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Purpose To study the clinical potential of a deep learning neural network (convolutional neural networks [CNN]) as a supportive tool for detection of intracranial aneurysms from 3D time-of-flight magnetic resonance angiography (TOF-MRA) by comparing the diagnostic performance to that of human readers. Methods In this retrospective study a pipeline for detection of intracranial aneurysms from clinical TOF-MRA was established based on the framework DeepMedic. Datasets of 85 consecutive patients served as ground truth and were used to train and evaluate the model. The ground truth without annotation was presented to two blinded human readers with different levels of experience in diagnostic neuroradiology (reader 1: 2 years, reader 2: 12 years). Diagnostic performance of human readers and the CNN was studied and compared using the χ 2 -test and Fishers’ exact test. Results Ground truth consisted of 115 aneurysms with a mean diameter of 7 mm (range: 2–37 mm). Aneurysms were categorized as small (S; <3 mm; N  = 13), medium (M; 3–7 mm; N  = 57), and large (L; >7 mm; N  = 45) based on the diameter. No statistically significant differences in terms of overall sensitivity (OS) were observed between the CNN and both of the human readers (reader 1 vs. CNN, P  = 0.141; reader 2 vs. CNN, P  = 0.231). The OS of both human readers was improved by combination of each readers’ individual detections with the detections of the CNN (reader 1: 98% vs. 95%, P  = 0.280; reader 2: 97% vs. 94%, P  = 0.333). Conclusion A CNN is able to detect intracranial aneurysms from clinical TOF-MRA data with a sensitivity comparable to that of expert radiologists and may have the potential to improve detection rates of incidental findings in a clinical setting.

Introduction There is only very limited data about complications in mechanical thrombectomy for acute ischemic stroke. The purpose of this study was to evaluate the frequency and the clinical relevance of procedure-related complications in mechanical thrombectomy. Methods We conducted a retrospective analysis of 176 consecutive acute ischemic stroke cases that were treated with mechanical thrombectomy. Primary outcome measures included the following: symptomatic intracranial hemorrhage (sICH), vessel dissection, emboli to new vascular territories, vasospasm, and stent dislocation/occlusion whenever appropriate. Secondary outcome measures included mTICI score, time from symptom onset to revascularization, and time from groin puncture to revascularization as well as the early clinical outcome at discharge. Results Complications occurred in 20/176 patients (11 %) comprising 23 adverse events at the following rates: sICH 8/176 (5 %), emboli to new vascular territories 4/176 (2 %); vessel dissection 3/176 (2 %); vasospasm of the access vessel 5/176 (3 %); stent dislocation in 1/42 (2 %); and stent occlusion in 2/42 (5 %). Two out of 20 (10 %) suffered from two or more procedure-related complications. There was a statistically significant correlation of complications with time from groin puncture to revascularization, unfavorable revascularization results, and unfavorable clinical outcome. Conclusion Overall, the frequency of procedure-related complications lies within acceptable limits for an emergency procedure. The endovascular treatment does not seem to add significantly to the stroke patients’ risk of sICH but implies an innate risk of stroke in an initially uninvolved territory. Furthermore, a prolonged endovascular procedure beyond an hour is correlated with higher complication rates, which underlines the importance of a swift and complete revascularization.

The recent success of endovascular stroke treatment has heralded a new era in the management of acute ischemic stroke (AIS) with significantly improved outcome for patients. A large number of patients may be amenable to this new treatment and as the evidence expands the number of patients eligible for mechanical thrombectomy continues to increase. Recent evidence suggests that the time window for treatment can be extended up to 24 h after symptom onset for patients with anterior circulation strokes; however, many clinicians and medical professionals may not be aware of these recent changes and it is important that they are kept up-to-date with this rapidly evolving treatment. This review provides an overview of the recent successful trials and highlights important steps that should be instituted in order to achieve rapid reperfusion and optimize the outcome for ischemic stroke patients. It also looks at the remaining controversies facing the field of thrombectomy. A short summary of each of these contentious areas is provided and the current state of the art.

