Fe-implanted ZnO: Magnetic precipitates versus dilution

Nowadays ferromagnetism is often found in potential diluted magnetic semiconductor systems. However, many authors argue that the observed ferromagnetism stems from ferromagnetic precipitates or spinodal decomposition rather than from carrier mediated magnetic impurities, as required for a diluted magnetic semiconductor. In the present paper we answer this question for Fe-implanted ZnO single crystals comprehensively. Different implantation fluences and temperatures and post-implantation annealing temperatures have been chosen in order to evaluate the structural and magnetic properties over a wide range of parameters. Three different regimes with respect to the Fe concentration and the process temperature are found: 1) Disperse Fe$^{2+}$ and Fe$^{3+}$ at low Fe concentrations and low processing temperatures, 2) FeZn$_2$O$_4$ at very high processing temperatures and 3) an intermediate regime with a co-existence of metallic Fe (Fe$^0$) and ionic Fe (Fe$^{2+}$ and Fe$^{3+}$). Ferromagnetism is only observed in the latter two cases, where inverted ZnFe$_2$O$_4$ and $\alpha$-Fe nanocrystals are the origin of the observed ferromagnetic behavior, respectively. The ionic Fe in the last case could contribute to a carrier mediated coupling. However, their separation is too large to couple ferromagnetically due to the lack of p-type carrier. For comparison investigations of Fe-implanted epitaxial ZnO thin films are presented.Comment: 14 pages, 17 figure

Prognostic significance of third ventricle blood volume in intracerebral haemorrhage with severe ventricular involvement

Background and purpose: Intraventricular haemorrhage (IVH) is an independent predictor of poor outcome in spontaneous intracerebral haemorrhage (ICH). Larger IVH volume and increasing number of affected ventricles have been associated with worse prognosis, however, little is known about the prognostic value of blood volume in the different parts of the ventricular system. Therefore, the correlation of IVH volume in the third, fourth and lateral ventricles with outcome in patients with ICH and severe IVH, treated with intraventricular fibrinolysis (IVF), was investigated. Methods: Patients with ICH <40 ml, severe IVH and acute hydrocephalus were treated with IVF. The course of IVH volume for each ventricle was measured by CT based volumetry. Outcome at 90 days was assessed by a telephone follow-up survey and correlated with initial IVH volume. Results: 50 patients aged 62.5±10.3 years with spontaneous ICH (12.5±10.8 ml) and severe IVH (33.5±25 ml) were included. Clearance of the third and fourth ventricle from blood occurred after 3±1.9 days. Initial IVH volume in the third ventricle (3.8±3.3 ml) was predictive for poor outcome (OR 2.6 per ml, p=0.02). Correlation between larger IVH volume in the fourth ventricle and poor outcome showed a trend towards significance (p=0.07). Total IVH volume and lateral ventricle IVH volume were not correlated with outcome. Conclusion: Despite rapid clot removal, initial IVH volume in the third ventricle was a strong and independent negative predictor. This is possibly explained by irreversible damage of brainstem structures by the initial mass effect of IVH

