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BackgroundThe Neqstent coil-assisted flow diverter (NQS) is a neck bridging device to facilitate coil occlusion of intracranial aneurysms. CAFI is a prospective, single-arm, multicenter study on the safety and performance of the NQS adjunctive therapy device together with platinum coils for treatment of unruptured intracranial aneurysms., Methods: Thirty-eight patients were enrolled. Primary endpoints were occlusion at 6 months for efficacy, and any major stroke or non-accidental death up to 30 days or major disabling stroke within 6 months for safety. Secondary endpoints were re-treatment rate, procedure time, and procedure/device-related adverse events. Procedural and follow-up imaging was reviewed by an independent core laboratory. Adverse events were reviewed and adjudicated by a clinical events committee., Results: The NQS was successfully implanted in 36/38 aneurysms, 2/38 in the intention-to-treat group did not receive a NQS and were excluded from follow-up after 30 days. In the per protocol group (PP), 33/36 patients were available for angiographic follow-up. Device related adverse events were recorded in 4/38 (10.5%) patients, one hemorrhagic and three thromboembolic. In the PP group, immediate post-treatment adequate occlusion (RR1 and RR2) was seen in 9/36 (25%) and progressed to 28/36 (77.8%) at 6 months. Complete occlusion (RR1) was achieved in 29/36 (80.6%) at the last available angiogram (3/36 were post procedure). The mean procedure time was 129 min (50-300 min, median 120 min)., Conclusion: The NQS in conjunction with coils appears to be effective in the treatment of intracranial wide-neck bifurcation aneurysms, but its safety remains to be proved in larger series., Trial Registration Number: NCT04187573., Competing Interests: Competing interests: TL proctors and consults for CERUS Medical, Inc. and has in the past 3 years received service-related fees from Stryker, Acandis, Microvention, Medtronic, Pfizer, Balt, and Cercare; GG proctors and consults for CERUS Endovascular; COK has no conflict of interest; FW proctors and consults for Cerus Endovascular, outside this study and within the past 3 years he has proctored or received service-related fees from MicroVention, Acandis, Cerenovus, Route 92, and Daiichi Sankyo; IT has no conflict of interest; M-NP has no conflict of interest, YO has no conflict of interest; JF receives research support from EU, BMBF, BMWi, DFG, Acandis, Medtronic, Microvention, Stryker, holds an executive function at Eppdata and stock in Tegus. He consults for Acandis, Cerenovus, Medtronic, Microvention, Penumbra, Phenox, and Stryker and is acting as a member of the editorial board of JNIS; MK-O consults for Cerus Endovascular, outside this study and within the past 3 years she has received service-related fees from MicroVention, Medtronic and Stryker; MB has no conflict of interest; OJ receives research support from BMBF and DFG. During the past 3 years he consulted for Acandis, Cerenovus, Cerus Endovascular, Microvention, Philips, Radiologie Holding, Route 92, and Stryker., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Flow diverters (FDs) have become an integral part of treatment for brain aneurysms., Aim: To summarize available evidence of factors associated with aneurysm occlusion (AO) after treatment with a FD., Methods: References were identified using the Nested Knowledge AutoLit semi-automated review platform between January 1, 2008 and August 26, 2022. The review focuses on preprocedural and postprocedural factors associated with AO identified in logistic regression analysis. Studies were included if they met the inclusion criteria of study details (ie, study design, sample size, location, (pre)treatment aneurysm details). Evidence levels were classified by variability and significancy across studies (eg, low variability ≥5 studies and significance in ≥60% throughout reports)., Results: Overall, 2.03% (95% CI 1.22 to 2.82; 24/1184) of screened studies met the inclusion criteria for predictors of AO based on logistic regression analysis. Predictors of AO with low variability in multivariable logistic regression analysis included aneurysm characteristics (aneurysm diameter), particularly complexity (absence of branch involvement) and younger patient age. Predictors of moderate evidence for AO included aneurysm characteristics (neck width), patient characteristics (absence of hypertension), procedural (adjunctive coiling) and post-deployment variables (longer follow-up; direct postprocedural satisfactory occlusion). Variables with a high variability in predicting AO following FD treatment were gender, FD as re-treatment strategy, and aneurysm morphology (eg, fusiform or blister)., Conclusion: Evidence of predictors for AO after FD treatment is sparse. Current literature suggests that absence of branch involvement, younger age, and aneurysm diameter have the highest impact on AO following FD treatment. Large studies investigating high-quality data with well-defined inclusion criteria are needed for greater insight into FD effectiveness., Competing Interests: Competing interests: JF: research support from the German Ministry of Science and Education (BMBF), German Ministry of Economy and Innovation (BMWi), German Research Foundation (DFG), European Union (EU), Hamburgische Investitions-/Förderbank (IFB), Medtronic, Microvention, Philips, Stryker; consultancy appointments; Acandis, Bayer, Boehringer Ingelheim, Cerenovus, Covidien, Evasc Neurovascular, MD Clinicals, Medtronic, Medina, Microvention, Penumbra, Route92, Stryker, Transverse Medical; stock holdings for Tegus, JNIS associate editor. KMK: works for, and holds equity in, Nested Knowledge, works for Conway Medical, and holds equity in Piraeus Medical and Superior Medical Experts. TNN: reports research support from Medtronic and SVIN. KZ: support under the operational program Integrated Infrastructure for the project: TENSION—complementary project, IMTS: 313011W875, co-financed by the European Regional Development Fund. AR: consultant for Balt and Medtronic. LM: received financial compensation as a speaker for Balt Prime. MM-G: JNIS associate editor. The other authors report no conflict of interest., (© Author(s) (or their employer(s)) 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: The CLinical Assessment of WEB device in Ruptured aneurYSms (CLARYS) study has shown that the endovascular treatment of ruptured bifurcation aneurysms with the Woven EndoBridge (WEB) is safe and effective and provides protection against rebleeding at 1 month and 1 year. The 12-month angiographic follow-up is an important endpoint of the study., Methods: The CLARYS study is a prospective multicenter study conducted in 13 European centers. The study enrolled 60 patients with 60 ruptured aneurysms of the anterior and posterior circulation. The study was conducted with an independent assessment of safety outcomes and imaging., Results: Sixty patients with 60 ruptured bifurcation aneurysms to be treated with the WEB were included. Fifty-three aneurysms (88.3%) had a broad base with a dome to neck ratio <2 (mean 1.6). Of these, 46 patients were evaluated by an independent core laboratory with follow-up imaging performed at 12 months or before eventual retreatment. At 1 year, 19/46 aneurysms (41.3%) were completely occluded (Raymond-Roy grade I), 21/46 (45.7%) had a residual neck and 6/46 (13.0%) had residual aneurysm filling. Adequate occlusion was reported in 40/46 (87%) aneurysms. Six patients underwent target aneurysm retreatment., Conclusions: The CLARYS study has previously shown that the use of the WEB in the endovascular treatment of ruptured bifurcation aneurysms provides effective protection against rebleeding with a good safety profile. The angiographic occlusion rates at 1 year reported here are comparable to those already seen in previous multicenter studies which primarily included unruptured aneurysms., Competing Interests: Competing interests: JF is an associate editor of the Journal of NeuroInterventional Surgery. MM is a member of the editorial board of Neuroradiology., (© Author(s) (or their employer(s)) 2023. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Evaluating a new endovascular treatment for intracranial aneurysms must not only demonstrate short-term safety and efficacy, but also evaluate longer-term outcomes (eg, delayed complications, anatomical results, retreatment). The current analysis reports the 5-year clinical and anatomical results of Woven EndoBridge (WEB) treatment in two European combined trial populations (WEBCAST (WEB Clinical Assessment of Intrasaccular Aneurysm Therapy) and WEBCAST-2)., Methods: All adverse events occurring between the procedure and 5-year follow-up were independently evaluated by an expert. Aneurysm occlusion was evaluated by an independent core laboratory using a three-grade scale: complete occlusion, neck remnant, and aneurysm remnant. In cases where data were not available at 5-year follow-up, the last observation carry forward (LOCF) method was used., Results: The safety and efficacy populations comprised 100 patients and 95 aneurysms, respectively. No adverse event related to the device occurred after the procedure during the 5-year follow-up period. Mortality at 5 years was 7.0% (7/100 patients) including mortality related to the WEB (0/100, 0.0%), the procedure (1/100, 1.0%), and another condition (6/100, 6.0%). At 5 years, complete aneurysm occlusion was observed in 49/95 (51.6%) aneurysms, neck remnant in 25/95 (26.3%), and aneurysm remnant in 21/95 (22.1%). Retreatment rate at 5 years was 11.6% (11/95 aneurysms)., Conclusions: This analysis conducted in a population of patients with wide-neck bifurcation aneurysms confirms WEB's safety profile. Additional evidence demonstrates good stability of aneurysm occlusion with adequate occlusion (complete occlusion or neck remnant) at 5 years in 77.9% of aneurysms with a low retreatment rate (11.6%)., Clinical Trial Registration: WEBCAST and WEBCAST-2: Unique identifier: NCT01778322., Competing Interests: Competing interests: LP reports support for the present manuscript from Microvention; consulting fees from Balt, Microvention, Perflow, Phenox, Vesalio; payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing, or educational events from Balt, Microvention, Perflow, Phenox, Vesalio; support for attending meetings and/or travel from Balt, Microvention, Phenox. IS reports grants or contracts from National Brain Research Fund (Hungary); consulting fees from Stryker, Microvention, Medtronic, Cerenovus; payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing, or educational events from Medtronic, Stryker, Cerenovus; support for attending meetings and/or travel from Gabriel Vegh Neurointerventional Fondation (Hungary); leadership in European Board of NeuroIntervention (EBNI), Hungarian Sociaty of Neuroradiology, Hungarian Society of Neurosurgery, Hungarian Stroke Society. XB reports consulting fees from Sequent; payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing, or educational events from Sequent. MH reports consulting fees from Balt, Stryker, Medtronic, Microvention, Phenox; payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing, or educational events from Cerenovus, Phenox, Stryker, Microvention, Cerus Medical. LSp reports grants or contracts from Philips (institutional); consulting fees from Balt, Medtronic, Phenox, Microvention, Stryker; payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing, or educational events from Balt, Medtronic, Microvention, Stryker; support for attending meetings and/or travel from Balt, Medtronic, Microvention, Stryker. JK reports consulting fees from Microvention, Phenox. DH reports payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing, or educational events from Microvention; support for attending meetings and/or travel from Microvention. VC reports grants or contracts from Medtronic, Cerenovus, Stryker, Balt, Microvention; consulting fees from Medtronic, Stryker, Microvention; payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing, or educational events from Medtronic, Stryker, Microvention; leadership in Sim & Cure. JF reports grants or contracts from Microvention (institutional); consulting fees from Microvention, Sequent; payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing, or educational events from Microvention; leadership role in JNIS (Associate Editor). A-CJ reports payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing, or educational events from Microvention; leadership in European Society for Minimally Invasive Neurological Therapy (ESMINT). TL reports consulting fees from Microvention, Cerus Endovascular; payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing, or educational events from Stryker, Cerus Endovascular; support for attending meetings and/or travel from Stryker, Cerus Endovascular. LSt reports no disclosures. WW reports consulting fees from Microvention. JBe reports consulting fees from Siemens (institutional). JM reports consulting fees from Microvention: other financial interests from Balt. AM reports CEC services to Sequent Medical and Microvention (institutional); payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing, or educational events from Microvention; support for attending meetings and/or travel from Microvention. JBy reports core laboratory services to Sequent Medical and Microvention (institutional); consulting fees from Oxford Endovascular Ltd and Microvention; core laboratory activities for Sequent and Microvention; leadership (Board Member) of Oxford Endovascular Ltd; stock in Oxford Endovascular Ltd., (© Author(s) (or their employer(s)) 2023. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Stent sizing remains a challenging task for flow diverter implantation because of stent foreshortening. In this study, we aimed to quantify the change in length after implantation and assess the error in length prediction using AneuGuide TM software., Methods: In a retrospective cohort of 101 patients with 102 aneurysms undergoing treatment with a pipeline embolization device (PED; Covidien, Irvine, California, USA), we used AneuGuide TM software to obtain measured lengths (ML) and calculated lengths (CL) after stent implantation. Stent elongation was defined as the ratio of ML-LL to the labeled length (LL). Simulation error was defined as the ratio of the absolute value of CL-ML to ML. The correlation and consistency between ML and LL and between ML and CL were analyzed using Pearson's correlation test and the Bland-Altman plot. Statistical significance was set at p<0.05., Results: The mean elongation of ML was 32.6% (range 26.3-109.2%). Moderate consistency was observed between LL and ML (ρ=0.74, p<0.001). With the AneuGuide TM software, the mean simulation error was 6.6% (range 0.32-21.2%). Pearson's correlation test and the Bland-Altman plot showed a high correlation and consistency between ML and CL (ρ=0.96, p<0.001)., Conclusion: Labeled length provides only a low reference value for predicting the actual length of the flow diverter after implantation. The high consistency between ML and CL obtained from AneuGuide TM software shows its great potential for the optimization of the flow diverter sizing process., Competing Interests: Competing interests: XT,JC,XH,AL—None. YS,XL,JX—Stock or stock options: ArteryFlow Technology Co., Ltd. JF receives research support from the German Ministry of Science and Education (BMBF), German Ministry of Economy and Innovation (BMWi), German Research Foundation (DFG), European Union (EU), Hamburgische Investitions- und Förderbank (IFB), Medtronic, Microvention, Philips, Stryker; and serves as a consultant for Acandis, Boehringer Ingelheim, Cerenovus, Evasc Neurovascular, MD Clinicals, Medtronic, Medina, Microvention, Penumbra, Route92, Stryker, Transverse Medical; and serves as an Editorial Board member (Associate Editor) of the Journal of NeuroInterventional Surgery. AHS—Consulting fees: Amnis Therapeutics, Apellis Pharmaceuticals, Inc, Boston Scientific, Canon Medical Systems USA, Inc, Cardinal Health 200, LLC, Cerebrotech Medical Systems, Inc, Cerenovus, Cerevatech Medical, Inc, Cordis, Corindus, Inc, Endostream Medical, Ltd, Imperative Care, Integra, IRRAS AB, Medtronic, MicroVention, Minnetronix Neuro, Inc, Penumbra, Q’Apel Medical, Inc, Rapid Medical, Serenity Medical, Inc, Silk Road Medical, StimMed, LLC, Stryker Neurovascular, Three Rivers Medical, Inc, VasSol, Viz.ai, Inc, W.L. Gore & Associates. Leadership or fiduciary role in other board, society, committee or advocacy group: Secretary of the Board of the Society of NeuroInterventional Surgery, Chair of the Cerebrovascular Section of the AANS/CNS. Stock or stock options: Adona Medical, Inc, Amnis Therapeutics, Bend IT Technologies, Ltd, BlinkTBI, Inc, Buffalo Technology Partners, Inc, Cardinal Consultants, LLC, Cerebrotech Medical Systems, Inc, Cerevatech Medical, Inc, Cognition Medical, CVAID Ltd, E8, Inc, Endostream Medical, Ltd, Imperative Care, Inc, Instylla, Inc, International Medical Distribution Partners, Launch NY, Inc, NeuroRadial Technologies, Inc, Neurotechnology Investors, Neurovascular Diagnostics, Inc, PerFlow Medical, Ltd, Q’Apel Medical, Inc, QAS.ai, Inc, Radical Catheter Technologies, Inc, Rebound Therapeutics Corp. (Purchased 2019 by Integra Lifesciences, Corp), Rist Neurovascular, Inc (Purchased 2020 by Medtronic), Sense Diagnostics, Inc, Serenity Medical, Inc, Silk Road Medical, Adona Medical, Inc, Amnis Therapeutics, Bend IT Technologies, Ltd, BlinkTBI, Inc, Buffalo Technology Partners, Inc, Cardinal Consultants, LLC, Cerebrotech Medical Systems, Inc, Cerevatech Medical, Inc, Cognition Medical, CVAID Ltd, E8, Inc, Endostream Medical, Ltd, Imperative Care, Inc, Instylla, Inc, International Medical Distribution Partners, Launch NY, Inc, NeuroRadial Technologies, Inc, Neurotechnology Investors, Neurovascular Diagnostics, Inc, PerFlow Medical, Ltd, Q’Apel Medical, Inc, QAS.ai, Inc, Radical Catheter Technologies, Inc, Rebound Therapeutics Corp (Purchased 2019 by Integra Lifesciences, Corp), Rist Neurovascular, Inc (Purchased 2020 by Medtronic), Sense Diagnostics, Inc, Serenity Medical, Inc, Silk Road Medical, SongBird Therapy, Spinnaker Medical, Inc, StimMed, LLC, Synchron, Inc, Three Rivers Medical, Inc, Truvic Medical, Inc, Tulavi Therapeutics, Inc, Vastrax, LLC, VICIS, Inc, Viseon, Inc. Other financial or non-financial interests: National PI/Steering Committees: Cerenovus EXCELLENT and ARISE II Trial; Medtronic SWIFT PRIME, VANTAGE, EMBOLISE and SWIFT DIRECT Trials; MicroVention FRED Trial & CONFIDENCE Study; MUSC POSITIVE Trial; Penumbra 3D Separator Trial, COMPASS Trial, INVEST Trial, MIVI neuroscience EVAQ Trial; Rapid Medical SUCCESS Trial; InspireMD C-GUARDIANS IDE Pivotal Trial., (© Author(s) (or their employer(s)) 2023. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: The primary goal of the CLARYS study is to assess the protection against rebleeding when treating ruptured bifurcation aneurysms with the Woven EndoBridge (WEB) device., Methods: The CLARYS study is a prospective, multicenter study conducted in 13 European centers. Patients with ruptured bifurcation aneurysms were consecutively included between February 2016 and September 2017. The primary endpoint was defined as the rebleeding rate of the target aneurysm treated with the WEB within 30 days postprocedure. Secondary endpoints included periprocedural and postprocedural adverse events, total procedure and fluoroscopy times, and modified Rankin Scale score at 1 month and 1 year., Results: Sixty patients with 60 ruptured bifurcation aneurysms to be treated with the WEB were included. A WEB device was successfully implanted in 93.3%. The rebleeding rate at 1 month and 1 year was 0%. The mean fluoroscopy time was 27.0 min. Twenty-three periprocedural complications were observed in 18 patients and resolved without sequelae in 16 patients. Two of these complications were attributed to the procedure and/or the use of the WEB, leading to a procedure/device-related intraoperative complication rate of 3.3%. Overall mortality at 1 month and 1 year was 1.7% and 3.8%, respectively and overall morbidity at 1 month and 1 year was 15% and 9.6%, respectively. WEB-related 1-month and 1-year morbidity and mortality was 0%., Conclusions: The interim results of CLARYS show that the endovascular treatment of ruptured bifurcation aneurysms with the WEB is safe and effective and, in particular, provides effective protection against rebleeding. It may induce profound change in the endovascular management of ruptured bifurcation aneurysms., Competing Interests: Competing interests: JF acts as associate editor of the Journal of NeuroInterventional Surgery; MM acts as a member of the editorial board of Neuroradiology. LS: consultant for Microvention, Balt, Phenox, Stryker, Medtronic, PI for CLARYS, grant or contract from Philips with institution; DH: consultant for Microvention; XB: consultant for Microvention; JF: Consultant for Medtronic, Microvention, and Cerus; VCo: consultant for Microvention, educational grant and research grant with payment to institution; TL: consultant for Microvention/Sequent Medical, Stryker, Medtronic, and Cerus; MM: consultant and expert testimony for Medtronic, Microvention, and Stryker with payment to institution; WW: payment or honoraria for proctoring and lectures from Microvention; CC: consultant for Microvention, MIVI, Stryker, and Cerenovus; J-HB: payment or honoraria for proctoring and lectures from Microvention; MB: consultant for Microvention, Cerenovus, Acandis, and Rapid; GB: support for travel from Microvention; SF: honoraria for lecture and data preparations regarding WEB; AB: consultant for Microvention; JM: consultant for Microvention. LP: consultant for Microvention, Balt, Perflow, Phenox, Vesalio, clinical event adjudicator for CLARYS; JBy: core laboratory reviewer for CLARYS., (© Author(s) (or their employer(s)) 2022. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Data on outcome after endovascular treatment of basilar artery fenestration aneurysms (BAFAs) is limited. This study presents our multi-centre experience of BAFAs treated by different reconstructive techniques including coils, stent-assisted coiling (SAC), flow diversion and intra-saccular flow disruption with the Woven Endobridge (WEB)., Methods: Retrospective analysis of 38 BAFAs treated endovascularly between 2003 and 2020. The primary endpoint was complete aneurysm obliteration defined as Raymond-Roy occlusion classification (RROC) I on immediate and follow-up (FU) angiography. The secondary endpoints were procedure-related complications, rate of re-treatment, and clinical outcome., Results: Endovascular treatment was feasible in 36/38 aneurysms (95%). The most frequent strategy was coiling (21/36, 58%), followed by SAC (7/36, 19%), WEB embolization (6/36, 17%) and flow diversion (2/36, 6%). A successful aneurysm occlusion (defined as RROC 1 and 2) on the final angiogram was achieved in 30/36 (83%) aneurysms including all patients presenting with baseline subarachnoid haemorrhage and 25/36 (69%) were occluded completely. Complete occlusion (RROC 1) was more frequently achieved in ruptured BAFAs (15/25, 60% v. 2/11, 18%; p  = 0.031). Procedure-related complications occurred in 3/36 (8%) aneurysms. Re-treatment was executed in 12/36 (33%) aneurysms. After a median angiography FU of 38 months, 30/31 (97%) BAFAs were occluded successfully and 25/31 (81%) showed complete occlusion., Conclusion: Reconstructive endovascular treatment of BAFAs is technically feasible with a good safety profile. Although in some cases re-treatment was necessary, a high rate of final aneurysm occlusion was achieved.

