Wake-up stroke and CT perfusion: effectiveness and safety of reperfusion therapy

Sex differences in Wake-Up Stroke patients characteristics and outcomes

OBJECTIVES

Wake-up Stroke (WUS) accounts for about 25% of all ischemic strokes. Differences according to sex in the WUS subgroup has been poorly investigated so far, so we aimed to assess these differences by differentiating the enrolled population based on treatment administered.

MATERIALS & METHODS

We retrospectively analysed clinical and imaging data of WUS patients admitted to our hospital between November 2013 and December 2018 dividing them in two groups: rTPA-treated and non-rTPA treated group. To point out outcome differences we evaluated: NIHSS at 7 days or at discharge, mRS at discharge and ΔNIHSS.

RESULTS

We enrolled 149 WUS patients, 74 rTPA treated and 75 non-rTPA treated. Among rTPA treated patients, time from last known well (LKW) to Emergency Department (ED) admission was longer in females than males (610 vs 454 min), while females had a higher ΔNIHSS than males (5 vs 3). Finally, among non-rTPA treated patients, females were older than males (85 vs 79 years), had a higher pre-admission mRS (although very low in both cases), had a longer length of stay (17 vs 13 days) and shown a higher NIHSS at discharge (4 vs 2) compared to males.

CONCLUSIONS

Females not receiving thrombolytic treatment had worse functional outcome than males, showing a higher NIHSS at discharge but, in contrast, when treated with rTPA they showed better neurological recovery as measured by a greater ΔNIHSS. We emphasize the importance of a prompt recognition of WUS in females since they seem to benefit more from rTPA treatment.

Stroke heart injury: the effect of cerebral reperfusion treatment. A 3-year retrospective study

BACKGROUND

Cardiac involvement following an acute stroke (Stroke Heart Syndrome-SHS) is an established complication and it is linked to the involvement of sympathetic activation, inflammation, and neuro-endocrine response. Troponin "rise and fall pattern" > 30% is one marker of SHS. The aim of this study was to evaluate the role of reperfusion treatments in the prevention/pathogenesis of SHS with different stroke sizes and locations (OCSP classification).

METHODS

We retrospectively analyzed data of 890 patients admitted to the Stroke Unit of Trieste (Italy) between 2018 and 2020. Out of them, 411 met the inclusion criteria (acute ischemic non-lacunar stroke). Clinical data were collected for each patient, imaging characteristics, and markers of cardiac injury [troponin I (TnI), NT-proBNP, "rise and fall pattern" > 30%]. We compared different stroke subtypes according to OCSP, while evaluating any differences in patients with and without SHS.

RESULTS

In treated total anterior circulation infarct (TACI) patients, the rate of SHS is lower than in non-treated TACI. Similar SHS rate was found in partial anterior (PACI) and posterior stroke (POCI), and between treated and non-treated patients. Focusing on TACI group, we compared SHS-TACI and non-SHS-TACI, we performed a univariate and multivariate analysis; treatment (OR 0.408 CI95% 0.185-0.900; p = 0.026) and diabetes (OR 2.618 CI95% 1.181-5.803; p = 0.018) were significantly associated to SHS. No clear insular effect was found in SHS development.

CONCLUSIONS

In severe anterior stroke (TACI), reperfusion treatment may be effective in preventing SHS. Conversely, diabetes is an independent risk factor for SHS. PACI and POCI have similar troponin elevation rate.

Hyperglycemia Is Associated With Computed Tomography Perfusion Core Volume Underestimation in Patients With Acute Ischemic Stroke With Large-Vessel Occlusion

Background

CT Perfusion (CTP) predictions of infarct core play an important role in the determination of treatment eligibility in large vessel occlusion (LVO) acute ischemic stroke (AIS). Prior studies have demonstrated that blood glucose can affect cerebral blood flow (CBF). Here we examine the influence of acute and chronic hyperglycemia on CTP estimations of infarct core.

Methods

From our prospectively collected multi-center observational cohort, we identified patients with LVO AIS who underwent CTP with RAPID (IschemaView, Stanford, CA) post-processing, followed by endovascular therapy with substantial reperfusion (TICI 2b-3) within 90 minutes, and final infarct volume (FIV) determination by MRI 48-72 hours post-treatment. Core volume over- and under-estimations were defined as a difference of at least 20 mL between CTP-RAPID predicted infarct core and DWI FIV. Primary outcome was the association of presentation glucose and HgbA1c with underestimation (UE) of core volume and was measured using multivariable logistic regression adjusted for comorbidities and presentation characteristics. Secondary outcomes included frequency of overestimation (OE) of infarct core.

