Endovascular Therapy or Medical Management Alone for Isolated Posterior Cerebral Artery Occlusion: A Multicenter Study.

BACKGROUND: Whether endovascular therapy (EVT) added on best medical management (BMM), as compared to BMM alone, is beneficial in acute ischemic stroke with isolated posterior cerebral artery occlusion is unknown. METHODS: We conducted a multicenter international observational study of consecutive stroke patients admitted within 6 hours from symptoms onset in 26 stroke centers with isolated occlusion of the first (P1) or second (P2) segment of the posterior cerebral artery and treated either with BMM+EVT or BMM alone. Propensity score with inverse probability of treatment weighting was used to account for baseline between-groups differences. The primary outcome was 3-month good functional outcome (modified Rankin Scale [mRS] score 0-2 or return to baseline modified Rankin Scale). Secondary outcomes were 3-month excellent recovery (modified Rankin Scale score 0-1), symptomatic intracranial hemorrhage, and early neurological deterioration. RESULTS: Overall, 752 patients were included (167 and 585 patients in the BMM+EVT and BMM alone groups, respectively). Median age was 74 (interquartile range, 63-82) years, 329 (44%) patients were female, median National Institutes of Health Stroke Scale was 6 (interquartile range 4-10), and occlusion site was P1 in 188 (25%) and P2 in 564 (75%) patients. Baseline clinical and radiological data were similar between the 2 groups following propensity score weighting. EVT was associated with a trend towards lower odds of good functional outcome (odds ratio, 0.81 [95% CI, 0.66-1.01]; P=0.06) and was not associated with excellent functional outcome (odds ratio, 1.17 [95% CI, 0.95-1.43]; P=0.15). EVT was associated with a higher risk of symptomatic intracranial hemorrhage (odds ratio, 2.51 [95% CI, 1.35-4.67]; P=0.004) and early neurological deterioration (odds ratio, 2.51 [95% CI, 1.64-3.84]; P<0.0001). CONCLUSIONS: In this observational study of patients with proximal posterior cerebral artery occlusion, EVT was not associated with good or excellent functional outcome as compared to BMM alone. However, EVT was associated with higher rates of symptomatic intracranial hemorrhage and early neurological deterioration. EVT should not be routinely recommended in this population, but randomization into a clinical trial is highly warranted.

Inflammatory profile and white matter hyperintensity burden in acute ischemic stroke patients.

Inflammation is involved in small vessel disease (SVD). We aim to clarify whether inflammation related to white matter hyperintensities (WMH), a key component of SVD, may affect the inflammatory response in acute ischemic stroke (AIS) patients. For this, we sequentially measured 10 circulating inflammatory markers and assessed WMH burden on admission MRI in AIS patients treated with thrombectomy. Of 149 patients, 57 (38.3%) had a high WMH burden (Fazekas≥3). A high WMH burden was associated with 4 markers levels but this association did not remain following multivariable analyses. WMH burden is not associated with a specific inflammatory profile in AIS.

Safety and efficacy of prophylactic levetiracetam for prevention of epileptic seizures in the acute phase of intracerebral haemorrhage (PEACH): a randomised, double-blind, placebo-controlled, phase 3 trial.

