Prediction of malignant middle cerebral artery infarction by early perfusion- and diffusion-weighted magnetic resonance imaging

Factors associated with mortality and functional outcome after decompressive craniectomy in malignant middle cerebral artery infarction

OBJECTIVE

Identifying the predictive factors of mortality and functional outcomes following decompressive craniectomy (DC) surgery in patients with malignant middle cerebral artery infarction (MMCAI) is essential for decision-making regarding conservative versus surgical treatment. This study aimed to assess the mortality and functional outcomes of MMCAI patients after DC surgery and to identify the predictive factors associated with mortality and functional outcomes.

METHODS

A total of 76 patients with MMCAI who underwent surgical DC were included. The mortality rates and functional outcomes were assessed, and factors associated with mortality and functional outcomes were identified through univariate analysis followed by multivariate logistic regression analysis.

RESULTS

The mortality rate was 44.8%, while a favorable functional outcome was observed in 28.9% of the patients. modified Glasgow coma scale (GCS) before DC (OR = 0.416, 95% CI = 0.261-0.662, P < 0.001) and infarct volume before DC (OR = 1.000-1.012, 95% CI = 1.000-1.012, P = 0.037) were independent risk factors for death. Age (OR = 0.88, 95% CI = 0.812-0.952, P = 0.002), modified GCS before DC (OR = 2.477, 95% CI = 1.395-4.4, P = 0.002), and infarct volume before DC (OR = 0.987, 95% CI = 0.975-0.999, P = 0.035) were independent factors associated with favorable functional outcomes.

CONCLUSION

Preoperative modified GCS and preoperative infarct volume were independent factors associated with both mortality and functional outcomes. Age was only associated with functional outcomes.

A CT-based machine learning model for using clinical-radiomics to predict malignant cerebral edema after stroke: a two-center study

Purpose

This research aimed to create a machine learning model for clinical-radiomics that utilizes unenhanced computed tomography images to assess the likelihood of malignant cerebral edema (MCE) in individuals suffering from acute ischemic stroke (AIS).

Methods

The research included 179 consecutive patients with AIS from two different hospitals. These patients were randomly assigned to training (n = 143) and validation (n = 36) sets with an 8:2 ratio. Using 3DSlicer software, the radiomics features of regions impacted by infarction were derived from unenhanced CT scans. The radiomics features linked to MCE were pinpointed through a consistency test, Student's t test and the least absolute shrinkage and selection operator (LASSO) method for selecting features. Clinical parameters associated with MCE were also identified. Subsequently, machine learning models were constructed based on clinical, radiomics, and clinical-radiomics. Ultimately, the efficacy of these models was evaluated by measuring the operating characteristics of the subjects through their area under the curve (AUCs).

Results

Logistic regression (LR) was found to be the most effective machine learning algorithm, for forecasting the MCE. In the training and validation cohorts, the AUCs of clinical model were 0.836 and 0.773, respectively, for differentiating MCE patients; the AUCs of radiomics model were 0.849 and 0.818, respectively; the AUCs of clinical and radiomics model were 0.912 and 0.916, respectively.

Conclusion

This model can assist in predicting MCE after acute ischemic stroke and can provide guidance for clinical treatment and prognostic assessment.

Association of large core middle cerebral artery stroke and hemorrhagic transformation with hospitalization outcomes

Historically, investigators have not differentiated between patients with and without hemorrhagic transformation (HT) in large core ischemic stroke at risk for life-threatening mass effect (LTME) from cerebral edema. Our objective was to determine whether LTME occurs faster in those with HT compared to those without. We conducted a two-center retrospective study of patients with ≥ 1/2 MCA territory infarct between 2006 and 2021. We tested the association of time-to-LTME and HT subtype (parenchymal, petechial) using Cox regression, controlling for age, mean arterial pressure, glucose, tissue plasminogen activator, mechanical thrombectomy, National Institute of Health Stroke Scale, antiplatelets, anticoagulation, temperature, and stroke side. Secondary and exploratory outcomes included mass effect-related death, all-cause death, disposition, and decompressive hemicraniectomy. Of 840 patients, 358 (42.6%) had no HT, 403 (48.0%) patients had petechial HT, and 79 (9.4%) patients had parenchymal HT. LTME occurred in 317 (37.7%) and 100 (11.9%) had mass effect-related deaths. Parenchymal (HR 8.24, 95% CI 5.46-12.42, p < 0.01) and petechial HT (HR 2.47, 95% CI 1.92-3.17, p < 0.01) were significantly associated with time-to-LTME and mass effect-related death. Understanding different risk factors and sequelae of mass effect with and without HT is critical for informed clinical decisions.

Early venous filling after mechanical thrombectomy in acute ischemic stroke due to large vessel occlusion in anterior circulation

BACKGROUND

The significance of early venous filling (EVF) after mechanical thrombectomy (MT) in acute ischemic stroke (AIS) is not fully understood. In this study, we aimed to investigate the impact of EVF after MT.

METHODS

From January 2019 to May 2022, AIS patients with successful recanalization (modified Thrombolysis in Cerebral Infarction score (mTICI) ≥2b) after MT were retrospectively reviewed. EVF was evaluated on final digital subtraction angiography runs after successful recanalization and was categorized into phase subgroups (arterial phase and capillary phase) and pathway subgroups (cortical veins subgroup and thalamostriate veins subgroup), respectively. The impact of EVF subgroups on functional outcomes after successful recanalization were both investigated.

RESULTS

A total of 349 patients achieving successful recanalization after MT were included, including 45 patients in the EVF group and 304 patients in the non-EVF group. Multivariable logistic regression analysis showed the EVF group had a higher rate of intracranial hemorrhage (ICH; 66.7% vs 22%, adjusted odds ratio (aOR) 6.805, 95% CI 3.389 to 13.662, P<0.001), symptomatic ICH (sICH; 28.9% vs 4.9%, aOR 6.011, 95% CI 2.493 to 14.494, P<0.001) and malignant cerebral edema (MCE; 20% vs 6.9%, aOR 2.682, 95% CI 1.086 to 6.624, P=0.032) than the non-EVF group. Furthermore, the cortical veins subgroup of EVF had a higher rate of mortality than the thalamostriate veins subgroup (37.5% vs 10.3%, P=0.029).

CONCLUSIONS

EVF is independently associated with ICH, sICH and MCE after successful recanalization of MT, but not with favorable outcome and mortality.

Current and Emerging Endovascular and Neurocritical Care Management Strategies in Large-Core Ischemic Stroke

The volume of infarcted tissue in patients with ischemic stroke is consistently associated with increased morbidity and mortality. Initial studies of endovascular thrombectomy for large-vessel occlusion excluded patients with established large-core infarcts, even when large volumes of salvageable brain tissue were present, due to the high risk of hemorrhagic transformation and reperfusion injury. However, recent retrospective and prospective studies have shown improved outcomes with endovascular thrombectomy, and several clinical trials were recently published to evaluate the efficacy of endovascular management of patients presenting with large-core infarcts. With or without thrombectomy, patients with large-core infarcts remain at high risk of in-hospital complications such as hemorrhagic transformation, malignant cerebral edema, seizures, and others. Expert neurocritical care management is necessary to optimize blood pressure control, mitigate secondary brain injury, manage cerebral edema and elevated intracranial pressure, and implement various neuroprotective measures. Herein, we present an overview of the current and emerging evidence pertaining to endovascular treatment for large-core infarcts, recent advances in neurocritical care strategies, and their impact on optimizing patient outcomes.