Results

Among 256 patients meeting inclusion criteria, median age was 67 [IQR 57-77], 51.6% were female, and 132 (51.6%) and 93 (36.3%) had elevated presentation glucose and elevated HgbA1c, respectively. Median CTP-predicted core was 6 mL [IQR 0-30], median DWI FIV was 14 mL [IQR 6-43] and median difference was 12 mL [IQR 5-35]. Twenty-eight (10.9%) patients had infarct core OE and 68 (26.6%) had UE. Compared to those with no UE, patients with UE had elevated blood glucose (median 119 [103-155] vs 138 [117-195], p=0.002) and HgbA1c (median 5.80 [5.40-6.40] vs 6.40 [5.50-7.90], p=0.009). In multivariable analysis, UE was independently associated with elevated glucose (aOR 2.10, p=0.038) and HgbA1c (aOR 2.37, p=0.012). OE was associated with lower presentation blood glucose (median 109 [ 99-132] in OE vs 127 [107-172] in no OE, p=0.003) and HgbA1c (5.6 [IQR 5.1 - 6.2] in OE vs 5.90 [5.50-6.70] in no OE, p=0.012).

Conclusions

Acute and chronic hyperglycemia were strongly associated with CTP UE in patients with LVO AIS undergoing EVT. Glycemic state should be considered when interpreting CTP findings in patients with LVO AIS.

Status Epilepticus after mechanical thrombectomy: The role of early EEG assessment in Stroke Unit, clinical and radiological prognostication

BACKGROUND

Convulsive (CSE) and non-convulsive (NCSE) Status Epilepticus are a complication in 0.2-0.3% ischemic strokes. Large stroke and cortical involvement are the main risk factors for developing SE. This study evaluates the prevalence of SE in patients treated with endovascular thrombectomy (EVT) through EEG recording within 72- h from admission. Moreover, we compared clinical, radiological, and outcome measures in SE and no-SE patients.

MATERIALS AND METHODS

We collected retrospectively demographical and clinical characteristics of acute ischemic stroke patients who underwent EVT, admitted in the Stroke Unit (SU) of the University Hospital of Trieste between January 2018 and March 2020 who underwent EEG recording within 72- h from the symptoms' onset.

RESULTS

Out of 247 EVT patients, 138 met the inclusion criteria, of whom 9 (6.5%) showed SE with median onset time of 1 day (IQR 1-2). No difference was found between the two groups as for age, sex, risk factors, grade of recanalization, etiology of stroke, and closed vessel. The no-SE group presented higher NIHSS improvement rate (p=0.025) compared to the SE group. The sum of the lobes involved in the ischemic lesion was significantly higher in SE group (p=0.048).

CONCLUSION

SE after EVT in large strokes is a non-rare complication, with most being NCSE. Performing a rapid EEG assessment in a Stroke Unit setting may allow for a prompt recognition and treatment of SE in the acute/hyper-acute phase. SE may be correlated with worse clinical outcomes in patients with large vessel occlusion.

A prospective study of wake-up stroke patients presenting to the emergency department: a single-center cohort study

INTRODUCTION

This study aims to prospectively examine patients with ischemic wake-up stroke (WUS) presenting to the emergency department, to investigate the risk factors affecting the mortality occurring within 28, 90, and 180 days, and to create a new scoring system for the prediction of 28-day mortality.

MATERIALS AND METHOD

Patients who presented to the emergency department with WUS findings between 01.07.2019 and 30.06.2020 were prospectively analyzed. Logistic regression analysis was performed to determine the factors affecting mortality and the modified Rankin scale (mRS).

RESULTS

A total of 161 patients were included. Of the patients, 22.4% died within 28 days and 40.4% within 180 days. The presence of coronary artery disease (CAD) increased the 28-day mortality risk (p = 0.009) 3.57 times, 90-day mortality risk 2.15 times (p = 0.033), and 180-day mortality risk 2.18 times (p = 0.045). In order to be used in the prediction of 28-day mortality in patients with WUS, we developed the ischemic WUS mortality score (IWUSMOS), which consists of the middle cerebral artery (45 points), internal carotid artery (60 points), basilar artery (39 points), superior cerebellar artery (66 points) occlusion, hypertension (33 points), CAD (28 points), malignancy (100 points), and arrhythmia (23 points). With this scoring system, the 28-day mortality risk was determined as 0.05% when the total score was "43" whereas the mortality risk was found to be 95.0% when the total score was "187."

CONCLUSION

We propose that IWUSMOS, a new scoring system, can be used to predict the 28-day mortality risk of patients with WUS.

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

INTRODUCTION

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

METHODS AND ANALYSIS

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

ETHICS AND DISSEMINATION

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

PROSPERO REGISTRATION NUMBER

ChiCTR2100049133.