Quantitative Corticospinal Tract Assessment in Acute Intracerebral Hemorrhage

Abstract Intracerebral hemorrhage (ICH) prognostication during the acute phase is often subjective among physicians and often affects treatment decisions. The present study explores objective imaging parameters using quantitative corticospinal tract (CST) fiber reconstruction during the acute phase of ICH and correlates these parameters with functional outcome and patient recovery. We prospectively enrolled nonsurgical spontaneous supratentorial ICH patients and obtained an MRI scan on day 5 ± 1. Q-space diffeomorphic reconstruction was performed using DSI Studio, and quantitative anisotropy (QA) was calculated. The CST was reconstructed based on QA. The dichotomized modified Rankin Scale score on day 90 (favorable outcome = 0–2) and Barthel Index (favorable recovery = 100 on day 90 or improvement between discharge and day 90 > 60%) were assessed. Thirty-three patients, median age 72 years (interquartile range (IQR) 64–83), 21 female (64%), 21 (64%) with lobar hemorrhage, median ICH volume on admission 15.0 (IQR 7.0–27.4) mL, were included. Sixteen patients (48%) had a favorable outcome and 24 (73%) had a favorable recovery. The mean number of ipsilesional reconstructed CST fiber pathways was higher in patients with favorable outcomes (153 (standard deviation (SD) 103) vs. 60 (SD 39), p = 0.003) and predicted outcome after adjustment (Exp(B) = 1.016 (95% CI = 1.002–1.030)). QA in the ipsilesional posterior limb of the internal capsule showed a trend towards an association with favorable outcome (Exp(B) = 1.194 (95% CI = 0.991–1.439 (adjusted))). The total (ipsilesional + contralesional) number of reconstructed fiber pathways was associated with favorable recovery (Exp(B) = 1.025 (95% CI = 1.003–1.047 (adjusted))). Quantitative tractography parameters assessed in the acute phase of ICH may represent a promising predictor of long-term outcome and recovery. This might facilitate prognostic evaluation and organization of rehabilitation

Neutrophil-to-lymphocyte ratio is associated with increased cerebral blood flow velocity in acute bacterial meningitis

In community-acquired bacterial meningitis (CABM) intracranial vascular alterations are devastating complications which are triggered by neuroinflammation and result in worse clinical outcome. The Neutrophil-to-Lymphocyte ratio (NLR) represents a reliable parameter of the inflammatory response. In this study we analyzed the association between NLR and elevated cerebral blood flow velocity (CBFv) in CABM-patients. This study included all (CABM)-patients admitted to a German tertiary center between 2006 and 2016. Patients’ demographics, in-hospital measures, neuroradiological data and clinical outcome were retrieved from institutional databases. CBFv was assessed by transcranial doppler (TCD). Patients’, radiological and laboratory characteristics were compared between patients with/without elevated CBFv. Multivariate-analysis investigated parameters independently associated with elevated CBFv. Receiver operating characteristic(ROC-)curve analysis was undertaken to identify the best cut-off for NLR to discriminate between increased CBFv. 108 patients with CABM were identified. 27.8% (30/108) showed elevated CBFv. Patients with elevated CBFv and normal CBFv, respectively had a worse clinical status on admission (Glasgow Coma Scale: 12 [9–14] vs. 14 [11–15]; p = 0.005) and required more often intensive care (30/30 [100.0%] vs. 63/78 [80.8%]; p = 0.01).The causative pathogen was S. pneumoniae in 70%. Patients with elevated CBFv developed more often cerebrovascular complications with delayed cerebral ischemia (DCI) within hospital stay (p = 0.031). A significantly higher admission-NLR was observed in patients with elevated CBFv (median [IQR]: elevated CBFv:24.0 [20.4–30.2] vs. normal CBFv:13.5 [8.4–19.5]; p  20.9 15/78[19.2%]; p < 0.001). Intracranial vascular complications are common among CABM-patients and are a risk factor for unfavorable outcome at discharge. Elevated NLR is independently associated with high CBFv and may be useful in predicting patients’ prognosis

Influence of Early Enteral Nutrition on Clinical Outcomes in Neurocritical Care Patients With Intracerebral Hemorrhage

