the patient cohorts in which this might be most helpful. We also describe how imaging findings might be incorporated into the treatment paradigm for suspected with acute ischemic stroke and we allude to some of the most frequently encountered pitfalls associated with CTP which we think will be particularly helpful for radiologists and stroke physicians who are considering adding CT perfusion to their work-up for acute stroke.

Efficacy of Tirofiban Administered at Different Time Points after Intravenous Thrombolytic Therapy with Alteplase in Patients with Acute Ischemic Stroke

OBJECTIVE

To evaluate the efficacy of tirofiban administered at different time points within 24 hours of intravenous thrombolysis with alteplase in acute ischemic stroke.

METHODS

Patients who underwent intravenous thrombolysis with alteplase and fulfilled other inclusion criteria were randomly divided into 4 groups according to the time points of tirofiban administration: Group A (2 h), Group B (2-12 h), Group C (12-24 h), and Group D (control). The changes in National Institutes of Health Stroke Scale score, modified Rankin Scale score, and adverse events were analyzed.

RESULTS

At 7 ± 1 day, the efficacy in Group A was better than that in Group C (P = .006) and Group D (P = .001), but there was no significant difference in the efficacy between Groups A and B (P = .268). Similarly, at 14 ± 2 d, the efficacy in Group A was better than that in Group C (P = .026) and Group D (P = .001), but there was no significant difference in the efficacy between Groups A and B (P = .394). As evaluated by the modified Rankin Scale, the prognosis in Groups A, B, and C was better than that in Group D (P = .042, .008, .027, respectively), which was unrelated to the time points of tirofiban administration. There was no significant difference in the incidence of adverse events among the four groups.

CONCLUSIONS

Tirofiban combined with alteplase is effective and safe, and particularly beneficial when administered at 2 hour and 2-12 hours after intravenous thrombolysis with alteplase in acute ischemic stroke.

Predictive and individualized management of stroke-success story in Czech Republic

The model of centralized stroke care in the Czech Republic was created in 2010-2012 by Ministry of Health (MH) in cooperation with professional organization-Cerebrovascular Section of the Czech Neurological Society (CSCNS). It defines priorities of stroke care, stroke centers, triage of suspected stroke patients, stroke care quality indicators, their monitoring, and reporting. Thirteen complex cerebrovascular centers (CCC) provide sophisticated stroke care, including intravenous thrombolysis (IVT), mechanical thrombectomy (MTE), as well as other endovascular (stenting, coiling) and neurosurgical procedures. Thirty-two stroke centers (SC) provide stroke care except endovascular procedures and neurosurgery. The triage is managed by emergency medical service (EMS). The most important quality indicators of stroke care are number of hospitalized stroke patients, number of IVT, number of MTE, stenting and coiling, number of neurosurgical procedures, and percentage of deaths within 30 days. Indicators provided into the register of stroke care quality (RES-Q) managed by CSCNS are time from stroke onset to hospital admission, door-to-needle time, door-to-groin time, type of ischemic stroke, and others. Data from RES-Q are shared to all centers. Within the last 5 years, the Czech Republic becomes one of the leading countries in acute stroke care. The model of centralized stroke care is highly beneficial and effective. The quality indicators serve as tool of control of stroke centers activities. The sharing of quality indicators is useful tool for mutual competition and feedback control in each center. This comprehensive system ensures high standard of stroke care. This system respects the substantial principles of personalized medicine-individualized treatment of acute stroke and other comorbidities at the acute disease stage; optimal prevention, diagnosis and treatment of possible complications; prediction of further treatment and outcome; individualized secondary prevention, exactly according to the stroke etiology. The described model of stroke care optimally meets criteria of predictive, preventive, and personalized medicine (PPPM), and could be used in other countries as well with the aim of improving stroke care quality in general.

Further Development of Combined Techniques Using Stent Retrievers, Aspiration Catheters and BGC : The PROTECTPLUS Technique

PURPOSE

First pass complete (mTICI 3) reperfusion must be regarded as the ultimate goal in mechanical thrombectomy (MT) in patients suffering from an emergent large vessel occlusion (ELVO). With this in mind a technical modification of the previously published PROTECT (PRoximal balloon Occlusion TogEther with direCt Thrombus aspiration during stent retriever thrombectomy) approach, the PROTECT^PLUS technique was evaluated. Under proximal flow arrest using a balloon guide catheter (BGC), a stent retriever was only partially inserted into a large-bore aspiration catheter. This construction was subsequently retracted as a unit into the BGC with aspiration both at the aspiration catheter and at the BGC.