BACKGROUND: The incidence of early seizures (occurring within 7 days of stroke onset) after intracerebral haemorrhage reaches 30% when subclinical seizures are diagnosed by continuous EEG. Early seizures might be associated with haematoma expansion and worse neurological outcomes. Current guidelines do not recommend prophylactic antiseizure treatment in this setting. We aimed to assess whether prophylactic levetiracetam would reduce the risk of acute seizures in patients with intracerebral haemorrhage. METHODS: The double-blind, randomised, placebo-controlled, phase 3 PEACH trial was conducted at three stroke units in France. Patients (aged 18 years or older) who presented with a non-traumatic intracerebral haemorrhage within 24 h after onset were randomly assigned (1:1) to levetiracetam (intravenous 500 mg every 12 h) or matching placebo. Randomisation was done with a web-based system and stratified by centre and National Institutes of Health Stroke Scale (NIHSS) score at baseline. Treatment was continued for 6 weeks. Continuous EEG was started within 24 h after inclusion and recorded over 48 h. The primary endpoint was the occurrence of at least one clinical seizure within 72 h of inclusion or at least one electrographic seizure recorded on continuous EEG, analysed in the modified intention-to-treat population, which comprised all patients who were randomly assigned to treatment and who had a continuous EEG performed. This trial was registered at ClinicalTrials.gov, NCT02631759, and is now closed. Recruitment was prematurely stopped after 48% of the recruitment target was reached due to a low recruitment rate and cessation of funding. FINDINGS: Between June 1, 2017, and April 14, 2020, 50 patients with mild-to-moderate severity intracerebral haemorrhage were included: 24 were assigned to levetiracetam and 26 to placebo. During the first 72 h, a clinical or electrographic seizure was observed in three (16%) of 19 patients in the levetiracetam group versus ten (43%) of 23 patients in the placebo group (odds ratio 0·16, 95% CI 0·03-0·94, p=0·043). All seizures in the first 72 h were electrographic seizures only. No difference in depression or anxiety reporting was observed between the groups at 1 month or 3 months. Depression was recorded in three (13%) patients who received levetiracetam versus four (15%) patients who received placebo, and anxiety was reported for two (8%) patients versus one (4%) patient. The most common treatment-emergent adverse events in the levetiracetam group versus the placebo group were headache (nine [39%] vs six [24%]), pain (three [13%] vs ten [40%]), and falls (seven [30%] vs four [16%]). The most frequent serious adverse events were neurological deterioration due to the intracerebral haemorrhage (one [4%] vs four [16%]) and severe pneumonia (two [9%] vs two [8%]). No treatment-related death was reported in either group. INTERPRETATION: Levetiracetam might be effective in preventing acute seizures in intracerebral haemorrhage. Larger studies are needed to determine whether seizure prophylaxis improves functional outcome in patients with intracerebral haemorrhage. FUNDING: French Ministry of Health.

Brain virtual histology with X-ray phase-contrast tomography Part I: whole-brain myelin mapping in white-matter injury models.

White-matter injury leads to severe functional loss in many neurological diseases. Myelin staining on histological samples is the most common technique to investigate white-matter fibers. However, tissue processing and sectioning may affect the reliability of 3D volumetric assessments. The purpose of this study was to propose an approach that enables myelin fibers to be mapped in the whole rodent brain with microscopic resolution and without the need for strenuous staining. With this aim, we coupled in-line (propagation-based) X-ray phase-contrast tomography (XPCT) to ethanol-induced brain sample dehydration. We here provide the proof-of-concept that this approach enhances myelinated axons in rodent and human brain tissue. In addition, we demonstrated that white-matter injuries could be detected and quantified with this approach, using three animal models: ischemic stroke, premature birth and multiple sclerosis. Furthermore, in analogy to diffusion tensor imaging (DTI), we retrieved fiber directions and DTI-like diffusion metrics from our XPCT data to quantitatively characterize white-matter microstructure. Finally, we showed that this non-destructive approach was compatible with subsequent complementary brain sample analysis by conventional histology. In-line XPCT might thus become a novel gold-standard for investigating white-matter injury in the intact brain. This is Part I of a series of two articles reporting the value of in-line XPCT for virtual histology of the brain; Part II shows how in-line XPCT enables the whole-brain 3D morphometric analysis of amyloid- ß (A ß ) plaques.

Does the Brush-Sign Reflect Collateral Status and DWI-ASPECTS in Large Vessel Occlusion?

