The Impact of CT Perfusion Threshold on Predicted Viable and Nonviable Tissue Volumes in Acute Ischemic Stroke

Introduction : In acute ischemic stroke patients, current guidelines recommend noninvasive vascular imaging to identify intracranial vessel occlusions (VO) that may benefit from endovascular treatment (EVT). However, VO can be missed in CT angiography (CTA) readings. We aim to evaluate the impact of consistently including CT perfusion (CTP) in admission stroke imaging protocols on VO diagnosis and EVT rates. Methods : We included patients with a suspected acute ischemic stroke that underwent urgent non‐contrast CT, CTA and CTP from April to October 2020. Hypoperfusion areas defined by Tmax>6s delay (RAPID software), congruent with the clinical symptoms and a vascular territory, were considered due to a VO (CTP‐VO). Cases in which mechanical thrombectomy was performed were defined as therapeutically relevant VO (EVT‐VO). For patients that received EVT, site of VO according to digital subtraction angiography was recorded. Two experienced neuroradiologists blinded to CTP but not to clinical symptoms, retrospectively evaluated NCCT and CTA to identify intracranial VO (CTA‐VO). We analyzed CTA‐VO sensitivity and specificity at detecting CTP‐VO and EVT‐VO respecitvely. We performed a logistic regression to test the association of Tmax>6s volumes with CTA‐VO identification and indication of EVT. Results : Of the 338 patients included in the analysis, 157 (46.5%) presented a CTP‐VO, (median Tmax>6s: 73 [29‐127] ml). CTA‐VO was identified in 83 (24.5%) of the cases. Overall CTA‐VO sensitivity for the detection of CTP‐VO was 50.3% and specificity was 97.8%. Higher hypoperfusion volume was associated with an increased CTA‐VO detection, with an odds ratio of 1.03 (95% confidence interval 1.02‐1.04) (figure). DSA was indicated in 107 patients; in 4 of them no EVT was attempted due to recanalization or a too distal VO in the first angiographic run. EVT was performed in 103 patients (30.5%. Tmax>6s: 102 [63‐160] ml), representing 65.6% of all CTP‐VO. Overall CTA‐VO sensitivity for the detection of EVT‐VO was 69.9%. The CTA‐VO sensitivity for detecting patients with indication of EVT according to clinical guidelines was as follows: 91.7% for ICA occlusions and 84.4% for M1‐MCA occlusions. For all other occlusion sites that received EVT, the CTA‐VO sensitivity was 36.1%. The overall specificity was 95.3%. Among patients who received EVT, CTA‐VO was not detected in 31 cases, resulting in a false negative rate of 30.1%. False negative CTA‐VO cases had lower Tmax>6s volumes (69[46‐99.5] vs 126[84‐169.5]ml, p<0.001) and lower NIHSS (13[8.5‐16] vs 17[14‐21], p<0.001). Conclusions : Systematically including CTP perfusion in the acute stroke admission imaging protocols may increase the diagnosis of VO and rate of EVT.

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What is the impact of head movement on automated CT perfusion mismatch evaluation in acute ischemic stroke?

Journal of NeuroInterventional Surgery ◽

10.1136/neurintsurg-2021-017510 ◽

2021 ◽

pp. neurintsurg-2021-017510

Author(s):

Arne Potreck ◽

Fatih Seker ◽

Matthias Anthony Mutke ◽

Charlotte Sabine Weyland ◽

Christian Herweh ◽

...

Keyword(s):