Purpose: Identification of country-specific demographic, medical, lifestyle, and geoenvironmental risk factors for cerebral aneurysm rupture in the developing Asian country of Mongolia. First-time estimation of the crude national incidence of aneurysmal subarachnoid hemorrhage (aSAH)., Methods: A retrospective analysis of all intracranial digital subtraction angiographies (DSA) acquired in Mongolia during the 2‑year period 2016-2017 (1714 examinations) was performed. During this period, DSA was used as primary diagnostic imaging modality for acute severe neurological symptoms in the sole hospital nationwide dedicated to neurological patients. The catchment area of the hospital included the whole country. Patients with incidental and ruptured aneurysms were reviewed with respect to their medical history and living conditions. The data was used to install a Mongolian aneurysm registry., Results: The estimated annual crude incidence of cerebral aneurysm rupture was 6.71 for the country of Mongolia and 14.53 per 100,000 persons for the capital region of Ulaanbaatar. Risk factors common in developed countries also applied for the Mongolian population: A medical history of hypertension, smoking or the presence of multiple aneurysms led to a higher relative risk of rupture. In contrast, female gender was not associated with a higher risk in this national cohort. Males pursuing a traditional nomadic living may exhibit a specifically high risk of rupture., Conclusion: Disease management of over 200 individuals/year with aSAH constitutes a socioeconomic burden in Mongolia. Efforts to raise awareness of the risk factors hypertension and smoking among the Mongolian population are desirable. Measures to improve the nationwide availability of modern neurovascular treatment options are currently under consideration., (© 2021. The Author(s).)