Introduction: The relevance of the brush-sign remained poorly documented in large vessel occlusion (LVO). We aimed to assess the relationship between the brush-sign and collateral status and its potential impact on baseline diffusion-weighted imaging-Alberta Stroke Program Early Computed Tomography Score (DWI-ASPECTS) in acute ischemic stroke (AIS) patients eligible to mechanical thrombectomy (MT). Methods: Consecutive patients admitted in the Lyon Stroke Center with anterior circulation AIS due to intracranial internal carotid artery (ICA) and/or M1 or M2 segment of the middle cerebral artery (MCA) occlusion eligible for MT were included. The brush-sign was assessed on T2-gradient-echo MRI. Collateral status was assessed on digital subtraction angiography according to the American Society of Interventional and Therapeutic Neuroradiology/Society of Interventional Radiology (ASITN/SIR) score. Results: In this study, 504 patients were included, among which 171 (33.9%) patients had a brush-sign. Patients with a brush-sign more frequently had a poor collateral status [72 (42.1%) vs. 103 (30.9%); p = 0.017]. In univariable analysis, a DWI-ASPECTS < 7 was associated with a brush sign. Following multivariable analysis, the brush-sign no longer affected DWI-ASPECTS < 7 while the latter remained associated with younger age [odds ratio (OR) 0.97, 95% CI.96-0.99], male sex (OR 1.79, 95% CI 1.08-2.99), a higher National Institutes of Health Stroke Scale (NIHSS) score (OR 1.16, 95% CI 1.1-1.21), a poor collateral status (OR 9.35, 95% CI 5.59-16.02), MCA segment (OR 2.54, 95% CI 1.25-5.38), and intracranial ICA (OR 3.01, 95% CI 1.16-8) occlusion. Conclusions and Relevance: The brush-sign may be a marker of poor collateral status but did not independently predict a lower DWI-ASPECTS. Clinical Trial Registration: ClinicalTrials.gov, identifier: NCT04620642.

Neurofunctional and neuroimaging readouts for designing a preclinical stem-cell therapy trial in experimental stroke.

With the aim of designing a preclinical study evaluating an intracerebral cell-based therapy for stroke, an observational study was performed in the rat suture model of ischemic stroke. Objectives were threefold: (i) to characterize neurofunctional and imaging readouts in the first weeks following transient ischemic stroke, according to lesion subtype (hypothalamic, striatal, corticostriatal); (ii) to confirm that intracerebral administration does not negatively impact these readouts; and (iii) to calculate sample sizes for a future therapeutic trial using these readouts as endpoints. Our results suggested that the most relevant endpoints were side bias (staircase test) and axial diffusivity (AD) (diffusion tensor imaging). Hypothalamic-only lesions did not affect those parameters, which were close to normal. Side bias in striatal lesions reached near-normal levels within 2 weeks, while rats with corticostriatal lesions remained impaired until week 14. AD values were decreased at 4 days and increased at 5 weeks post-surgery, with a subtype gradient: hypothalamic < striatal < corticostriatal. Intracerebral administration did not impact these readouts. After sample size calculation (18-147 rats per group according to the endpoint considered), we conclude that a therapeutic trial based on both readouts would be feasible only in the framework of a multicenter trial.

Temporal trends in reperfusion therapy for patients with acute ischemic stroke.

OBJECTIVES: To analyze the temporal trends in thrombolysis rates after implementation of a regional emergency network for acute ischemic stroke (AIS). METHODS: We conducted a retrospective study based on a prospective multicenter observational registry. The AIS benefited from reperfusion therapy included in 1 of the 5 primary stroke units or 1 comprehensive stroke center and 37 emergency departments were included using a standardized case report form. The population covers 3 million inhabitants. RESULTS: In total, 32,319 AIS was reported in the regional hospitalization database of which 2215 thrombolyzed AIS patients were included in the registry and enrolled in this study. The annual incidence rate of thrombolysis continuously and significantly increased from 2010 to 2018 (10.2% to 17.3%, P-trend = 0.0013). The follow-up of the onset-to-door and the door-to-needle delays over the study period showed stable rates, as did the all-cause mortality rate at 3-months (13.2%). CONCLUSION: Although access to stroke thrombolysis has increased linearly since 2010, the 3-month functional outcome has not evolved as favorably. Further efforts must focus on reducing hospital delays.

In vivo targeting and multimodal imaging of cerebral amyloid-ß aggregates using hybrid GdF3 nanoparticles.