Background and purposeThrombectomy has become the standard of care for acute ischaemic stroke due to large vessel occlusion. Aim of this study was to compare the radiological outcomes and time metrics of the various thrombectomy techniques.MethodsIn this retrospective, multicenter study we analysed the data of 450 patients with occlusion of the anterior circulation, treated in five high-volume center from 2013 to 2016. The treatment techniques were divided in three categories: first-pass use of a large-bore aspiration-catheter; first-pass use of a stent-retriever; and primary combined approach (PCA) of an aspiration-catheter and stent-retriever. Primary endpoints were successful reperfusion and groin to reperfusion time. Secondary endpoints were the number of attempts and occurrence of emboli in new territory (ENT). The primary analysis was based on the intention to treat groups (ITT).ResultsThe ITT-analysis showed significantly higher reperfusion rates, with 86% of successful reperfusion in the PCA-group compared with 73% in the aspiration group and 65% in the stent-retriever group. There was no significant difference in groin to reperfusion time regarding the used technique. The secondary analysis showed an impact of the technique on the number of attempts and the occurrence of ENTs. Lowest ENT rates and attempts were reported with the combined approach.ConclusionsThe combined first-pass deployment of a stent-retriever and an aspiration-catheter was the most effective technique for reperfusion of anterior circulation large vessel occlusion. Our results correlate with the latest single-centrere studies, reporting very high reperfusion rates with PCA variations.

Due to their effect on aneurysm hemodynamics, flow diverters (FD) have become a routine endovascular therapy for intracranial aneurysms. Since over- and undersizing affect the device’s hemodynamic abilities, selecting the correct device diameter and accurately simulating FD placement can improve patient-specific outcomes. The purpose of this study was to validate the accuracy of virtual flow diverter deployments in the novel Derivo® 2 device. We retrospectively analyzed blood flows in ten FD placements for which 3D DSA datasets were available pre- and post-intervention. All patients were treated with a second-generation FD Derivo® 2 (Acandis GmbH, Pforzheim, Germany) and post-interventional datasets were compared to virtual FD deployment at the implanted position for implanted stent length, stent diameters, and curvature analysis using ANKYRAS (Galgo Medical, Barcelona, Spain). Image-based blood flow simulations of pre- and post-interventional configurations were conducted. The mean length of implanted FD was 32.61 (±11.18 mm). Overall, ANKYRAS prediction was good with an average deviation of 8.4% (±5.8%) with a mean absolute difference in stent length of 3.13 mm. There was a difference of 0.24 mm in stent diameter amplitude toward ANKYRAS simulation. In vessels exhibiting a high degree of curvature, however, relevant differences between simulated and real-patient data were observed. The intrasaccular blood flow activity represented by the wall shear stress was qualitatively reduced in all cases. Inflow velocity decreased and the pulsatility over the cardiac cycle was weakened. Virtual stenting is an accurate tool for FD positioning, which may help facilitate flow FDs’ individualization and assess their hemodynamic impact. Challenges posed by complex vessel anatomy and high curvatures must be addressed.

BackgroundWe studied patients treated with the EmboTrap revascularization device in a prospective registry which is core laboratory evaluated by physicians from external centers. The goal was to determine how the EmboTrap would perform under the everyday conditions of a high-volume stroke center.MethodsWe examined all patients with acute stroke treated with the Embotrap device from October 2013 to March 2017 in our center. Imaging parameters and times were adjudicated by core laboratory personnel blinded to clinical information, treating physician, and clinical outcomes. Clinical evaluation was performed by independent neurologists and entered in a national registry. Evaluated endpoints were: successful revascularization (modified Thrombolysis in Cerebral Infarction (mTICI) 2b–3) and good clinical outcomes at 3 months (modified Rankin Scale (mRS) 0–2).Results201 consecutive patients with a median NIH Stroke Scale (NIHSS) score of 15 (range 2–30) were included. 170 patients (84.6%) achieved mTICI 2b–3 reperfusion. The median number of attempts was 2 (range 1–10) with 52.8% of the population achieving good functional outcomes (mRS 0–2) at 3 months. On univariate analysis, good functional outcome was associated with the number of attempts, puncture-to-reperfusion time, anterior circulation occlusion, and NIHSS score. On multivariate analysis, pre-treatment NIHSS (OR 0.845 per point, 95% CI 0.793 to 0.908, P<0.001) and puncture-to-reperfusion time (OR 0.9952 per min, 95% CI 0.9914 to 0.9975, P=0.023) were associated with good functional outcomes at 3 months.ConclusionThe Embotrap device has a high rate of successful reperfusion. Our core laboratory-audited single-center experience suggests the technical feasibility and safety of the Embotrap for first-line use in a real-world setting.

