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Background Identifying the cause of non-traumatic coma in the emergency department is challenging. The clinical neurological examination is the most readily available tool to detect focal neurological deficits as indicators for cerebral causes of coma. Previously proposed clinical pathways have granted the interpretation of clinical findings a pivotal role in the diagnostic work-up. We aimed to identify the actual diagnostic reliability of the neurological examination with regard to identifying acute brain damage. Methods Eight hundred and fifty-three patients with coma of unknown etiology (CUE) were examined neurologically in the emergency department following a predefined routine. Coma-explaining pathologies were identified retrospectively and grouped into primary brain pathology with proof of acute brain damage and other causes without proof of acute structural pathology. Sensitivity, specificity and percentage of correct predictions of different examination protocols were calculated using contingency tables and binary logistic regression models. Results The full neurological examination was 74% sensitive and 60% specific to detect acute structural brain damage underlying CUE. Sensitivity and specificity were higher in non-sedated patients (87/61%) compared to sedated patients (64%/59%). A shortened four-item examination protocol focusing on pupils, gaze and pyramidal tract signs was only slightly less sensitive (67%) and more specific (65%). Conclusions Due to limited diagnostic reliability of the physical examination, the absence of focal neurological signs in acutely comatose patients should not defer from a complete work-up including brain imaging. In an emergency, a concise neurological examination should thus serve as one part of a multimodal diagnostic approach to CUE.

Koma unklarer Genese („coma of unknown origin“, CUO) ist ein haufiges unspezifisches Notfallleitsymptom mit hoher Mortalitat. Die Diagnostik steht unter Zeitdruck bei einem gleichzeitig breiten Spektrum moglicher zugrunde liegender Erkrankungen mit ca. 50 % primaren ZNS-Pathologien und ca. 50 % extrazerebralen, fast ausschlieslich internistischen Ursachen. Trotz der mit dem Leitsymptom assoziierten hohen Mortalitat gibt es keine verbindlichen Leitlinien fur das Akutmanagement erwachsener CUO-Patienten. Wir schlagen einen interdisziplinaren Voralarm fur CUO-Patienten vor, wie wir ihn an unserem Klinikum der Maximalversorgung etabliert haben. Der Alarm wird anhand einfacher, aber fur die praklinische Identifikation von CUO ausreichender Triagekriterien bereits vor Eintreffen des Patienten ausgelost. Die fachliche Fuhrung liegt bei der Neurologie. Die Behandlungsroutine beinhaltet eine strukturierte Interaktion mit Pflege, innerer Medizin, Anasthesie, Radiologie (CT, CTA) und Labor (inkl. Liquor, Toxikologie) mit fakultativer Hinzuziehung von Neurochirurgie und Traumatologie. Die von uns erhobenen Daten sprechen fur ein standardisiertes leitsymptombasiertes diagnostisches Management, das die Neurologie und innere Medizin an den Anfang des diagnostischen Vorgehens stellt. Bildgebende Diagnostik sollte nicht nur abhangig von der klinisch-syndromalen Zuordnung erfolgen, weil Sensitivitat, Spezifitat und Interrater-Variabilitat Letzterer nicht ausreichen und mehrfache Pathologien, die auch einzeln CUO erklaren konnten, haufig sind. Klinische Untersuchung, Bildgebung und Laboruntersuchungen sollten als Bausteine eines integrativen diagnostischen Ansatzes gesehen werden, in dem die atiologische Zuordnung erst nach kompletter diagnostischer Aufarbeitung erfolgen sollte.