Aim: To propose a new multimodal imaging agent targeting amyloid-ß (Aß) plaques in Alzheimer's disease. Materials & methods: A new generation of hybrid contrast agents, based on gadolinium fluoride nanoparticles grafted with a pentameric luminescent-conjugated polythiophene, was designed, extensively characterized and evaluated in animal models of Alzheimer's disease through MRI, two-photon microscopy and synchrotron x-ray phase-contrast imaging. Results & conclusion: Two different grafting densities of luminescent-conjugated polythiophene were achieved while preserving colloidal stability and fluorescent properties, and without affecting biodistribution. In vivo brain uptake was dependent on the blood-brain barrier status. Nevertheless, multimodal imaging showed successful Aß targeting in both transgenic mice and Aß fibril-injected rats.

The design and study of a new contrast agent targeting amyloid-ß (Aß) plaques in Alzheimer's disease (AD) is proposed. Aß plaques are the earliest pathological sign of AD, silently appearing in the brain decades before the symptoms of the disease are manifested. While current detection of Aß plaques is based on nuclear medicine (a technique using a radioactive agent), a different kind of contrast agent is here evaluated in animal models of AD. The contrast agent consists of a nanoparticle made of gadolinium and fluorine ions (core), and decorated with a molecule previously shown to bind to Aß plaques (grafting). The core is detectable with MRI and x-ray imaging, while the grafting molecule is detectable with fluorescence imaging, thus allowing different imaging methods to be combined to study the pathology. In this work, the structure, stability and properties of the contrast agent have been verified in vitro (in tubes and on brain sections). Then the ability of the contrast agent to bind to Aß plaques and provide a detectable signal in MRI, x-ray or fluorescence imaging has been demonstrated in vivo (in rodent models of AD). This interdisciplinary research establishes the proof of concept that this new class of versatile agent contrast can be used to target pathological processes in the brain.

A lower admission level of interleukin-6 is associated with first-pass effect in ischemic stroke patients.

BACKGROUND: First-pass effect (FPE) defined as a complete or near-complete reperfusion achieved after a single thrombectomy pass is predictive of favorable outcome in acute ischemic stroke (AIS) patients. We aimed to assess whether admission levels of inflammatory markers are associated with FPE. METHODS: HIBISCUS-STROKE (CoHort of Patients to Identify Biological and Imaging markerS of CardiovascUlar Outcomes in Stroke) includes AIS patients with large vessel occlusion treated with mechanical thrombectomy following brain MRI. C-reactive protein, interleukin (IL)-6, IL-8, IL-10, monocyte chemoattractant protein-1, soluble tumor necrosis factor receptor I, soluble form suppression of tumorigenicity 2, matrix metalloproteinase-9 (MMP-9), soluble P-selectin, and vascular cellular adhesion molecule-1 were measured in admission sera using an ELISA assay. FPE was defined as a complete or near-complete reperfusion (thrombolysis in cerebral infarction scale (TICI) 2c or 3) after the first pass. A multivariate logistic regression analysis was performed to assess independent factors associated with FPE. RESULTS: A total of 151 patients were included. Among them, 43 (28.5%) patients had FPE. FPE was associated with low admission levels of IL-6, MMP-9, and platelet count, an older age, lack of hypertension, lack of tandem occlusion, a shorter thrombus length, and a reduced procedural time. Following multivariate analysis, a low admission level of IL-6 was associated with FPE (OR 0.66, 95% CI 0.46 to 0.94). Optimal cut-off of IL-6 level for distinguishing FPE from non-FPE was 3.0 pg/mL (sensitivity 92.3%, specificity 42.3%). CONCLUSION: A lower admission level of IL-6 is associated with FPE.

Effect of the COVID-19 pandemic on acute stroke reperfusion therapy: data from the Lyon Stroke Center Network.

