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BACKGROUND: Among patients with acute ischemic stroke due to occlusions in the proximal anterior intracranial circulation, less than 40% regain functional independence when treated with intravenous tissue plasminogen activator (t-PA) alone. Thrombectomy with the use of a stent retriever, in addition to intravenous t-PA, increases reperfusion rates and may improve long-term functional outcome.METHODS: We randomly assigned eligible patients with stroke who were receiving or had received intravenous t-PA to continue with t-PA alone (control group) or to undergo endovascular thrombectomy with the use of a stent retriever within 6 hours after symptom onset (intervention group). Patients had confirmed occlusions in the proximal anterior intracranial circulation and an absence of large ischemic-core lesions. The primary outcome was the severity of global disability at 90 days, as assessed by means of the modified Rankin scale (with scores ranging from 0 [no symptoms] to 6 [death]).RESULTS: The study was stopped early because of efficacy. At 39 centers, 196 patients underwent randomization (98 patients in each group). In the intervention group, the median time from qualifying imaging to groin puncture was 57 minutes, and the rate of substantial reperfusion at the end of the procedure was 88%. Thrombectomy with the stent retriever plus intravenous t-PA reduced disability at 90 days over the entire range of scores on the modified Rankin scale (PCONCLUSIONS: In patients receiving intravenous t-PA for acute ischemic stroke due to occlusions in the proximal anterior intracranial circulation, thrombectomy with a stent retriever within 6 hours after onset improved functional outcomes at 90 days. (Funded by Covidien; SWIFT PRIME ClinicalTrials.gov number, NCT01657461.).

In our observation, wall enhancement MRI allows for directly identifying areas of disturbed contrast permeability, i.e. inflammation, thrombus or a combination of both, and thus visualizes areas of instability in the aneurysm wall. In presented cases, regions of enhancements were compared with wall shear stress (WSS) distribution obtained from computational fluid dynamics (CFD). In our findings, areas of wall enhancement match well with either low or high WSS, however, other areas of low or high WSS were observed without identification of any wall enhancement.

Working towards a system to match intracranial aneurysms of similar morphology, we examine how a variety of established shape descriptors relate to expert assessments of aneurysm morphology. For this purpose, we extract 3D models of aneurysms from 3D angiographies and calculate numerical values (geometry indices and moment invariants) that describe the size and shape of the aneurysm and the surrounding arteries. We then compare these shape descriptors with human assessments of qualitative morphological characteristics like irregularity or the presence/absence of blebs. Here, we present preliminary results based on 137 aneurysm models.

Introduction: To date, it is difficult for clinicians to judge the associated risks of intracranial aneurysms reliably. Because the 3D-shape of an aneurysm is strongly linked to the underlying formation processes it is very likely that the presence or absence of certain shape features indicate the disease status of the aneurysm. Shape (extracted from medical imaging data) already plays a significant role in the qualitative assessment of the aneurysm by the clinician and has been associated with risk prediction. Still, no consensus exists about which shape features reliably predict instability or whether there exist any that qualify as biomarkers at all. In an effort to find support for the assumption that aneurysm shape carries information about the aneurysm status, we developed a flexible classification pipeline that extracts shape features and tests their applicability. Methods: 3D models of aneurysms are extracted from medical imaging data (mostly 3DRA) by a standardized vessel segmentation method. The aneurysm is cut from its parent vessels according to a simple and reproducible cut protocol. Different representations of the 3D shape that have been suggested by literature are calculated for the extracted aneurysm. So far we have looked at Zernike moments (ZM), their invariants (ZMI) and simple geometry indices such as undulation or non-sphericity. Different feature reduction techniques (for ZMI) and machine-learning methods are applied to find linking patterns between shape features and aneurysm stability. This processing pipeline is applied to a relatively large clinical dataset (ca. 400 cases), whereas the collection of new cases is an on-going effort. We will present the findings on the latest state of the database. Results: Initial results indicate that the ZMI alone are insufficient to classify aneurysms reliably in terms of rupture or stability status. Because of their global support, ZMI bare a strong dependency on the placement of the cuts. In a preliminary study, ZMI were only slightly superior regarding rupture prediction compared to much simpler geometry indices. Conclusions: We implemented a framework to test the performance of different combinations of shape features and machine learning techniques. While the shape-only representation of an aneurysm does carry information about its disease status, the classification results will benefit from the stratification of the aneurysms in terms of location, size and clinical factors.

Alzheimer's disease (AD) is the most common form of dementia seen in the elderly. No curing medicine for AD exists at this moment. In the search for an effective medicine, research is directed towards the prediction of conversion of mild cognitive impairment (MCI) to AD. White matter hyperintensities (WMHs) have been shown to contain information regarding the development of AD, although non-conclusive results are found in literature. These studies often use qualitative measures to describe WMHs, which is time consuming and prone to variability. To investigate the relation between WMHs and the development of AD, algorithms to automatically determine quantitative properties in terms of volume and spatial distribution of WMHs are developed and compared between normal controls and MCI subjects. MCI subjects have a significantly higher total volume of WMHs than normal controls. This difference persists when lesions are classified according to their distance to the ventricular wall. Spatial distribution is also described by defining different brain regions based on a common coordinate system. This reveals that MCI subjects have a larger WMH volume in the upper part of the brain compared to normal controls. In four subjects, the change of WMH properties over time is studied in detail. Although such a small dataset cannot be used to give definitive conclusions, the data suggests that progression of WMHs in subjects with a low lesion load is caused by an increase in the number of lesions and by the progression of juxtacortical lesions. In subjects with a larger lesion load, progression is caused by expansion of pre-existing lesions.

