Stroke Program Early Computed Tomography Score Research Articles

Importance of computed tomography perfusion on assessing collateral circulation and prognosis of patients with acute anterior circulation large vessel occlusion after endovascular therapy

This study probed the importance of computed tomography perfusion (CTP) on assessing collateral circulation and prognosis in patients with acute anterior circulation large vessel occlusion (AAC-LVO) after endovascular therapy (EVT). Retrospective analysis was performed on the case data of 124 AAC-LVO patients who achieved EVT in the First People's Hospital of Lianyungang. All patients received computed tomography (CT) examination. Based on the multi-phase computed tomography angiography (mCTA) score, patients were separated into poor collateral circulation group and good collateral circulation group. Based on modified Rankin scale (mRS) score, patients were separated into good prognosis group and poor prognosis group. The receiver operating characteristic (ROC) curve was used to measure the efficacy of CTP parameters in predicting good collateral circulation or good prognosis. Correlation between CTP parameters with mCTA collateral and 90-day mRS circulation score was analyzed using the Spearman correlation analysis. The age and admission national Institutes of Health stroke scale (NIHSS) scores of the good collateral circulation group were lower than the poor collateral circulation group, and low perfusion area volume with Tmax > 6 s (VTmax>6s), infarct core area volume (VCBF<30%)and hypoperfusion intensity ratio (HIR) were also lower. The mCTA collateral cycle score was negatively related to VTmax>6 s, VCBF<30% and HIR. The area under the curve (AUC) values of VTmax>6 s and VCBF<30% and HIR for predicting good collateral circulation were 0.763, 0.884 and 0.842, respectively, which suggested that perfusion parameters VTmax>6 s, VCBF<30% and HIR could effectively indicate the status of patients’ collateral circulation. Relative to the poor prognosis group, patients in the good prognosis group possessed lower admission NIHSS score, younger age, smaller final infarct volume, lower HIR, VCBF<30%, VTmax>6s, Alberta Stroke Program Early CT(ASPECT) score, and higher mCTA score. Spearman correlation analysis unveiled that ASPECT score, mCTA score and 90-day mRS were negatively correlated. The final infarct volume, perfusion parameters HIR and VCBF<30% were positively correlated with 90-day mRS. ROC analysis showed that all variates had good prognostic value for acute anterior circulation great vessel occlusion patients, while VCBF<30% and HIR had high diagnostic value for prognosis. To sum up, CTP can provide a comprehensive imaging assessment of the collateral circulation of patients with AAC-LVO and has a higher predictive value for the prognosis assessment of patients with EVT in terms of VCBF<30%, HIR score and mCTA collateral circulation score.

Association of clinical outcome and imaging endpoints in extensive ischemic stroke—comparing measures of cerebral edema

Abstract Objectives Ischemic edema is associated with worse clinical outcomes, especially in large infarcts. Computed tomography (CT)–based densitometry allows direct quantification of absolute edema volume (EV), which challenges indirect biomarkers like midline shift (MLS). We compared EV and MLS as imaging biomarkers of ischemic edema and predictors of malignant infarction (MI) and very poor clinical outcome (VPCO) in early follow-up CT of patients with large infarcts. Materials and methods Patients with anterior circulation stroke, large vessel occlusion, and Alberta Stroke Program Early CT Score (ASPECTS) ≤ 5 were included. VPCO was defined as modified Rankin scale (mRS) ≥ 5 at discharge. MLS and EV were quantified at admission and in follow-up CT 24 h after admission. Correlation was analyzed between MLS, EV, and total infarct volume (TIV). Multivariable logistic regression and receiver operating characteristics curve analyses were performed to compare MLS and EV as predictors of MI and VPCO. Results Seventy patients (median TIV 110 mL) were analyzed. EV showed strong correlation to TIV (r = 0.91, p &lt; 0.001) and good diagnostic accuracy to classify MI (EV AUC 0.74 [95%CI 0.61–0.88] vs. MLS AUC 0.82 [95%CI 0.71–0.94]; p = 0.48) and VPCO (EV AUC 0.72 [95%CI 0.60–0.84] vs. MLS AUC 0.69 [95%CI 0.57–0.81]; p = 0.5) with no significant difference compared to MLS, which did not correlate with TIV &lt; 110 mL (r = 0.17, p = 0.33). Conclusion EV might serve as an imaging biomarker of ischemic edema in future studies, as it is applicable to infarcts of all volumes and predicts MI and VPCO in patients with large infarcts with the same accuracy as MLS. Clinical relevance statement Utilization of edema volume instead of midline shift as an edema parameter would allow differentiation of patients with large and small infarcts based on the extent of edema, with possible advantages in the prediction of treatment effects, complications, and outcome. Key Points • CT densitometry–based absolute edema volume challenges midline shift as current gold standard measure of ischemic edema. • Edema volume predicts malignant infarction and poor clinical outcome in patients with large infarcts with similar accuracy compared to MLS irrespective of the lesion extent. • Edema volume might serve as a reliable quantitative imaging biomarker of ischemic edema in acute stroke triage independent of lesion size.