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic would have particularly affected acute stroke care. However, its impact is clearly inherent to the local stroke network conditions. We aimed to assess the impact of COVID-19 pandemic on acute stroke care in the Lyon comprehensive stroke center during this period. METHODS: We conducted a prospective data collection of patients with acute ischemic stroke (AIS) treated with intravenous thrombolysis (IVT) and/or mechanical thrombectomy (MT) during the COVID-19 period (from 29/02/2020 to 10/05/2020) and a control period (from 29/02/2019 to 10/05/2019). The volume of reperfusion therapies and pre and intra-hospital delays were compared during both periods. RESULTS: A total of 208 patients were included. The volume of IVT significantly decreased during the COVID-period [55 (54.5%) vs 74 (69.2%); p = 0.03]. The volume of MT remains stable over the two periods [72 (71.3%) vs 65 (60.8%); p = 0.14], but the door-to-groin puncture time increased in patients transferred for MT (237 [187-339] vs 210 [163-260]; p < 0.01). The daily number of Emergency Medical Dispatch calls considerably increased (1502 [1133-2238] vs 1023 [960-1410]; p < 0.01). CONCLUSIONS: Our study showed a decrease in the volume of IVT, whereas the volume of MT remained stable although intra-hospital delays increased for transferred patients during the COVID-19 pandemic. These results contrast in part with the national surveys and suggest that the impact of the pandemic may depend on local stroke care networks.

Association of Interleukin-6 Levels and Futile Reperfusion After Mechanical Thrombectomy.

OBJECTIVE: To assess whether interleukin-6 (IL-6) level is a marker of futile reperfusion in patients with acute ischemic stroke (AIS) with large vessel occlusion treated with mechanical thrombectomy (MT). METHODS: The Cohort of Patients to Identify Biological and Imaging Markers of Cardiovascular Outcomes in Stroke (HIBISCUS-STROKE) includes patients with AIS treated with MT after MRI. We performed a sequential assessment of IL-6 (admission, 6 hours, 24 hours, 48 hours and 3 months from admission). Among patients with successful reperfusion (Thrombolysis in Cerebral Infarction scale 2b/3), reperfusion was considered effective if 3-month modified Rankin Scale (mRS) score was 0 to 2 and futile if 3-month mRS score was 3 to 6. Our model was adjusted for the main confounding variables. RESULTS: One hundred sixty-four patients represent the study population. One hundred thirty-three patients had successful reperfusion (81.1%), while in 46 (34.6%), reperfusion was classified as futile. In single-variable analyses, high IL-6 levels at 6, 24, and 48 hours in combination with a higher age, a prestroke mRS score >2, a history of hypertension or diabetes, lack of current smoking, a higher baseline NIH Stroke Scale score, the absence of associated intravenous thrombolysis, an intracranial internal carotid artery or a tandem occlusion, and an increased infarct growth were associated with futile reperfusion. After multivariable analyses, a high IL-6 level at 24 hours (odds ratio 6.15, 95% confidence interval 1.71-22.10) remained associated with futile reperfusion. CONCLUSIONS: IL-6 is a marker of futile reperfusion in the setting of MT.

Prevalence and Outcome of Potential Candidates for Left Atrial Appendage Closure After Stroke With Atrial Fibrillation: WATCH-AF Registry.

BACKGROUND AND PURPOSE: As a result of contraindications (eg, frailty, cognitive impairment, comorbidities) or patient refusal, many patients with stroke and atrial fibrillation cannot be discharged on oral anticoagulant. Among them, the proportion of potential candidates for left atrial appendage closure (LAAC) and their 12-month outcome is not well known. METHODS: The prospective WATCH-AF registry (Warfarin Aspirin Ten-A Inhibitors and Cerebral Infarction and Hemorrhage and Atrial Fibrillation) enrolled consecutive patients admitted within 72 hours of an acute stroke associated with atrial fibrillation in 2 stroke centers. Scales to evaluate stroke severity, disability, functional independence, risk of fall, cognition, ischemic and hemorrhagic risk-stratification, and comorbidities were systematically collected at admission, discharge, 3, 12 months poststroke. The 2 main end points were death or dependency (modified Rankin Scale score >3) and recurrent stroke (brain infarction and brain hemorrhage). RESULTS: Among 400 enrolled patients (370 with brain infarction, 30 with brain hemorrhage), 31 died before discharge and 57 (14.3%) were possible European Heart Rhythm Association/European Society of Cardiology and American Heart Association/American College of Cardiology/Heart Rhythm Society candidates for LAAC. At 12 months, the rate of death or dependency was 17.9%, and the rate of stroke recurrence was 9.8% in the 274/400 (68.5%) patients discharged on a long-term oral anticoagulant strategy, as compared with 17.5% and 24.7%, respectively, in 57 patients candidate for LAAC. As compared with patients on a long-term oral anticoagulant strategy, there was a 2-fold increase in the risk of stroke recurrence in the group with an indication for LAAC (adjusted hazard ratio, 2.58 [95% CI, 1.40-4.76]; P=0.002). CONCLUSIONS: Fourteen percent of patients with stroke associated with atrial fibrillation were potential candidates for LAAC. The 12-month stroke risk of these candidates was 3-fold the risk of anticoagulated patients.