Multimodal CT Imaging Characteristics in Predicting Prognosis of Wake-Up Stroke

Background: Multimodal CT imaging can evaluate cerebral hemodynamics and stroke etiology, playing an important role in predicting prognosis. This study aimed to summarize the comprehensive image characteristics of wake-up stroke (WUS), and to explore its value in prognostication.

Methods: WUS patients with anterior circulation large vessel occlusion were recruited into this prospective study. According to the 90-day modified Rankin Scale (mRS), all patients were divided into good outcome (mRS 0–2) or bad (mRS 3–6). Baseline clinical information, multimodal CT imaging characteristics including NECT ASPECTS, clot burden score (CBS), collateral score, volume of penumbra and ischemic core on perfusion were compared. Multivariate logistic regression analysis was further used to analyze predictive factors for good prognosis. Area under curve (AUC) was calculated from the receiver operating characteristic (ROC) curve to assess prognostic value.

Results: Forty WUS were analyzed in this study, with 20 (50%) achieving good outcome. Upon univariable analysis, the good outcome group demonstrated higher ASPECTS, higher CBS, higher rate of good collateral filling and lower penumbra volume when compared with the poor outcome group. Upon logistic regression analysis, poor outcome significantly correlated with penumbra volume (OR: 1.023, 95% CI = 1.003–1.043) and collateral score (OR: 0.140, 95% CI = 0.030–0.664). AUC was 0.715 for penumbra volume (95% CI, 0.550–0.846) and 0.825 for good collaterals (95% CI, 0.672–0.927) in predicting outcome.

Conclusions:Penumbra volume and collateral score are the most relevant baseline imaging characters in predicting outcome of WUS patients. These imaging characteristics might be instructive to treatment selection. As the small sample size of current study, further studies with larger sample size are needed to confirm these observations.

Study on Model Iterative Reconstruction Algorithm vs. Filter Back Projection Algorithm for Diagnosis of Acute Cerebral Infarction Using CT Images

The aim was to explore the application value of computed tomography (CT) perfusion (CTP) imaging based on the iterative model reconstruction (IMR) in the diagnosis of acute cerebral infarction (ACI). 80 patients with ACI, admitted to hospital, were selected as the research objects and divided randomly into a routine treatment group (group A) and a low-dose group (group B) (each group with 40 patients). Patients in group A were scanned at 80 kV–150 mAs, and the traditional filtered back projection (FBP) algorithm was employed to reconstruct the images; besides, 80 kV–30 mAs was adopted to scan the patients in group B, and the images were reconstructed by IMR1, IMR2, IMR3, iDose4 (a kind of hybrid iterative reconstruction technology), and FBP, respectively. The application values of different algorithms were evaluated by CTP based on the collected CTP images of patients and detecting indicators. The results showed that the gray and white matter CT value, SD value, SNR, CNR, and subjective image scores of patients in group B were basically consistent with those of group A (p > 0.05) after the IMR1 reconstruction, and the CT and SD of gray and white matter in patients from group B reduced steeply (p < 0.05), while SNR and CNR increased dramatically after IMR2 and IMR3 reconstruction in contrast to group A (p < 0.05). Furthermore, the cerebral blood volume (CBV), cerebral blood flow (CBF), mean transit time (MTT) of contrast agent, and time to peak (TTP) of contrast agent in patients from group B after iDose4 and IMR reconstruction were basically the same as those of group A (p > 0.05). Therefore, IMR combined with low-dose CTP could obtain high-quality CTP images of the brain with stable perfusion indicators and low radiation dose, which could be clinically applied in the diagnosis of ACI.

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.

Incremental value of Alberta Stroke Program Early CT Score to collateral score for predicting target mismatch in stroke patients with extended time window or unknown onset time

PURPOSE

To evaluate whether Alberta Stroke Program Early CT Score (ASPECTS) could provide incremental value to collateral score, and their integration could be an effective surrogate of CTP in predicting target mismatch.

MATERIAL AND METHODS

One hundred and fifty-nine stroke patients (onset time 6-16 h or with unknown onset time) with MCA and/or ICA occlusion underwent non-contrast computed tomography (NCCT) and CT perfusion (CTP) scan for initial assessment. Simulated single-phase CT angiography (sCTA, peak arterial phase) and multiphase CTA (mCTA) were reconstructed from CTP. ASPECTS was assessed on NCCT and sCTA. Collateral score was evaluated on mCTA. Target mismatch was defined as infarct core volume < 70 mL, the mismatch ratio ≥ 1.8, and the absolute mismatch volume ≥ 15 mL. Pearson correlation analysis, Mann-Whitney U test, chi-square test, and receiver operating characteristic curve analyses were performed.