Surgery for Malignant Acute Ischemic Stroke: A Narrative Review of the Knowns and Unknowns

Malignant acute ischemic stroke (AIS) is characterized by acute neurological deterioration caused by progressive space-occupying brain edema, often occurring in the first hours to days after symptom onset. Without any treatment, the result is often fatal. Despite advances in treatment for AIS, up to 80% of patients with a large hemispheric stroke or cerebellar stroke are at risk of poor outcome. Decompressive surgery can be life-saving in a subgroup of patients with malignant AIS, but uncertainties exist on patient selection, predictors of malignant infarction, perioperative management, and timing of intervention. Although survivors are left disabled, most agree with the original decision to undergo surgery and would make the same decision again. In this narrative review, we focus on the clinical and radiological predictors of malignant infarction in AIS and outline the technical aspects of decompressive surgery as well as duraplasty and cranioplasty. We discuss the current evidence and recommendations for surgery in AIS, highlighting gaps in knowledge, and suggest directions for future studies. KEY POINTS: · Acute ischemic stroke from occlusion of a proximal intracranial artery can progress quickly to malignant edema, which can be fatal in 80% of patients despite medical management.. · Decompression surgery is life-saving within 48 hours of stroke onset, but the benefits beyond this time and in the elderly are unknown.. · Decompressive surgery is associated with high morbidity, particularly in the elderly. The decision to operate must be made after considering the individual's preference and expectations of quality of life in the context of the clinical condition.. · Further studies are needed to refine surgical technique including value of duraplasty and understand the role monitoring intracranial pressure during and after decompressive surgery.. · More studies are needed on the pathophysiology of malignant cerebral edema, prediction models including imaging and biomarkers to identify which subgroup of patients will benefit from decompressive surgery.. · More research is needed on factors associated with morbidity and mortality after cranioplasty, safety and efficacy of implants, and comparisons between them.. · Further studies are needed to assess the long-term effects of physical disability and quality of life of survivors after surgery, particularly those with severe neurological deficits..

Massive Neonatal Arterial Ischemic Stroke

BACKGROUND

Massive infarction in adults is a devastating entity characterized by signs of extreme swelling of the brain's parenchyma. We explored whether a similar entity exists in neonates, which we call massive neonatal arterial ischemic stroke (M-NAIS), and assess its potential clinical implications.

METHODS

Prospective multicenter cohort study comprising 48 neonates with gestational age ≥35 weeks with middle cerebral artery (MCA) NAIS was performed. Diagnosis with magnetic resonance imaging (MRI) was performed within the first three days after symptom onset. The presence of signs of a space-occupying mass, such as brain midline shift and/or ventricular and/or extra-axial space collapse, was recorded. The volume of the infarct and brain midline shift were determined with semiautomatic procedures. Neurodevelopment was assessed at age 24 months.

RESULTS

Fifteen (31%) neonates presented MRI signs of a space-occupying mass effect and were considered to have an M-NAIS. The relative volume (infarct volume/total brain volume) of the infarct was on average significantly greater in the M-NAIS subgroup (29% vs 4.9%, P < 0.001). Patients with M-NAIS consistently presented lesions involving the M1 arterial territory of the MCA and showed more apneic and tonic seizures, which had an earlier onset and lasted longer. Moderate to severe adverse neurodevelopmental outcomes were present in most M-NAIS cases (79% vs 6%, P < 0.001).

CONCLUSIONS

M-NAIS appears to be a distinctive subtype of neonatal infarction, defined by characteristic neuroimaging signs. Neonates with M-NAIS frequently present a moderate to severe adverse outcome. Early M-NAIS identification would allow for prompt, specific rehabilitation interventions and would provide more accurate prognostic information to families.

Optic nerve sheath diameter and optic nerve sheath diameter/eyeball transverse diameter ratio in prediction of malignant progression in ischemic stroke

Background

The optic nerve sheath diameter (ONSD)/eyeball transverse diameter (ETD) ratio has been suggested in the evaluation of intracranial pressure (ICP). The aim of this study was to evaluate the predictive value of ONSD and ONSD/ETD in relation to risk for secondary malignant middle cerebral artery infarction (MMI).

Methods

A total of 91 patients with MCA occlusion were included in this study. Data were divided into two groups based on development of MMI or not. ONSD and ETD were measured by unenhanced computed tomography (CT). The differences in ONSD and the ONSD/ETD ratios between the MMI and non-MMI groups were compared. Receiver operating characteristic curve analyses were used to test the diagnostic value of ONSD and ONSD/ETD independently, to predict MMI.

Results

The ONSD in the MMI group and non-MMI group were 5.744 ± 0.140 mm and 5.443 ± 0.315 mm, respectively (P = 0.001). In addition, the ONSD/ETD ratios in the MMI group and non-MMI group were 0.258 ± 0.008 and 0.245 ± 0.006, respectively (P = 0.001). The receiver operating characteristic (ROC) curve demonstrated an area under the curve (AUC) for ONSD of 0.812 [95% confidence interval (CI): 0.718–0.906, P = 0.001], with a sensitivity of 97.4% and a specificity of 66.0% at the cut-off value of 5.520 mm. The AUC for ONSD/ETD ratio in predicting occurrence of MMI was 0.895 (95% CI: 0.823–0.968, P = 0.001), with a sensitivity of 84.2% and a specificity of 92.5% at a cut-off value of 0.250.

Conclusion

In acute stroke patients with massive cerebral infarction, an increased ONSD or ONSD/ETD ratio increases the odds of malignant progression and may be used as an indicator for emergent therapeutic interventions. In addition, the ONSD/ETD ratio may be more valuable than ONSD in predicting the malignant progression of acute stroke patients.

Association between pre-treatment perfusion profile and cerebral edema after reperfusion therapies in ischemic stroke

The relationship between reperfusion and edema is unclear, with experimental and clinical data yielding conflicting results. We investigated whether the extent of salvageable and irreversibly-injured tissue at baseline influenced the effect of therapeutic reperfusion on cerebral edema. In a pooled analysis of 415 patients with anterior circulation large vessel occlusion from the Tenecteplase-versus-Alteplase-before-Endovascular-Therapy-for-Ischemic-Stroke (EXTEND-IA TNK) part 1 and 2 trials, associations between core and mismatch volume on pre-treatment CT-Perfusion with cerebral edema at 24-hours, and their interactions with reperfusion were tested. Core volume was associated with increased edema (p < 0.001) with no significant interaction with reperfusion (p = 0.82). In comparison, a significant interaction between reperfusion and mismatch volume (p = 0.03) was observed: Mismatch volume was associated with increased edema in the absence of reperfusion (p = 0.009) but not with reperfusion (p = 0.27). When mismatch volume was dichotomized at the median (102 ml), reperfusion was associated with reduced edema in patients with large mismatch volume (p < 0.001) but not with smaller mismatch volume (p = 0.35). The effect of reperfusion on edema may be variable and dependent on the physiological state of the cerebral tissue. In patients with small to moderate ischemic core volume, the benefit of reperfusion in reducing edema is related to penumbral salvage.

Cerebral Edema in Patients With Large Hemispheric Infarct Undergoing Reperfusion Treatment: A HERMES Meta-Analysis

BACKGROUND AND PURPOSE

Whether reperfusion into infarcted tissue exacerbates cerebral edema has treatment implications in patients presenting with extensive irreversible injury. We investigated the effects of endovascular thrombectomy and reperfusion on cerebral edema in patients presenting with radiological evidence of large hemispheric infarction at baseline.

METHODS

In a systematic review and individual patient-level meta-analysis of 7 randomized controlled trials comparing thrombectomy versus medical therapy in anterior circulation ischemic stroke published between January 1, 2010, and May 31, 2017 (Highly Effective Reperfusion Using Multiple Endovascular Devices collaboration), we analyzed the association between thrombectomy and reperfusion with maximal midline shift (MLS) on follow-up imaging as a measure of the space-occupying effect of cerebral edema in patients with large hemispheric infarction on pretreatment imaging, defined as diffusion-magnetic resonance imaging or computed tomography (CT)-perfusion ischemic core 80 to 300 mL or noncontrast CT-Alberta Stroke Program Early CT Score ≤5. Risk of bias was assessed using the Cochrane tool.