Matrix Metalloproteinase-9 Relationship With Infarct Growth and Hemorrhagic Transformation in the Era of Thrombectomy.

Objective: To assess the relationship between matrix metalloproteinase 9 (MMP-9), a proteolytic enzyme involved in the breakdown of the blood-brain barrier, and infarct growth and hemorrhagic transformation in acute ischemic stroke (AIS) with large vessel occlusion (LVO) in the era of mechanical thrombectomy (MT) using the kinetics of MMP-9 and sequential magnetic resonance imaging (MRI). Methods: HIBISCUS-STROKE is a cohort study including AIS patients with LVO treated with MT following admission MRI. Patients underwent sequential assessment of MMP-9, follow-up CT at day 1, and MRI at day 6. The CT scan at day 1 classified any hemorrhagic transformation according to the European Co-operative Acute Stroke Study-II (ECASS II) classification. Infarct growth was defined as the difference between final Fluid-Attenuated Inversion Recovery volume and baseline diffusion-weighted imaging volume. Conditional logistic regression analyses were adjusted for main confounding variables including reperfusion status. Results: One hundred and forty-eight patients represent the study population. A high MMP-9 level at 6 h from admission (H6) (p = 0.02), a high glucose level (p = 0.01), a high temperature (p = 0.04), and lack of reperfusion (p = 0.02) were associated with infarct growth. A high MMP-9 level at H6 (p = 0.03), a high glucose level (p = 0.03) and a long delay from symptom onset to groin puncture (p = 0.01) were associated with hemorrhagic transformation. Conclusions: In this MT cohort study, MMP-9 level at H6 predicts infarct growth and hemorrhagic transformation.

Matrix Metalloproteinase-9 and Monocyte Chemoattractant Protein-1 Are Associated With Collateral Status in Acute Ischemic Stroke With Large Vessel Occlusion.

BACKGROUND AND PURPOSE: In ischemic stroke, inflammatory status may condition the development of collateral circulation. Here we assessed the relationship between systemic inflammatory biomarkers and collateral status in large vessel occlusion before mechanical thrombectomy. METHODS: HIBISCUS-STROKE is a cohort study including acute ischemic stroke patients with large vessel occlusion treated with mechanical thrombectomy following admission magnetic resonance imaging. MMP-9 (matrix metalloproteinase-9) and MCP-1 (monocyte chemoattractant protein-1) were measured on blood sampling collected at admission. Collateral status was assessed on pretreatment Digital subtraction angiography and categorized into poor (Higashida score, 0-2) and good (Higashida score, 3-4). A multiple logistic regression model was performed to detect independent markers of good collateral status. RESULTS: One hundred and twenty-two patients were included, of them 71 patients (58.2%) had a good collateral status. In univariate analysis, low MMP-9 levels (P=0.01), high MCP-1 levels (P<0.01), a low National Institute of Health Stroke Score (P=0.046), a high diastolic blood pressure (P=0.049), the absence of tandem occlusion (P=0.046), a high Alberta Stroke Program Early CT Score (P<0.01) and a low volume on the diffusion-weighted imaging (P<0.01) were associated with good collateral status. Following multivariate analysis, low MMP-9 levels (P=0.02) and high MCP-1 levels (P<0.01) remained associated with good collateral status. CONCLUSIONS: Low MMP-9 and high MCP-1 levels were associated with good pretreatment collateral status in patients with acute ischemic stroke with large vessel occlusion. These results might suggest a relationship between collateral status and inflammation.