RESULTS

Median CTA source image (CTA-SI) ASPECTS was significantly lower than NCCT ASPECTS (p = 0.001). NCCT ASPECTS, CTA-SI ASPECTS, and mCTA collateral score correlated significantly with infarct core volume and mismatch ratio (all p < 0.05). Mismatch group showed significantly higher NCCT ASPECTS, CTA-SI ASPECTS, and mCTA collateral score than non-mismatch group (all p < 0.001). NCCT ASPECTS and CTA-SI ASPECTS showed comparable predicting performance with mCTA collateral score (p > 0.05). Adding CTA-SI ASPECTS to mCTA collateral score improved the performance of mCTA in predicting target mismatch (area under curve, 0.905 vs. 0.804, p = 0.003).

CONCLUSION

ASPECTS can provide incremental information to collateral score in predicting target mismatch. If CTP scan fails, clinical decision based on ASPECTS and collateral score might be reasonable.

A Novel Fast CT Perfusion Core-Penumbra Mismatch Score: Correlation With Stroke Outcome

BACKGROUND

Advanced neuroimaging can identify patients who can most benefit from reperfusion treatment, discriminating between ischemic core and penumbra area in a quick and accurate manner. Despite core-penumbra mismatch being an independent prognostic factor, computed tomography perfusion (CTP) assessment is still debated in hyperacute decision-making. The authors aimed to study a novel CTP mismatch score in emergency settings and to investigate its relation with clinical outcome in acute ischemic stroke patients treated with intravenous thrombolysis (IVT).

METHODS

Neuroimaging and clinical data of 226 consecutive acute ischemic stroke patients were analyzed. The study population was divided into 5 different CTP scores: (0) without perfusion deficit, (1) only penumbra, (2) penumbra > core, (3) core ≥ penumbra, (4) only core. For differences in outcome between treated and nontreated patients, and among CTP core-penumbra groups to be assessed, the authors have evaluated the outcome in terms of National Institutes of Health Stroke Scale (NIHSS) and modified Rankin scale (mRS) at discharge and symptomatic intracerebral hemorrhage.

RESULTS

A decrease in NIHSS was statistically greater in IVT-treated patients compared to nontreated patients showing only penumbra (ΔNIHSS%: 80.0% vs. 50.0%; P=0.0023) or no perfusion deficit (ΔNIHSS%: 89.4% vs. 61.5%; P=0.027) on CTP maps. The same trend was found in other groups without significant difference. A significant correlation was found in IVT patients between core/penumbra score and outcome in terms of ΔNIHSS (Kendall τ=-0.19; P=0.004).

CONCLUSIONS

The authors proposed a novel immediate CTP assessment to score perfusion mismatch in emergency settings to guide clinicians' decision-making for aggressive treatment and to prevent stroke-related disability.

Multimodal CT pc-ASPECTS in infratentorial stroke: diagnostic and prognostic value

BACKGROUND AND PURPOSE

Diagnosis of posterior circulation stroke may be challenged. National Institutes of Health Stroke Scale (NIHSS) and brain imaging (non-contrast brain computed tomography-CT) are used for diagnosis; evaluation on posterior circulation stroke remains a limit of NIHSS, and the value of non-contrast CT (NCCT) is limited due to artifacts caused by the bones of the base of the skull. We tested the validity and prognostic value of posterior circulation Alberta Stroke Program Early CT Score (pc-ASPECTS) in patients with posterior circulation stroke.

METHODS

Pc-ASPECTS allots the posterior circulation 10 points. We studied 50 patients with posterior circulation stroke. We applied pc-ASPECTS to NCCT, CT angiography, and CT Perfusion. We evaluated the correlation of pc-ASPECT with outcome parameters for stroke.

RESULTS

Out of 50 patients, CTP showed abnormalities in 34 cases. The pc-ASPECT score calculated on brain CT and on the brain CT + angio CT had a sensibility of 24%, calculated on brain CT, angio CT and CTPerfusion gain a sensibility of 72%. Pc-ASPECT MTT resulted to be the more reliable parameter: outcome given by NIHSS score at discharge, mRS at discharge, and at 3 months was more severe in patients with Pc-ASPECT MTT alteration. Outcome given by NIHSS score at discharge and mRS at discharge and 1 at 3 months was more severe in patients with higher NIHSS score at admission.

CONCLUSION

We evaluated the usefulness of pc-ASPECTS on CTP in predicting functional outcome in acute posterior circulation stroke that appears to be a powerful marker for predicting functional outcome.

