1,721,039 research outputs found
SOP: thrombolysis in ischemic stroke under oral anticoagulation therapy
No full textAbstract Introduction Based on demographical trends and the expected worldwide increase in the number of individuals with atrial fibrillation, the rate of patients who are on oral anticoagulation therapy for secondary prevention of stroke rises continuously. Despite correct drug intake and good adherence to the respective medication, recurrent ischemic stroke still occurs in ~ 3% of patients. The question how to deal with such patients with regard to intravenous thrombolysis with rt-PA within the 4.5 h time window is of great relevance for daily clinical routine. However, international guidelines can be considered heterogenous or do even lack recommendations on this topic especially in light of available reversal agents. Therefore, we provide this SOP. Comments Beyond the identification of acute stroke patients on oral anticoagulation therapy, the type of medication, time since last intake, renal function and laboratory exams as well as the availability of reversal agents have to be considered before rt-PA application and potential endovascular therapy. Treatment on a Stroke Unit or Neuro-ICU is certainly recommended in any of those patients. Conclusions This standardized operating procedure was designed to guide stroke physicians through questions on eligibility for rt-PA treatment in patients with acute ischemic stroke who are on approved oral anticoagulation therapy thereby increasing the number of patients benefitting from thrombolysis and minimizing door-to-needle times
The similarity of brain morphology in healthy monozygotic twins
No full textAim of the study was to investigate the degree of similarity of twin brains with respect to their outer shape and gyrification. High resolution MRI was obtained from 26 healthy monozygotic twins (MZ) and three-dimensional renderings of the brains were generated. Similarity was rated by human investigators and by computer analysis. Three different image types were analyzed: whole-brain views, silhouettes and a bird's-eye view of a segment showing the central region. For each of the three image types, 13 tasks (identifying the related twin-pair out of a set of five brains) had to be solved by the human raters. For whole brain, views and silhouettes 66/91 (p < 0.005) and for segment views 44/91 (p < 0.02) correct identifications were made. Using cross correlation coefficients, the computer-based analysis as well significantly often identified related twins. Again correct identification was more likely based on whole-brain views and silhouettes than on segment views of the central region. In conclusion, we found that overall brain shape is probably strongly influenced by genetic effects but the variation in sulcal and gyral patterns is also affected by non-genetic influences to a considerable extent. (C) 2004 Elsevier B.V. All rights reserved
The treatment of cochleovestibular incidents after diving
No full textBackground. There has been a steady increase of recreational scuba divers in the last years. The majority of diving associated diseases involve otorhinolaryngology, the most important of which are cochleovestibular dysfunctions as these can lead to permanent inner ear failure. Material and methods. We discuss the origin and clinical symptoms, as well as the therapy, of both inner ear barotrauma and inner ear decompression illness. Our own experiences are considered together with a review of the literature from the last decade. Results. Inner ear decompression illness seems to be a relatively common diving associated incident and is not as rare as previously thought. Discussion. Hyperbaric oxygen therapy is the treatment of choice for patients with inner ear decompression sickness, but is contraindicated in patients with inner ear barotrauma. As long as an inner ear decompression illness can not be ruled out, we suggest that every patient should be treated using hyperbaric oxygen therapy but only after bilateral paracentesis
Microhemorrhages in nonfatal high-altitude cerebral edema