RESULTS

Among 1764 patients, 177 presented with large hemispheric infarction. Thrombectomy and reperfusion were associated with functional improvement (thrombectomy common odds ratio =2.30 [95% CI, 1.32-4.00]; reperfusion common odds ratio =4.73 [95% CI, 1.66-13.52]) but not MLS (thrombectomy β=-0.27 [95% CI, -1.52 to 0.98]; reperfusion β=-0.78 [95% CI, -3.07 to 1.50]) when adjusting for age, National Institutes of Health Stroke Score, glucose, and time-to-follow-up imaging. In an exploratory analysis of patients presenting with core volume >130 mL or CT-Alberta Stroke Program Early CT Score ≤3 (n=76), thrombectomy was associated with greater MLS after adjusting for age and National Institutes of Health Stroke Score (β=2.76 [95% CI, 0.33-5.20]) but not functional improvement (odds ratio, 1.71 [95% CI, 0.24-12.08]).

CONCLUSIONS

In patients presenting with large hemispheric infarction, thrombectomy and reperfusion were not associated with MLS, except in the subgroup with very large core volume (>130 mL) in whom thrombectomy was associated with increased MLS due to space-occupying ischemic edema. Mitigating cerebral edema-mediated secondary injury in patients with very large infarcts may further improve outcomes after reperfusion therapies.

The association between white matter changes and development of malignant middle cerebral artery infarction: A case-control study

ABSTRACT

Disrupted blood-brain barrier (BBB) in patients with ischemic stroke plays a critical role in malignant middle cerebral artery infarction (MMI) development.Cerebral white matter changes (WMC), particularly in the deep subcortical area or in severe one, may be also underlain by disrupted BBB. It is unclear whether the presence of WMC with potential premorbid disruption of BBB makes patients susceptible to MMI. Therefore, this study aimed to clarify any putative relationship between the MMI and WMC in terms of their severity and locations.In this case-control study, patients with infarction in the middle cerebral artery territory were retrospectively reviewed. Brain magnetic resonance images were analyzed according to Fazekas scale, and identified WMC were divided into periventricular WMC (PV-WMC) and deep subcortical WMC (deep-WMC). Patients were scored as having WMC, PV-WMC, deep-WMC, severe PV-WMC, and severe deep-WMC according to the severity and locations. Patients were defined as having MMI if either a progressive conscious disturbance or signs of uncal herniation was recorded in combination with a midline shift >5 mm identified on the follow-up computed tomography.Among 297 patients admitted between July 2009 and February 2015, 92 patients were eligible for final analysis. Compared to patients without MMI, patients with MMI had a higher score of National Institutes of Health Stroke Scale, a larger infarct volume, and an increasingly greater proportion of severe PV-WMC, deep-WMC, and severe deep-WMC, respectively. After adjustment for sex, age, infarct volume, and history of hypertension, severe deep-WMC (odds ratio [OR] = 6.362, 95% confidence interval [CI] = 1.444-28.023, P = .0144) and severe PV-WMC (odds ratio = 5.608, 95% confidence interval = 1.107-28.399, P = .0372) were significantly associated with MMI development.MMI and WMC are significantly associated such that MMI development is more likely when PV-WMC or deep-WMC is more severe. We hypothesize that Fazekas scale-defined severe deep-WMC and PV-WMC may be considered as clinically approachable predictors of MMI development. These findings support that the WMC with potential premorbid disrupted BBB may make patients susceptible to MMI, and further prospective study should be conducted to clarify this hypothesis.

Decompressive Hemicraniectomy for Large Hemispheric Strokes

Large hemispheric infarcts occur in up to 10% of all ischemic strokes and can cause devastating disability. Significant research and clinical efforts have been made in hopes of mitigating the morbidity and mortality of this disease. Areas of interest include identifying predictors of malignant edema, optimizing medical and surgical techniques, selecting the patient population that would benefit most from decompressive hemicraniectomy, and studying the impact on quality of life of those who survive. Decompressive surgery can be a life-saving measure, and here we discuss the most up-to-date literature and provide a review on the surgical management of large hemispheric ischemic strokes.

What is the Role of Hyperosmolar Therapy in Hemispheric Stroke Patients?

The role of hyperosmolar therapy (HT) in large hemispheric ischemic or hemorrhagic strokes remains a controversial issue. Past and current stroke guidelines state that it represents a reasonable therapeutic measure for patients with either neurological deterioration or intracranial pressure (ICP) elevations documented by ICP monitoring. However, the lack of evidence for a clear effect of this therapy on radiological tissue shifts and clinical outcomes produces uncertainty with respect to the appropriateness of its implementation and duration in the context of radiological mass effect without clinical correlates of neurological decline or documented elevated ICP. In addition, limited data suggest a theoretical potential for harm from the prophylactic and protracted use of HT in the setting of large hemispheric lesions. HT exerts effects on parenchymal volume, cerebral blood volume and cerebral perfusion pressure which may ameliorate global ICP elevation and cerebral blood flow; nevertheless, it also holds theoretical potential for aggravating tissue shifts promoted by significant interhemispheric ICP gradients that may arise in the setting of a large unilateral supratentorial mass lesion. The purpose of this article is to review the literature in order to shed light on the effects of HT on brain tissue shifts and clinical outcome in the context of large hemispheric strokes, as well as elucidate when HT should be initiated and when it should be avoided.

External Validation and Modification of the EDEMA Score for Predicting Malignant Brain Edema After Acute Ischemic Stroke

BACKGROUND

Accurate prediction of malignant brain edema (MBE) after stroke is paramount to facilitate close monitoring and timely surgical intervention. The Enhanced Detection of Edema in Malignant Anterior Circulation Stroke (EDEMA) score was useful to predict potentially lethal malignant edema in Western populations. We aimed to validate and modify it to achieve a better predictive value for MBE in Chinese patients.

METHODS

Of ischemic stroke patients consecutively admitted in the Department of Neurology, West China Hospital between January 2010 and December 2017, we included patients with anterior circulation stroke, early signs of brain edema on computed tomography within 24 h of onset, and admission National Institutes of Health Stroke Scale (NIHSS) score ≥ 8. MBE was defined as the development of signs of herniation (including decrease in consciousness and/or anisocoria), accompanied by midline shift ≥ 5 mm on follow-up imaging. The EDEMA score consisted of five parameters: glucose, stroke history, reperfusion therapy, midline shift, and cistern effacement. We created a modified score by adding admission NIHSS score to the original EDEMA score. The discrimination of the score was assessed by the area under the receiver operating characteristics curve (AUC). Calibration was assessed by Hosmer-Lemeshow test and calibration plot. We compared the discrimination of the original and modified score by AUC, net reclassification improvement (NRI), and integrated discrimination improvement (IDI). Clinical usefulness of the two scores was compared by plotting net benefits at different threshold probabilities in the decision curve analysis.

RESULTS

Of the 478 eligible patients (mean age 67.3 years; median NIHSS score 16), 93 (19%) developed MBE. The EDEMA score showed moderate discrimination (AUC 0.72, 95% confidence interval [CI] 0.67-0.76) and good calibration (Hosmer-Lemeshow test, P = 0.77). The modified score showed an improved discriminative ability (AUC 0.80, 95% CI 0.76-0.84, P < 0.001; NRI 0.67, 95% CI 0.55-0.78, P < 0.001; IDI 0.07, 95% CI 0.06-0.09, P < 0.001). Decision curves showed that the modified score had a higher net benefit than the original score in a range of threshold probabilities lower than 60%.