Background: Vascular hyperintensities of brain-supplying arteries on stroke FLAIR MRI are common and represent slow flow or stasis. FLAIR vascular hyperintensities (FVH) are discussed as an independent marker for cerebral hypoperfusion, but the impact on infarct size and clinical outcome in acute stroke patients is controversial. This study evaluates the association of FVH with infarct morphology, clinical stroke severity and infarct growth in patients with symptomatic internal carotid artery (ICA) or middle cerebral artery (MCA) occlusion. Methods: MR images of 84 patients [median age 73 years (IQR 65–80), 56.0% male, median NIHSS 7 (IQR 3–13)] with acute stroke due to symptomatic ICA or MCA occlusion or stenosis were reviewed. Vessel occlusions were identified by MRA time of flight and graded with the TIMI score. Diffusion and perfusion deficit volumes on admission and FLAIR lesion volumes on discharge were assessed. The presence and number of FVH were evaluated according to MCA-ASPECT areas, and associations with MR volumes, morphology of infarction, recanalization status, presence of white matter disease and hemorrhagical transformation as well as with stroke severity (NIHSS), stroke etiology and thrombolysis rate were analyzed. Results: FVH were detectable in 75 (89.3%) patients. The median number of FVH was 4 (IQR 2–7). Patients with FVH >4 presented with more severe strokes due to NIHSS (p = 0.021), had larger initial DWI lesions (p = 0.008), perfusion deficits (p = 0.001) and mismatch volumes/ratios (p = 0.005). The final infarct volume was larger (p = 0.005), and hemorrhagic transformation was more frequent (p = 0.029) in these patients. Conclusions: The presence of FVH indicates larger ischemic areas in brain parenchyma predominantly caused by proximal anterior circulation vessel occlusion. A high count of FVH might be a further surrogate marker for initial ischemic mismatch and stroke severity.

The aim of this study was to test the feasibility of vessel size imaging with precise evaluation of apparent diffusion coefficient and cerebral blood volume and to apply this novel technique in acute stroke patients within a pilot group to observe the microvascular responses in acute ischemic tissue. Microvessel density-related quantity Q and mean vessel size index ( VSI) were assessed in 9 healthy volunteers and 13 acute stroke patients with vessel occlusion within 6hours after symptom onset. Our results in healthy volunteers matched with general anatomical observations. Given the limitation of a small patient cohort, the median VSI in the ischemic area was higher than that in the mirrored region in the contralateral hemisphere ( P < 0.05). Decreased Q was observed in the ischemic region in 2 patients, whereas no obvious changes of Q were found in the remaining 11 patients. In a patient without recanalization, the VSI hyperintensity in the subcortical area matched well with the final infarct. These data reveal that different observations of microvascular response in the acute ischemic tissue seem to emerge and vessel size imaging may provide useful information for the definition of ischemic penumbra and have an impact on future therapeutic approaches.

Background: The MRI-based mismatch concept has been used to estimate the risk of infarction in ischemic stroke. Based on multiple studies on magnetic resonance perfusion imaging, it seems unlikely that any perfusion parameter threshold will provide a reliable prediction of radiological or clinical outcome for all patients. The goal of our study was to find a minimally biased yet maximally useful perfusion postprocessing protocol which would offer the treating physician a useful estimate of tissue fate. Methods: One hundred and forty-five acute ischemic stroke patients, admitted within 24 h after stroke to the Charité – University Medicine Hospital in Berlin between March 2008 and November 2009, were included in this study. Using three different software packages (Perfscape/Neuroscape, PMA and Stroketool), maps of mean transit time, cerebral blood flow (CBF) and Tmax were created. Three different thresholds were applied on each parameter map and subsequent volumes of hypoperfused tissue were calculated. Results: Overall, the maps and thresholds giving the least amount of overestimation of the final infarct volume were Tmax 8 s in Perfscape/Neuroscape, CBF 20 ml/100 g/min in PMA and CBF 15% (of the highest value on the scale for a given patient) in Stroketool. In patients with persistent vessel occlusion, a CBF map with a restrictive threshold showed volumes of tissue at definite risk of infarction in up to 100% of patients. The additional use of a CBF map with a high threshold enabled identification of patients without penumbras. Conclusions: No combination of software, map and threshold was able to give a reliable estimate of tissue fate for either all patients or any subgroup of patients. However, in patients with vessel occlusion, combination of a CBF map with a low and a high threshold can enable calculation of the minimum volume of brain tissue that will inevitably be lost if the occlusion persists.