No full textVasogenic edema in the corpus callosum is a characteristic finding in high-altitude cerebral edema (HACE). Furthermore, microhemorrhages have been found at autopsies in brains of HACE victims. The objective of this study was to determine if microhemorrhages also occur in nonlethal HACE. Consequently, magnetic resonance imaging (MRI) was performed in patients who had suffered from HACE and in patients who had suffered from severe acute mountain sickness (AMS) by applying imaging techniques highly susceptible to blood or blood remnants. Two experienced neuroradiologists independently evaluated the exams blinded to clinical data. The MRI was performed 2 to 31 months after the event. The MRI of the HACE patients revealed multiple hemosiderin depositions in the brain-predominantly found in the corpus callosum-indicative of microhemorrhages. These changes were not present in the three AMS patients. In summary, hemosiderin deposits detectable by MRI predominantly in the corpus callosum indicate that microhemorrhages occur in nonlethal HACE, which may serve as a novel diagnostic MRI sign for HACE even many months after the event
Comparison of perfusion computed tomography and computed tomography angiography source images with perfusion-weighted imaging and diffusion-weighted Imaging in patients with acute stroke of less than 6 hours' duration
No full textBackground and Purpose - We aimed to determine the diagnostic value of perfusion computed tomography (PCT) and CT angiography (CTA) including CTA source images (CTA-SI) in comparison with perfusion-weighted magnetic resonance imaging (MRI) (PWI) and diffusion-weighted MRI (DWI) in acute stroke <6 hours. Methods - Noncontrast-enhanced CT, PCT, CTA, stroke MRI, including PWI and DWI, and MR angiography (MRA), were performed in patients with symptoms of acute stroke lasting <6 hours. We analyzed ischemic lesion volumes on patients' arrival as shown on NECT, PCT, CTA-SI, DWI, and PWI ( Wilcoxon, Spearman, Bland - Altman) and compared them to the infarct extent as shown on day 5 NECT. Results - Twenty-two stroke patients underwent CT and MRI scanning within 6 hours. PCT time to peak (PCT-TTP) volumes did not differ from PWI-TTP ( P = 0.686 for patients who did not undergo thrombolysis/P = 0.328 for patients who underwent thrombolysis), nor did PCT cerebral blood volume (PCT-CBV) differ from PWI-CBV ( P = 0.893/ P = 0.169). CTA-SI volumes did not differ from DWI volumes ( P = 0.465/ P = 0.086). Lesion volumes measured in PCT maps significantly correlated with lesion volumes on PWI ( P = 0.0047, r = 1.0/ P = 0.0019, r = 0.897 for TTP; P = 0.0054, r = 0.983/P = 0.0026, r = 0.871 for CBV). Also, PCT-CBV lesion volumes significantly correlated with follow-up CT lesion volumes ( P = 0.0047, r = 1.0/ P = 0.0046, r = 0.819). Conclusions - In hyperacute stroke, the combination of PCT and CTA can render important diagnostic information regarding the infarct extent and the perfusion deficit. Lesions on PCT-TTP and PCT-CBV do not differ from lesions on PWI-TTP and PWI-CBV; lesions on CTA source images do not differ from lesions on DWI. The combination of noncontrast-enhanced CT ( NECT), perfusion CT ( PCT), and CT angiography ( CTA) can render additional information within <15 minutes and may help in therapeutic decision-making if PWI and DWI are not available or cannot be performed on specific patients
Perfusion CT in Hyperacute Cerebral Hemorrhage Within 3 Hours after Symptom Onset: Is There an Early Perihemorrhagic Penumbra?
No full textINTRODUCTION In the recent years numerous studies have been undertaken to study cerebral perfusion in the surrounding of intracerebral hemorrhage, addressing the question of whether there is a secondary ischemic damage. Most of these studies found a reduced perfusion adjacent to the hematoma. However, the meaning of these findings remains controversial. METHODS We used perfusion computed tomography in 17 patients to study time to peak, cerebral blood flow, and cerebral blood volume as markers of the perihemorrhagic perfusion within 3 hours after symptom onset to search for an early difference between the extent of edema and reduced perfusion. RESULTS All patients showed a significant reduction of all perfusion parameters in the perihemorrhagic area, while there was no difference between the latitude of the reduced perfusion and the edema. CONCLUSION We did not find a difference between the extension of edema and that of restricted perfusion at a very early time point and therefore could not identify any tissue at risk of ischemia. Our findings suggest reduced perfusion and edema to have a common cause rather than presupposing one another
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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