A physiological perspective of the associations between hydration status and CTP neuroimaging parameters in hyper-acute ischaemic stroke patients

Hypohydration may be associated with vascular diseases, poor prognosis and worse outcomes in stroke. The underlying mechanisms have not yet been completely investigated, although some studies suggested potential associations with brain perfusion and collaterals status. Despite the potentially different mechanisms promoting serum or urine biomarkers of hypohydration, few studies have investigated both markers separately. A prospective descriptive study was conducted in stroke patients admitted to a stroke unit <4.5 h from symptoms onset. All patients underwent neurological evaluation and whole-brain computed tomography perfusion (CTP) upon admission. Blood and urine samples were immediately collected at admission, and patients were defined as "hypohydrated" (HYP) if blood urea nitrogen-to-creatinine ratio was >15 and "underhydrated" (UND) if urine osmolality was >500 mOsm/kg. CTP images were processed to calculate core, penumbra, their mismatch and total hypoperfused volume. Forty-six patients were included and were grouped according to hydration status. Despite no different NIHSS at baseline, at CTP HYP was independently associated with core-penumbra mismatch (β: -0.157, 95% CI: -0.305 to -0.009; p = .04), while UND was independently associated with the total hypoperfused volume (β: 31.502, 95% CI: 8.522-54.481; p = .01). Using CTP imaging, this study proposes a physiological insight of some possible mechanisms associated with the better outcomes observed in acute stroke patients when properly hydrated. These results suggest different associations between hydration status and CTP parameters depending on serum or urine biomarkers in the hyper-acute phase and encourage the association between hydration status and stroke characteristics.

Predictors of Good Outcomes in Stroke Thrombolysis Guided by Tissue-Window

BACKGROUND

Recently studies suggested that assessment of tissue-window can effectively guide thrombolysis in acute ischemic stroke patients with unknown time of onset or late presenting. This study aimed to evaluate predictors of good outcomes from thrombolysis in these patients.

METHODS

Acute ischemic stroke patients received thrombolysis guided by computed tomography perfusion (CTP) from October 2018 to August 2019 were reviewed. Baseline characteristics and outcomes were collected. Good outcomes were defined as modified Rankin scale scores of 0 to 2 at 90 days. Logistic regression analysis was performed and the receiver operating characteristics analysis was used to determine cut-off values for the predictors of outcomes.

RESULTS

Sixty-three patients were enrolled. The median age was 64 (interquartile range 57.75 to 72.5) years. The median baseline National Institutes of Health Stroke Scale (NIHSS) score was 8 (interquartile range 3 to 13) and 41 (65.1%) patients had a good outcome at 90 days. Multivariate regression analysis showed smaller perfusion lesion (the sum of ischemic penumbra and infarcted core) (odds ratio: 0.961; 95% confidence interval, 0.931-0.992; P=0.013) and lower baseline NIHSS score (odds ratio: 0.759; 95% confidence interval, 0.644-0.895; P=0.001) were significant predictors for good outcomes. Receiver operating characteristics analysis was utilized to define optimal cut-off values for perfusion lesion [cut-off, 59 mL; area under curve (AUC), 0.761; sensitivity, 0.57; specificity, 0.93; P=0.001], ischemic penumbra (cut-off, 43.5 mL; AUC, 0.761; sensitivity, 0.62; specificity, 0.90; P=0.001), infarcted core (cut-off, 9.5 mL; AUC, 0.665; sensitivity, 0.43; specificity, 0.93; P=0.035), and baseline NIHSS score (cut-off, 8.5; AUC, 0.880; sensitivity, 0.81; specificity, 0.88; P<0.001).

CONCLUSIONS

This study suggested that smaller perfusion lesion and lower baseline NIHSS score may be helpful to predict favorable prognosis of stroke patients who receive thrombolysis guided by tissue-window.

Hyper-acute EEG alterations predict functional and morphological outcomes in thrombolysis-treated ischemic stroke: a wireless EEG study

Owing to the large inter-subject variability, early post-stroke prognosis is challenging, and objective biomarkers that can provide further prognostic information are still needed. The relation between quantitative EEG parameters in pre-thrombolysis hyper-acute phase and outcomes has still to be investigated. Hence, possible correlations between early EEG biomarkers, measured on bedside wireless EEG, and short-term/long-term functional and morphological outcomes were investigated in thrombolysis-treated strokes. EEG with a wireless device was performed in 20 patients with hyper-acute (< 4.5 h from onset) anterior ischemic stroke before reperfusion treatment. The correlations between outcome parameters (i.e., 7-day/12-month National Institutes of Health Stroke Scale NIHSS, 12-month modified Rankin Scale mRS, final infarct volume) and the pre-treatment EEG parameters were studied. Relative delta power and alpha power, delta/alpha (DAR), and (delta+theta)/(alpha+beta) (DTABR) ratios significantly correlated with NIHSS 7-day (rho = 0.80, − 0.81, 0.76, 0.75, respectively) and NIHSS 12-month (0.73, − 0.78, 0.74, 0.73, respectively), as well as with final infarct volume (0.75, − 0.70, 0.78, 0.62, respectively). A good outcome in terms of mRS ≤ 2 at 12 months was associated with DAR parameter (p = 0.008). The neurophysiological biomarkers obtained by non-invasive and portable technique as wireless EEG in the early pre-treatment phase may contribute as objective parameters to the short/long-term outcome prediction pivotal to better establish the treatment strategies.