Ischemic Stroke ◽

Acute Ischemic Stroke ◽

Head Movement ◽

Ct Perfusion ◽

Treatment Decision ◽

Brain Perfusion ◽

Left Middle Cerebral Artery ◽

Ct Scanner ◽

Infarct Core ◽

The Impact

ObjectivesAutomated CT perfusion mismatch assessment is an established treatment decision tool in acute ischemic stroke. However, the reliability of this method in patients with head motion is unclear. We therefore sought to evaluate the influence of head movement on automated CT perfusion mismatch evaluation.MethodsUsing a realistic CT brain-perfusion-phantom, 7 perfusion mismatch scenarios were simulated within the left middle cerebral artery territory. Real CT noise and artificial head movement were added. Thereafter, ischemic core, penumbra volumes and mismatch ratios were evaluated using an automated mismatch analysis software (RAPID, iSchemaView) and compared with ground truth simulated values.ResultsWhile CT scanner noise alone had only a minor impact on mismatch evaluation, a tendency towards smaller infarct core estimates (mean difference of −5.3 (−14 to 3.5) mL for subtle head movement and −7.0 (−14.7 to 0.7) mL for strong head movement), larger penumbral estimates (+9.9 (−25 to 44) mL and +35 (−14 to 85) mL, respectively) and consequently larger mismatch ratios (+0.8 (−1.5 to 3.0) for subtle head movement and +1.9 (−1.3 to 5.1) for strong head movement) were noted in dependence of patient head movement.ConclusionsMotion during CT perfusion acquisition influences automated mismatch evaluation. Potentially treatment-relevant changes in mismatch classifications in dependence of head movement were observed and occurred in favor of mechanical thrombectomy.

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The impact of antihypertensive use in the treatment of acute ischemic stroke in patients receiving alteplase

The American Journal of Emergency Medicine ◽

10.1016/j.ajem.2021.07.037 ◽

2021 ◽

Author(s):

Megan A. Rech ◽

Elisabeth Donahey ◽

Joshua M. DeMott ◽

Laura L. Coles ◽

Gary D. Peksa

Keyword(s):

Ischemic Stroke ◽

Acute Ischemic Stroke ◽

The Impact

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Predictive value of time-variant color-coded multiphase CT angiography (mCTA) regarding clinical outcome of acute ischemic stroke: in comparison with conventional mCTA and CT perfusion

Acta Radiologica ◽

10.1177/0284185120981770 ◽

2020 ◽

pp. 028418512098177

Author(s):

Yu Lin ◽

Nannan Kang ◽

Jianghe Kang ◽

Shaomao Lv ◽

Jinan Wang

Keyword(s):

Ischemic Stroke ◽

Acute Ischemic Stroke ◽

Predictive Value ◽

Ct Perfusion ◽

Roc Curves ◽

Multivariate Logistic Regression Model ◽

Infarct Core ◽

Predictive Values ◽

Significant Difference ◽

Core Volume

Background Color-coded multiphase computed tomography angiography (mCTA) can provide time-variant blood flow information of collateral circulation for acute ischemic stroke (AIS). Purpose To compare the predictive values of color-coded mCTA, conventional mCTA, and CT perfusion (CTP) for the clinical outcomes of patients with AIS. Material and Methods Consecutive patients with anterior circulation AIS were retrospectively reviewed at our center. Baseline collateral scores of color-coded mCTA and conventional mCTA were assessed by a 6-point scale. The reliabilities between junior and senior observers were assessed by weighted Kappa coefficients. Receiver operating characteristic (ROC) curves and multivariate logistic regression model were applied to evaluate the predictive capabilities of color-coded mCTA and conventional mCTA scores, and CTP parameters (hypoperfusion and infarct core volume) for a favorable outcome of AIS. Results A total of 138 patients (including 70 cases of good outcomes) were included in our study. Patients with favorable prognoses were correlated with better collateral circulations on both color-coded and conventional mCTA, and smaller hypoperfusion and infarct core volume (all P < 0.05) on CTP. ROC curves revealed no significant difference between the predictive capability of color-coded and conventional mCTA ( P = 0.427). The predictive value of CTP parameters tended to be inferior to that of color-coded mCTA score (all P < 0.001). Both junior and senior observers had consistently excellent performances (κ = 0.89) when analyzing color-coded mCTA maps. Conclusion Color-coded mCTA provides prognostic information of patients with AIS equivalent to or better than that of conventional mCTA and CTP. Junior radiologists can reach high diagnostic accuracy when interpreting color-coded mCTA images.