CONCLUSIONS

The original EDEMA score showed an acceptable predictive value for MBE in Chinese patients. By adding the admission NIHSS score, the modified score allowed for a more accurate prediction and clinical usefulness. Further validation in large cohorts of different ethnicities is needed to confirm our findings.

Oxygen metabolism MRI - A comparison with perfusion imaging in a rat model of MCA branch occlusion and reperfusion

The penumbra is sustained by an increased extraction of oxygen (OEF) from blood to brain tissue. Metabolic imaging may improve penumbra specificity when examining stroke patients with wake-up stroke and a long time between admission and symptom onset. We used MRI to examine OEF, and compared the volume of regions with elevated OEF to the volume of regions with perfusion deficit in a M2 occlusion model (M2CAO) with preserved collateral blood flow. OEF was calculated from BOLD MRI examining tissue R2', with ASL perfusion imaging employed to determine cerebral blood flows (CBF) and volumes. Diffusion imaging was used to identify the ischemic core (IC). Examinations were performed during and after transient M2CAO in rats. The IC-OEF mismatch was significantly smaller than the IC-CBF mismatch during M2CAO. The penumbra OEF was significantly increased during M2CAO, and decreased significantly after reperfusion. The IC-OEF mismatch may provide increased penumbra specificity compared to IC-CBF mismatch regimens. Results strongly indicate the potential of metabolic MRI for thrombectomy patient selection in cases with a long time from symptom onset to admission. Results demonstrate the effectiveness of reperfusion in alleviating metabolic disturbances in ischemic regions, emphasizing fast treatment to achieve significant neurological recovery in stroke patients.

Clinical benefit of thrombectomy in stroke patients with low ASPECTS is mediated by oedema reduction

The impact of endovascular vessel recanalization on patients with a low initial Alberta Stroke Program Early Computer Tomography Score (ASPECTS) is still uncertain. We hypothesized that vessel recanalization leads to an improvement in mortality and degree of disability by reducing brain oedema and malignant mass effect. In this multicentre observational study, patients with acute ischaemic stroke due to large vessel occlusion in the anterior circulation and an ASPECTS of ≤ 5 were analysed. Patients were assembled into two groups: successful vessel recanalization (thrombolysis in cerebral infarctions, TICI scale 2b/3) or persistent vessel occlusion (no endovascular procedure or TICI scale 0-2a). Observers were blinded to clinical data. Net water uptake within brain infarct, a quantitative biomarker based on CT densitometry, was used to quantify oedema in admission and follow-up CT and Δ-water uptake was calculated as difference between water uptake at both time points. Occurrence of malignant infarctions and secondary parenchymal haemorrhage was documented. Furthermore, modified Rankin scale score at 90 days was used for functional outcome. We included 117 patients admitted between March 2015 and August 2017 in three German stroke centres: 71 with persistent vessel occlusion and 46 with successful recanalization. The mean water uptake in the admission imaging was not different between both groups: 10.0% (±4.8) in patients with persistent vessel occlusion and 9.0% (±4.8) in patients with vessel recanalization (P = 0.4). After follow-up CT, the mean Δ-water uptake was 16.0% (±7.5) in patients with persistent vessel occlusion and 8.0% (±5.7) in patients with vessel recanalization (P < 0.001). Successful reperfusion was independently associated with a lowered Δ-water uptake of 8.0% (95% confidence interval, CI: -10.5 to -5.3%; P < 0.001) and lowered modifed Rankin scale score after 90 days of 1.5 (95% CI: -2.2 to -0.8; P < 0.001). The prevalence of malignant infarctions was 44.3% in patients with persistent vessel occlusion and 26.1% in patients with vessel recanalization. There was no significant difference for secondary haemorrhage in both groups (P = 0.7). In conclusion, successful recanalization in patients with low initial ASPECTS resulted in a significant reduction of oedema formation and was associated with a decreased prevalence of malignant infarctions and an improvement of clinical outcome.

Acute Parent Artery Occlusion in Thrombosed Middle Cerebral Artery Aneurysm Presenting with Ischemic Stroke

BACKGROUND

Thrombosed intracranial aneurysms are complex and unstable lesions that are especially associated with ischemic stroke. Although acute parent artery occlusion manifesting with ischemic stroke is very rare, it can lead to catastrophic consequences.

CASE DESCRIPTION

This study presents 2 cases of acute parent artery occlusion in thrombosed large and giant middle cerebral artery bifurcation aneurysms manifesting with ischemic stroke. Both patients were successfully treated with emergent double-barrel superficial temporal artery-to-middle cerebral artery bypass followed by aneurysm trapping.

CONCLUSIONS

Emergent superficial temporal artery-to-middle cerebral artery bypass could be a salvageable treatment option in patients with progressive neurologic deficits and significant mismatch between diffusion- and perfusion-weighted imaging in acute parent artery occlusions associated with large or giant thrombosed aneurysms. Besides diffusion- and perfusion-weighted imaging, preoperative assessment of the collaterals will help in predicting postoperative prognosis.

Early Prediction of Malignant Brain Edema After Ischemic Stroke

Background and Purpose- Malignant brain edema after ischemic stroke has high mortality but limited treatment. Therefore, early prediction is important, and we systematically reviewed predictors and predictive models to identify reliable markers for the development of malignant edema. Methods- We searched Medline and Embase from inception to March 2018 and included studies assessing predictors or predictive models for malignant brain edema after ischemic stroke. Study quality was assessed by a 17-item tool. Odds ratios, mean differences, or standardized mean differences were pooled in random-effects modeling. Predictive models were descriptively analyzed. Results- We included 38 studies (3278 patients) with 24 clinical factors, 7 domains of imaging markers, 13 serum biomarkers, and 4 models. Generally, the included studies were small and showed potential publication bias. Malignant edema was associated with younger age (n=2075; mean difference, -4.42; 95% CI, -6.63 to -2.22), higher admission National Institutes of Health Stroke Scale scores (n=807, median 17-20 versus 5.5-15), and parenchymal hypoattenuation >50% of the middle cerebral artery territory on initial computed tomography (n=420; odds ratio, 5.33; 95% CI, 2.93-9.68). Revascularization (n=1600, odds ratio, 0.37; 95% CI, 0.24-0.57) were associated with a lower risk for malignant edema. Four predictive models all showed an overall C statistic >0.70, with a risk of overfitting. Conclusions- Younger age, higher National Institutes of Health Stroke Scale, and larger parenchymal hypoattenuation on computed tomography are reliable early predictors for malignant edema. Revascularization reduces the risk of malignant edema. Future studies with robust design are needed to explore optimal cutoff age and National Institutes of Health Stroke Scale scores and to validate and improve existing models.

Computed tomography perfusion in detecting malignant middle cerebral artery infarct

Background:

Computed tomography perfusion (CTP) is an emerging modality which produces maps of time-to- peak (TTP), cerebral blood flow (CBF), and cerebral blood volume (CBV), with a computerized automated map of the infarct and penumbra. This modality provides a better evaluation of the extent of infarction, making it a potential method for assessing patients suffering from large middle cerebral artery (MCA) infarctions.

Methods:

A prospective cohort study of all patients in Hospital Kuala Lumpur, Malaysia, who presented with the clinical diagnosis of a large MCA infarction within 48 h of onset were subjected to CT brain, and CTP scans on admission and were followed up to determine the development of malignant infarction requiring surgical decompression.