Objective: Early enteral nutrition (EEN) represents the current standard of care for patients treated in general intensive care units (ICU). Specific nutritional recommendations for patients receiving dedicated neurocritical care are not established. This study investigated associations of EEN with clinical outcomes for patients suffering from intracerebral hemorrhage treated at a neurological ICU (NICU). Methods: This retrospective cohort study included patients admitted to the NICU with atraumatic ICH over a 4-year period. Nutritional data, demographic, clinical, radiological, and laboratory characteristics were assessed. EEN was defined as any enteral nutrition within 48 hours after admission. Comparisons were undertaken for patients with EEN vs. those without, further propensity score (PS) matching (caliper 0.2; one: many) was used to account for baseline imbalances. Primary outcome was the modified Rankin Scale (0–3 = favorable, 4–6 = unfavorable) at 12 months, secondary outcomes comprised perihemorrhagic edema (PHE) volume, infectious complications during the hospital stay, and mRS at 3 months, as well as mortality rates at 3 and 12 months. Results: Of 166 ICH-patients treated at the NICU, 51 (30.7%) patients received EEN, and 115 (69.3%) patients received no EEN (nEEN). After propensity score matching, calories delivered from enteral nutrition (EEN 161.4 [106.4–192.3] kcal/day vs. nEEN 0.0 [0.0–0.0], P < 0.001) and the total calories (EEN 190.0 [126.0–357.0] kcal/day vs. nEEN 33.6 [0.0–190.0] kcal/day, P < 0.001) were significantly different during the first 48 h admitted in NICU. Functional outcome at 12 months (mRS 4–6, EEN 33/43 [76.7%] vs. nEEN, 49/64 [76. 6%]; P = 1.00) was similar in the two groups. There were neither differences in mRS at 3 months, nor in mortality rates at 3 and 12 months between the two groups. EEN did not affect incidence of infective complications or gastrointestinal adverse events during the hospital stay; however, EEN was associated with significantly less extent of PHE evolution [maximum absolute PHE (OR 0.822, 95% CI 0.706–0.957, P = 0.012); maximum relative PHE (OR 0.784, 95% CI 0.646–0.952, P = 0.014)]. Conclusion: In our study, EEN was associated with reduced PHE in ICH-patients treated at a NICU. However, this observation did not translate into improved survival or functional outcome at 3 and 12 months

Etiology, 3-Month Functional Outcome and Recurrent Events in Non-Traumatic Intracerebral Hemorrhage.

BACKGROUND AND PURPOSE Knowledge about different etiologies of non-traumatic intracerebral hemorrhage (ICH) and their outcomes is scarce. METHODS We assessed prevalence of pre-specified ICH etiologies and their association with outcomes in consecutive ICH patients enrolled in the prospective Swiss Stroke Registry (2014 to 2019). RESULTS We included 2,650 patients (mean±standard deviation age 72±14 years, 46.5% female, median National Institutes of Health Stroke Scale 8 [interquartile range, 3 to 15]). Etiology was as follows: hypertension, 1,238 (46.7%); unknown, 566 (21.4%); antithrombotic therapy, 227 (8.6%); cerebral amyloid angiopathy (CAA), 217 (8.2%); macrovascular cause, 128 (4.8%); other determined etiology, 274 patients (10.3%). At 3 months, 880 patients (33.2%) were functionally independent and 664 had died (25.1%). ICH due to hypertension had a higher odds of functional independence (adjusted odds ratio [aOR], 1.33; 95% confidence interval [CI], 1.00 to 1.77; P=0.05) and lower mortality (aOR, 0.64; 95% CI, 0.47 to 0.86; P=0.003). ICH due to antithrombotic therapy had higher mortality (aOR, 1.62; 95% CI, 1.01 to 2.61; P=0.045). Within 3 months, 4.2% of patients had cerebrovascular events. The rate of ischemic stroke was higher than that of recurrent ICH in all etiologies but CAA and unknown etiology. CAA had high odds of recurrent ICH (aOR, 3.38; 95% CI, 1.48 to 7.69; P=0.004) while the odds was lower in ICH due to hypertension (aOR, 0.42; 95% CI, 0.19 to 0.93; P=0.031). CONCLUSIONS Although hypertension is the leading etiology of ICH, other etiologies are frequent. One-third of ICH patients are functionally independent at 3 months. Except for patients with presumed CAA, the risk of ischemic stroke within 3 months of ICH was higher than the risk of recurrent hemorrhage