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Eosinophil-to-monocyte ratio is a potential biomarker in the prediction of functional outcome among patients with acute ischemic stroke

BMC Neuroscience ◽

10.1186/s12868-021-00610-x ◽

2021 ◽

Vol 22 (1) ◽

Author(s):

Shuhong Yu ◽

Yi Luo ◽

Tan Zhang ◽

Chenrong Huang ◽

Yu Fu ◽

...

Keyword(s):

Ischemic Stroke ◽

Acute Ischemic Stroke ◽

Functional Outcome ◽

Odds Ratio ◽

Poor Outcome ◽

Net Reclassification Improvement ◽

Potential Biomarker ◽

The Impact ◽

The Relationship ◽

Integrated Discrimination Improvement

Abstract Background It has been shown that eosinophils are decreased and monocytes are elevated in patients with acute ischemic stroke (AIS), but the impact of eosinophil-to-monocyte ratio (EMR) on clinical outcomes among AIS patients remains unclear. We aimed to determine the relationship between EMR on admission and 3-month poor functional outcome in AIS patients. Methods A total of 521 consecutive patients admitted to our hospital within 24 h after onset of AIS were prospectively enrolled and categorized in terms of quartiles of EMR on admission between August 2016 and September 2018. The endpoint was the poor outcome defined as modified Rankin Scale score of 3 to 6 at month 3 after admission. Results As EMR decreased, the risk of poor outcome increased (p < 0.001). Logistic regression analysis revealed that EMR was independently associated with poor outcome after adjusting potential confounders (odds ratio, 0.09; 95% CI 0.03–0.34; p = 0.0003), which is consistent with the result of EMR (quartile) as a categorical variable (odds ratio, 0.23; 95% CI 0.10–0.52; ptrend < 0.0001). A non-linear relationship was detected between EMR and poor outcome, whose point was 0.28. Subgroup analyses further confirmed these associations. The addition of EMR to conventional risk factors improved the predictive power for poor outcome (net reclassification improvement: 2.61%, p = 0.382; integrated discrimination improvement: 2.41%, p < 0.001). Conclusions EMR on admission was independently correlated with poor outcome in AIS patients, suggesting that EMR may be a potential prognostic biomarker for AIS.

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Impact of Post-Stroke Recanalization on General and Upper Limb Functioning: A Prospective, Observational Study

Neurology International ◽

10.3390/neurolint13010005 ◽

2021 ◽

Vol 13 (1) ◽

pp. 46-58

Author(s):

João Paulo Branco ◽

Filipa Rocha ◽

João Sargento-Freitas ◽

Gustavo C. Santo ◽

António Freire ◽

...

Keyword(s):

Ischemic Stroke ◽

Observational Study ◽

Acute Ischemic Stroke ◽

Upper Limb ◽

Functional Recovery ◽

Prospective Observational Study ◽

Positive Impact ◽

Rehabilitation Program ◽

Patient Functioning ◽

The Impact

The objective of this study is to assess the impact of recanalization (spontaneous and therapeutic) on upper limb functioning and general patient functioning after stroke. This is a prospective, observational study of patients hospitalized due to acute ischemic stroke in the territory of the middle cerebral artery (n = 98). Patients completed a comprehensive rehabilitation program and were followed-up for 24 weeks. The impact of recanalization on patient functioning was evaluated using the modified Rankin Scale (mRS) and Stroke Upper Limb Capacity Scale (SULCS). General and upper limb functioning improved markedly in the first three weeks after stroke. Age, gender, and National Institutes of Health Stroke Scale (NIHSS) score at admission were associated with general and upper limb functioning at 12 weeks. Successful recanalization was associated with better functioning. Among patients who underwent therapeutic recanalization, NIHSS scores ≥16.5 indicate lower general functioning at 12 weeks (sensibility = 72.4%; specificity = 78.6%) and NIHSS scores ≥13.5 indicate no hand functioning at 12 weeks (sensibility = 83.8%; specificity = 76.5%). Recanalization, either spontaneous or therapeutic, has a positive impact on patient functioning after acute ischemic stroke. Functional recovery occurs mostly within the first 12 weeks after stroke, with greater functional gains among patients with successful recanalization. Higher NIHSS scores at admission are associated with worse functional recovery.