Results:

CTP parameters were generally lower in patients with malignant brain infarct (MBI) group compared to the nonMBI group. The largest mean difference between the group was noted in the TTP values (P = 0.005). CTP parameters had a comparable positive predictive value (83%–90%) and high net present value (88–93). CBF with cutoff value of >32.85 of the hemisphere could accurately predict malignant infarctions in 81.4% of cases. The National Institutes of Health Stroke Scale score of more than 13.5 was also found to be able to accurately determine malignant infarct (97.6%). Functional outcome of patients based on Glasgow outcome scale was similar on discharge, however, showed improvement at 6 months during reviewed base on modified Rankin scale (P < 0.001).

Conclusion:

CTP parameters should be included in the initial evaluation of patients to predict malignant brain infarction and facilitate surgical treatment of large MCA infarctions.

Key messages:

CT perfusion parameters have an important role in predicting malignant brain infarction and should be included in the initial evaluation of patients to facilitate the early identification and surgical treatment of large middle cerebral artery infarctions, to improve patient’s prognosis.

Infarct Evolution in a Large Animal Model of Middle Cerebral Artery Occlusion

Mechanical thrombectomy for the treatment of ischemic stroke shows high rates of recanalization; however, some patients still have a poor clinical outcome. A proposed reason for this relates to the fact that the ischemic infarct growth differs significantly between patients. While some patients demonstrate rapid evolution of their infarct core (fast evolvers), others have substantial potentially salvageable penumbral tissue even hours after initial vessel occlusion (slow evolvers). We show that the dog middle cerebral artery occlusion model recapitulates this key aspect of human stroke rendering it a highly desirable model to develop novel multimodal treatments to improve clinical outcomes. Moreover, this model is well suited to develop novel image analysis techniques that allow for improved lesion evolution prediction; we provide proof-of-concept that MRI perfusion-based time-to-peak maps can be utilized to predict the rate of infarct growth as validated by apparent diffusion coefficient-derived lesion maps allowing reliable classification of dogs into fast versus slow evolvers enabling more robust study design for interventional research.

Quantitative Lesion Water Uptake in Acute Stroke Computed Tomography Is a Predictor of Malignant Infarction

Background and Purpose- Early selection of patients with acute middle cerebral artery infarction at risk for malignant edema is critical to initiate timely decompressive surgery. Net water uptake (NWU) per brain volume is a quantitative imaging biomarker of space-occupying ischemic edema which can be measured in computed tomography. We hypothesize that NWU in early infarct lesions can predict development of malignant edema. The aim was to compare NWU in acute brain infarct against other common predictors of malignant edema. Methods- After consecutive screening of single-center registry data, 153 patients with acute proximal middle cerebral artery occlusion fulfilled the inclusion criteria. A total of 29 (18.2%) patients developed malignant edema defined as end point in follow-up imaging leading to decompressive surgery and death as a direct implication of mass effect. Early infarct lesion volume and NWU were quantified in multimodal admission computed tomography; time from symptom onset to admission imaging was recorded. Results- Mean time from onset to admission imaging was equivalent between patients with and without malignant infarcts (mean±SD: 3.3±1.4 hours and 3.3±1.7 hours, respectively). Edematous tissue expansion by NWU within infarct lesions occurred across all patients in this cohort (NWU: 9.1%±6.8%; median, 7.9%; interquartile range, 8.8%; range, 0.1%-35.6%); 7.0% (±5.2) in nonmalignant and 18.0% (±5.7) in malignant infarcts. Based on univariate receiver operating characteristic curve analysis, NWU >12.7% or an edema rate >3.7% NWU/h identified malignant infarcts with high discriminative power (area under curve, 0.93±0.02). In multivariate binary logistic regression, the probability of malignant infarct was significantly associated with early infarct volume and NWU. Conclusions- Computed tomography-based quantitative NWU in early infarct lesions is an important surrogate marker for developing malignant edema. Besides volume of early infarct, the measurements of lesion water uptake may further support identifying patients at risk for malignant infarction.

A Novel Neuroimaging Model to Predict Early Neurological Deterioration After Acute Ischemic Stroke

Objective:

In acute ischemic stroke, early neurological deterioration (END) may occur in up to one-third of patients. However, there is still no satisfying or comprehensive predictive model for all the stroke subtypes. We propose a practical model to predict END using magnetic resonance imaging (MRI).

Method:

Patients with anterior circulation infarct were recruited and they underwent an MRI within 24 hours of stroke onset. END was defined as an elevation of ≥2 points on the National Institute of Health Stroke Scale (NIHSS) within 72 hours of stroke onset. We examined the relationships of END to individual END models, including: A, infarct swelling; B, small subcortical infarct; C, mis-match; and D, recurrence.

Results:

There were 163 patients recruited and 43 (26.4%) of them had END. The END models A, B and C significantly predicted END respectively after adjusting for confounding factors (p=0.022, p=0.007 and p<0.001 respectively). In END model D, we examined all imaging predictors of Recur-rence Risk Estimator (RRE) individually and only the “multiple acute infarcts” pattern was signifi-cantly associated with END (p=0.032). When applying END models A, B, C and D, they success-fully predicted END (p<0.001; odds ratio: 17.5[95% confidence interval: 5.1–60.8]), with 93.0% sensitivity, 60.0% specificity, 45.5% positive predictive value and 96.0% negative predictive value.

Conclusion:

The results demonstrate that the proposed model could predict END in all stroke sub-types of anterior circulation infarction. It provides a practical model for clinical physicians to select high-risk patients for more aggressive treatment to prevent END.

Computed Tomography-Based Imaging of Voxel-Wise Lesion Water Uptake in Ischemic Brain: Relationship Between Density and Direct Volumetry

OBJECTIVES

Net water uptake per volume of brain tissue may be calculated by computed tomography (CT) density, and this imaging biomarker has recently been investigated as a predictor of lesion age in acute stroke. However, the hypothesis that measurements of CT density may be used to quantify net water uptake per volume of infarct lesion has not been validated by direct volumetric measurements so far. The purpose of this study was to (1) develop a theoretical relationship between CT density reduction and net water uptake per volume of ischemic lesions and (2) confirm this relationship by quantitative in vitro and in vivo CT image analysis using direct volumetric measurements.

MATERIALS AND METHODS

We developed a theoretical rationale for a linear relationship between net water uptake per volume of ischemic lesions and CT attenuation. The derived relationship between water uptake and CT density was tested in vitro in a set of increasingly diluted iodine solutions with successive CT measurements. Furthermore, the consistency of this relationship was evaluated using human in vivo CT images in a retrospective multicentric cohort. In 50 edematous infarct lesions, net water uptake was determined by direct measurement of the volumetric difference between the ischemic and normal hemisphere and was correlated with net water uptake calculated by ischemic density measurements.

RESULTS

With regard to in vitro data, water uptake by density measurement was equivalent to direct volumetric measurement (r = 0.99, P < 0.0001; mean ± SD difference, -0.29% ± 0.39%, not different from 0, P < 0.0001). In the study cohort, the mean ± SD uptake of water within infarct measured by volumetry was 44.7 ± 26.8 mL and the mean percent water uptake per lesion volume was 22.7% ± 7.4%. This was equivalent to percent water uptake obtained from density measurements: 21.4% ± 6.4%. The mean difference between percent water uptake by direct volumetry and percent water uptake by CT density was -1.79% ± 3.40%, which was not significantly different from 0 (P < 0.0001).

CONCLUSIONS

Volume of water uptake in infarct lesions can be calculated quantitatively by relative CT density measurements. Voxel-wise imaging of water uptake depicts lesion pathophysiology and could serve as a quantitative imaging biomarker of acute infarct lesions.

Stereotactic Aspiration of Necrotic Brain Tissue for Treating Malignant Middle Cerebral Artery Infarction: A Report of 13 Consecutive Cases

BACKGROUND

This study aimed to evaluate the efficacy and safety of stereotactic aspiration of necrotic brain tissue for treating malignant middle cerebral artery infarction (MMI) in patients older than 60 years of age.