Graphical abstract

A CT perfusion based model predicts outcome in wake-up stroke patients treated with recombinant tissue plasminogen activator

OBJECTIVE

Advanced neuroimaging has proved to be pivotal in the management of acute ischemic stroke. The use of CT perfusion (CTP) core and penumbra parameters to predict the outcome in wake-up stroke (WUS) patients in everyday clinical scenarios has not yet been investigated. The aim of our study was to investigate the predictive power of CTP parameters on functional and morphological outcomes in WUS patients treated with recombinant tissue plasminogen activator (rTPA).

APPROACH

We analyzed clinical data and processed CTP images of 83 consecutive WUS patients treated with rTPA. The predictive power of whole-brain CTP features and of the clinical stroke-related parameters to predict the National Institutes of Health Stroke Scale (NIHSS) score at the seventh day and ischemic lesion volume outcome was investigated by means of multivariate regression analysis as well as least absolute shrinkage and selection operator (LASSO) modeling.

MAIN RESULTS

Multivariate analysis showed that CTP core volume (β = 0.403, p = 0.000), NIHSS at admission (β = 0.323, p = 0.005) and Alberta Stroke Program Early CT (ASPECT) score (β = -0.224, p = 0.012) predict NIHSS at 7 days, while total hypoperfused volume (β = 0.542, p = 0.000) and core volume on CTP (β =0.441, p = 0.000) predict infarct lesion volume at follow-up CT. The LASSO modeling approach confirmed the significant predictive power of CTP core volume, total hypoperfused CTP volume, NIHSS at baseline and ASPECT score, producing a sparse model with adequate reliability (the root mean square error on a previously unseen testing dataset was 3.68).

SIGNIFICANCE

Our findings highlight the importance of CT multimodal imaging features for decision-making and prediction in the hyperacute phase of WUS. The predictive model supports the hypothesis that an irreversible necrotic core rather than the extent of the penumbra is the main prognostic factor in WUS patients treated with rTPA.

Wake-up stroke: imaging-based diagnosis and recanalization therapy

Wake-up stroke (WUS) is a subgroup of ischemic stroke in which patients show no abnormality before sleep while wake up with neurological deficits. In addition to the uncertain onset, WUS patients have difficulty to receive prompt and effective thrombolytic or reperfusion therapy, leading to relatively poor prognosis. A number of researches have indicated that CT or MRI based thrombolysis and endovascular therapy might have benefits for WUS patients. This review article narratively discusses the pathogenesis, risk factors, imaging-based diagnosis and recanalization treatments of WUS with the purpose of expanding current treatment options for this group of stroke patients and exploring better therapeutic methods. The result showed that multimodal MRI or CT scan might be the best methods for extending the time window of WUS and, therefore, a large proportion of WUS patients could have favorable prognosis.

Novel quantitative approach for crossed cerebellar diaschisis detection in acute ischemic stroke using CT perfusion

PURPOSE

Crossed cerebellar diaschisis (CCD) is a common finding in hyper-acute ischemic stroke, related to supratentorial dysfunction of the contralateral hemisphere. Several studies investigated a possible relationship between CCD and clinical outcomes but still no evidence emerged. We proposed a novel quantitative whole cerebellum analysis using CT perfusion (CTP) imaging to investigate the relationship between CCD and stroke severity, hypoperfused volume and outcome measures.

METHODS

55 patients with supratentorial ischemic stroke who underwent CTP evaluation within 4.5 h since symptom onset were enrolled. CCD was evaluated by CTP image-processing and by calculating the mean transit time (MTT)-map asymmetry index in the whole cerebellum. MTT asymmetry correlation with ischemic volume and clinical outcomes was investigated.

RESULTS

MTT asymmetry was found in most of the included patients and significantly correlated with NIH Stroke Scale (NIHSS) score at baseline and CTP ischemic volume. MTT asymmetry was significantly correlated with hemorrhagic transformation, NIHSS and modified Rankin Scale (mRS) score on discharge in treated patients.

CONCLUSIONS

CCD was detectable by CTP in acute supratentorial ischemic stroke by processing the whole cerebellum volume. CCD perfusion asymmetry was significantly correlated with neurological and perfusion deficit on admission as well as with clinical outcomes in treated patients.