Background: Woven EndoBridge (WEB) shape modification (WSM) is a frequently observed phenomenon after aneurysm embolization., Objective: To test our hypothesis that WSM is associated with worse aneurysm occlusion on short-term angiographic follow-up images., Methods: Patients with short-term follow-up digital subtraction angiography (DSA) available were included. Baseline patient characteristics, aneurysm morphometrics, and WEB dimensions ("conventional" parameters) and height and width WSM ("WSM" parameters) in the initial and the follow-up examination were analyzed. For ordinal regression analyses, aneurysm occlusion was graded according to the Bicêtre Occlusion Scale Score (BOSS; grades 0, 0', 1, 2, 3, and 1 + 3). Receiver operating characteristic curve analysis was used to distinguish adequately (BOSS 0, 0', and 1) from incompletely (BOSS 2, 3, and 1 + 3) occluded aneurysms., Results: We included 93 patients with 96 aneurysms. Adequate occlusion was observed in 72 cases (75.0%). In univariate ordinal regression analysis, width WSM in anteroposterior DSA (odds ratio = 0.96, 95% CI: 0.94-0.99, P = .010) and in lateral DSA (odds ratio = 0.98, 95% CI: 0.97-0.99, P = .049) were significantly associated with the BOSS after 6 months. In multivariate regression analysis, WSM was not independently associated with aneurysm occlusion. Based on receiver operating characteristic curve analysis, the area under the curve (AUC) of the "conventional" model (AUC = 0.83, 95% CI 0.74-0.90) was higher than the AUC of the "WSM" model (WSM; AUC = 0.70, 95% CI 0.60-0.79)., Conclusion: WSM was not independently associated with angiographic aneurysm occlusion status after 6 months. However, the "conventional" parameters including sex, rupture state, WEB type, WEB width, aneurysm width, height, and volume were associated with partial aneurysm recanalization in WEB-treated patients at the short-term follow-up., (Copyright © Congress of Neurological Surgeons 2022. All rights reserved.)

Background: The Contour is a novel intra-aneurysmal flow disrupting device to treat intracranial aneurysms., Objective: To evaluate the safety and effectiveness of the Contour device for treatment of nonruptured intracranial bifurcation aneurysms through a prospective, multicenter, single-arm study., Methods: Thirty-four patients were enrolled. Primary end points were successful occlusion at 6 mo for efficacy and any major stroke or nonaccidental death up to 30 d or major disabling stroke within 6 mo for safety. Secondary end points were occlusion at 12 mo, retreatment rate, procedure time, and procedure-related/device-related adverse events. Procedural and follow-up imaging was reviewed by an independent core laboratory. Adverse events were reviewed and adjudicated by a clinical events committee., Results: In total, 32 of 34 aneurysms were successfully implanted and, 2 of 34 in the intention-to-treat (ITT) group did not receive the Contour and were excluded from follow-up after 30 d. In addition, 2 of 32 were lost to angiographic follow-up and regarded as treatment failure. The primary safety end point was met in 2 patients in the ITT group. In the perprotocol (PP) group, complete occlusion was seen in 14 of 32 (44%) at 6 mo and 22 of 32 (69%) at 12 mo. Adequate occlusion (Raymond-Roy [RR] 1 and 2) was reached in 84% at a last available follow-up. One patient from the ITT group and 1 from the PP group received additional treatment during follow-up., Conclusion: The Contour seems to be both safe and effective in the treatment of intracranial bifurcation aneurysms., (Copyright © 2021 The Author(s). Published by Wolters Kluwer Health, Inc on behalf of Congress of Neurological Surgeons.)