CASE DESCRIPTION

A total of 13 consecutive patients with MMI (mean age, 67 ± 6.62 years) were enrolled in the study. These patients were treated with stereotactic aspiration of necrotic brain tissue within 72 hours from stroke onset between January 2016 and June 2017. The surgical results and clinical outcomes were evaluated in response to stereotactic aspiration of necrotic brain tissue. The mean preoperative infarction volume in the patients was found to be 153.46 ± 9.39 mL according to the latest computed tomography scan. The 30-day mortality was 2 out of 13 patients (15.4%). Patients were followed-up for 6 months to evaluate the efficacy of stereotactic aspiration of necrotic brain tissue using the modified Rankin Scale (mRS). Among the 11 surviving surgical patients, 6 (54.5%) had an mRS score of 3 (defined as moderate disability), 4 (36.4%) had an mRS score of 4 (defined as moderate to severe disability), and 1 (9.1%) had an mRS score of 5 (defined as severe disability). The probability of 6-month unfavorable outcome, defined as an mRS score of 5 or 6 (death), was 3 out of 13 (23.1%).

CONCLUSIONS

Our results suggest the stereotactic aspiration of necrotic brain tissue is an effective and safe method in patients with MMI who are over 60 years of age.

Factors associated with favourable outcome in large hemispheric infarctions

BACKGROUND

Large hemispheric infarction (LHI) is a devastating condition with high mortality and poor functional outcome in most conservatively treated patients. The purpose of this study was to explore factors associated with favorable outcome in patients with LHI.

METHODS

We prospectively enrolled consecutive patients with LHI. Favorable outcome was defined as a modified Rankin Scale (mRS) score of 0 to 3 at 90 days. Multivariate logistic regression analysis was employed to identify the independent factors associated with favorable outcome.

RESULTS

Two hundred fifty-six cases with LHI were identified: 41 (16.0%) died during hospitalization, 94 (36.7%) died at 3 month, and 113 (44.1%) survived with favorable outcome at day 90. Compared with patients with unfavorable outcome, the favorable cases were younger (55.8 ± 14.7 vs. 66.2 ± 14.1), had less history of hypertension (38.9% vs. 59.3%), lower baseline NIHSS score (median NIHSS score 11 vs. 17), lower blood pressure on admission (systolic 134.7 ± 24.9 vs. 145.1 ± 26.1 mmHg; diastolic 80.2 ± 14.9 vs. 86.9 ± 16.2 mmHg; respectively), lower level of baseline serum glucose (7.2 ± 3.3 vs. 8.2 ± 3.3 mmol/L), a lower frequency of stroke-related complications (55.8% vs. 91.4%), more use of antiplatelets (93.8% vs. 57.1%) and statins (46.9% vs. 25.7%) in the acute phase of stroke, but less use of osmotic agents (69.9% vs. 89.3%), mechanical ventilation (1.8% vs. 20.0%) or decompressive hemicraniectomy (1.8% vs. 15.7%). Multivariable analysis identified the following factors associated with favorable outcome: age (odds ratio, OR 0.95, 95% confidence interval [CI] 0.92-0.98, p < 0.001), baseline NIHSS score (OR 0.90, 95% CI 0.84-0.96, p = 0.002), statins used in acute phase (OR 2.49, 95% CI 1.10-5.65, p = 0.029), brain edema (OR 0.05, 95% CI 0.01-0.21, p < 0.001) and pneumonia (OR 0.42, 95% CI 0.19-0.93, p = 0.032).

CONCLUSION

More than one third of patients with LHI have relatively favorable clinical outcomes at 90 days. Younger age, lower baseline NIHSS score, absence of brain edema and pneumonia, and statins used in the acute phase were associated with favorable outcome of patients with LHI at 90 days.

What to Look for on Post-stroke Neuroimaging

The most feared complication after acute ischemic stroke is symptomatic or asymptomatic hemorrhagic conversion. Neuroimaging and clinical criteria are used to predict development of hemorrhage. Seizures after acute ischemic stroke or stroke-like symptoms from seizures are not common but may lead to confusion in the peristroke period, especially if seizures are repetitive or evolve into status epilepticus, which could affect neuroimaging findings. Malignant infarction develops when cytotoxic edema is large enough to lead to herniation and death. Post-stroke neuroimaging prognosticators have been described and should be assessed early so that appropriate treatment is offered before herniation leads to additional tissue injury.

Infarct volume predicts outcome after decompressive hemicraniectomy for malignant hemispheric stroke

The decision to perform decompressive hemicraniectomy (DHC) by default in malignant hemispheric stroke (MHS) remains controversial. Even under ideal conditions, DHC usually results in moderate to severe disability. The present study for the first time uses neuroimaging to identify independent outcome predictors in a prospective cohort of 96 MHS patients undergoing DHC. The primary outcome was functional status according to the modified Rankin Scale (mRS) at 12 months and categorized as favorable (mRS 0-3) or unfavorable (mRS 4-6). At 12 months, 19 patients (20%) reached favorable and 77 patients (80%) unfavorable outcome. The overall mean infarct volume was 328 ± 114 ml. Multivariable logistic regression identified age per year (OR 1.14, 95% CI 1.04-1.24; p = 0.005), infarct volume per cm³ (OR 1.012, 95% CI 1.003-1.022; p = 0.013), thalamic involvement (OR 8.65, 95% CI 1.04-72.15; p = 0.046) and postoperative pneumonia (OR 5.52, 95% CI 1.03-29.57; p = 0.046) as independent outcome predictors, which was confirmed by multivariable ordinal regression for age ( p = 0.004) and infarct volume ( p = 0.015). The infarct volume threshold for reasonable prediction of unfavorable outcome in our patients was 270 cm³, which in the future may help prognostication and development of clinical trials on DHC and outcome in MHS.

Collateral pial circulation relates to the degree of brain edema on CT 24 hours after ischemic stroke

Background Cerebral edema is frequent in patients with acute ischemic stroke (AIS) who undergo reperfusion therapy and is associated with high mortality. The impact of collateral pial circulation (CPC) status on the development of edema has not yet been determined. Methods We studied consecutive patients with AIS and documented M1-middle cerebral artery (MCA) and/or distal internal carotid artery (ICA) occlusion who underwent reperfusion treatment. Edema was graded on the 24-hour non-contrast computed tomography (NCCT) scan. CPC was evaluated at the acute phase (≤6 hours) by transcranial color-coded Doppler, angiography and/or CT angiography. We performed an ordinal regression model for the effect of CPC on cerebral edema, adjusting for age, baseline National Institutes of Health Stroke Scale, Alberta Stroke Program Early Computed Tomography Score (ASPECTS) on admission, NCCT, parenchymal hemorrhagic transformation at 24 hours and complete recanalization at six hours. Results Among the 108 patients included, 49.1% were male and mean age was 74.2 ± 11.6 years. Multivariable analysis showed a significant association between cerebral edema and CPC status (OR 0.22, 95% CI 0.08-0.59, p = 0.003), initial ASPECTS (OR 0.72, 95% CI 0.57-0.92, p = 0.007) and parenchymal hemorrhagic transformation (OR 23.67, 95% CI 4.56-122.8, p < 0.001). Conclusions Poor CPC is independently associated with greater cerebral edema 24 hours after AIS in patients who undergo reperfusion treatment.

