Imaging features and safety and efficacy of endovascular stroke treatment: a meta-analysis of individual patient-level data

Background: Evidence regarding whether imaging can be used effectively to select patients for endovascular thrombectomy (EVT) is scarce. We aimed to investigate the association between baseline imaging features and safety and efficacy of EVT in acute ischaemic stroke caused by anterior large-vessel occlusion. Methods: In this meta-analysis of individual patient-level data, the HERMES collaboration identified in PubMed seven randomised trials in endovascular stroke that compared EVT with standard medical therapy, published between Jan 1, 2010, and Oct 31, 2017. Only trials that required vessel imaging to identify patients with proximal anterior circulation ischaemic stroke and that used predominantly stent retrievers or second-generation neurothrombectomy devices in the EVT group were included. Risk of bias was assessed with the Cochrane handbook methodology. Central investigators, masked to clinical information other than stroke side, categorised baseline imaging features of ischaemic change with the Alberta Stroke Program Early CT Score (ASPECTS) or according to involvement of more than 33% of middle cerebral artery territory, and by thrombus volume, hyperdensity, and collateral status. The primary endpoint was neurological functional disability scored on the modified Rankin Scale (mRS) score at 90 days after randomisation. Safety outcomes included symptomatic intracranial haemorrhage, parenchymal haematoma type 2 within 5 days of randomisation, and mortality within 90 days. For the primary analysis, we used mixed-methods ordinal logistic regression adjusted for age, sex, National Institutes of Health Stroke Scale score at admission, intravenous alteplase, and time from onset to randomisation, and we used interaction terms to test whether imaging categorisation at baseline modifies the association between treatment and outcome. This meta-analysis was prospectively designed by the HERMES executive committee but has not been registered. Findings: Among 1764 pooled patients, 871 were allocated to the EVT group and 893 to the control group. Risk of bias was low except in the THRACE study, which used unblinded assessment of outcomes 90 days after randomisation and MRI predominantly as the primary baseline imaging tool. The overall treatment effect favoured EVT (adjusted common odds ratio [cOR] for a shift towards better outcome on the mRS 2·00, 95% CI 1·69–2·38; p<0·0001). EVT achieved better outcomes at 90 days than standard medical therapy alone across a broad range of baseline imaging categories. Mortality at 90 days (14·7% vs 17·3%, p=0·15), symptomatic intracranial haemorrhage (3·8% vs 3·5%, p=0·90), and parenchymal haematoma type 2 (5·6% vs 4·8%, p=0·52) did not differ between the EVT and control groups. No treatment effect modification by baseline imaging features was noted for mortality at 90 days and parenchymal haematoma type 2. Among patients with ASPECTS 0–4, symptomatic intracranial haemorrhage was seen in ten (19%) of 52 patients in the EVT group versus three (5%) of 66 patients in the control group (adjusted cOR 3·94, 95% CI 0·94–16·49; pinteraction=0·025), and among patients with more than 33% involvement of middle cerebral artery territory, symptomatic intracranial haemorrhage was observed in 15 (14%) of 108 patients in the EVT group versus four (4%) of 113 patients in the control group (4·17, 1·30–13·44, pinteraction=0·012). Interpretation: EVT achieves better outcomes at 90 days than standard medical therapy across a broad range of baseline imaging categories, including infarcts affecting more than 33% of middle cerebral artery territory or ASPECTS less than 6, although in these patients the risk of symptomatic intracranial haemorrhage was higher in the EVT group than the control group. This analysis provides preliminary evidence for potential use of EVT in patients with large infarcts at baseline. Funding: Medtronic

Extracorporeal Membrane Oxygenation for Severe Acute Respiratory Distress Syndrome associated with COVID-19: An Emulated Target Trial Analysis.

RATIONALE: Whether COVID patients may benefit from extracorporeal membrane oxygenation (ECMO) compared with conventional invasive mechanical ventilation (IMV) remains unknown. OBJECTIVES: To estimate the effect of ECMO on 90-Day mortality vs IMV only Methods: Among 4,244 critically ill adult patients with COVID-19 included in a multicenter cohort study, we emulated a target trial comparing the treatment strategies of initiating ECMO vs. no ECMO within 7 days of IMV in patients with severe acute respiratory distress syndrome (PaO2/FiO2 <80 or PaCO2 ≥60 mmHg). We controlled for confounding using a multivariable Cox model based on predefined variables. MAIN RESULTS: 1,235 patients met the full eligibility criteria for the emulated trial, among whom 164 patients initiated ECMO. The ECMO strategy had a higher survival probability at Day-7 from the onset of eligibility criteria (87% vs 83%, risk difference: 4%, 95% CI 0;9%) which decreased during follow-up (survival at Day-90: 63% vs 65%, risk difference: -2%, 95% CI -10;5%). However, ECMO was associated with higher survival when performed in high-volume ECMO centers or in regions where a specific ECMO network organization was set up to handle high demand, and when initiated within the first 4 days of MV and in profoundly hypoxemic patients. CONCLUSIONS: In an emulated trial based on a nationwide COVID-19 cohort, we found differential survival over time of an ECMO compared with a no-ECMO strategy. However, ECMO was consistently associated with better outcomes when performed in high-volume centers and in regions with ECMO capacities specifically organized to handle high demand. This article is open access and distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives License 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/)