Telemedizin in der Schlaganfallversorgung – versorgungsrelevant für Deutschland

Background and objective Telemedical stroke networks improve stroke care and provide access to time-dependent acute stroke treatment in predominantly rural regions. The aim is a presentation of data on its utility and regional distribution. Methods The working group on telemedical stroke care of the German Stroke Society performed a survey study among all telestroke networks. Results Currently, 22 telemedical stroke networks including 43 centers (per network: median 1.5, interquartile range, IQR, 1–3) as well as 225 cooperating hospitals (per network: median 9, IQR 4–17) operate in Germany and contribute to acute stroke care delivery to 48 million people. In 2018, 38,211 teleconsultations (per network: median 1340, IQR 319–2758) were performed. The thrombolysis rate was 14.1% (95% confidence interval 13.6–14.7%) and transfer for thrombectomy was initiated in 7.9% (95% confidence interval 7.5–8.4%) of ischemic stroke patients. Financial reimbursement differs regionally with compensation for telemedical stroke care in only three federal states. Conclusion Telemedical stroke care is utilized in about 1 out of 10 stroke patients in Germany. Telemedical stroke networks achieve similar rates of thrombolysis and transfer for thrombectomy compared with neurological stroke units and contribute to stroke care in rural regions. Standardization of network structures, financial assurance and uniform quality measurements may further strengthen the importance of telestroke networks in the future.Hintergrund und Ziel Telemedizinische Schlaganfall-Netzwerke tragen dazu bei, die Schlaganfallversorgung und insbesondere den Zugang zu zeitkritischen Schlaganfalltherapien in vorrangig strukturschwachen, ländlichen Regionen zu gewährleisten. Ziel ist eine Darstellung der Nutzungsfrequenz und regionalen Verteilung dieser Versorgungsstruktur. Methoden Die Kommission „Telemedizinische Schlaganfallversorgung“ der Deutschen Schlaganfall-Gesellschaft führte eine Umfragestudie in allen Schlaganfall-Netzwerken durch. Ergebnisse In Deutschland sind 22 telemedizinische Schlaganfall-Netzwerke aktiv, welche insgesamt 43 Zentren (pro Netzwerk: Median 1,5, Interquartilsabstand [IQA] 1–3) sowie 225 Kooperationskliniken (pro Netzwerk: Median 9, IQA 4–17) umfassen und an einem unmittelbaren Zugang zur Schlaganfallversorgung für 48 Mio. Menschen teilhaben. Im Jahr 2018 wurden 38.211 Telekonsile (pro Netzwerk: Median 1340, IQA 319–2758) durchgeführt. Die Thrombolyserate betrug 14,1 % (95 %-Konfidenzintervall 13,6–14,7 %), eine Verlegung zur Thrombektomie wurde bei 7,9 % (95 %-Konfidenzintervall 7,5–8,4 %) der ischämischen Schlaganfallpatienten initiiert. Das Finanzierungssystem ist uneinheitlich mit einem Vergütungssystem für die Zentrumsleistungen in nur drei Bundesländern. Diskussion Etwa jeder 10. Schlaganfallpatient wird telemedizinisch behandelt. Die telemedizinischen Schlaganfall-Netzwerke erreichen vergleichbar hohe Lyseraten und Verlegungen zur Thrombektomie wie neurologische Stroke-Units und tragen zur Sicherstellung einer flächendeckenden Schlaganfallversorgung bei. Eine netzwerkübergreifende Sicherstellung der Finanzierung und einheitliche Erhebung von Qualitätssicherungsdaten haben das Potenzial diese Versorgungsstruktur zukünftig weiter zu stärken

Absolute risk and predictors of the growth of acute spontaneous intracerebral haemorrhage: a systematic review and meta-analysis of individual patient data.