Abstract TP217: Thrombus Migration in Acute Ischemic Stroke Patients Receiving Mechanical Thrombectomy

Background: Thrombus migration is occasionally observed during mechanical thrombectomy in acute ischemic stroke patients. However, the factors influencing migration and its impact on imaging and clinical prognosis remain unclear. We investigated the clinical and imaging predictors of thrombus migration and to evaluate the corresponding outcomes. Methods: We retrospectively analyzed data from patients with acute anterior circulation (internal carotid artery, M1, M2) stroke who underwent mechanical thrombectomy at two comprehensive stroke centers. Thrombus migration was defined as any distal movement of the proximal end of the thrombus on digital subtraction angiography (DSA) compared to pre-interventional computed tomography (CT) angiography. A comprehensive imaging review was performed, including Alberta Stroke Program Early CT Score, hyperdense vessel sign on non-contrast CT, collateral flow grading on CT angiography and DSA. Univariate and multivariable logistic regression analyses were performed to determine the association between clinical and imaging parameters and thrombus migration. In addition, we compared clinical outcomes according to the presence of thrombus migration. Results: Of the 365 patients enrolled, thrombus migration was observed in 81 patients (22.2%). In 40 of these, the thrombus migrated beyond the vessel segment. In multivariable analysis, hyperdense vessel sign (adjusted odds ratio [aOR], 5.41; 95% CI 2.9-10.07), older age (aOR, 1.04; 95% CI, 1.01-1.08), and onset-to-image time (aOR 1.00; 95% CI 0.99-1.00) were associated with thrombus migration. In particular, thrombus migration is an independent predictor of first-pass effect (aOR 2.17; 95% CI, 1.15-4.1). However, there was no significant effect on functional outcome as measured by modified Rankin Scale at 3 months. Conclusions: In large-vessel occlusion stroke, the location of the thrombus may change before mechanical thrombectomy compared to pre-interventional angiographic imaging. The composition of the thrombus, as indicated by the hyperdense vessel sign, may influence its tendency to migrate. While thrombus migration is associated with a first-pass effect, it does not influence functional outcomes.

Association between infarct location and haemorrhagic transformation of acute ischaemic stroke after intravenous thrombolysis

To evaluate the association between computed tomography (CT)-based imaging variables at the time of admission and haemorrhagic transformation (HT) after intravenous thrombolysis (IVT). One hundred and eight patients who were treated with IVT for acute ischaemic stroke (AIS) during January 2021 to July 2023 were analysed retrospectively. The infarct location was classified as cortical or subcortical in accordance with the Alberta Stroke Program Early CT Score (ASPECTS) system. Logistic regression and receiver operating characteristic curve analyses were performed to determine the relationship between ischaemic variables and HT. Of the total, 18 (16.7%) patients had HT and seven (6.5%) had symptomatic intracerebral haemorrhage (sICH). Multivariate analysis revealed that cortical ASPECTS was independently associated with HT (odds ratio [OR], 0.197; 95% confidence interval [CI], 0.076-0.511; p=0.001) and cortical ASPECTS was independently associated with sICH (OR, 0.066; 95% CI, 0.009-0.510; p=0.009). To predict HT and sICH, cortical ASPECTS (HT area under the curve [AUC]=0.881, sICH AUC=0.971) provided a higher AUC compared with ASPECTS (HT AUC=0.850, sICH AUC=0.918). Cortical ASPECTS seen on CT at the time of admission is associated with HT and sICH after IVT.

Abstract 256: Proposal of multimodal CT‐based scoring system in prediction of hemorrhagic transformation in acute ischemic stroke

Introduction The routinely used computed tomography (CT)‐based workup in the setting of acute ischemic stroke (AIS) includes non‐contrast brain CT, CT angiography (CTA), and CT perfusion. Several CT, CTA, CTP‐based radiological biomarkers of hemorrhagic transformation (HT) were reported. To assess the predictive value of the combined multimodal CT parameters for HT after AIS and proposal of predictive scoring scale. Methods The source images of the NCCT, CTA and CTP of 282 AIS patients involving the anterior circulation (HT = 91, non‐HT = 191) were retrospectively reviewed and the following biomarkers were recorded and analyzed: Early subtle ischemic signs, hyperdense middle cerebral artery sign (HMCAS) and Alberta Stroke Program Early CT Score (ASPECTS) &lt; 7 in NCCT, large‐vessel occlusion (LVO), clot burden score (CBS) &lt; 6, large‐vessel occlusion, poor collateral score (CS) and Tmax &gt; 6 s ≥ 56.5 ml. A scoring system to predict HT based on these biomarkers was developed. Each biomarker counts for a single point with the total score ranging from 0 to 7. Results All the aforementioned multimodal CT biomarkers and the selected cut offs were significantly associated with higher HT risk. The calculated scores were statistically significant different between the HT and the non‐HT groups with AUC 0.761 (95% CI 0.703–0.819, P &lt; 0.0000001). Rates of HT were approximately five times higher in patients with score ≥ 3. Conclusion Multimodal CT‐based scoring system may provide highly reliable predictive model of hemorrhagic transformation in acute ischemic stroke.