Background: Clinical outcome after endovascular stroke therapy (EVT) for proximal anterior circulation stroke is often disappointing despite high recanalization rates. The ENDOSTROKE study aims to determine predictors of clinical outcome in patients undergoing EVT. Here we focus on the impact of age and recanalization on proximal middle cerebral artery (M1-MCA) or carotid T occlusion. Methods: ENDOSTROKE is an investigator-initiated, industrially independent multicenter registry launched in January, 2011, for consecutive patients undergoing EVT for large-vessel stroke. This analysis focuses on patients treated in 11 academic and nonacademic stroke centers with angiographically proven M1-MCA (n = 259) or carotid T occlusion (n = 103). Recanalization was defined as Thrombolysis in Myocardial Infarction (TIMI) score 2 or 3, and in patients with available Thrombolysis in Cerebral Ischemia (TICI) data (n = 309) as TICI scores 2b-3. Good outcome was defined as modified Rankin Scale (mRS) score of 0-2 assessed after 3 months or later. Results: The median age was 68 years (25th and 75th percentiles: 56, 76 years), and the median National Institutes of Health Stroke Scale (NIHSS) score at admission was 16 (13, 19); 41% of the patients had a favorable (mRS scores 0-2), and 59% had an unfavorable (mRS scores 3-6) outcome; 83% reached TIMI 2-3 flow. Independent predictors of good outcome were younger age, lower initial NIHSS scores, TIMI 2/3 recanalization and lower serum glucose levels. Outcome was highly dependent on patients' age: 60% of the patients within the lowest age quartile (range: 18-56 years) experienced good clinical outcome, decreasing stepwise over 47% (57-68 years) and 37% (69-76 years) to 17% in the highest age quartile (77-94 years). The proportion of patients with poor clinical outcome despite TIMI 2/3 recanalization (‘futile recanalization') increased dramatically from only 29% in the lowest age quartile over 34% and 40% (2nd and 3rd age quartiles) up to 53% in the highest age quartile. Results were similar in patients with available TICI scores, with ‘futile recanalization' rates increasing from 24% to 46% (lowest to highest age quartile). Conclusions: This study emphasizes the dramatic impact of patients' age on outcome in EVT for M1-MCA or carotid T occlusion, even in the presence of recanalization. Reasons for this age-related decrease in clinically successful recanalization rates urgently need clarification and may comprise patient-related factors (age-related increase in cardioembolic strokes, collateral status, comorbidities) as well as periprocedural issues (tortuous vessel anatomy in the elderly, age-dependent negative impact of general anesthesia in EVT).

Knowledge of the collateralization of an occluded vessel is important for the risk-benefit analysis of difficult revascularization maneuvers during mechanical thrombectomy. If the territory behind a clot is well perfused, one could desist from performing a risky thrombectomy maneuver. The arterial pulse pressure curve may serve as an indicator for the collateralization of an occluded target vessel. We investigated the feasibility of arterial pulse measurements with a standard microcatheter. We measured the intra-arterial blood pressure proximal and distal to the clot in 40 thrombectomy maneuvers in a porcine stroke model. We used a microcatheter (Trevo Pro 18, Stryker, Kalamazoo, CA, USA), a pressure transducer (MEMSCAP SP844), an AdInstruments Powerlab 16/35 workstation, and LabChart 8 Software (AdInstruments, Dunedin, New Zealand). Median arterial blood pressure proximal and distal to the clot was 96.0 mmHg (IQR, 23.8 mmHg) and 47.5 mmHg (IQR, 43.5 mmHg), respectively (p < .001). The median difference between systolic maximum and diastolic minimum proximal and distal to the clot decreased significantly from 1.8 mmHg (IQR, 3.6 mmHg) to 0.0 mmHg (IQR, 0.5 mmHg) (p < .001). There was loss of the curve in 26 of 40 cases and loss of pressure in 23 of 40 cases (p = .008). There was no significant correlation between vessel diameter and either loss of the pulse pressure curve (p = .20) or overall pressure loss (p = .31). It is possible to measure the pulse pressure proximal and distal to the clot with a standard microcatheter used during mechanical thrombectomy.

Broad based bifurcation aneurysms are challenging. Various endovascular techniques aim at stabilizing the coil package in the aneurysm. Among these, the waffle cone technique provides a viable alternative to Y stenting in selected cases, incorporating a less complex delivery, and the reduced inherent risk of a single stenting procedure compared with the use of two stents in Y configuration. Unlike conventional stents, the distal end of the new pCONus device opens like a blossoming flower inside of the aneurysm to facilitate the waffle cone technique. In a case with tandem unruptured broad based middle cerebral artery bifurcation aneurysms, the complex anatomical challenge was resolved by a unique combination of both techniques: two pCONus deployed in Y configuration, offering stable neck coverage for coiling both aneurysms. The angiographic results with complete occlusion of both aneurysms and the uneventful clinical course at 90 days with continued daily administration of dual antiplatelet therapy are encouraging.