Purpose: Endovascular therapy with the Woven EndoBridge (WEB) device is a safe treatment approach, whereby neoendothelialization at the neck area is a crucial element for aneurysm occlusion. We hypothesized that WEB sizing at the aneurysmal neck level has an impact on early aneurysm occlusion., Methods: Patients with short-term follow-up digital subtraction angiography following WEB treatment of unruptured aneurysms were included. Aneurysms were categorized according to the Bicêtre Occlusion Scale Score (BOSS) as adequately (BOSS 0, 0', 1) or partially occluded (BOSS 2, 3, 1 + 3). The WEB device dimensions, including the average aneurysm diameter (AADi) and the average neck diameter (ANDi) as well as baseline patient characteristics were documented., Results: In this study 75 patients with 76 aneurysms were included and 65 aneurysms showed adequate occlusion at short-term follow-up (86%). In univariable logistic regression analysis, smaller differences in WEB size to ANDi (D-ANDi) were significantly associated with adequate aneurysm occlusion (odds ratio, OR = 0.41, 95% confidence interval, CI 0.23-0.71, p = 0.002). Receiver operating characteristic (ROC) curve analyses displayed higher discriminative power for the D‑ANDi (AUC = 0.77, 95% CI 0.66-0.86, cut-off ≤2.9 mm) compared to the difference in WEB size to the average aneurysm diameter (D-AADi, AUC = 0.65, 95% CI 0.53-0.75, cut-off ≤1.0 mm)., Conclusion: Smaller differences between the WEB width and ANDi were associated with adequate early aneurysm occlusion and might thus have a higher impact on the results than the traditional device sizing considering the mean aneurysm diameter. D‑ANDi ≤2.9 mm served as an optimal cut-off to classify occlusion after WEB treatment at the short-term follow-up. Further external validation is warranted., (© 2021. The Author(s).)

Background: WEB treatment is an endovascular approach for wide-neck bifurcation aneurysms that has demonstrated high safety and good efficacy in mid-term follow-up. While evaluating safety in the long term is important to determine if delayed adverse events occur affecting late morbidity and mortality, the most important point to evaluate is the long-term stability of aneurysm occlusion. The current analysis reports the 3-year clinical and anatomical results of WEB treatment in the combined population of two European trials (WEBCAST (WEB Clinical Assessment of Intrasaccular Aneurysm Therapy) and WEBCAST-2)., Methods: Aneurysm occlusion was evaluated using a 3-grade scale: complete occlusion, neck remnant, and aneurysm remnant., Results: The safety population comprised 79 patients. The efficacy population comprised 61 aneurysms. Aneurysm locations were middle cerebral artery in 32/61 aneurysms (52.5%), anterior communicating artery in 13/61 (21.3%), basilar artery in 9/61 (14.8%), and internal carotid artery terminus in 7/61 (11.5%). No adverse events related to the device or procedure occurred between 2 and 3 years. At 3 years, complete occlusion was observed in 31/61 (50.8%) aneurysms, neck remnant in 20/61 (32.8%), and aneurysm remnant in 10/61 (16.4%). Between 1 year and 3 years, aneurysm occlusion was improved or stable in 53/61 (86.9%) aneurysms and worsened in 8/61 (13.1%). Worsening was mostly from complete occlusion to neck remnant in 6/61 (9.8%) aneurysms. The retreatment rate at 3 years was 11.4%., Conclusions: This analysis confirms the high safety profile of WEB. Moreover, evidence demonstrates the great stability of aneurysm occlusion with adequate occlusion (complete occlusion or neck remnant) in 83.6% of aneurysms., Clinical Trial Registration: URL: http://www.clinicaltrials.gov. WEBCAST and WEBCAST-2: Unique identifier: NCT01778322., Competing Interests: Competing interests: LP consults for Balt, MicroVention, Neuravi, and Penumbra. ISI consults for Codman, Medtronic, Sequent, and Stryker. XB consults for MicroVention and Stryker. LS consults for Stryker, MicroVention, Medtronic, and Balt. JF has received fees as consultant or lecturer from Acandis, Bayer, Boehringer-Ingelheim, Codman, Covidien, MicroVention, Penumbra, Philips, Sequent, Siemens, and Stryker; his institution received funding from MicroVention, Medtronic, BMBF, BMWi, DFG, and the EU. VC consults for MicroVention and Balt, and receives educational grants from Medtronic and Stryker. JK consults for MicroVention/Sequent. WW consults for MicroVention, Phenox, and Medtronic. TL consults for Medtronic, Mentice, Microvention, and Route 92. JM consults for Medtronic, MicroVention, Stryker, and Balt. AM consults for MicroVention/Sequent and Cerus Endovascular. JB consults for, and is shareholder of, Oxford Endovascular Ltd; his institution received funding from MicroVention., (© Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

This is a report of the first three cases of endovascular aneurysm treatment that were proctored by a remote interventionalist using a novel high-resolution low-latency streaming technology. The proctor was located in a neurovascular centre and supported the treating interventional teams in two distant cities (up to 800 km/500 miles apart). All aneurysms were treated using the Woven EndoBridge (WEB) embolisation system, either electively or following subarachnoid haemorrhage. On-site proctoring was not possible due to travel restrictions during the COVID-19 pandemic. WEB placement was feasible in all cases. Good rapport between proctors and treating physicians was reported, enabled by the high-resolution image transmission and uninterrupted feedback/discussion via audiostream. No clinical complications were encountered. Short-term follow-up revealed adequate occlusion of all treated aneurysms. The employed streaming technology provided effective remote proctoring during complex aneurysm cases, including the management of technical complications., Competing Interests: Competing interests: JF: research support: German Ministry of Science and Education, German Ministry of Economy and Innovation, German Research Foundation, European Union, Hamburgische Investitions- und Förderbank, Medtronic, Microvention, Route92, Stryker; consultant for Acandis, Bayer, Boehringer Ingelheim, Cerenovus, Evasc Neurovascular, MD Clinicals, Medtronic, Microvention, Penumbra, Phenox, Stryker and Transverse Medical; stock holder: Tegus Medical., (© BMJ Publishing Group Limited 2021. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

It is of utmost importance to avoid errors and subsequent complications when performing neurointerventional procedures, particularly when treating low-risk conditions such as unruptured intracranial aneurysms. We used endovascular treatment of unruptured intracranial aneurysms as an example and took a survey-based approach in which we reached out to 233 neurointerventionalists. They were asked what they think are the most important points staff should teach their trainees to avoid errors and subsequent complications in endovascular treatment of unruptured intracranial aneurysms. One hundred twenty-one respondents (51.9%) provided answers in the form of free text responses, which were thematically clustered in an affinity diagram and summarized in this Practice Perspectives. The article is primarily intended for neurointerventional radiology fellows and junior staff and will hopefully provide them the opportunity to learn from the mistakes of their more experienced colleagues., (© 2021 by American Journal of Neuroradiology.)

This is a report of the first three cases of endovascular aneurysm treatment that were proctored by a remote interventionalist using a novel high-resolution low-latency streaming technology. The proctor was located in a neurovascular centre and supported the treating interventional teams in two distant cities (up to 800 km/500 miles apart). All aneurysms were treated using the Woven EndoBridge (WEB) embolisation system, either electively or following subarachnoid haemorrhage. On-site proctoring was not possible due to travel restrictions during the COVID-19 pandemic. WEB placement was feasible in all cases. Good rapport between proctors and treating physicians was reported, enabled by the high-resolution image transmission and uninterrupted feedback/discussion via audiostream. No clinical complications were encountered. Short-term follow-up revealed adequate occlusion of all treated aneurysms. The employed streaming technology provided effective remote proctoring during complex aneurysm cases, including the management of technical complications., Competing Interests: Competing interests: JF: research support: German Ministry of Science and Education, German Ministry of Economy and Innovation, German Research Foundation, European Union, Hamburgische Investitions- und Förderbank, Medtronic, Microvention, Route92, Stryker; consultant for Acandis, Bayer, Boehringer Ingelheim, Cerenovus, Evasc Neurovascular, MD Clinicals, Medtronic, Microvention, Penumbra, Phenox, Stryker and Transverse Medical; stock holder: Tegus Medical., (© BMJ Publishing Group Limited 2020. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background and Purpose: There is a paucity of data regarding antiplatelet management strategies in the setting of stent-assisted coiling/flow diversion for ruptured intracranial aneurysms. This study aimed to identify current challenges in antiplatelet management during stent-assisted coiling/flow diversion for ruptured intracranial aneurysms and to outline possible antiplatelet management strategies., Materials and Methods: The modified DELPHI approach with an on-line questionnaire was sent in several iterations to an international, multidisciplinary panel of 15 neurointerventionalists. The first round consisted of open-ended questions, followed by closed-ended questions in the subsequent rounds. Responses were analyzed in an anonymous fashion and summarized in the final manuscript draft. The statement received endorsement from the World Federation of Interventional and Therapeutic Neuroradiology, the Japanese Society for Neuroendovascular Therapy, and the Chinese Neurosurgical Society., Results: Data were collected from December 9, 2019, to March 13, 2020. Panel members achieved consensus that platelet function testing may not be necessary and that antiplatelet management for stent-assisted coiling and flow diversion of ruptured intracranial aneurysms can follow the same principles. Preprocedural placement of a ventricular drain was thought to be beneficial in cases with a high risk of hydrocephalus. A periprocedural dual, intravenous, antiplatelet regimen with aspirin and a glycoprotein IIb/IIIa inhibitor was preferred as a standard approach. The panel agreed that intravenous medication can be converted to oral aspirin and an oral P2Y12 inhibitor within 24 hours after the procedure., Conclusions: More and better data on antiplatelet management of patients with ruptured intracranial aneurysms undergoing stent-assisted coiling or flow diversion are urgently needed. Panel members in this DELPHI consensus study preferred a periprocedural dual-antiplatelet regimen with aspirin and a glycoprotein IIb/IIIa inhibitor., (© 2020 by American Journal of Neuroradiology.)