Automated Large Vessel Occlusion Detection Software and Thrombectomy Treatment Times

The benefit of endovascular stroke therapy (EVT) in large vessel occlusion (LVO) ischemic stroke is highly time dependent. Process improvements to accelerate in-hospital workflows are critical. To determine whether automated computed tomography (CT) angiogram interpretation coupled with secure group messaging can improve in-hospital EVT workflows. This cluster randomized stepped-wedge clinical trial took place from January 1, 2021, through February 27, 2022, at 4 comprehensive stroke centers (CSCs) in the greater Houston, Texas, area. All 443 participants with LVO stroke who presented through the emergency department were treated with EVT at the 4 CSCs. Exclusion criteria included patients presenting as transfers from an outside hospital (n = 158), in-hospital stroke (n = 39), and patients treated with EVT through randomization in a large core clinical trial (n = 3). Artificial intelligence (AI)-enabled automated LVO detection from CT angiogram coupled with secure messaging was activated at the 4 CSCs in a random-stepped fashion. Once activated, clinicians and radiologists received real-time alerts to their mobile phones notifying them of possible LVO within minutes of CT imaging completion. Primary outcome was the effect of AI-enabled LVO detection on door-to-groin (DTG) time and was measured using a mixed-effects linear regression model, which included a random effect for cluster (CSC) and a fixed effect for exposure status (pre-AI vs post-AI). Secondary outcomes included time from hospital arrival to intravenous tissue plasminogen activator (IV tPA) bolus in eligible patients, time from initiation of CT scan to start of EVT, and hospital length of stay. In exploratory analysis, the study team evaluated the impact of AI implementation on 90-day modified Rankin Scale disability outcomes. Among 243 patients who met inclusion criteria, 140 were treated during the unexposed period and 103 during the exposed period. Median age for the complete cohort was 70 (IQR, 58-79) years and 122 were female (50%). Median National Institutes of Health Stroke Scale score at presentation was 17 (IQR, 11-22) and the median DTG preexposure was 100 (IQR, 81-116) minutes. In mixed-effects linear regression, implementation of the AI algorithm was associated with a reduction in DTG time by 11.2 minutes (95% CI, -18.22 to -4.2). Time from CT scan initiation to EVT start fell by 9.8 minutes (95% CI, -16.9 to -2.6). There were no differences in IV tPA treatment times nor hospital length of stay. In multivariable logistic regression adjusted for age, National Institutes of Health Stroke scale score, and the Alberta Stroke Program Early CT Score, there was no difference in likelihood of functional independence (modified Rankin Scale score, 0-2; odds ratio, 1.3; 95% CI, 0.42-4.0). Automated LVO detection coupled with secure mobile phone application-based communication improved in-hospital acute ischemic stroke workflows. Software implementation was associated with clinically meaningful reductions in EVT treatment times. ClinicalTrials.gov Identifier: NCT05838456.

Development and validation of a nomogram for the risk prediction of malignant cerebral edema after acute large hemispheric infarction involving the anterior circulation.

Malignant cerebral edema (MCE) is a life-threatening complication of large hemisphere infarction (LHI). Therefore, a fast, accurate, and convenient tool for predicting MCE can guide triage services and facilitate shared decision-making. In this study, we aimed to develop and validate a nomogram for the early prediction of MCE risk in acute LHI involving the anterior circulation and to understand the potential mechanism of MCE. This retrospective study included 312 consecutive patients with LHI from 1 January 2019 to 28 February 2023. The patients were divided into MCE and non-MCE groups. MCE was defined as an obvious mass effect with ≥5 mm midline shift or basal cistern effacement. Least absolute shrinkage and selection operator (LASSO) and logistic regression were performed to explore the MCE-associated factors, including medical records, laboratory data, computed tomography (CT) scans, and independent clinic risk factors. The independent factors were further incorporated to construct a nomogram for MCE prediction. Among the 312 patients with LHI, 120 developed MCE. The following eight factors were independently associated with MCE: Glasgow Coma Scale score (p = 0.007), baseline National Institutes of Health Stroke Scale score (p = 0.006), Alberta Stroke Program Early CT Score (p < 0.001), admission monocyte count (p = 0.004), white blood cell count (p = 0.002), HbA1c level (p < 0.001), history of hypertension (p = 0.027), and history of atrial fibrillation (p = 0.114). These characteristics were further used to establish a nomogram for predicting prognosis. The nomogram achieved an AUC-ROC of 0.89 (95% CI, 0.82-0.96). Our nomogram based on LASSO-logistic regression is accurate and useful for the early prediction of MCE after LHI. This model can serve as a precise and practical tool for clinical decision-making in patients with LHI who may require aggressive therapeutic approaches.

Hemodynamic Characteristics of Intracranial Atherosclerotic Stenosis: A Pilot Study of Contrast Enhancement Time-Density Curves Based on Regions of Interest.