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Non-contrast head CT alone for thrombectomy in acute ischemic stroke: analysis of the ANGEL-ACT registry

Journal of NeuroInterventional Surgery ◽

10.1136/neurintsurg-2021-017940 ◽

2021 ◽

pp. neurintsurg-2021-017940

Author(s):

Zeguang Ren ◽

Gaoting Ma ◽

Maxim Mokin ◽

Ashutosh P Jadhav ◽

Baixue Jia ◽

...

Keyword(s):

Ischemic Stroke ◽

Acute Ischemic Stroke ◽

Clinical Outcomes ◽

Primary Outcome ◽

Ct Perfusion ◽

Non Invasive ◽

Vessel Imaging ◽

Baseline Characteristics ◽

Procedural Outcomes ◽

Head Computed Tomography

BackgroudThe goal of this study was to determine if the choice of imaging paradigm performed in the emergency department influences the procedural or clinical outcomes after mechanical thrombectomy (MT).MethodsThis is a retrospective comparative outcome study which was conducted from the ANGEL-ACT registry. Comparisons were made between baseline characteristics and clinical outcomes of patients with acute ischemic stroke undergoing MT with non-contrast head computed tomography (NCHCT) alone versus patients undergoing NCHCT plus non-invasive vessel imaging (NVI) (including CT angiography (with or without CT perfusion) and magnetic resonance angiography). The primary outcome was the modified Rankin Scale (mRS) score at 90 days. Secondary outcomes included change in mRS score from baseline to 90 days, the proportions of mRS 0–1, 0–2, and 0–3, and dramatic clinical improvement at 24 hours. The safety outcomes were any intracranial hemorrhage (ICH), symptomatic ICH, and mortality within 90 days.ResultsA total of 894 patients met the inclusion criteria; 476 (53%) underwent NCHCT alone and 418 (47%) underwent NCHCT + NVI. In the NCHCT alone group, the door-to-reperfusion time was shorter by 47 min compared with the NCHCT + NVI group (219 vs 266 min, P<0.001). Patients in the NCHCT alone group showed a smaller increase in baseline mRS score at 90 days (median 3 vs 2 points; P=0.004) after adjustment. There were no significant differences between groups in the remaining clinical outcomes.ConclusionsIn patients selected for MT using NCHCT alone versus NCHCT + NVI, there were improved procedural outcomes and smaller increases in baseline mRS scores at 90 days.

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Abstract P119: Factors Influencing Door to Needle Administration for Acute Stroke Patients in the Emergency Department

Stroke ◽

10.1161/str.52.suppl_1.p119 ◽

2021 ◽

Vol 52 (Suppl_1) ◽

Author(s):

Nicolle W Davis ◽

Meghan Bailey ◽

Natalie Buchwald ◽

Amreen Farooqui ◽

Anna Khanna

Keyword(s):

Emergency Department ◽

Ischemic Stroke ◽

Acute Stroke ◽

Acute Ischemic Stroke ◽

Patient Outcomes ◽

Time Of Day ◽

Stroke Patients ◽

Acute Stroke Care ◽

The Impact ◽

Iv Tpa

Background/Objective: There is growing importance on discovering factors that delay time to intervention for acute ischemic stroke (AIS) patients, as rapid intervention remains essential for better patient outcomes. The management of these patients involves a multidisciplinary effort and quality improvement initiatives to safely increase treatment with intravenous thrombolytic (IV tPa). The objective of this pilot is to evaluate factors of acute stroke care in the emergency department (ED) and the impact they have on IV tPa administration. Methods: A sample of 89 acute ischemic stroke patients that received IV tPa from a single academic medical institution was selected for retrospective analysis. System characteristics (presence of a stroke nurse and time of day) and patient characteristics (mode of arrival and National Institutes of Health Stroke Scale score (NIHSS) on arrival) were analyzed using descriptive statistics and multiple regression to address the study question. Results: The mean door to needle time is 53.74 minutes ( + 38.06) with 74.2% of patients arriving to the ED via emergency medical services (EMS) and 25.8% having a stroke nurse present during IV tPa administration. Mode of arrival ( p = .001) and having a stroke nurse present ( p = .022) are significant predictors of door to needle time in the emergency department (ED). Conclusion: While many factors can influence door to needle times in the ED, we did not find NIHSS on arrival or time of day to be significant factors. Patients arriving to the ED by personal vehicle will have a significant delay in IV tPa administration, therefore emphasizing the importance of using EMS. Perhaps more importantly, collaborative efforts including the addition of a specialized stroke nurse significantly decreased time to IV tPa administration for AIS patients. With this dedicated role, accelerated triage and more effective management of AIS patients is accomplished, leading to decreased intervention times and potentially improving patient outcomes.