METHODS

A case-control study was performed comparing the PROTECT technique with the PROTECT^PLUS technique with respect to the technical and procedural parameters. Patients n = 165 (101 PROTECT, 64 PROTECT^PLUS) with ELVO of either the terminus of the internal carotid artery or the proximal middle cerebral artery were included.

RESULTS

Using the PROTECT^PLUS resulted in a higher rate of first pass complete reperfusions (59.4% vs. 27.7%, p < 0.001) as compared with PROTECT. The PROTECT^PLUS also led to shorter procedure times (21 min vs. 37 min, p = 0.001) and higher rates of overall complete reperfusion (73.5% vs. 49.5%, p = 0.014) compared to PROTECT.

CONCLUSION

The PROTECT^PLUS technique is a promising technical modification to further optimize endovascular stroke treatment.

Mechanical Thrombectomy by a Direct Aspiration First Pass Technique (ADAPT) in Ischemic Stroke: Results of Monocentric Study Based on Multimodal CT Patient Selection

Introduction

Mechanical thrombectomy with ADAP-technique of ischemic stroke has been reported as fast and effective. Aim of this study is to evaluate imaging criteria as possible predictors of stroke severity, therapeutic success, and outcome.

Materials and Methods

Patients (30) presenting from October 2015 to April 2017 with Emergent Large Vessel Occlusion of the anterior circulation were treated with ADAP-technique. 22 received also IV tPA; 8 underwent endovascular treatment only. Every patient was evaluated with noncontrast CT, multiphase angiography-CT, and perfusion CT. Clinical and radiological characteristics were measured. Good clinical outcome was an improvement of 8 points on NIHSS at discharge or a modified Rankin Scale ≤2 at discharge and at 90 days.

Results

Successful revascularization was obtained in 57% of patients, no procedural complications were witnessed, and only two hemorrhages were reported. Good outcome at discharge was obtained in 11 patients (37%) and predicted by NCCT ASPECT and TICI; outcome at 90 days was predicted by NCCT ASPECT, clot length, and premorbid mRS. Mortality was 23% at discharge and 30% at 90 days.

Conclusion

ADAPT is an effective endovascular method of stroke treatment with fast procedural times. Multimodal CT evaluation is effective in assessing stroke severity, providing important prognostic information, which is able to select patients for the appropriate treatment.

Ghost Infarct Core and Admission Computed Tomography Perfusion: Redefining the Role of Neuroimaging in Acute Ischemic Stroke

Background

Determining the size of infarct extent is crucial to elect patients for reperfusion therapies. Computed tomography perfusion (CTP) based on cerebral blood volume may overestimate infarct core on admission and consequently include ghost infarct core (GIC) in a definitive lesional area.

Purpose

Our goal was to confirm and better characterize the GIC phenomenon using CTP cerebral blood flow (CBF) as the reference parameter to determine infarct core.

Methods

We performed a retrospective, single-center analysis of consecutive thrombectomies of middle cerebral or intracranial internal carotid artery occlusions considering noncontrast CT Alberta Stroke Program Early CT Score ≥6 in patients with pretreatment CTP. We used the RAPID® software to measure admission infarct core based on initial CBF. The final infarct was extracted from follow-up CT. GIC was defined as initial core minus final infarct > 10 mL.

Results

A total of 123 patients were included. The median National Institutes of Health Stroke Scale score was 18 (13-20), the median time from symptoms to CTP was 188 (67-288) min, and the recanalization rate (Thrombolysis in Cerebral Infarction score 2b, 2c, or 3) was 83%. Twenty patients (16%) presented with GIC. GIC was associated with shorter time to recanalization (150 [105-291] vs. 255 [163-367] min, p = 0.05) and larger initial CBF core volume (38 [26-59] vs. 6 [0-27] mL, p < 0.001). An adjusted logistic regression model identified time to recanalization < 302 min (OR 4.598, 95% CI 1.143-18.495, p = 0.032) and initial infarct volume (OR 1.01, 95% CI 1.001-1.019, p = 0.032) as independent predictors of GIC. At 24 h, clinical improvement was more frequent in patients with GIC (80 vs. 49%, p = 0.01).

Conclusions

CTP CBF < 30% may overestimate infarct core volume, especially in patients imaged in the very early time window and with fast complete reperfusion. Therefore, the CTP CBF technique may exclude patients who would benefit from endovascular treatment.

Clinical Outcome After Mechanical Thrombectomy in Patients with Diabetes with Major Ischemic Stroke of the Anterior Circulation

BACKGROUND

Among patients with acute ischemic stroke treated with mechanical thrombectomy (MT), patients with diabetes (DP) show a poorer outcome compared with patients without diabetes (NDP). This study aims to provide a comprehensive analysis of factors associated with unfavorable outcome in DP receiving MT for stroke of the anterior circulation.