White matter burden does not influence the outcome of mechanical thrombectomy.

BACKGROUND AND PURPOSE: The significance of white matter hyperintensities (WMHs) in the setting of mechanical thrombectomy (MT) remains poorly documented. We assessed whether pre-existing WMHs burden was associated with baseline clinical and imaging factors and neurological outcome in patients undergoing MT. METHODS: This retrospective single-center study included consecutive acute ischemic stroke (AIS) patients with stroke due to large vessel occlusion treated with MT. WMHs were assessed on baseline T2 fluid-attenuated inversion recovery magnetic resonance imaging. Neurological outcome was assessed at day 90 by the modified Rankin Scale (mRS). We analyzed the association between WMH burden and clinical and imaging factors by univariate and multivariate logistic regression analyses. RESULTS: Between July 2013 and June 2019, 293 patients with anterior circulation AIS met the inclusion criteria. WMHs burden was not associated to baseline NIHSS score severity (OR 0.89, 95% CI 0.54-1.49, p = 0.66), poor collateral status, Higashida score < 3 (OR 1.5 95% CI 0.62-3.56, p = 0.36), higher DWI volume (OR 0.69, 95% CI 0.41-1.15, p = 0.16) or to a lower recanalization rate, TICI 0/2a (OR 0.98 95% CI 0.56-1.69, p = 0.95). WMHs severity did not influence the risk of parenchymal hemorrhage (OR 0.97 95% 0.26-3, p = 0.96). WMHs burden was not an independent predictor of poor outcome in multivariate analysis. The rate of futile recanalization in patients with TICI grades 2b and 3 according to mRs score at 3 months was not influenced by WMHs burden. CONCLUSIONS: WMHs burden does not seem to influence clinical outcome and imaging parameters in patients treated by MT.

MRI coupled with clinically-applicable iron oxide nanoparticles reveals choroid plexus involvement in a murine model of neuroinflammation.

Choroid plexus (ChPs) are involved in the early inflammatory response that occurs in many brain disorders. However, the activation of immune cells within the ChPs in response to neuroinflammation is still largely unexplored in-vivo. There is therefore a crucial need for developing imaging tool that would allow the non-invasive monitoring of ChP involvement in these diseases. Magnetic resonance imaging (MRI) coupled with superparamagnetic particles of iron oxide (SPIO) is a minimally invasive technique allowing to track phagocytic cells in inflammatory diseases. Our aim was to investigate the potential of ultrasmall SPIO (USPIO)-enhanced MRI to monitor ChP involvement in-vivo in a mouse model of neuroinflammation obtained by intraperitoneal administration of lipopolysaccharide. Using high resolution MRI, we identified marked USPIO-related signal drops in the ChPs of animals with neuroinflammation compared to controls. We confirmed these results quantitatively using a 4-points grading system. Ex-vivo analysis confirmed USPIO accumulation within the ChP stroma and their uptake by immune cells. We validated the translational potential of our approach using the clinically-applicable USPIO Ferumoxytol. MR imaging of USPIO accumulation within the ChPs may serve as an imaging biomarker to study ChP involvement in neuroinflammatory disorders that could be applied in a straightforward way in clinical practice.

Does Small Vessel Disease Burden Impact Collateral Circulation in Ischemic Stroke Treated by Mechanical Thrombectomy?