Background: Woven EndoBridge (WEB; Sequent Medical) treatment is an innovative endovascular approach for treatment of wide-neck bifurcation aneurysms. Initial studies have shown high safety with good efficacy at short term confirmed by trials conducted in United States (WEB-Intrasaccular Therapy) and in Europe (WEB Clinical Assessment of Intrasaccular Aneurysm Therapy [WEBCAST], French Observatory, and WEBCAST-2)., Objective: To report the 2-yr clinical and anatomical results of WEB treatment in the combined population of 3 European trials., Methods: In a French Observatory, 2-yr clinical and anatomical data were collected. In WEBCAST and WEBCAST-2, 2-yr follow-up was optional, and data were collected when follow-up was performed. Aneurysm occlusion was evaluated using a 3-grade scale: complete occlusion, neck remnant, and aneurysm remnant., Results: The population for safety was 138/168 patients (82.1%), including 89 females (64.5%), with mean age of 55.5 ± 10.2 yr. The population for efficacy was 121/169 aneurysms (71.6%). Aneurysm locations were middle cerebral artery in 65/121 aneurysms (53.7%), anterior-communicating artery in 25/121 (20.7%), basilar artery in 17/121 (14.0%), and internal carotid artery terminus in 14/121 (11.6%). No clinically relevant adverse events occurred between years 1 and 2. At 2 yr, complete occlusion was observed in 62/121 (51.2%) aneurysms, neck remnant in 36/121 (29.8%) aneurysms, and aneurysm remnant in 23/121 (19.0%) aneurysms. The global retreatment rate at 2 yr was 9.3%., Conclusion: This analysis confirms the high safety profile of WEB treatment at 2 yr. Aneurysm occlusion is generally stable at 2 yr, and the retreatment rate between 1 yr and 2 yr is low (2.0%)., (© Congress of Neurological Surgeons 2020.)

Background and Purpose: The Woven EndoBridge (WEB) device is an established technique for the treatment of intracranial aneurysms. Occasionally, persistent opacification inside the WEB lumen can be observed at follow-up (previously described as Bicêtre Occlusion Scale Score 1). We evaluated potential risk factors of this phenomenon, hypothesizing that initial deviation of the WEB device from the aneurysm axis, size of the aneurysmal neck surface, or inappropriate WEB sizing correlates with Bicêtre Occlusion Scale Score 1 findings., Materials and Methods: We systematically reviewed all patients treated with the WEB device between February 2014 and December 2018 in our neurointerventional center. Patients with midterm follow-up DSA available were considered for aneurysm evaluation applying the Bicêtre Occlusion Scale Score. WEB angle deviation from the aneurysm axis, neck widths, and WEB sizes were collected., Results: We included 65 patients with 67 intracranial aneurysms. Eleven of 67 (16.4%) intracranial aneurysms showed the Bicêtre Occlusion Scale Score 1 phenomenon at follow-up. Anterior-posterior projections of WEB axis deviation (angles measured in degrees) were significantly different between the Bicêtre Occlusion Scale Score 1 cohort (median ± interquartile range, 17 ± 17) and all other Bicêtre Occlusion Scale Scores (median ± interquartile range, 7 ± 11; P = .023), whereas in lateral projections, no significant difference was observed (median ± interquartile range, 10 ± 10 versus 8 ± 9; P = .169). Neck or aneurysm recurrence, but not the Bicêtre Occlusion Scale Score 1 phenomenon, occurred significantly more often in patients with inappropriate WEB sizing compared with appropriate WEB sizing (median ± interquartile range, 1 ± 1.3 versus 0 ± 0; P  < .001/ P = .664)., Conclusions: The Bicêtre Occlusion Scale Score 1 phenomenon is associated with an initial deviation of the WEB device from the aneurysm axis but does not correlate with aneurysmal neck surface measurements or WEB sizing., (© 2020 by American Journal of Neuroradiology.)

Background: Rapid development in endovascular aneurysm therapy continuously drives demand for suitable neurointerventional training opportunities., Objective: To investigate the value of an integrated modular neurovascular training environment for aneurysm embolization using additively manufactured vascular models., Methods: A large portfolio of 30 patient-specific aneurysm models derived from different treatment settings (eg, coiling, flow diversion, flow disruption) was fabricated using additive manufacturing. Models were integrated into a customizable neurointerventional simulator with interchangeable intracranial and cervical vessel segments and physiological circuit conditions ('HANNES'; Hamburg ANatomic Neurointerventional Endovascular Simulator). Multiple training courses were performed and participant feedback was obtained using a questionnaire., Results: Training for aneurysm embolization could be reliably performed using HANNES. Case-specific clinical difficulties, such as difficult aneurysm access or coil dislocation, could be reproduced. During a training session, models could be easily exchanged owing to standardized connectors in order to switch to a different treatment situation or to change from 'treated' back to 'untreated' condition. Among 23 participants evaluating hands-on courses using a five-point scale from 1 (strongly agree) to 5 (strongly disagree), HANNES was mostly rated as 'highly suitable for practicing aneurysm coil embolization' (1.78±0.79)., Conclusion: HANNES offers a wide variability and flexibility for case-specific hands-on training of intracranial aneurysm treatment, providing equal training conditions for each situation. The high degree of standardization offered may be valuable for analysis of device behavior or assessment of physician skills. Moreover, it has the ability to reduce the need for animal experiments., Competing Interests: Competing interests: The prepared patent is currently being reviewed by the corresponding authority; no other relationships or activities that could appear to have influenced the submitted work., (© Author(s) (or their employer(s)) 2020. No commercial re-use. See rights and permissions. Published by BMJ.)

Background and Purpose: Although the role of wall shear stress (WSS) in the initiation, growth, and rupture of intracranial aneurysms has been well studied, its influence on aneurysm recurrence after endovascular treatment requires further investigation. We aimed to compare WSS at necks of recurrent and nonrecurrent aneurysms., Methods: Nine recurrent coil-embolized aneurysms were identified and matched with nine nonrecurrent aneurysms. Patient-specific vessel geometries reconstructed from follow-up 3-D time-of-flight magnetic resonance angiography were analyzed using computational fluid dynamics (CFD) simulations. Absolute WSS and the percentage of abnormally low and high WSS at the aneurysm neck compared to the near artery were measured., Results: The median percentage of abnormal WSS at the aneurysm neck was 49.3% for recurrent and 34.7% for nonrecurrent aneurysms (P = .011). The area under the receiver-operating-characteristic curve for distinguishing these aneurysms according to the percentage of abnormal WSS was .86 (95% CI .62 to .98). The optimal cut-off value of 45.1% resulted in a sensitivity and a specificity of 88.89% (95% CI 51.8% to 99.7%)., Conclusion: Our findings indicate that necks of recurrent aneurysms are exposed to abnormal WSS to a larger extent. Abnormal WSS may serve as a metric to distinguish them from nonrecurrent aneurysms with CFD simulations a priori., (© 2019 by the American Society of Neuroimaging.)

Background and Purpose: To evaluate factors influencing the confidence of management recommendation for unruptured intracranial aneurysms (UIAs) and to assess the ability of neurointerventionalists to predict procedure-related neurological complications compared with a 3-point risk score., Materials and Methods: Twenty-eight neurointerventionalists were asked to evaluate digital subtraction angiographies examinations of patients with UIAs by determining the best management approach, their level of confidence in their management recommendation, and estimating the risk of procedure-related neurological complications. Knowledge and experience in interventional neuroradiology (INR) of each participant were assessed., Results: Reliability was moderate regarding any treatment recommendation (ICC=0.49) and low regarding the estimation of risk of complications (ICC=0.38). The recommendation of clipping was less likely with more experience in INR (OR=0.6) and more likely with increasing knowledge (OR=1.7). Odds of recommending WEB device were lower with more experience in INR (OR=0.6), higher in patients with multiple aneurysms (OR=3.6) and increasing neck width (OR=2.7). The recommendation of stent-assisted coiling was more likely with increasing neck width (OR=2.4) and when cerebral ischemic comorbidities were present (OR=2.9). The participants were significantly worse than the risk score (mean area under the curve of 0.53) and not better than random guess in predicting complications. Neither knowledge nor experience in INR was significantly associated with the participants' ability to predict neurological complications., Conclusions: Our study shows a moderate interrater reliability of treatment recommendations of UIAs. Confidence in treatment recommendation varied significantly according to recommended treatments. Overall performance in predicting neurological complications was worse than the risk score and not better than random guess., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2019. No commercial re-use. See rights and permissions. Published by BMJ.)