The present study aimed to analyze the hemodynamic characteristics of occluded vessels responsible for acute ischemic stroke and to diagnose the occlusion types. Multimodal computed tomography (CT) was used to accurately identify the range of occlusion of large intracranial vessels. Regions of interest (ROI 1-3 ) were manually delineated at sites 2 mm away from the proximal, middle, and distal portions of each occlusion, generating 3 contrast enhancement time-density curves. The peak CT attenuation values, or Hounsfield units (H 1-3 ), and time-to-peak values (T 1-3 ) were extracted from each curve. H 0 and T 0 of the time-density curve, based on ROI 0 of the automatically recognized input artery, were used as the baseline values with which the odds ratios of each parameter, H 1-3/0 and T 1-3/0 , were obtained. The present study aimed to establish prediction models for intracranial atherosclerotic stenosis (ICAS) based on each ROI's time-density curve. Among the 33 acutely occluded intracranial vessels, 10 were found to have ICAS, whereas 23 did not, based on the diagnostic criteria. Significant differences were observed in patient sex, neutrophil-to-lymphocyte ratio upon admission, Alberta Stroke Program Early CT Score 24-48 hours after reperfusion therapy, and H 1/0 , H 3/0 , and T 3/0 between the ICAS and non-ICAS groups ( P < 0.05). The prediction model (model 3) based on the ROI 3 time-density curve showed the best performance for the diagnosis of ICAS (area under the curve, 0.944; 95% confidence interval, 0.854-1.000). The prediction models based on ROI 1 (model 1) and ROI 2 (model 2) showed moderate diagnostic performance (area under the curve, 0.817 vs 0.822, respectively). The best visualization for proximal occlusions was in the first phase (arterial phase) of multiphase CT angiography, and in the second phase (early venous phase) for distal occlusions. The contrast enhancement time-density curves of the ROIs at all evaluated portions of the acute ischemic stroke occlusions provided a visual display of the blood flow characteristics of the responsible vessels. The time-density curve of the ROI placed 2 mm from the distal occlusion was a combined effect of residual blood flow and collateral establishment, thus providing good performance for the diagnosis of ICAS.

Low-flow extra-intracranial bypass in acute carotid and vertebrobasilar ischemic stroke (literature review)

Introduction. The effectiveness of the method of revascularization of the brain using extra‑intracranial bypass in chronic insufficiency of blood supply to the brain has been studied in several randomized multicenter studies. The analysis of available publications devoted to this technique for 10 years with acute strokes in the carotid basin and for 20 years with ischemic strokes in the vertebrobasilar basin was carried out.Aim. To improve the results of treatment of ischemic strokes with the help of emergency extra‑intracranial low‑flow bypasses in the acute and acute period. In 12 publications over the past 10 years, selected from the PubMed search engine, 194 cases of the use of emergency extra‑intracranial microbypasses in the acute and acute period of ischemic stroke in the carotid basin were identified, 127 cases of emergency extra‑intracranial bypass were found in 6 articles during the last 20 years in the acute phase of vertebra‑basilar area stroke. Middle patient age in carotid group was 61.9 years, and 65 years in vertebral patient’s group. The male / female ratio was 3 / 1. The main indications for the bypass creation were: worsening of neurologic deficit from 4 and more according to the Stroke Severity Scale of the US National Institutes of Health, mini mal or not significant computed tomography (CT) or diffusion‑weighted magnetic resonance imaging (DW‑MRI) ischemia brain changes (not lower than 8 points on the scale of assessment of initial changes in the computed tomographic (CT) examination for stroke Alberta Stroke Program Early CT Score, ASPECTS), signs of significant brachiocephalic arteries atherosclerotic stenosis. In 83 carotid group cases perfusion‑diffusion mismatch was distinguished before bypass creation. In 111 carotid cases and in priority of vertebra‑basilar cases clinic‑diffusion mismatch was the only indication for emergency extra‑intracranial bypass creation. During the first 24 hours 65 % of carotid group bypass were performed, in other 35 % of cases bypasses were performed during 1 week after the stroke onset. There were 78 % of good results (&lt;2 on the Rankin outcome scale, mRS) and 22 % of poor (mRS &gt;2) in carotid stroke group. Mortality was 3 %. In vertebral group, coma was not contraindication for emergence extra‑intracranial bypass creation. In most cases, 70 % of bypass were performed between superficial temporal artery and superior cerebellar artery. Mortality in vertebral stroke group was 5 %, mostly because of somatic pathology worsening. Good results were achieved in76 % of cases.Conclusion. In some cases of atherosclerotic carotid and vertebrobasilar ischemic stroke, results of recovery can be approved greatly with use of emergency low‑flow extra‑intracranial bypass, if intravenous thrombolysis and endovascular tromboextraction were failed.

Outcomes of mechanical thrombectomy at a single-centre tertiary level public healthcare hospital in South Africa.