A simple prediction score system for malignant brain edema progression in large hemispheric infarction

Malignant brain edema (MBE) due to hemispheric infarction can result in brain herniation, poor outcomes, and death; outcome may be improved if certain interventions, such as decompressive craniectomy, are performed early. We sought to generate a prediction score to easily identify those patients at high risk for MBE. 121 patients with large hemispheric infarction (LHI) (2011 to 2014) were included. Patients were divided into two groups: those who developed MBE and those who did not. Independent predictors of MBE were identified by logistic regression and a score was developed. Four factors were independently associated with MBE: baseline National Institutes of Health Stroke Scale (NIHSS) score (p = 0.048), Alberta Stroke Program Early Computed Tomography Score (ASPECTS) (p = 0.007), collateral score (CS) (p<0.001) and revascularization failure (p = 0.013). Points were assigned for each factor as follows: NIHSS ≤ 8 (= 0), 9–17 (= 1), ≥ 18 (= 2); ASPECTS≤ 7 (= 1), >8 (= 0); CS<2 (= 1), ≥2 (= 0); revascularization failure (= 1),success (= 0). The MBE Score (MBES) represents the sum of these individual points. Of 26 patients with a MBES of 0 to 1, none developed MBE. All patients with a MBES of 6 developed MBE. Both MBE development and functional outcomes were strongly associated with the MBES (p = 0.007 and 0.002, respectively). The MBE score is a simple reliable tool for the prediction of MBE.

Functional Outcome After Decompressive Craniectomy in Patients with Dominant or Non-Dominant Malignant Middle Cerebral Infarcts

BACKGROUND

 The use of decompressive craniectomy (DC) has been studied in the setting of different conditions, including traumatic brain injury, subarachnoid hemorrhage, and malignant middle cerebral artery (MCA) infarction. The rationale of this study is to determine the functional outcome after DC in patients with malignant MCA infarcts.

METHODS

 A longitudinal cohort study was performed based on patients diagnosed with malignant MCA territory infarction admitted to the Neurosurgery Department of a tertiary care hospital in Islamabad, Pakistan between July 2015 and November 2016. All patients had a clinical diagnosis of stroke according to the World Health Organization (WHO) stroke criteria.

RESULTS

 A total of 34 patients participated in this study, out of which 20/31 (64.5%) were males while 11/31 (35.5%) were females with a mean age of 51.61 ± 13.96 years. The mean time from diagnosis to surgery was 60.61 ± 49.83 hours. Out of 31 patients, 18 (58.1%) had a right middle cerebral artery infarct (RMCAI) and 13 (41.9%) had a left middle cerebral artery infarct (LCAI). Logistic regression was applied to assess the association between the type of MCA infarct with the National Institutes of Health Stroke Scale (NIHSS), modified Rankin Scale (mRS), modified Barthel Index (mBI) scores, and upper and lower limb motor power. However, the logistic regression model was not statistically significant χ² (4) = 3.896, p = 0.866. There was a statistically significant mild improvement of neurological scores and upper and lower motor power over a course of six months, but the overall functional outcome was poor with mBI < 60 and mRS > 4 (p < 0.001) with total mortality of 8.7%.

CONCLUSION

 Decompressive craniectomy is a life-saving surgery that appears to benefit patients with malignant MCA infarcts of either the dominant or non-dominant cerebral hemisphere. Decompressive craniectomy results in mild improvements in neurological scores but still poor functional outcome after six months.

Preserved Collateral Blood Flow in the Endovascular M2CAO Model Allows for Clinically Relevant Profiling of Injury Progression in Acute Ischemic Stroke

Interventional treatment regimens have increased the demand for accurate understanding of the progression of injury in acute ischemic stroke. However, conventional animal models severely inhibit collateral blood flow and mimic the malignant infarction profile not suitable for treatment. The aim of this study was to provide a clinically relevant profile of the emergence and course of ischemic injury in cases suitable for acute intervention, and was achieved by employing a M2 occlusion model (M2CAO) that more accurately simulates middle cerebral artery (MCA) occlusion in humans. Twenty-five Sprague-Dawley rats were subjected to Short (90 min), Intermediate (180 min) or Extended (600 min) transient M2CAO and examined longitudinally with interleaved diffusion-, T2- and arterial spin labeling perfusion-weighted magnetic resonance imaging before and after reperfusion. We identified a rapid emergence of cytotoxic edema within tissue regions undergoing infarction, progressing in several distinct phases in the form of subsequent moderation and then reversal at 230 min (p < 0.0001). We identified also the early emergence of vasogenic edema, which increased consistently before and after reperfusion (p < 0.0001). The perfusion of the penumbra correlated more strongly to the perfusion of adjacent tissue regions than did the perfusion of regions undergoing infarction (p = 0.0088). This was interpreted as an effect of preserved collateral blood flow during M2CAO. Accordingly, we observed only limited recruitment of penumbra regions to the infarction core. However, a gradual increase in infarction size was still occurring as late as 10 hours after M2CAO. Our results indicate that patients suffering MCA branch occlusion stand to benefit from interventional therapy for an extended time period after the emergence of ischemic injury.

Prediction of Malignant Middle Cerebral Artery Infarction in Elderly Patients

BACKGROUND

We evaluated the clinical outcomes of malignant middle cerebral artery (MCA) infarction (MMI) and determined an infarcted brain volume (BV) threshold value for accurate MMI prediction in elderly patients.

METHODS

We analyzed 69 consecutive patients (mean, 75.6 ± 11.7) with internal carotid artery or MCA infarction within 48 hours from onset. Diffusion-weighted high-intensity volume (DHV) and BV were measured in all patients. The percentage of DHV within BV (DHV/BV ratio) was calculated to standardize the DHV difference for each individual BV. Patients were stratified based upon their MMI status and age, compared with the following: (1) MMI versus non-MMI groups and (2) age ≥75 years group versus age <75 years group, based on DHV values, DHV/BV ratio, Glasgow Coma Scale (GCS) scores on admission, and modified Rankin Scale (mRS) scores at 3 months after onset.

RESULTS

The MMI group (n = 14) showed significantly larger DHV values (P < .001), larger DHV/BV ratios (P < .001), lower GCS scores on admission (P < .01), and higher mRS scores at 3 months (P < .001) than the non-MMI group. The DHV threshold value predicting MMI was 102 cm(3) (sensitivity 85%, specificity 91%, P < .01) and DHV/BV threshold ratio was 7.8% (sensitivity 86%, specificity 87%, P < .01). Both the age ≥75 years group and the age <75 years group with MMI showed equally poor outcomes (mRS 5.7 ± .7 versus 5.3 ± 1.3).

CONCLUSIONS

DHV and DHV/BV can provide reliable information for MMI prediction in elderly patients.

Systematic Review and Pooled Analyses of Recent Neurointerventional Randomized Controlled Trials: Setting a New Standard of Care for Acute Ischemic Stroke Treatment after 20 Years

BACKGROUND

Recent advances in the treatment of ischemic stroke have focused on revascularization and led to better clinical and functional outcomes. A systematic review and pooled analyses of 6 recent multicentered prospective randomized controlled trials (MPRCT) were performed to compare intravenous tissue plasminogen activator (IV tPA) and endovascular therapy (intervention) with IV tPA alone (control) for anterior circulation ischemic stroke (AIS) secondary to large vessel occlusion (LVO).

OBJECTIVES

Six MPRCTs (MR CLEAN, ESCAPE, EXTEND IA, SWIFT PRIME, REVASCAT and THERAPY) incorporating image-based LVO AIS were selected for assessing the following: (1) prespecified primary clinical outcomes of AIS patients in intervention and control arms: good outcomes were defined by a modified Rankin Scale score of 0-2 at 90 days; (2) secondary clinical outcomes were: (a) revascularization rates [favorable outcomes defined as modified Thrombolysis in Cerebral Infarction scale (mTICI) score of 2b/3]; (b) symptomatic intracranial hemorrhage (sICH) rates and mortality; (c) derivation of number needed to harm (NNH), number needed to treat (NNT), and relative percent difference (RPD) between intervention and control groups, and (d) random effects model to determine overall significance (forest and funnel plots).