Background and Purpose: Evidence on how to select microcatheters to facilitate aneurysm catheterization during coil embolization is sparse. We developed a new method to define microcatheter tip location inside a patient-specific aneurysm model as a 3-dimensional probability map. We hypothesized that precision and accuracy of microcatheter tip positioning depend on catheter tip shape and aneurysmal geometry., Materials and Methods: Under fluoroscopic guidance two to three operators introduced differently shaped microcatheters (straight, 45°, 90°) into eight aneurysm models targeting the anatomic center of the aneurysm. Each microcatheter position was recorded with flat-panel CT, and 3-dimensional probability maps of the microcatheter tip positions were generated. Maps were assessed with histogram analyses and compared between tip shapes, aneurysm locations and operators., Results: Among a total of 530 microcatheter insertions, the precision (mean distance between catheter positions) and accuracy (mean distance to target position) were significantly higher for the 45° tip (1.10±0.64 mm, 3.81±1.41 mm, respectively) than for the 90° tip (1.27±0.57 mm, p=0.010; 4.21±1.60 mm p=0.014, respectively). Accuracy was significantly higher in posterior communicating artery aneurysms (3.38±1.20 mm) than in aneurysms of the internal carotid artery (4.56±1.54 mm, p<0.001)., Conclusion: Our method can be used tostatistically describe statistically microcatheter behavior in patient-specific anatomy, which may improve the available evidence guiding microcatheter shape selection. Experience increases the ability to reach the intended position with a microcatheter (accuracy) that is also dependent on the aneurysm location, whereas catheter tip choice determines the variability of catheter tip placements versus each other (precision). Clinical validation is required., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2019. No commercial re-use. See rights and permissions. Published by BMJ.)

Rationale: Unruptured intracranial aneurysms are currently left untreated if the presumed complication risk of preventive endovascular or neurosurgical intervention is higher than the risk of rupture. Aneurysm wall inflammation and blood pressure are attractive modifiable risk factors of aneurysm rupture and growth., Aim: To investigate in patients with an unruptured intracranial aneurysm who do not qualify for preventive endovascular or neurosurgical intervention whether a treatment strategy of acetylsalicylic acid 100 mg/day plus intensive blood pressure treatment (targeted systolic blood pressure < 120 mmHg, monitored with a home blood pressure measuring device) reduces the risk of aneurysm rupture or growth compared with care as usual (no acetylsalicylic acid, targeted office systolic blood pressure < 140 mmHg, no home blood pressure measuring device)., Sample Size: We aim to randomize 776 patients 1:1 to the intervention arm or care as usual., Design: Bi-national (Germany and the Netherlands) multicenter, prospective, randomized, open-label phase III trial with blinded outcome assessment., Outcomes: The primary outcome is aneurysm rupture or growth (increase in any aneurysm diameter by ≥ 1 mm) on repeated MR or CT angiography within 36 ± 6 months after randomization., Discussion: The Prospective Randomized Open-label Trial to Evaluate risk faCTor management in patients with Unruptured intracranial aneurysms (PROTECT-U) is the first randomized trial to investigate if a medical strategy reduces the risk of rupture or growth of intracranial aneurysms in patients not undergoing preventive endovascular or neurosurgical aneurysm treatment. Clinical trial Registration: NCT03063541.

Objective: To evaluate multiparametric MRI including non-contrast and contrast-enhanced morphological and angiographic techniques for intracranial aneurysms treated with the single-layer Woven EndoBridge (WEB) embolization system applying simultaneous digital subtraction angiography (DSA) as the reference of standard., Materials and Methods: We retrospectively identified all patients with incidental and acute ruptured intracranial aneurysms treated with a WEB device (WEB SL and WEB SLS) between March 2014 and June 2016 in our neurovascular center with early (within 7 days) postinterventional multiparametric MRI as well as mid-term (5-8 months) follow-up MRI and DSA available. Occlusion rates were recorded both in DSA and MR angiography (MRA). In MRI, signal intensities within the WEB as well as in the occluded dome distal to the WEB, if present, were measured by region-of-interest (ROI) analysis., Results: Twenty-five patients fulfilled the inclusion criteria. Rates of complete/adequate occlusion at mid-term follow-up were 84% with both MRA and DSA. A strong signal loss within the WEB was observed in all MR sequences at initial and follow-up examinations. ROI analysis did not reveal significant differences in non-contrast (P=0.946) and contrast-enhanced imaging (P=0.377). A T1-hyperintense thrombus in the non-WEB-carrying dome was a frequent observation., Conclusions: Signal intensity measurements in multiparametric MRI suggest that neither contrast-enhanced MRA nor morphological sequences are capable of revealing reliable information on the WEB lumen, presumably due to radio frequency shielding. MRI is therefore not suitable for confirming complete thrombus formation within the WEB., Competing Interests: Competing interests: None declared., (© Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

Cardiac-cycle related pulsatile aneurysm motion and deformation is assumed to provide valuable information for assessing cerebral aneurysm rupture risk. Accordingly, numerous studies addressed quantification of cerebral aneurysm wall motion and deformation. Most of them utilized in vivo imaging data, but image-based aneurysm deformation quantification is subject to pronounced uncertainties: unknown ground-truth deformation; image resolution in the order of the expected deformation; direct interplay between contrast agent inflow and image intensity. To analyze the impact of the uncertainties on deformation quantification, a multi-imaging modality ground-truth phantom study is performed. A physical flow phantom was designed that allowed simulating pulsatile flow through a variety of modeled cerebral vascular structures. The phantom was imaged using different modalities [MRI, CT, 3D-RA] and mimicking physiologically realistic flow conditions. Resulting image data was analyzed by an established registration-based approach for automated wall motion quantification. The data reveals severe dependency between contrast media inflow-related image intensity changes and the extent of estimated wall deformation. The study illustrates that imaging-related uncertainties affect the accuracy of cerebral aneurysm deformation quantification, suggesting that in vivo imaging studies have to be accompanied by ground-truth phantom experiments to foster data interpretation and to prove plausibility of the applied image analysis algorithms.

Background: Understanding aneurysm growth is critical for the appropriate follow-up of patients after coil embolization and the need for retreatment. The purpose of the study was to stratify the growth dynamics of aneurysm recurrences after coiling by volumetric analysis and to determine predictive factors for aneurysm recurrences., Methods: Source images of follow-up three-dimensional time of flight MR angiography (ToF-MRA) scans were compared with the first post-interventional ToF-MRA scan and analyzed for residual flow after co-registration using ANALYZE-software. In the event of incomplete occlusion, the residual volume was segmented and calculated. Growth dynamic was determined for each aneurysm after embolization., Results: We analyzed 326 patients with 345 aneurysms from two centers. Each case had at least two ToF-MRA examinations after endovascular therapy. The mean observation interval was 59 months. Volumetric analysis of 1139 follow-up MRAs revealed that 218/345 aneurysms (63.2%) showed complete occlusion on initial follow-up imaging, and of these 95.0% remained stable. A steady increase in intra-aneurysmal flow was observed in 83/345 (24.1%). Less frequent observations were a steep increase (21/345; 6.1%) and a decrease (27/345; 7.8%). Independent predictors of increasing residual flow were greatest aneurysm diameter, total coil length, and incomplete occlusion., Conclusions: Volumetric analysis of registered three-dimensional ToF-MRA follow-up datasets allows the detection of different growth patterns with high precision, avoids the low inter-rater reliability, and represents a promising approach for future studies that include analysis of more complex predictors of residual flow. In cases of aneurysm recurrence after coiling, the major pattern seems to be a steady increase in intra-aneurysmal flow over several months., Competing Interests: Competing interests: None declared., (© Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