Objective: To present clinical, angiographical and therapeutical characteristics of patients with sporadic multiple AVMs, treated in our institution. Method: Patients with cerebral AVMs, treated in our department between 1990 and 2013, were analyzed retrospectively. Basic demographic data, vascular[for full text, please go to the a.m. URL], 66. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC)

OBJECT The underlying mechanisms causing intracranial perianeurysmal edema (PAE) are still poorly understood. Since PAE is most frequently observed in giant intracranial aneurysms (GIAs), the authors designed a study to examine the occurrence of PAE in relation to the location, size, and partial thrombosis (PT) of GIAs along with the clinical impact of PAE. METHODS Magnetic resonance imaging data for patients with a diagnosis of unruptured GIA from the international multicenter Giant Intracranial Aneurysm Registry were retrospectively analyzed with regard to location and size of the GIA, PAE volume, and the presence of PT. The occurrence of PAE was correlated to clinical findings. RESULTS Imaging data for 69 GIAs were eligible for inclusion in this study. Perianeurysmal edema was observed in 33.3% of all cases, with the highest frequency in GIAs of the middle cerebral artery (MCA; 68.8%) and the lowest frequency in GIAs of the cavernous internal carotid artery (ICA; 0.0%). Independent predictors of PAE formation were GIA volume (OR 1.13, p = 0.02) and the occurrence of PT (OR 9.84, p = 0.04). Giant intracranial aneurysm location did not predict PAE occurrence. Giant aneurysms with PAE were larger than GIAs without PAE (p < 0.01), and GIA volume correlated with PAE volume (rs = 0.51, p = 0.01). Perianeurysmal edema had no influence on the modified Rankin Scale score (p = 0.30 or the occurrence of aphasia (p = 0.61) or hemiparesis (p = 0.82). CONCLUSIONS Perianeurysmal edema was associated with GIA size and the presence of PT. As no PAE was observed in cavernous ICA aneurysms, even though they exerted mass effect on the brain and also displayed PT, the dura mater may serve as a barrier protecting the brain from PAE formation.

Objectives: Pulsatile tinnitus (PT) is a rare complaint, but can be a symptom of life-threatening disease. It is often caused by vascular pathologies, e.g. dural arteriovenous fistula (dAVF), arteriovenous malformation (AVM) or vascularized tumors. The current diagnostic pathway includes clinical examination, cranial MRI and additional DSA. The aim of this study was to evaluate the diagnostic impact of DSA in the diagnostic workup of patients with PT in comparison to MRI alone. Methods: Retrospectively, 54 consecutive patients with pulsatile tinnitus were evaluated. All patients had a diagnostic workup including cranial MRI and DSA. MRI examinations were blinded to the results of DSA and retrospectively analyzed in consensus by two experienced neuroradiologists. The MR-examinations were evaluated for each performed sequence separately: time-of-flight-angiography, ce-MRA, T2, ce-T1-sequence and ce-T1-sequence with fat saturation. Results: 37 of the 54 patients revealed a pathology explaining PT on MRI, which was detected by the readers in 100% and proofed by means of DSA. 24 dAVF, four paraganglioma, two AVM and seven more pathologies were described. All patients without pathology on MRI did also not show any pathology in DSA. Conclusions: MR imaging is sufficient to exclude pathology in patients with pulsatile tinnitus. OA Förderung 2015

Objective: The aim of our retrospective study is to demonstrate our experience in the treatment of spinal dural arteriovenous fistulas and to identify factors that influence the neurological outcome of our patients. Method: Between 2001 and 2013, a consecutive series of 32 patients diagnosed with[for full text, please go to the a.m. URL], 65. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC)

Objective: To determine the clinical presentation, the multimodal interdisciplinary treatment strategies and outcome of posterior fossa arterio-venous malformations (AVM). Method: Between 1998 and 2012, a total of 53 patients (mean age 43.8 years) with a posterior fossa AVM were treated either alone[for full text, please go to the a.m. URL], 64. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie (DGNC)

We present a clinical perspective, supported by biological findings, reflecting the potential of computational tools to understand and treat intracranial aneurysms. Thrombus formation and chronic inflammation are integral to disease progression, driven by blood flow energy. The interplay between flow energy, blood clotting and remodeling of the tissue is key to an enhanced disease understanding, to improve patient counseling and ultimately endovascular treatment planning. Current concepts suggest that blood governs wall remodeling by multiple biological steps. The process starts with flow induced thrombus adhesion (atherothrombosis) to the wall that secondarily leads to the release of biological mediators of inflammation entertaining destructive remodeling. Destructive wall remodeling jeopardizes the mechanical wall integrity with ensuing circumscribed softening and expansion of the aneurysm shape. The shape of an aneurysm is the visible result of these complex pathological processes and characterizes its disease status. Wall adherent thrombus formation, inflammatory reactions and the driving force of blood flow cause lumen shape changes. Here, shape irregularity is a distinctive sign of focal wall weakening. The integration of shape-analysis,vascular biology and phenotypical information will allow for personalized characterization of aneurysmal vascular disease and help to identify and establish shape as an image-based biomarker. Future translational efforts should aim at providing adequate IT tools and contributing to validation and disease understanding. Ensuing results will have a high likelihood to impact significantly on current clinical disease management.