Mechanical thrombectomy (MT) is standard of care for acute ischaemic stroke from large vessel occlusion following randomised controlled trials performed largely in high-income countries. Limited data exists on its effectiveness in the setting of low-and-middle-income countries. We aimed to evaluate the safety and efficacy of MT in a tertiary level public hospital in Cape Town, South Africa. Patients with acute ischaemic stroke presenting consecutively to Groote Schuur Hospital between 1 January 2018 to 1 January 2022 with proximal intracranial occlusion in the anterior circulation treated with MT within 6 h from onset using computed tomography (CT) and CT angiography imaging-based protocols were evaluated. Demographic, clinical, radiological and procedural data were obtained from the stroke unit database. Recanalisation was evaluated post-procedure by modified Treatment in Cerebral Infarction score (mTICI). Functional independence (modified Rankin scores 0-2) and mortality at 90 days were also assessed. Thrombectomies were performed in 84 patients during the study period. The median age was 56 years (interquartile range, IQR) and 51% of participants were female. Median National Institute of Health Stroke Score was 18 and median baseline Alberta Stroke Programme Early CT score was 8. Bridging thrombolysis was given to 65% of participants. Median time from symptom onset to reperfusion was 339 min (IQR). Successful recanalisation (mTICI 2b/3) was obtained in 62%. At 90 days, 34% of participants gained functional independence and mortality was 34%. This study demonstrated similar rates of recanalisation and functional independence to that seen in trials in high-income countries using basic imaging despite a higher mortality and longer median time to reperfusion. This data supports the effectiveness of MT in a tertiary level public hospital in South Africa despite the challenges of providing emergent stroke care in a resource-constrained setting.

Endovascular Thrombectomy Versus Best Medical Management Beyond 24 Hours From Last Known Well in Acute Ischemic Stroke Due to Large Vessel Occlusion

Background The safety and efficacy of endovascular thrombectomy (EVT) in patients with acute ischemic stroke due to large vessel occlusion presenting beyond 24 hours from last known well (LKW) remains undetermined. Methods In this single center study, we identified patients with large vessel occlusion who were eligible for EVT based on noncontrast computed tomography (CT)/CT angiography (without CT perfusion or magnetic resonance imaging) using an Alberta Stroke Program Early CT Score of ≥5, National Institutes of Health Stroke Scale of ≥6, and presenting beyond 24 hours from LKW, between January 2018 and March 2022. During the study period, EVT service limitations meant patients eligible for EVT presenting outside service hours, routinely received best medical management (BMM). Functional and safety outcomes were compared between patients receiving EVT or BMM following multivariable adjustment for age, baseline stroke severity, Alberta Stroke Program Early CT Score, time from LKW, IV thrombolysis, and clot location. Results Among 35 patients presenting beyond 24 hours from LKW and eligible for EVT, 19 (54%) were treated with EVT and 16 (46%) with BMM. Alberta Stroke Program Early CT Score were similar across both groups (EVT: 7 [6.75–8] versus BMM: 7 [6–8]), but not the baseline National Institutes of Health Stroke Scale (EVT: 17 [11–19.5] versus BMM: 20 [9.75–26]). No significant difference was observed between the EVT and BMM groups in the symptomatic intracranial hemorrhage (5.3% versus 0%; P =0.28) or mortality (26.3% versus 37.5%; P =0.42) rates, respectively. The modified Rankin scale at 90 days (adjusted common odds ratio [OR], 1.94; [95% CI 0.42–8.87]; P =0.39) and functional independence rate, although numerically higher in the EVT group compared with the BMM group (modified Rankin scale≤2; 36.9% versus 18.8%; adjusted OR, 4.34; [95% CI 0.34–54.83]; P =0.25), were not significantly different. 94.7% of patients treated with EVT achieved successful reperfusion (modified thrombolysis in cerebral infarction 2b–3). Conclusion In routine clinical practice, EVT beyond 24 hours from LKW appears safe and feasible, when performed in patients with acute ischemic stroke who were deemed eligible for EVT by noncontrast CT /CT angiography alone. A large collaborative randomized trial assessing the efficacy of EVT beyond 24 hours is warranted. Our findings provide a basis for the sample size estimate for an adequately powered trial.

Proposal of multimodal computed tomography-based scoring system in prediction of hemorrhagic transformation in acute ischemic stroke.

The routinely used computed tomography (CT)-based workup in the setting of acute ischemic stroke (AIS) includes non-contrast brain CT, CT angiography (CTA), and CT perfusion. Several CT, CTA, CTP-based radiological biomarkers of hemorrhagic transformation (HT) were reported. To assess the predictive value of the combined multimodal CT parameters for HT after AIS and proposal of predictive scoring scale. The source images of the NCCT, CTA and CTP of 282 AIS patients involving the anterior circulation (HT = 91, non-HT = 191) were retrospectively reviewed and the following biomarkers were recorded and analyzed: Early subtle ischemic signs, hyperdense middle cerebral artery sign (HMCAS) and Alberta Stroke Program Early CT Score (ASPECTS) < 7 in NCCT, large-vessel occlusion (LVO), clot burden score (CBS) < 6, large-vessel occlusion, poor collateral score (CS) and Tmax > 6s ≥ 56.5ml. A scoring system to predict HT based on these biomarkers was developed. Each biomarker counts for a single point with the total score ranging from 0 to 7. All the aforementioned multimodal CT biomarkers and the selected cut offs were significantly associated with higher HT risk. The calculated scores were statistically significant different between the HT and the non-HT groups with AUC 0.761 (95% CI 0.703-0.819, P < 0.0000001). Rates of HT were approximately five times higher in patients with score ≥ 3. Multimodal CT-based scoring system may provide highly reliable predictive model of hemorrhagic transformation in acute ischemic stroke.