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Abstract 3200: Comparison of CT Perfusion Mismatch with Perfusion-Diffusion MRI in Ischemic Stroke - a Reliable Alternative?

Stroke ◽

10.1161/str.43.suppl_1.a3200 ◽

2012 ◽

Vol 43 (suppl_1) ◽

Author(s):

Bruce C Campbell ◽

Søren Christensen ◽

Christopher R Levi ◽

Patricia M Desmond ◽

Geoffrey A Donnan ◽

...

Keyword(s):

Ischemic Stroke ◽

Acute Ischemic Stroke ◽

Diffusion Mri ◽

Roc Analysis ◽

Ct Perfusion ◽

Residue Function ◽

Infarct Core ◽

Widespread Application ◽

Time To Peak ◽

Value Decomposition

Background and purpose: CT-perfusion (CTP) is widely and rapidly accessible for imaging acute ischemic stroke. However, there has been limited validation of CTP parameters against the more intensively studied MRI perfusion-diffusion mismatch paradigm. We tested the correspondence of CTP with contemporaneous perfusion-diffusion MRI. Methods: Acute ischemic stroke patients <6hr after onset had CTP and perfusion-diffusion MRI within 1hr, before reperfusion therapies. Relative cerebral blood flow (relCBF) and time-to-peak of the deconvolved tissue-residue-function (Tmax) were calculated (standard singular value decomposition deconvolution). The diffusion lesion was registered to the CTP slabs and manually outlined to its maximal visual extent. CT-infarct core was defined as relCBF<31% contralateral mean as previously published using this software. The volumetric accuracy of relCBF core compared to the diffusion lesion was tested in isolation, but also when restricted to pixels with relative time-to-peak (TTP) >4sec, to reduce artifactual false positive low CBF (eg in leukoaraiosis). The MR Tmax>6sec perfusion lesion (previously validated to define penumbral tissue at risk of infarction) was automatically segmented and registered to the CTP slabs. Receiver operating characteristic (ROC) analysis determined the optimal CT-Tmax threshold to match MR-Tmax>6sec, confidence intervals generated by bootstrapping. Agreement of these CT parameters with MR perfusion-diffusion mismatch on co-registered slabs was assessed (mismatch ratio >1.2, absolute mismatch>10mL, infarct core<70mL). Results: In analysis of 98 CTP slabs (54 patients, median onset to CT 190min, median CT to MR 30min), volumetric agreement with the diffusion lesion was substantially improved by constraining relCBF<31% within the automated TTP perfusion lesion ROI (median magnitude of volume difference 9.0mL vs unconstrained 13.9mL, p<0.001). ROC analysis demonstrated the best CT-Tmax threshold to match MR-Tmax>6sec was 6.2sec (95% confidence interval 5.6-7.3sec, ie not significantly different to 6sec), sensitivity 91%, specificity 70%, AUC 0.87. Using CT-Tmax>6s “penumbra” and relCBF<31% (restricted to TTP>4s) “core”, volumetric agreement was sufficient for 90% concordance between CT and MRI-based mismatch status (kappa 0.80). Conclusions: Automated CTP mismatch classification using relCBF and Tmax is similar to perfusion-diffusion MRI. CTP may allow more widespread application of the “mismatch” paradigm in clinical practice and trials.

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