Silent brain infarctions are associated with an increased risk of stroke in healthy individuals. Risk of recurrent stroke in patients with both symptomatic and silent brain infarction (SBI) has only been investigated in patients with cardioembolic stroke in the European Atrial Fibrillation Trial. We assessed whether patients with recent noncardioembolic stroke and SBI detected on MRI are at increased risk for recurrent stroke, other cardiovascular events, and mortality.The prevalence of SBI detected on MRI was assessed in 1014 patients enrolled in the imaging substudy of the Prevention Regimen for Effectively Avoiding Second Strokes (PRoFESS) trial. The primary outcome was first recurrence of stroke in patients with both symptomatic stroke and SBI in comparison with age- and sex-matched patients with stroke without SBI. Secondary outcomes were a combined vascular end point, other vascular events, and mortality. The 2 groups were compared using conditional logistic regression.Silent brain infarction was detected in 207 (20.4%) of the 1014 patients. Twenty-seven (13.0%) patients with SBI and 19 (9.2%) without SBI had a recurrent stroke (OR, 1.42; 95% CI, 0.79-2.56; P=0.24) during a mean follow-up of 2.5 years. Similarly, there was no statistically significant difference for all secondary outcome parameters between patients with SBI and matched patients without SBI.The presence of SBI in patients with recent mild noncardioembolic ischemic stroke could not be shown to be an independent risk factor for recurrent stroke, other vascular events, or a higher mortality rate.URL: http://clinicaltrials.gov. Unique identifier: NCT00153062.

White matter hyperintensities are known to play a role in the cognitive decline experienced by patients suffering from neurological diseases. Therefore, accurately detecting and monitoring these lesions is of importance. Automatic methods for segmenting white matter lesions typically use multimodal MRI data. Furthermore, many methods use a training set to perform a classi﬿cation task or to determine necessary parameters. In this work, we describe and evaluate an unsupervised segmentation method that is based solely on the histogram of FLAIR images. It approximates the histogram by a mixture of three Gaussians in order to ﬿nd an appropriate threshold for white matter hyperintensities. We use a context-sensitive Expectation-Maximization method to determine the Gaussian mixture parameters. The segmentation is subsequently corrected for false positives using the knowledge of the location of typical FLAIR artifacts. A preliminary validation with the ground truth on 6 patients revealed a Similarity Index of 0.73 ± 0.10, indicating that the method is comparable to others in the literature which require multimodal MRI and/or a preliminary training step.

BACKGROUND AND PURPOSE: Currently available stents for intracranial use usually are balloon-expandable coronary stents that carry the risk of damaging a dysplastic segment of the artery, with potential vessel rupture. We assessed the technical feasibility and efficacy of the combined application of a flexible, self-expanding neurovascular stent and detachable coils in the management of wide-necked intracranial aneurysms in humans. METHODS: Four consecutive patients with a wide-necked intracranial aneurysm were treated with a combined approach that consisted of delivery of a flexible self-expanding neurovascular stent through a microcather to cover the neck of the aneurysm and subsequent filling of the aneurysm with coils through the stent interstices. The aneurysms were located at the internal carotid artery (n=2) and the basilar tip encroaching the P1 segment (n=2). Previous attempts with conventional endosaccular coil packing alone failed in all cases. RESULTS: Stent placement in the desired position with complete or nearly complete occlusion of the aneurysms was feasible in all patients. In one patient, aneurysm perforation with the microcatheter occurred and necessitated ventricular drainage, which led to a large parenchymal and intraventricular hemorrhage because of the strong anticoagulation regimen. Six-month follow-up demonstrated no focal neurologic sequelae in any of the patients, except slight memory dysfunction in the patient with bleeding. CONCLUSION: Preliminary data demonstrate that this extremely flexible stent is technically easy to deploy and can be easily and safely maneuvered through severely tortuous vessels, enabling the treatment of intracranial wide-necked aneurysms. The combination of endovascular reconstruction of the parent vessel with use of a self-expanding stent followed by coil embolization offers a promising therapeutic alternative for wide-necked aneurysms not amenable to coil embolization alone. Although immediate angiographic results are promising, long-term angiographic and clinical follow-up is essential to determine permanent vessel patency and aneurysm occlusion rate.

Der Neuroradiologe beschäftigt sich mit der Diagnostik und interventionellen Therapie von Erkrankungen des zentralen Nervensystems. Wie kaum ein anderes Fach profitierte die Neuroradiologie von den technischen Neuerungen in den letzten zehn Jahren.