Background: Flow disruption with the WEB is an innovative endovascular approach for treatment of wide-neck bifurcation aneurysms. Initial studies have shown a low complication rate with good efficacy., Purpose: To report clinical and anatomical results of the WEB treatment in the cumulative population of three Good Clinical Practice (GCP) studies: WEBCAST (WEB Clinical Assessment of Intrasaccular Aneurysm), French Observatory, and WEBCAST-2., Methods: WEBCAST, French Observatory, and WEBCAST-2 are single-arm, prospective, multicenter, GCP studies dedicated to the evaluation of WEB treatment. Clinical data were independently evaluated. Postoperative and 1-year aneurysm occlusion was independently evaluated using the 3-grade scale: complete occlusion, neck remnant, and aneurysm remnant., Results: The cumulative population comprised 168 patients with 169 aneurysms, including 112 female subjects (66.7%). The patients' ages ranged between 27 and 77 years (mean 55.5±10.2 years). Aneurysm locations were middle cerebral artery in 86/169 aneurysms (50.9%), anterior communicating artery in 36/169 (21.3%), basilar artery in 30/169 (17.8%), and internal carotid artery terminus in 17/169 (10.1%). The aneurysm was ruptured in 14/169 (8.3%). There was no mortality at 1 month and procedure/device-related morbidity was 1.2% (2/168). At 1 year, complete aneurysm occlusion was observed in 81/153 aneurysms (52.9%), neck remnant in 40/153 aneurysms (26.1%), and aneurysm remnant in 32/153 aneurysms (20.9%). Re-treatment was carried out in 6.9%., Conclusions: This series is at the moment the largest prospective, multicenter, GCP series of patients with aneurysms treated with WEB. It shows the high safety and good mid-term efficacy of this treatment., Clinical Trial Registration: French Observatory: Unique identifier (NCT18069); WEBCAST and WEBCAST-2: Unique identifier (NCT01778322)., Competing Interests: Competing interests: LP: consultant for Balt, Microvention, Neuravi, and Penumbra. JM: consultant for Medtronic, Microvention, Stryker, and Balt. XB: consultant for Microvention and Stryker. ISI: consultant for Codman, Medtronic, Sequent, and Stryker. VC: consultant for Microvention and Balt and receives educational grants from Medtronic and Stryker. JF: has received fees as consultant or lecturer from Acandis, Bayer, Boehringer-Ingelheim, Codman, Covidien, MicroVention, Penumbra, Philips, Sequent, Siemens, and Stryker; his institution received funding from MicroVention, Medtronic, BMBF, BMWi, DFG, EU. JK: consultant for Microvention/Sequent. WW: consultant for Microvention, Phenox, and Medtronic. TL: consultant for Medtronic, Mentice, Microvention, and Route92. AM: consultant for Microvention/Sequent and Cerus Endovascular. JB: consultant and shareholder for Oxford Endovascular Ltd; his institution received funding from MicroVention. LS: consultant for Stryker, MicroVention, Medtronic, Balt. J-YG, HD, and SV have no disclosures., (© Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

Background and Purpose: Angiographic occlusion and retreatment of coiled aneurysms are commonly used as surrogate end points in clinical trials. We aimed to evaluate the influence of aneurysm, patient, and rater characteristics on the confidence of visual evaluation of aneurysm coiling and retreatment decisions., Materials and Methods: Twenty-six participants of the Advanced Course in Endovascular Interventional Neuroradiology of the European Society of Neuroradiology were asked to evaluate digital subtraction angiography examinations of patients who had undergone endovascular coiling, by determining the grade of aneurysm occlusion, the change between immediate postprocedural and follow-up angiograms, their level of confidence, the technical difficulty of retreatment, and the best therapeutic approach. The experience, knowledge, and skills of each participant were assessed. The influence of rater and case characteristics on indicated confidence in diagnostic ratings and retreatment recommendations was analyzed., Results: Interrater reliability was moderate regarding the assessment of aneurysm occlusion grade (intraclass correlation coefficient = 0.581) and substantial regarding change (intraclass correlation coefficient = 0.776). Overall confidence in the diagnostic rating was high (median, "very certain"). Confidence was statistically significantly higher in cases that were generally rated as "worse." The odds of recommending retreatment were significantly higher in cases that were generally rated with higher mean confidence., Conclusions: Although overall confidence in the diagnostic rating was high, our study confirms the suboptimal interrater reliability of visual assessment of aneurysm occlusion as well as retreatment recommendations, rendering both questionable as primary outcome measures. Besides recurrence status, recommendation of retreatment is significantly influenced by patient age, aneurysm neck width, and characteristics of the therapist., (© 2018 by American Journal of Neuroradiology.)

Background and Purpose: Endovascular embolization of intracranial aneurysms with hydrogel-coated coils lowers the risk of major recurrence, but technical limitations (coil stiffness and time restriction for placement) have prevented their wider clinical use. We aimed to assess the efficacy of softer, second-generation hydrogel coils., Methods: A randomized controlled trial was conducted at 22 centers in France and Germany. Patients aged 18 to 75 years with untreated ruptured or unruptured intracranial aneurysms measuring 4 to 12 mm in diameter were eligible and randomized (1:1 using a web-based system, stratified by rupture status) to coiling with either second-generation hydrogel coils or bare platinum coils. Assist devices were allowed as clinically required. Independent imaging core laboratory was masked to allocation. Primary end point was a composite outcome measure including major aneurysm recurrence, aneurysm retreatment, morbidity that prevented angiographic controls, and any death during treatment and follow-up. Data were analyzed as randomized., Results: Randomization began on October 15, 2009, and stopped on January 31, 2014, after 513 patients (hydrogel, n=256; bare platinum, n=257); 20 patients were excluded for missing informed consent and 9 for treatment-related criteria. Four hundred eighty-four patients (hydrogel, n=243; bare platinum, n=241) were included in the analysis; 208 (43%) were treated for ruptured aneurysms. Final end point data were available for 456 patients. Forty-five out of 226 (19.9%) patients in the hydrogel group and 66/230 (28.7%) in the control group had an unfavorable composite primary outcome, giving a statistically significant reduction in the proportion of an unfavorable composite primary outcome with hydrogel coils-adjusted for rupture status-of 8.4% (95% confidence interval, 0.5-16.2; P =0.036). Adverse and serious adverse events were evenly distributed between groups., Conclusions: Our results suggest that endovascular coil embolization with second-generation hydrogel coils may reduce the rate of unfavorable outcome events in patients with small- and medium-sized intracranial aneurysms., Clinical Trial Registration: URL: https://www.drks.de/drks&#95;web/. Unique identifier: DRKS00003132., (© 2018 The Authors.)

Background and Purpose: Flow disruption achieved by braided intrasaccular implants is a novel treatment strategy for cerebrovascular aneurysms. We hypothesized that the degree of intra-aneurysmal flow disruption can be quantified in vitro and is influenced by device position across the aneurysm neck. We tested this hypothesis using the Medina® Embolization Device (MED)., Methods: Ten different patient-specific elastic vascular models were manufactured. Models were connected to a pulsatile flow circuit, filled with a blood-mimicking fluid and treated by two operators using a single MED. Intra-aneurysmal flow velocity was measured using conventional and high-frequency digital subtraction angiography (HF-DSA) before and after each deployment. Aneurysm neck coverage by the implanted devices was assessed with flat detector computed tomography on a three-point Likert scale., Results: A total of 80 individual MED deployments were performed by the two operators. The mean intra-aneurysmal flow velocity reduction after MED implantation was 33.6% (27.5-39.7%). No significant differences in neck coverage (p = 0.99) or flow disruption (p = 0.84) were observed between operators. The degree of flow disruption significantly correlated with neck coverage (ρ = 0.42, 95% CI: 0.21-0.59, p = 0.002) as well as with neck area (ρ = -0,35, 95% CI: -0.54 --0.13, p = 0.024). On multiple regression analysis, both neck coverage and total neck area were independent predictors of flow disruption., Conclusions: The degree of intra-aneurysmal flow disruption after MED implantation can be quantified in vitro and varies considerably between different aneurysms and different device configurations. Optimal device coverage across the aneurysm neck improves flow disruption and may thus contribute to aneurysm occlusion.

Background and Purpose: Flow disruption with the Woven EndoBridge (WEB) device is an innovative technique for the endovascular treatment of wide-neck bifurcation aneurysms. The initial version of the device (WEB Double-Layer) was evaluated in the WEB Clinical Assessment of IntraSaccular Aneurysm Therapy (WEBCAST) study, whereas the French Observatory study evaluated both WEB Double-Layer and Single-Layer versions of the device. WEBCAST 2 was designed to evaluate the WEB Single-Layer with Enhanced Visualization., Materials and Methods: Patients with wide-neck bifurcation aneurysms for which WEB treatment was possible were included. Clinical data including adverse events and clinical status at 1 month and 1 year were collected and analyzed. A core laboratory evaluated anatomic results at 1 year following the procedure., Results: Ten European neurointerventional centers included 55 patients (38 women; 27-77 years of age; mean, 54.4 ± 10.0 years) with 55 aneurysms. Aneurysm locations were the middle cerebral artery in 25 aneurysms (45.5%), the anterior communicating artery in 16 (29.1%), the basilar artery in 9 (16.4%), and the internal carotid artery terminus in 5 (9.1%). Procedural morbidity and mortality at 1 month were, respectively, 1.8% (1/55 patients) and 0.0% (0/55 patients). Morbidity and mortality at 1 year were, respectively, 3.9% (2/51 patients) and 2.0% (1/51 patients). At 1 year, complete occlusion was observed in 27/50 aneurysms (54.0%); neck remnant, in 13/50 (26.0%); and aneurysm remnant, in 10/50 (20.0%) (adequate occlusion in 40/50, 80.0%)., Conclusions: WEBCAST 2 confirms the high safety and efficacy of WEB aneurysm treatment demonstrated in the WEBCAST and French Observatory studies., (© 2017 by American Journal of Neuroradiology.)