A novel computed tomography perfusion-based quantitative tool for evaluation of perfusional abnormalities in migrainous aura stroke mimic

BACKGROUND

Migrainous aura (MA) represents the third most common stroke mimic (SM). Advanced neuroimaging is pivotal in the assessment of patients with focal neurological acute symptoms. We investigated brain perfusion alterations in MA-SM patients using a novel CT perfusion (CTP)-based quantitative approach in order to improve differential diagnosis between MA and acute stroke.

METHODS

We processed and analysed the clinical and neuroimaging CTP data, acquired within 4.5 h from symptom onset, of patients with acute focal neurological symptoms receiving a final diagnosis of MA. The differences between ROI, compatible with MA symptoms, and contralateral side were automatically estimated in terms of asymmetry index (AI%) by the newly developed tool for mean transit time (MTT), CBF, and cerebral blood volume (CBV) CTP parameters. The AI% ≥ 10% was considered significant.

RESULTS

Out of 923 admitted patients, 14 patients with MA were included. In 13 out of 14 cases, a significant pattern of hypoperfusion was observed by quantitative analysis in at least one of the CTP maps. In 7 patients, all three CTP maps were significantly altered. In particular, MTT-AI% increased in 11 (79%) cases, while CBF-AI% and CBV-AI% decreased in 12 (86%) and in 9 (64%) patients, respectively. All CBV values were above ischemic stroke core threshold and all MTT-AI were below ischemic penumbra threshold.

CONCLUSIONS

Our data suggest that a novel CTP-quantitative approach may detect during MA a moderate hypoperfusion pattern in the cerebral regions compatible with aura symptoms. The use of this novel tool could support differential diagnosis between MA and acute stroke.

CT Perfusion as a Selection Tool for Mechanical Thrombectomy, a Single-Centre Study

Background:

Recently, CT perfusion (CTP) has been proposed as a selection tool for stroke patients to be treated with endovascular thrombectomy. We investigated whether functional outcome following endovascular treatment was improved after the introduction of CTP.

Methods:

This retrospective single-centre study includes all patients with a major vessel occlusion in the anterior circulation that received a CTP and underwent a mechanical thrombectomy from 2014 up to 2015. CTP were visually evaluated. Demographics, stroke and time data, procedural data, functional outcomes as measured by the modified Rankin Scale (mRS) and the association between these variables were studied. A comparison was made with the results of a similar local retrospective study from before the CTP “era”.

Results:

Eighty-nine patients were included in this study. Median National Institutes of Health Stroke Scale (NIHSS) was 16 (Interquartile range 6). At three months, good functional outcome (GFO; mRS 0–2) was achieved in 48.4% and excellent functional outcome (EFO; mRS 0–1) in 34.4% of patients. The mortality rate at three months was 14.5%. GFO at one year was 44.8%, EFO was 31.3% and mortality 21.1%. The duration of the thrombectomy procedure and the EFO were associated (p = 0.032). The outcome improvement achieved with CTP was higher compared to the reference study (GFO 48.4% versus 44%; EFO 34.4% versus 29%) but remained below the statistical significance.

Conclusions:

Mechanical thrombectomy for anterior circulation strokes based on CTP did not result in a significant functional outcome improvement. The duration of the thrombectomy procedure was the sole time-interval related to improved functional outcome.

Endovascular treatment for ischemic stroke beyond the time window: A meta-analysis

Currently, endovascular treatment has been proven to be effective when conducted within 6 hours of symptom onset. However, when patients have symptoms for more than 6 hours, have a daytime-unwitnessed stroke (DUS) or wake up with a stroke (wake-up stroke, WUS), the safety and efficacy of endovascular treatment need to be further elucidated. Therefore, we performed a systematic review and meta-analysis to compare the clinical outcomes of endovascular treatment in patients with ischemic stroke beyond the time window with that ≤6 hours. PubMed, EMBASE, and Ovid MEDLINE were searched from inception to November 2018. The following outcomes were evaluated by a random-effects model: efficacy outcomes, that is, functional independence and successful recanalization, and safety outcomes, that is, symptomatic intracranial hemorrhage and mortality. Subgroup analyses were also performed to examine whether patient or study characteristics were associated with the outcomes. Nine observational studies, including 5192 patients (1414 patients with extended time windows [ETWs]; 3778 patients ≤6 hours), were eligible for analysis. The overall analysis demonstrated that the functional independence was worse in patients with ETWs vs those ≤6 hours (OR, 0.78; 95% CI, 0.68-0.90, P = .0006). However, subgroup analysis showed that there was no significant difference in functional independence between the two groups when patients were selected for a perfusion mismatch by imaging (OR, 1.00; 95% CI, 0.70-1.43, P = 1.000). Therefore, compared with a window ≤6 hours, endovascular treatment with ETWs for ischemic stroke may not result in poor outcomes when patients are typically selected by perfusion techniques.