Evaluation et optimisation de lʹacquisition et du post-traitement de lʹétude de la perfusion cérébrale par ʺ Arterial Spin Labeling ʺ

L étude de la perfusion cérébrale par marquage des protons artériels ou arterial spin labeling (ASL) est une technique IRM, qui utilise comme traceur endogène les protons du sang artériel marqués magnétiquement. Cette technique permet une quantification fiable et reproductible du débit sanguin cérébral sans injection de produit de contraste exogène ni rayonnement ionisant. Son principal inconvénient est son faible rapport signal-sur-bruit. Alors que cette technique devient disponible sur les IRM cliniques, l objectif de ce travail a été d évaluer et d optimiser l acquisition et le traitement des données ASL de séquences disponibles sur deux IRM 3T. Nous avons ainsi étudié l influence des paramètres hémodynamiques carotidiens sur le choix de paramètres de la séquences et nous avons montré l intérêt de l utilisation d une antenne 32 canaux et de l imagerie parallèle sur la qualité des cartographies. Au niveau du traitement des images, de nouvelles méthodes de débruitage spécifique des images ASL ont été étudiées et la mise en œuvre d une chaîne de traitement complète a permis la comparaison de l ASL fonctionnelle à l IRMf BOLD. Une approche Template a aussi été évaluée pour la détection de variations individuelles focales de la perfusion. Nous avons appliqué l ASL à la phase aiguë de l accident vasculaire constitué ischémique et dans un domaine où l ASL a été peu utilisée, la psychiatrie. Nos résultats ont montré que la conjonction des conditions optimales d acquisition et d un traitement optimisé des données devrait rendre plus pertinente l utilisation de l ASL dans le domaine de la recherche clinique mais aussi en routine clinique.Arterial spin labeling (ASL) is a magnetic resonance perfusion imaging technique for measuring cerebral blood flow (CBF) which uses magnetically labeled arterial blood water as an endogenous tracer. ASL is completely noninvasive and can be repeated because it is performed without injection of contrast media, or radiation exposure. Moreover, CBF quantification is convenient and reproducible. However ASL is a low signal-to-noise ratio measurement technique. This technique becomes available on clinical MRI scanner. In this context, the aim of this work was to assess and optimize the image acquisition and the data processing acquired with two clinical techniques. We have demonstrated a correlation between acquisition parameters and hemodynamic parameters and we showed a maps quality improving using 32-channel coil combined with parallel imaging. New denoising methods were implemented and an optimized complete workflow was used to compare fASL and BOLD fMRI. A template approach was also assessed to detect individual increased perfusion area. Clinically, we used ASL to detect hypoperfusion defect on acute ischemic stroke and focal perfusion abnormalities in patients with chronic and resistant depression. Our results showed that a combination of optimized conditions acquisition and dedicated processing could help ASL to be more accurate in clinical research and practice.RENNES1-BU Santé (352382103) / SudocSudocFranceF

Evaluation du risque hémorragique des fistules durales intracraniennes par ARM dynamique à 3 teslas (confrontation à l'artériographie)

RENNES1-BU Santé (352382103) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Variations anatomiques de la partie antérieure du cercle artériel du cerveau en angioscanner multidétecteur (comparaison à l'angiographie rotationnelle 3D)

L'angioscanner multi-détecteurs (AMD) est devenu l'examen de première ligne en cas d'hémorragie sous-arachnoïdienne, pour détecter les anévrysmes et déterminer la prise en charge thérapeutique en permettant notamment la détection des variations anatomiques. Le but de notre étude est d'évaluer l'AMD 64 barrettes (AMD 64) pour la détection et la caractérisation des variations de la circulation antérieure, par rapport à l'angiographie rotationnelle 3D (AR3D). Chez 104 patients, AMD et AR3D des artères carotides internes ont été relus à la recherche de variations sur la circulation antérieure. 114 variations sur 624 segments (18,3 %) ont été détectés en AMD et 90 sur 453 segments (19,9 %) en AR3D (p=0,56). 15 erreurs de caractérisation ont été notées ( >0,8). Sensibilité, spécificités, valeurs prédictives positive et négative étaient supérieurs à 90 %. Aucune différence significative entre AMD 64 et AR3D concernant la détection et la caractérisation des variations n'a été mise en évidence.Multidetector computed tomography angiography (MD-CTA) became the first-line screening technique in patient with subarachnoid hemorrhage for detecting aneurysms and to discuss the treatment method, in particular by detecting anatomic variations. The aim of our study was to assess the diagnostic performance of 64-section MD-CTA for detection and characterization of variations of the anterior circulation, compared with 3D rotational angiography (3DRA). In 104 patients, MD-CTA and 3DRA of internal carotid arteries were reviewed for the presence and location of variations. 114 variations in 624 segments (18,3 %) were detected with MD-CTA and 90 in 453 segments (19,9 %) with 3DRA (p=0,56). 15 cases in 453 segments were misclassified with MD-CTA ( >0,8). Sensitivity, specificity, positive an negative predictive values were above 90 %. No significant difference was found between 64-section MD-CTA an 3DRA about detection and characterization of variations in the anterior circulation.RENNES1-BU Santé (352382103) / SudocSudocFranceF