Background: Randomized controlled clinical trials are the gold standard for scientific evaluation of clinical diagnostic and treatment concepts. Frequently, recruitment of participants is slower than expected, especially in acute conditions with a short time frame for inclusion. Simple prediction models have been proposed to extrapolate recruitment rates. We hypothesized a significant overestimation of recruitment when ignoring interdependence of selection criteria, leading to an insufficient representation of reality by available models. We proposed that slight modifications to inclusion criteria might augment recruitment without causing selection bias. Methods: We analyzed recruitment in an acute intervention trial of acute ischemic stroke initiated by our facility. Frequencies of selection criteria were recorded and analyzed individually as well as cumulatively. We then amended the trial protocol by moderate modifications to the selection criteria. The main outcome criterion was the rate of recruited over screened patients, with the goal of increasing recruitment fourfold without adding unacceptable selection bias. A previously presented prediction model was applied to our trial and compared with actual recruitment. Data were compared between screening periods at recruitment prior to and after the implementation of the amendments. Results: The impact of typical as well as novel inclusion criteria such as age limits, imaging-based definition of pathology, time between onset and presentation as well as inability to consent were quantified. Age restriction, definition of index event and late arrival after ictus were identified as the most challenging modifiable selection criteria. Amending those criteria increased recruitment by a factor of 4.1. Inability to consent was a significant exclusion criterion gaining impact with the target population. The selection criteria had a cumulative rather than separate recruitment-limiting impact. A previously presented model did not predict recruitment sufficiently. Conclusion: We describe frequencies of selection criteria in a typical cohort of patients suffering from acute cerebrovascular events, and their cumulative impact. These data may help to better understand recruitment limitations and allow designing future trials more effectively. Ability to consent especially is a major contributor to trial exclusion, strongly interfering with the targeted trial population of ischemic stroke. Tentative prescreening phases before site or trial initiation should be considered. No predictive statistical models of recruitment have been established so far.

The burden of cerebrovascular disease (CVD) is huge and therapeutic options are limited. Physical activity is effective in preventing coronary heart and peripheral artery disease both experimentally and clinically. It is likely that the protective effects of exercise can be extended to both CVD and cognitive impairment. The pleiotropic protective and preventive mechanisms induced by physical activity include increased perfusion as well as mechanisms of collateral recruitment and neovascularization mediated by arterio- and angiogenesis. Physical activity increases the bioavailability of nitric oxide, bone marrow-derived CD34+ cells and growth factors, all of which promote neovascularization. Additionally, shear stress is discussed as a potential mechanism for vessel growth. Moreover, physical activity plays a role in endothelial function and cerebral autoregulation in small- and large-artery CVD. The vascular niche hypothesis highlights the complex interactions of neuro- and angiogenesis for regenerative and repair mechanisms in the human brain. Experimental and clinical studies demonstrate the positive impact of prior physical activity on stroke lesion size and on outcome after stroke. Clinical trials are necessary to further address the impact of physical activity on primary and secondary stroke prevention, outcome and cognitive function.

Objectives: Vessel size imaging is a novel technique to evaluate pathological changes of the microvessel density quantity Q and the mean vessel size index (VSI). As a follow-up study, we assessed these parameters for microscopic description of ischemic penumbra and their potentials in predicting lesion growth. Methods: Seventy-five patients with a perfusion-diffusion mismatch were examined within 24 h from symptom onset. We defined three regions of interest: the initial infarct (INF), the ischemic penumbra (IPE), and the healthy region (HEA) symmetric to the IPE. For 23 patients with a 6th-day follow-up, IPE regions were divided into areas of infarct growth and areas of oligemia. Result: The median values of Q and VSI were: for INF 0.29 s-1/3 and 15.8 µm, for IPE 0.33 s-1/3 and 20.6 µm and for HEA 0.36 s-1/3 and 17.4 µm. The Q in the IPE was significantly smaller than in HEA, and VSI was significantly larger. The Q with a threshold of 0.32 s-1/3 predicted the final infarction with a sensitivity of 69% and a specificity of 64%. Conclusions: The reduced Q and increased VSI in the IPE confirmed our previous pilot results. Although Q showed a trend to identify the severity of ischemia in an overall voxel population, its potential in predicting infarct growth needs to be further tested in a larger cohort including a clear status of reperfusion and recanalization.

Background: We have recently shown that ischemic stroke causes a stress-mediator-induced long-lasting immunodepressive state in mice. Methods: Using head magnetic resonance imaging and standardized immunoassays, we prospectively investigated whether poststroke immunodepression is also seen in humans. Results: Compared to healthy volunteers (n = 30), a rapid depression of lymphocyte counts and a functional deactivation of monocytes and T helper type 1 cells was observed in acute stroke patients (SP; n = 40). Immunodepression was more pronounced in patients with severe clinical deficit or large infarction. On admission the combination of monocytic tumor necrosis factor α release ex vivo and the National Institute of Health Stroke Scale score were the best predictors for nosocomial infection, preferentially affecting older SP. Conclusion: Our data provide evidence for an immediate suppression of cell-mediated immune responses after ischemic stroke in humans.