Thrombolysis safety and effectiveness in acute ischemic stroke patients with pre-morbid disability

INTRODUCTION

Recombinant tissue plasminogen activator (rt-PA) is the first-line therapy demonstrated to be safe and effective in acute ischemic stroke. People with pre-existing severe dementia or physical disability are usually excluded from rt-PA. The aim of our study was to investigate rt-PA safety and effectiveness in acute stroke with pre-existing disability (mRS ≥ 2).

METHODS

The study encompassed 35 acute ischemic stroke patients with mRS ≥ 2 treated with rt-PA. In order to assess the differences in clinical outcome in three disability groups (mRS = 2; 3; 4/5), the following parameters were evaluated: intracerebral hemorrhage, mortality, NIHSS, ΔNIHSS and mRS.

RESULTS

Baseline-NIHSS and age were not significantly different among groups. Mortality was higher in the pre-morbid mRS 4/5 group (44%) than in the pre-morbid mRS2 (16.7%) and mRS 3 groups (21.4%). In survived patients, median ΔNIHSS% was higher in the mRS2 and 3 groups (-63.3% and -92.3%, respectively) than in the mRS4/5 group (-9.1%). The 247 rt-PA treated subjects with mRS < 2 in the same period showed lower mortality rate (4.7%), lower sICH (5%), lower mRS at discharge (median 1; range 0-6) and similar ΔNIHSS% (-75%).

CONCLUSION

Patients with mRS 2 and 3 may benefit from rt-PA with a moderate risk of sICH and mortality.

Wake-up stroke: thrombolysis reduces ischemic lesion volume and neurological deficit

BACKGROUNDS

Wake-Up Stroke (WUS) patients are generally excluded from thrombolytic therapy (rTPA) due to the unknown time of stroke onset. This study aimed to investigate the effects of rTPA in WUS patients during every day clinical scenarios, by measuring ischemic lesion volume and functional outcomes compared to non-treated WUS patients.

METHODS

We retrospectively analyzed clinical and imaging data of 149 (75 rTPA; 74 non-rTPA) patients with acute ischemic WUS. Ischemic volume was calculated on follow-up CT and functional outcomes were the NIHSS and mRS comparing rTPA and non-rTPA WUS. Patients were selected using ASPECTS > 6 on CT and/or ischemic penumbra > 50% of hypoperfused tissue on CTP.

RESULTS

A reduced volume was measured on the follow-up CT for rTPA (1 mL, 0-8) compared to the non-rTPA patients (10 mL, 0-40; p = 0.000). NIHSS at 7 days from admission was significantly lower in the rTPA (1, 0-4) compared to non-rTPA group (3, 1-9; p = 0.015), as was the percentage of improvement (ΔNIHSS) (70% vs 50%; p = 0.002). A higher prevalence of mRS 0-2 was observed in the rTPA compared to the non-rTPA (54% vs 39%; p = 0.060). Multivariate analysis showed that NIHSS at baseline and rTPA treatment are significant predictors of good outcome both in terms of NIHSS at 7 days and ischemic lesion volume on follow-up CT (p < 0.05).

CONCLUSIONS

rTPA in WUS patients selected with CT and/or CTP resulted in reduced ischemic infarct volume on follow-up CT and better functional outcome without increment of intracranial hemorrhages and in-hospital mortality.

Brain oscillatory activity and CT perfusion in hyper-acute ischemic stroke

OBJECTIVES

The combined use of perfusion neuroimaging and brain oscillatory activity may provide a better clinical picture of neurovascular coupling of the injured area in ischemic stroke. The aim is to assess stroke-related topographic electroencephalography (EEG) changes during the earliest phase of ischemic stroke and to compare them with hypoperfusion identified by computer tomography perfusion (CTP).

PATIENTS AND METHODS

The study included 15 patients with ischemic stroke, who underwent both CTP and EEG recording within 4.5 h. Topographic representation of power for each band was calculated and compared with hypoperfusion areas estimated by CTP maps.

RESULTS

Predominance of slow delta frequencies was found in all patients. The main finding is the agreement between slow rhythms hemispheric prevalence on EEG maps and cerebral hypoperfusion area identified using CTP.

CONCLUSION

The results of this preliminary study show that the combined use of EEG and CTP, as highly available techniques, in acute ischemic stroke may be helpful in clinical practice and provide information about functional and metabolic aspects of brain involvement. The joint use of these methodologies may give a better clinical insight of the functionality of injured area in the hyperacute phase.