Background Intracerebral haemorrhage growth is associated with poor clinical outcome and is a therapeutic target for improving outcome. We aimed to determine the absolute risk and predictors of intracerebral haemorrhage growth, develop and validate prediction models, and evaluate the added value of CT angiography. Methods In a systematic review of OVID MEDLINE—with additional hand-searching of relevant studies' bibliographies— from Jan 1, 1970, to Dec 31, 2015, we identified observational cohorts and randomised trials with repeat scanning protocols that included at least ten patients with acute intracerebral haemorrhage. We sought individual patient-level data from corresponding authors for patients aged 18 years or older with data available from brain imaging initially done 0·5–24 h and repeated fewer than 6 days after symptom onset, who had baseline intracerebral haemorrhage volume of less than 150 mL, and did not undergo acute treatment that might reduce intracerebral haemorrhage volume. We estimated the absolute risk and predictors of the primary outcome of intracerebral haemorrhage growth (defined as >6 mL increase in intracerebral haemorrhage volume on repeat imaging) using multivariable logistic regression models in development and validation cohorts in four subgroups of patients, using a hierarchical approach: patients not taking anticoagulant therapy at intracerebral haemorrhage onset (who constituted the largest subgroup), patients taking anticoagulant therapy at intracerebral haemorrhage onset, patients from cohorts that included at least some patients taking anticoagulant therapy at intracerebral haemorrhage onset, and patients for whom both information about anticoagulant therapy at intracerebral haemorrhage onset and spot sign on acute CT angiography were known. Findings Of 4191 studies identified, 77 were eligible for inclusion. Overall, 36 (47%) cohorts provided data on 5435 eligible patients. 5076 of these patients were not taking anticoagulant therapy at symptom onset (median age 67 years, IQR 56–76), of whom 1009 (20%) had intracerebral haemorrhage growth. Multivariable models of patients with data on antiplatelet therapy use, data on anticoagulant therapy use, and assessment of CT angiography spot sign at symptom onset showed that time from symptom onset to baseline imaging (odds ratio 0·50, 95% CI 0·36–0·70; p<0·0001), intracerebral haemorrhage volume on baseline imaging (7·18, 4·46–11·60; p<0·0001), antiplatelet use (1·68, 1·06–2·66; p=0·026), and anticoagulant use (3·48, 1·96–6·16; p<0·0001) were independent predictors of intracerebral haemorrhage growth (C-index 0·78, 95% CI 0·75–0·82). Addition of CT angiography spot sign (odds ratio 4·46, 95% CI 2·95–6·75; p<0·0001) to the model increased the C-index by 0·05 (95% CI 0·03–0·07). Interpretation In this large patient-level meta-analysis, models using four or five predictors had acceptable to good discrimination. These models could inform the location and frequency of observations on patients in clinical practice, explain treatment effects in prior randomised trials, and guide the design of future trials

Inflammation, edema, hematoma and etiology - a rectangular relationship?

It was with great interest that we read the publication by Iglesias-Rey et al. [1], who found an association of elevated body temperature with perihemorrhagic edema (PHE) evolution exclusively in hypertension-related intracerebral hemorrhage (ICH). In accordance with pathophysiologic findings, others found an independent association of PHE evolution with inflammatory parameters including fever in ICH without further etiological differentiation [2,3]. Etiological classification of ICH may be challenging. Classifying patients with several identified etiological factors as unknown may pose possible bias. Identifying cerebral amyloid angiopathy (CAA)related ICH may require specific criteria and possibly further diagnostic testing [4,5]. A detailed description would be helpful. Furthermore, a larger sample size may be necessary to detect mechanisms related to PHE evolution in subgroups of ICH patients (e.g. CAA-related) due to the complex pathophysiological processes associated with PHE [2,3,6]. Here, ICH volume in particular and related measures are considered to be a major factor contributing to PHE evolution [6,7]. Thus, it is important to adjust analyses correlating PHE with other variables for ICH volume to assess independent associations. Delineation of PHE may be difficult on computed tomography scans. Although volumetric assessments using the ABC/2 formula may be considered when analysing hematoma volumes [8], validated algorithms are recommended in PHE assessment [9,10]. Although increasing evidence supports the association of inflammation and temperature with PHE evolution, further research is required to elucidate the complex interaction between inflammation, edema, hematoma and etiology