Quantitative indices for an intracranial aneurysm and subarachnoid hemorrhage in early childhood: a case report

BackgroundIntracranial aneurysms (ICA) rarely occur in children under 3 years of age. Little is known for neuroimaging parameters that predict survival and clinical outcomes of patients with ICA in early childhood.Case presentationA 2-year-old girl showed intracranial hemorrhage due to a rupture of aneurysm at the middle cerebral artery. Quantitative measurements of ischemic damages on the head computed tomography (CT) marked an extremely low score of 2 points with modified Alberta Stroke Program Early CT Score (mASPECTS). She died 15 days after admission. In publications from 2021 to 2022, we found 21 children who were under 3 years of age at onset of ICA. None of them died, but two of three patients who had mASPECTS scores 0–8 showed developmental delay and/or epilepsy as neurological complications.ConclusionEarly CT findings are applicable for predicting survival and neurological outcomes of young children with intracranial hemorrhage.

CT after interhospital transfer in acute ischemic stroke: Imaging findings and impact of prior intravenous contrast administration.

Large vessel occlusion (LVO) stroke patients routinely undergo interhospital transfer to endovascular thrombectomy capable centers. Imaging is often repeated with residual intravenous (IV) iodine contrast at post-transfer assessment. We determined imaging findings and the impact of residual contrast on secondary imaging. Anterior circulation LVO stroke patients were selected out of a consecutive cohort. Directly admitted patients were contrast naïve, and transferred patients had previously received IV iodine contrast for stroke assessment at the referring hospital. Two independent readers rated the visibility of residual contrast on non-contrast computed tomography (CT) after transfer and assessed the hyperdense vessel sign. Multivariate linear regression analysis was used to investigate the association of the Alberta Stroke Program Early CT score (ASPECTS) with prior contrast administration, time from symptom onset (TFSO), and CTP ischemic core volume in both directly admitted and transferred patients. We included 161 patients, with 62 (39%) transferred and 99 (62%) directly admitted patients. Compared between these groups, transferred patients had a longer TFSO-to-imaging at our institution (median: 212 vs. 75 min, p < 0.001) and lower ASPECTS (median: 8 vs. 9, p < 0.001). Regression analysis presented an independent association of ASPECTS with prior contrast administration (β = -0.25, p = 0.004) but not with TFSO (β = -0.03, p = 0.65). Intergroup comparison between transferred and directly admitted patients pointed toward a stronger association between ASPECTS and CTP ischemic core volume in transferred patients (β = -0.39 vs. β = -0.58, p = 0.06). Detectability of the hyperdense vessel sign was substantially lower after transfer (66 vs. 10%, p < 0.001). Imaging alterations due to residual IV contrast are frequent in clinical practice and render the hyperdense vessel sign largely indetectable. Larger studies are needed to clarify the influence on the association between ASPECTS and ischemic core.

Endovascular Thrombectomy Versus Best Medical Therapy for Late Presentation Acute Ischemic Stroke With Proximal Large‐Vessel Occlusion Selected on the Basis of Noncontrast Computed Tomography: A Retrospective Analysis of 2 Prospectively Defined Cohorts

Background The efficacy and safety of endovascular thrombectomy (EVT) &gt;6 hours from acute ischemic stroke (AIS) onset for patients selected without computed tomography (CT) perfusion or magnetic resonance imaging is undetermined in routine clinical practice. Methods In this single‐center study, we identified consecutive late‐presenting patients with AIS who were eligible for EVT on the basis of noncontrast CT/CT angiography (without CT perfusion or magnetic resonance imaging) using an Alberta Stroke Program Early CT Score of ≥6, &gt;6 hours from stroke onset, between January 2018 and March 2022. During the study period, EVT capacity limitations meant EVT‐eligible patients presenting out of regular working hours, consistently received best medical management (BMM). Functional outcomes (modified Rankin Scale at 90 days), symptomatic intracranial hemorrhage, and mortality at 90 days were compared between patients receiving EVT or BMM following multivariable adjustment for age, sex, baseline stroke severity, Alberta Stroke Program Early CT Score, onset‐to‐neuroimaging time, intravenous thrombolysis, and clot location. Results Among 4802 patients with AIS, 150 patients (3.1%) presenting beyond 6 hours of onset were eligible for EVT: 74 (49%) treated with EVT and 76 (51%) with BMM. Compared with the BMM group, patients treated with EVT had significantly improved functional outcome (modified Rankin Scale) (adjusted common odds ratio, 2.23 [95% CI, 1.18–4.22]; P =0.013), and higher rates of functional independence (modified Rankin Scale ≤2; 39.2.% versus 9.2%; adjusted odds ratio, =4.73 [95% CI, 1.64–13.63]; P =0.004). No significant difference was observed between the EVT and BMM groups in the symptomatic intracranial hemorrhage (5.4% versus 2.6%; P =0.94) or mortality (20.2% versus 47.3%; P =0.16) rates, respectively. Conclusion In routine clinical practice, of the 3.1% of patients in our AIS population presenting after 6 hours from stroke onset who were deemed eligible for EVT by noncontrast CT/CT angiography alone, those treated with EVT achieved significantly improved functional outcome, compared with patients treated with BMM only. No significant differences were noted between the 2 groups with respect to symptomatic intracranial hemorrhage and mortality. While confirmatory randomized trials are awaited, these findings suggest that EVT is effective and safe when performed in patients with AIS selected without CT perfusion or magnetic resonance imaging &gt;6 hours from stroke onset.