Background and Purpose- The development of leptomeningeal collateral artery network might be adversely affected by small vessel wall alteration. We sought to determine whether small vessel disease (SVD) burden may impact collateral development in patients treated by mechanical thrombectomy for anterior circulation acute ischemic stroke. Methods- The patients admitted in our center for anterior circulation acute ischemic stroke and (1) treated by mechanical thrombectomy with or without thrombolysis and (2) who underwent a baseline magnetic resonance imaging were included in the study. The SVD burden and the pial collaterality were assessed through the cerebral SVD score (severe when ≥1) and the Higashida score (favorable when ≥ 3) on magnetic resonance imaging and digital subtraction angiography, respectively. Any association between the cerebral SVD score and the collaterality were assessed through comparative and regression analyses. Results- Between January 2013 and March 2018, 240 patients met the inclusion criteria (68.7±16.1 years old; 49.2 % female). The cerebral SVD scores were of 0 in 125 (52.1%), 1 in 74 (30.8%), 2 in 30 (12.5%), and 3 in 11 (4.6%) patients. Hundred and thirty-six patients (58.1%) presented a favorable collaterality score. The favorable collaterality subgroup presented a significantly higher proportion of female (79%), lower baseline National Institutes of Health Stroke Scale ( P<0.001), and higher Diffusion-Weighted Imaging-Alberta Stroke Program Early CT Scores ( P<0.001). The regression analyses showed no impact of the cerebral SVD score on the collaterality pattern (odds ratio, 1.11, 95% CI, 0.82-1.50; P=0.51). Conclusions- In patients with anterior circulation acute ischemic stroke, collateral flow status does not seem to be influenced by SVD burden.

Clinical Imaging of Choroid Plexus in Health and in Brain Disorders: A Mini-Review.

The choroid plexuses (ChPs) perform indispensable functions for the development, maintenance and functioning of the brain. Although they have gained considerable interest in the last years, their involvement in brain disorders is still largely unknown, notably because their deep location inside the brain hampers non-invasive investigations. Imaging tools have become instrumental to the diagnosis and pathophysiological study of neurological and neuropsychiatric diseases. This review summarizes the knowledge that has been gathered from the clinical imaging of ChPs in health and brain disorders not related to ChP pathologies. Results are discussed in the light of pre-clinical imaging studies. As seen in this review, to date, most clinical imaging studies of ChPs have used disease-free human subjects to demonstrate the value of different imaging biomarkers (ChP size, perfusion/permeability, glucose metabolism, inflammation), sometimes combined with the study of normal aging. Although very few studies have actually tested the value of ChP imaging biomarkers in patients with brain disorders, these pioneer studies identified ChP changes that are promising data for a better understanding and follow-up of diseases such as schizophrenia, epilepsy and Alzheimer's disease. Imaging of immune cell trafficking at the ChPs has remained limited to pre-clinical studies so far but has the potential to be translated in patients for example using MRI coupled with the injection of iron oxide nanoparticles. Future investigations should aim at confirming and extending these findings and at developing translational molecular imaging tools for bridging the gap between basic molecular and cellular neuroscience and clinical research.

MRI Profile and Collateral Status in Patients with a Transient Ischemic Attack and an Intracranial Artery Occlusion.

BACKGROUND AND PURPOSE: Transient ischemic attack may rarely reveal an intracranial artery occlusion. We analyzed acute magnetic resonance imaging (MRI) patterns and early outcome after reperfusion therapy in these cases. METHOD: Clinical and imaging data were taken retrospectively from our comprehensive stroke center registry. Two MRI patterns were determined. Pattern A: full mismatch with negative diffusion-weighted imaging (DWI) and perfusion defect. Pattern B: large mismatch with positive DWI and perfusion defect. MRI-derived collateral flow maps were automatically generated from the raw of dynamic susceptibility contrast MRI. Patients were treated either by recombinant tissue plasminogen activator (rtPA) alone or in combination with mechanical thrombectomy. RESULTS: From October 1, 2010 to May 15, 2016, 1,019 patients were admitted and treated by t-PA within 4.5 hours of stroke onset of them; 14 had a transient ischemic attack (TIA) within the 6 hours preceding MRI. Perfusion imaging was performed in 11 patients. An arterial occlusion was found in all of them, 11 patients had a distal anterior circulation occlusion, whereas 3 patients (21%) had a proximal occlusion. According to MRI, 6 patients showed pattern A, whereas 5 patients had pattern B. Good collaterals were observed in 10 patients (6 patients with grade 3 and 4 patients with grade 4), whereas 1 patient had poor collaterals (grade 2). The day 1 National Institutes of Health Stroke Scale median was 0. Modified Rankin Scale median at 3 months was 0. CONCLUSION: TIAs may reveal acute intracranial artery occlusion. Acute MRI may able to assist in therapeutic decision.