METHODS

This study included 317 of 498 consecutive patients who received interventional treatment for acute ischemic stroke in the terminal internal carotid artery and/or middle cerebral artery, including 46 DP. The study data included pre- and posttreatment stroke computed tomography, including perfusion data, collateral status, treatment data including treatment times, pre-existing cardiovascular risk factors, cerebrovascular events, comorbidities, laboratory parameters, and medication. Neurologic status was assessed at baseline (National Institute of Health Stroke Scale [NIHSS]/modified Rankin Scale [mRS]) and after 90 days (mRS 90).

RESULTS

Compared with NDP, DP showed a significantly poorer outcome (mRS90 >2) (P < 0.05). Collateralization and infarct core size did not differ between groups, whereas the penumbra was significantly smaller in DP than in NDP (P < 0.05). The poorer mRS90 outcome (mRS90 > 2) in DP was associated with poor collaterals (P = 0.01) and hyperglycemia on admission (P < 0.05). Shorter time to reperfusion was associated with favorable mRS90 in the NDP (P < 0.001) but not the DP (P = 0.49) group. In univariate logistic regression, the following parameters were significantly associated with mRS90: diabetes, hyperglycemia at admission, time to reperfusion, and the NIHSS score (P < 0.05 each). In multivariate analyses and partition regression models of all variables, DP with admission hyperglycemia (≥132 mg/dL) and older age (≥66 years) showed a particularly poor outcome.

CONCLUSIONS

The main factors for an unfavorable outcome of DP after MT are admission hyperglycemia, age, and NIHSS score.

Linalyl acetate prevents hypertension-related ischemic injury

Ischemic stroke remains an important cause of disability and mortality. Hypertension is a critical risk factor for the development of ischemic stroke. Control of risk factors, including hypertension, is therefore important for the prevention of ischemic stroke. Linalyl acetate (LA) has been reported to have therapeutic effects in ischemic stroke by modulating intracellular Ca2+ concentration and having anti-oxidative properties. The preventive efficacy of LA has not yet been determined. This study therefore investigated the preventive efficacy of LA in rat aortas exposed to hypertension related-ischemic injury, and the mechanism of action of LA.Hypertension was induced in vivo following ischemic injury to the aorta induced by oxygen-glucose deprivation and reoxygenation in vitro. Effects of LA were assayed by western blotting, by determining concentrations of lactate dehydrogenase (LDH) and reactive oxygen species (ROS) and by vascular contractility assays. LA significantly reduced systolic blood pressure in vivo. In vitro, LA suppressed ischemic injury-induced expression of the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subunit p47phox, as well as ROS production, LDH release, and ROS-induced endothelial nitric oxide synthase suppression. These findings indicate that LA has anti-hypertensive properties that can prevent hypertension-related ischemic injury and can prevent NADPH oxidase-induced production of ROS.

Revealing the Penumbra through Imaging Elemental Markers of Cellular Metabolism in an Ischemic Stroke Model

Stroke exacts a heavy financial and economic burden, is a leading cause of death, and is the leading cause of long-term disability in those who survive. The penumbra surrounds the ischemic core of the stroke lesion and is composed of cells that are stressed and vulnerable to death, which is due to an altered metabolic, oxidative, and ionic environment within the penumbra. Without therapeutic intervention, many cells within the penumbra will die and become part of the growing infarct, however, there is hope that appropriate therapies may allow potential recovery of cells within this tissue region, or at least slow the rate of cell death, therefore, slowing the spread of the ischemic infarct and minimizing the extent of tissue damage. As such, preserving the penumbra to promote functional brain recovery is a central goal in stroke research. While identification of the ischemic infarct, and the infarct/penumbra boundary is relatively trivial using classical histology and microscopy techniques, accurately assessing the penetration of the penumbra zone into undamaged brain tissue, and evaluating the magnitude of chemical alterations in the penumbra, has long been a major challenge to the stroke research field. In this study, we have used synchrotron-based X-ray fluorescence imaging to visualize the elemental changes in undamaged, penumbra, and infarct brain tissue, following ischemic stroke. We have employed a Gaussian mixture model to cluster tissue areas based on their elemental characteristics. The method separates the core of the infarct from healthy tissue, and also demarcates discrete regions encircling the infarct. These regions of interest can be combined with elemental and metabolic data, as well as with conventional histology. The cell populations defined by clustering provide a reproducible means of visualizing the size and extent of the penumbra at the level of the single cell and provide a critically needed tool to track changes in elemental status and penumbra size.