Association of concomitant headache with hypoperfusion in ischemic stroke: A multimodal CT-based study.

Previous investigations indicate that vessel wall elasticity may contribute to the occurrence of an ischemic stroke-associated headache. In this prospective study, the association between radiologic parameters of intracranial hemodynamic changes and concomitant headaches during the early phase of ischemic stroke was examined. Consecutive patients with acute ischemic stroke (AIS) from the First Affiliated Hospital of Soochow University were recruited and divided into two groups according to their questionnaire results and the International Classification of Headache Disorder 3 criteria. Baseline data, including stroke sub-types and neurological function, at admission and discharge were collected. Non-contrast computed tomography (CT), CT angiography, and CT perfusion were performed to assess intracranial hemodynamic changes. Multiple adjusted logistic models were used and possible confounding factors were included in sequential models. A total of 190 patients with AIS (93 headaches and 97 non-headache) were recruited. There were significant differences between the two groups in gender, hypertension, Alberta stroke program early CT score, relative cerebral blood flow (rCBF), and relative cerebral blood volume (rCBV). Furthermore, rCBV (adjusted odds ratio [OR] 0.160; 95% confidence interval [CI], 0.055-0.461; p < 0.001) and rCBF (adjusted OR, 0.309; 95% CI, 0.113-0.844; p < 0.05) were significantly associated with concomitant headache during the early phase of AIS in fully adjusted models. After adjusting for sociodemographic characteristics and other confounding factors, p values for the ORs were robust and intensified. Patients with lower rCBV and rCBF tended to experience the concomitant headache during the early phase of AIS. Regional hypoperfusion and microcirculation might play an important role in this separate clinical entity.

Venous Outflow Profiles Are Linked to Clinical Outcomes in Ischemic Stroke Patients with Extensive Baseline Infarct.

Background and Purpose The benefit of endovascular thrombectomy (EVT) treatment is still unclear in stroke patients presenting with extensive baseline infarct. The use of additional imaging biomarkers could improve clinical outcome prediction and individualized EVT selection in this vulnerable cohort. We hypothesized that cerebral venous outflow (VO) may be associated with functional outcomes in patients with low Alberta Stroke Program Early CT Score (ASPECTS). Methods We conducted a retrospective multicenter cohort study of patients with acute ischemic stroke due to large vessel occlusion (AIS-LVO). Extensive baseline infarct was defined by an ASPECTS of ≤5 on admission computed tomography (CT). VO profiles were assessed on admission CT angiography using the Cortical Vein Opacification Score (COVES). Favorable VO was defined as COVES ≥3. Multivariable logistic regression was used to determine the association between cerebral VO and good clinical outcomes (90-day modified Rankin Scale score of ≤3). Results A total of 98 patients met the inclusion criteria. Patients with extensive baseline infarct and favorable VO achieved significantly more often good clinical outcomes compared to patients with unfavorable VO (45.5% vs. 10.5%, P<0.001). Higher COVES were strongly associated with good clinical outcomes (odds ratio, 2.17; 95% confidence interval, 1.15 to 4.57; P=0.024), independent of ASPECTS, National Institutes of Health Stroke Scale, and success of EVT. Conclusions Cerebral VO profiles are associated with good clinical outcomes in AIS-LVO patients with extensive baseline infarct. VO profiles could serve as a useful additional imaging biomarker for treatment selection and outcome prediction in low ASPECTS patients.

External Validation of e-ASPECTS Software for Interpreting Brain CT in Stroke.