Etude qualitative de l'ARM dynamique à 3 TESLA (comparaison à l'artériographie)

RENNES1-BU Santé (352382103) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

IRM dans le suivi post-opératooire des ventriculo-cisternostomies endoscopiques (corrélation radio-clinique)

RENNES1-BU Santé (352382103) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Diagnostic value of fractal analysis for the differentiation of brain tumors using 3-Tesla magnetic resonance susceptibility-weighted imaging

BACKGROUND: Susceptibility-weighted imaging (SWI) of brain tumors provides information about neoplastic vasculature and intratumoral micro- and macrobleedings. Low- and high-grade gliomas can be distinguished by SWI due to their different vascular characteristics. Fractal analysis allows for quantification of these radiological differences by a computer-based morphological assessment of SWI patterns. OBJECTIVE: To show the feasibility of SWI analysis on 3-T magnetic resonance imaging to distinguish different kinds of brain tumors. METHODS: Seventy-eight patients affected by brain tumors of different histopathology (low- and high-grade gliomas, metastases, meningiomas, lymphomas) were included. All patients underwent preoperative 3-T magnetic resonance imaging including SWI, on which the lesions were contoured. The images underwent automated computation, extracting 2 quantitative parameters: the volume fraction of SWI signals within the tumors (signal ratio) and the morphological self-similar features (fractal dimension [FD]). The results were then correlated with each histopathological type of tumor. RESULTS: Signal ratio and FD were able to differentiate low-grade gliomas from grade III and IV gliomas, metastases, and meningiomas (P < .05). FD was statistically different between lymphomas and high-grade gliomas (P < .05). A receiver-operating characteristic analysis showed that the optimal cutoff value for differentiating low- from high-grade gliomas was 1.75 for FD (sensitivity, 81%; specificity, 89%) and 0.03 for signal ratio (sensitivity, 80%; specificity, 86%). CONCLUSION: FD of SWI on 3-T magnetic resonance imaging is a novel image biomarker for glioma grading and brain tumor characterization. Computational models offer promising results that may improve diagnosis and open perspectives in the radiological assessment of brain tumors.8 page(s

Distribution of Escherichia coli O157:H7 in ground beef: Assessing the clustering intensity for an industrial-scale grinder and a low and localized initial contamination

Undercooked ground beef is regularly implicated in food-borne outbreaks involving pathogenic Shiga toxin-producing Escherichia coli. The dispersion of bacteria during mixing processes is of major concern for quantitative microbiological risk assessment since clustering will influence the number of bacteria the consumers might get exposed to as well as the performance of sampling plans used to detect contaminated ground beef batches. In this study, batches of 25 kg of ground beef were manufactured according to a process mimicking an industrial scale grinding with three successive steps: primary grinding, mixing and final grinding. The ground beef batches were made with 100% of chilled trims or with 2/3 of chilled trims and 1/3 of frozen trims. Prior grinding, one beef trim was contaminated with approximately 10(6)-10(7) CFU of E. coli 0157:H7 on a surface of 0.5 cm(2) to reach a concentration of 10-100 cells/g in ground beef. The E. coli O157:H7 distribution in ground beef was characterized by enumerating 60 samples (20 samples of 5 g, 20 samples of 25 g and 20 samples of 100 g) and fitting a Poisson gamma model to describe the variability of bacterial counts. The shape parameter of the gamma distribution, also known as the dispersion parameter reflecting the amount of clustering, was estimated between 1.0 and 1.6. This k-value of approximately 1 expresses a moderate level of clustering of bacterial cells in the ground beef. The impact of this clustering on the performance of sampling strategies was relatively limited in comparison to the classical hypothesis of a random repartition of pathogenic cells in mixed materials (purely Poisson distribution instead of Poisson-gamma distribution)

Evaluating the reliability of cervical spine magnetization transfer imaging in the context of multicenter longitudinal studies

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