RESULTS

A total of 1,386 patients were included. Good outcomes at 90 days were seen in 46% of patients in the intervention (p < 0.00001) and in 27% of patients in the control groups (p < 0.00002). An mTICI score of 2b/3 was achieved in 70.2% of patients in the intervention arm. The sICH and mortality in the intervention arm compared with the control arm were 4.7 and 14.3% versus 7.9 and 17.8%, respectively. The NNT and NNH in the intervention and control groups were 5.3 and 9.1, respectively. Patients in the intervention arm had a 50.1% (RPD) better chance of achieving a good 90-day outcome as compared to controls.

CONCLUSIONS

Endovascular therapy combined with IV tPA (in appropriately selected patients) for LVO-related AIS is superior to IV tPA alone. These results support establishing an endovascular therapy in addition to IV tPA as the standard of care for AIS secondary to LVO.

Predicting Mortality in Patients With "Malignant" Middle Cerebral Artery Infarction Using Susceptibility-Weighted Magnetic Resonance Imaging: Preliminary Findings

To evaluate malignant middle cerebral artery (MCA) infarction (defined as space-occupying edema in more than 50% to 75% of the MCA territory) on magnetic resonance imaging (MRI) with susceptibility-weighted imaging (SWI) sequence and assess the usefulness of SWI findings, diffusion-weighted imaging (DWI) findings, and apparent diffusion coefficient (ADC) as predictors of clinical outcome.Data from 16 patients with large MCA infarction previously admitted to our institution between December 2009 and October 2012 were retrospectively collected and analyzed. Within 7 days after stroke onset, 1 neurologist and 1 neuroradiologist estimated the area of infarction on DWI/ADC and extent of prominent vessel sign (PVS) on SWI images using the Stroke Program Early MR Score (SPEMRS). The PVS on SWI was defined as a local prominence of hypointense vessels with either increased vessel number or diameter in the target area, when compared with the number or diameter of the contralateral MCA territory vessels.Six patients died and 10 survived. Although the DWI/ADC-SPEMRS and clinical profiles were similar between the nonsurvivor and survivor groups, SWI-SPEMRS was significantly lower in the nonsurvivor group (P < 0.001).The area of deoxygenation on SWI in patients with malignant MCA infarction can predict mortality. Lower SWI-SPEMRS is a potentially better predictor of poor outcome than lower DWI-SPEMRS. A larger prospective study is needed to clarify the role of SWI as a therapeutic guide in malignant MCA.

Evidence-based guidelines for the management of large hemispheric infarction : a statement for health care professionals from the Neurocritical Care Society and the German Society for Neuro-intensive Care and Emergency Medicine

Large hemispheric infarction (LHI), also known as malignant middle cerebral infarction, is a devastating disease associated with significant disability and mortality. Clinicians and family members are often faced with a paucity of high quality clinical data as they attempt to determine the most appropriate course of treatment for patients with LHI, and current stroke guidelines do not provide a detailed approach regarding the day-to-day management of these complicated patients. To address this need, the Neurocritical Care Society organized an international multidisciplinary consensus conference on the critical care management of LHI. Experts from neurocritical care, neurosurgery, neurology, interventional neuroradiology, and neuroanesthesiology from Europe and North America were recruited based on their publications and expertise. The panel devised a series of clinical questions related to LHI, and assessed the quality of data related to these questions using the Grading of Recommendation Assessment, Development and Evaluation guideline system. They then developed recommendations (denoted as strong or weak) based on the quality of the evidence, as well as the balance of benefits and harms of the studied interventions, the values and preferences of patients, and resource considerations.

Novel Imaging Markers of Ischemic Cerebral Edema and Its Association with Neurological Outcome

Ischemic cerebral edema (ICE) is a recognized cause of secondary neurological deterioration after large hemispheric stroke, but little is known about the scope of its impact. To study edema in less severe stroke, our group has developed several markers of cerebral edema using brain magnetic resonance imaging (MRI). These tools, which are based on categorical and volumetric measurements in serial diffusion-weighted imaging (DWI), are applicable to a wide variety of stroke volumes. Further, these metrics provide distinct volumetric measurements attributable to ICE, infarct growth, and hemorrhagic transformation. We previously reported that ICE independently predicted neurological outcome after adjustment for known risk factors. We found that an ICE volume of 11 mL or greater was associated with worse neurological outcome.

Recommendations for management of large hemispheric infarction

PURPOSE OF REVIEW

Large hemispheric infarction is a devastating disease that continues to be associated with significant mortality and morbidity. Most often these patients are admitted to the ICU requiring significant physician and nursing resources. This review will address some of the ICU management issues and review the evidence supporting medical and surgical management of malignant cerebral edema.

RECENT FINDINGS

The most recent changes in management of large hemispheric infarct include the American Heart Association and Neurocritical Care Guidelines. These guidelines address airway management and mechanical ventilation, blood pressure control, fluid management, and glucose and temperature control. In addition, they addressed the indication for surgical management of cerebral edema. We review the recent guidelines updates and trials of surgical management of large hemispheric infarcts.

SUMMARY

Large hemispheric infarcts continue to have significant morbidity and mortality. Recent guidelines have provided an excellent framework to help intensivists manage these complicated patients. Recent surgical data continue to support early hemicraniectomy even in elderly patients.

[Neurovisualisation predictors of malignant cerebral infarction and hemorrhagic transformation]

Neuroimaging plays a central role in the assessment of patients with acute ischemic stroke. Within a few minutes, modern multimodal imaging protocols can provide one with comprehensive information about prognosis, management, and outcome of the disease, and may detect changes in the intracranial structures reflecting severity of the ischemic injury depicted by four Ps: parenchyma (of the brain), pipes (i.e., the cerebral blood vessels), penumbra, and permeability (of the blood brain barrier). In this article, we have reviewed neuroradiological predictors of malignant middle cerebral artery infarction and hemorrhagic transformation in light of the aforementioned four Ps.

Hemispheric differences in malignant middle cerebral artery stroke

BACKGROUND

We recently reported that left versus right hemisphere cerebral infarctions patients more frequently have worse outcomes. However our clinical experience led us to suspect that the incidence of malignant middle cerebral artery infarctions (MMCA) was higher in the right compared to the left hemispheric strokes.

OBJECTIVE

To determine whether laterality in MMCA stroke is an important determinant of stroke sequelae.

METHODS

A systematic search was performed for publications in PubMed using "malignant middle cerebral artery and infarction". A total of 73 relevant studies were abstracted.

RESULTS

MMCA laterality data were available for 2673 patients, with 1687 (63%) right hemispheric involvement, thus right being more commonly associated with MMCA (binomial test, p<0.05). While mortality rates were similar, right hemispheric MMCA (n=271) had mortality of 31% (n=85) whereas left hemispheric MMCA (n=144) had mortality of 36% (n=53), morbidity rates were worse on the right.

CONCLUSION

MMCA stroke appears to be more common on the right, and this laterality is also associated with significantly higher morbidity. Further prospective studies are needed to more completely understand the nature of this laterality as well as test possible new treatments to reduce mortality and morbidity associated with MMCA.

Treatment of malignant brain edema and increased intracranial pressure after stroke

OPINION STATEMENT

The management of patients with large territory ischemic strokes and the subsequent development of malignant brain edema and increased intracranial pressure is a significant challenge in modern neurology and neurocritical care. These patients are at high risk of subsequent neurologic decline and are best cared for in an intensive care unit or a comprehensive stroke center with access to neurosurgical support. Risks include hemorrhagic conversion, herniation, poor functional outcome, and death. This review discusses recent advances in understanding the pathophysiology of edema formation, identifying patients at risk, current management strategies, and emerging therapies.