The purpose of this study was to test e-ASPECTS software in patients with stroke. Marketed as a decision-support tool, e-ASPECTS may detect features of ischemia or hemorrhage on computed tomography (CT) imaging and quantify ischemic extent using Alberta Stroke Program Early CT Score (ASPECTS). Using CT from 9 stroke studies, we compared software with masked experts. As per indications for software use, we assessed e-ASPECTS results for patients with/without middle cerebral artery (MCA) ischemia but no other cause of stroke. In an analysis outside the intended use of the software, we enriched our dataset with non-MCA ischemia, hemorrhage, and mimics to simulate a representative "front door" hospital population. With final diagnosis as the reference standard, we tested the diagnostic accuracy of e-ASPECTS for identifying stroke features (ischemia, hyperattenuated arteries, and hemorrhage) in the representative population. We included 4,100 patients (51% women, median age=78 years, National Institutes of Health Stroke Scale [NIHSS]= 10, onset to scan=2.5 hours). Final diagnosis was ischemia (78%), hemorrhage (14%), or mimic (8%). From 3,035 CTs with expert-rated ASPECTS, most (2084/3035, 69%) e-ASPECTS results were within one point of experts. In the representative population, the diagnostic accuracy of e-ASPECTS was 71% (95% confidence interval [CI]= 70-72%) for detecting ischemic features, 85% (83-86%) for hemorrhage. Software identified more false positive ischemia (12% vs 2%) and hemorrhage (14% vs <1%) than experts. On independent testing, e-ASPECTS provided moderate agreement with experts and overcalled stroke features. Therefore, future prospective trials testing impacts of artificial intelligence (AI) software on patient care and outcome are required before widespread implementation of stroke decision-support software. ANN NEUROL 2022;92:943-957.

Risk Factors of Futile Recanalization Following Endovascular Treatment in Patients With Large‐Vessel Occlusion: Systematic Review and Meta‐Analysis

Background Although successful recanalization (modified Thrombolysis in Cerebral Infarction score 2b–3) can be achieved in &gt;80% of patients experiencing stroke attributable to large‐vessel occlusion, up to 50% of patients may develop poor clinical outcomes (modified Rankin scale score at 90 days of 3–6), termed as futile recanalization (FR). The meta‐analysis aims to determine various risk factors associated with FR. Methods In February 2021, a comprehensive literature search on risk factors associated with FR was performed with keywords, including “stroke,” “thrombectomy,” “treatment outcome,” and “risk factors.” Their correlations with FR were evaluated using the random effect size meta‐analysis model. Results Twenty studies with 3037 patients were included with an FR rate of 51.0%. Our meta‐analyses showed that age (mean difference [MD], 5.6; 95% CI, 4.7–6.6), National Institutes of Health Stroke Scale score (MD, 4.2; 95% CI, 3.2–5.1), Alberta Stroke Program Early Computed Tomography (CT) Score (MD, −0.5; 95% CI, 0.8–0.3), hypertension (odds ratio [OR], 1.5; 95% CI, 1.3–1.9), systolic blood pressure (MD, 6.9; 95% CI, 3.6–8.7), atrial fibrillation (OR, 1.5; 95% CI, 1.2–1.8), IV tPA (tissue‐type plasminogen activator) (OR, 0.7; 95% CI, 0.5–0.8), puncture to recanalization time (MD, 9.6; 95% CI, 5.3–13.8), and time of onset to recanalization (MD, 32.1; 95% CI, 6.5–47.7) were significantly associated with FR ( P &lt;0.001). Conclusions Age, admission National Institutes of Health Stroke Scale score, Alberta Stroke Program Early CT Score, comorbidities, including hypertension, systolic blood pressure, atrial fibrillation, and use of IV tPA, as well as time frames, including onset to recanalization and onset to arrival, were significant influencing factors for FR after mechanical thrombectomy. Future research on the mechanism underlying FR is warranted.

Interpretable Machine Learning Modeling for Ischemic Stroke Outcome Prediction.

Background and PurposeMechanical thrombectomy greatly improves stroke outcomes. Nonetheless, some patients fall short of full recovery despite good reperfusion. The purpose of this study was to develop machine learning (ML) models for the pre-interventional prediction of functional outcome at 3 months of thrombectomy in acute ischemic stroke (AIS), using clinical and auto-extractable radiological information consistently available upon first emergency evaluation.Materials and MethodsA two-center retrospective cohort of 293 patients with AIS who underwent thrombectomy was analyzed. ML models were developed to predict dichotomized modified Rankin score at 90 days (mRS-90) using clinical and imaging features, both separately and combined. Conventional and experimental imaging biomarkers were quantified using automated image-processing software from non-contract computed tomography (CT) and computed tomography angiography (CTA). Shapley Additive Explanation (SHAP) was applied for model interpretability and predictor importance analysis of the optimal model.ResultsMerging clinical and imaging features returned the best results for mRS-90 prediction. The best performing classifier was Extreme Gradient Boosting (XGB) with an area under the receiver operating characteristic curve (AUC) = 84% using selected features. The most important classifying features were age, baseline National Institutes of Health Stroke Scale (NIHSS), occlusion side, degree of brain atrophy [primarily represented by cortical cerebrospinal fluid (CSF) volume and lateral ventricle volume], early ischemic core [primarily represented by e-Alberta Stroke Program Early CT Score (ASPECTS)], and collateral circulation deficit volume on CTA.ConclusionMachine learning that is applied to quantifiable image features from CT and CTA alongside basic clinical characteristics constitutes a promising automated method in the pre-interventional prediction of stroke prognosis. Interpretable models allow for exploring which initial features contribute the most to post-thrombectomy outcome prediction overall and for each individual patient outcome.