Background and Purpose: The analysis of the pulsation of unruptured intracranial aneurysms might improve the assessment of their stability and risk of rupture. Pulsations can easily be concealed due to the small movements of the aneurysm wall, making post-processing highly demanding. We hypothesized that the quantification of aneurysm pulsation is technically feasible and can be improved by computer-aided post-processing., Materials and Methods: Images of 14 cerebral aneurysms were acquired with an ECG-triggered 4D CTA. Aneurysms were post-processed manually and computer-aided on a 3D model. Volume curves and random noise-curves were compared with the arterial pulse wave and volume curves were compared between both post-processing modalities., Results: The aneurysm volume curves showed higher similarity with the pulse wave than the random curves (Hausdorff-distances 0.12 vs 0.25, p<0.01). Both post-processing methods did not differ in intra- (r = 0.45 vs r = 0.54, p>0.05) and inter-observer (r = 0.45 vs r = 0.54, p>0.05) reliability. Time needed for segmentation was significantly reduced in the computer-aided group (3.9 ± 1.8 min vs 20.8 ± 7.8 min, p<0.01)., Conclusion: Our results show pulsatile changes in a subset of the studied aneurysms with the final prove of underlying volume changes remaining unsettled. Semi-automatic post-processing significantly reduces post-processing time but cannot yet replace manual segmentation., Competing Interests: The authors have declared that no competing interests exist.

Introduction: Hybrid hydrogel-platinum coils (HydroCoil) have proven effective for endovascular aneurysm treatment. To overcome technical limitations (coil stiffness, time restriction for placement), a second generation of softer hydrogel coils has been brought to clinical practice (HydroSoft, HydroFrame). We report on procedural safety and core-lab-assessed angiographic results from an open-label multicenter randomized controlled trial., Methods: Web-based randomization occurred in 15 medical centers in France and seven in Germany between coil embolization with second-generation hydrogel coils and treatment with any bare platinum coil. Assist devices could be used as clinically required. Primary endpoint is a composite outcome including major aneurysm recurrence and poor clinical outcome at 18 months follow-up., Results: Five hundred thirteen patients were randomized (hydrogel n = 256, bare platinum n = 257). Twenty patients were excluded for missing informed consent and nine patients for treatment related criteria. Four hundred eighty-four patients were analyzed as randomized (hydrogel n = 243, bare platinum n = 241). Two hundred eight had ruptured aneurysms (43 %). Prespecified procedural complications occurred in 58 subjects (hydrogel n = 28, bare platinum n = 30, p = 0.77). The 14-day mortality rate was 2.1 % in both arms of the study. The median calculated packing densities for aneurysms assigned to hydrogel and bare platinum were 39 and 31 % respectively (p < 0.001). No statistically significant differences were found between arms in the post procedural angiographic occlusion rate (p = 0.8)., Conclusion: Second-generation hydrogel coils can be used in a wide spectrum of aneurysms with a risk profile equivalent to bare platinum. Packing density was significantly higher in aneurysms treated with hydrogel coils., Trial Registration: http://www.germanctr.de , DRKS00003132.

Purpose: Considerable inter-observer variability in the visual assessment of aneurysm recurrences limits its use as an outcome parameter evaluating new coil generations. The purpose of this study was to compare visual assessment of aneurysm recurrences and aneurysm recurrence volumetry with an example dataset of HydroSoft coils (HSC) versus bare platinum coils (BPC)., Methods: For this retrospective study, 3-dimensional time-of-flight magnetic resonance angiography datasets acquired 6 and 12 months after endovascular therapy using BPC only or mainly HSC were analyzed. Aneurysm recurrence volumes were visually rated by two observersas well as quantified by subtraction of the datasets after intensity-based rigid registration., Results: A total of 297 aneurysms were analyzed (BPC: 169, HSC: 128). Recurrences were detected by aneurysm recurrence volumetry in 9 of 128 (7.0 %) treated with HSC and in 24 of 169 (14.2 %) treated with BPC (odds ratio: 2.39, 95 % confidence interval: 1.05-5.48; P = 0.039). Aneurysm recurrence volumetry revealed an excellent correlation between observers (Cronbach's alpha = 0.93). In contrast, no significant difference in aneurysm recurrence was found for visual assessment (3.9 % in HSC cases and 4.7 % in BPC cases). Recurrences were observed in aneurysms smaller than the sample median in 10 of 33 (30.3 %) by aneurysm recurrence volumetry and in 1 of 13 (7.7 %) by visual assessment., Conclusions: Aneurysm recurrences were detected more frequently by aneurysm recurrence volumetry when compared with visual assessment. By using aneurysm recurrence volumetry, differences between treatment groups were detected with higher sensitivity and inter-observer validity probably because of the higher detection rate of recurrences in small aneurysms.

Background and Purpose: As part of a multicenter cooperation (Aneurysm-Like Synthetic bodies for Testing Endovascular devices in 3D Reality) with focus on implementation of additive manufacturing in neuroradiologic practice, we systematically assessed the technical feasibility and accuracy of several additive manufacturing techniques. We evaluated the method of fused deposition modeling for the production of aneurysm models replicating patient-specific anatomy., Materials and Methods: 3D rotational angiographic data from 10 aneurysms were processed to obtain volumetric models suitable for fused deposition modeling. A hollow aneurysm model with connectors for silicone tubes was fabricated by using acrylonitrile butadiene styrene. Support material was dissolved, and surfaces were finished by using NanoSeal. The resulting models were filled with iodinated contrast media. 3D rotational angiography of the models was acquired, and aneurysm geometry was compared with the original patient data., Results: Reproduction of hollow aneurysm models was technically feasible in 8 of 10 cases, with aneurysm sizes ranging from 41 to 2928 mm(3) (aneurysm diameter, 3-19 mm). A high level of anatomic accuracy was observed, with a mean Dice index of 93.6% ± 2.4%. Obstructions were encountered in vessel segments of <1 mm., Conclusions: Fused deposition modeling is a promising technique, which allows rapid and precise replication of cerebral aneurysms. The porosity of the models can be overcome by surface finishing. Models produced with fused deposition modeling may serve as educational and research tools and could be used to individualize treatment planning., (© 2016 by American Journal of Neuroradiology.)

Background and Purpose: Angiographic occlusion as a surrogate marker of satisfactory aneurysm treatment is commonly used in clinical trials although some pitfalls have to be considered. To investigate the inter-rater reliability of visual rating of aneurysm occlusion as study end point, we performed a systematic review and meta-analysis., Methods: Electronic databases (MEDLINE, EMBASE, PubMed, and the Cochrane Library) were searched up to June 2014. Assessment of risk for bias was based on the Quality Appraisal Tool for Studies of Diagnostic Reliability and the Guidelines for Reporting Reliability and Agreement studies. Inter-rater reliability estimates were pooled across studies using meta-analysis, and the influence of several factors (eg, imaging methods, grading scales, and occlusion rate) was tested with meta-regression., Results: From 1193 titles, 644 abstracts and 87 full-text versions were reviewed. Twenty-six articles met the inclusion criteria and provided 77 reliability estimates. Twenty-one different rating scales were used, and statistical analysis varied. Mean inter-rater agreement of the pooled studies was substantial (κ=0.65; 95% confidence interval, 0.60-0.69). Reliability varied significantly as a function of imaging methods, grading scales, occlusion rates, and their interaction. Observer agreement substantially increased with increasing occlusion rate in digital subtraction angiography but not in MR angiography. Reliability was higher in studies using 2- or 3-value grading scales than in studies with 4-value grading scales., Conclusions: There is significant heterogeneity between studies evaluating the reliability of visual evaluation of aneurysm coiling. On the basis of our analysis, we found that the combination of magnetic resonance angiography, 3-value grading scale, and 2 trained raters seems most promising for usage as surrogate study end points., (© 2015 American Heart Association, Inc.)

Background and Purpose: Electrocardiogram-gated 4D-CTA is a promising technique allowing new insight into aneurysm pathophysiology and possibly improving risk prediction of cerebral aneurysms. Due to the extremely small pulsational excursions (<0.1 mm in diameter), exact segmentation of the aneurysms is of critical importance. In vitro examinations have shown improvement of the accuracy of vessel delineation by iterative reconstruction methods. We hypothesized that this improvement shows a measurable effect on aneurysm pulsations in vivo., Materials and Methods: Ten patients with cerebral aneurysms underwent 4D-CTA. Images were reconstructed with filtered back-projection and iterative reconstruction. The following parameters were compared between both groups: image noise, absolute aneurysm volumes, pulsatility, and sharpness of aneurysm edges., Results: In iterative reconstruction images, noise was significantly reduced (mean, 9.8 ± 4.0 Hounsfield units versus 8.0 ± 2.5 Hounsfield units; P = .04), but the sharpness of aneurysm edges just missed statistical significance (mean, 3.50 ± 0.49 mm versus 3.42 ± 0.49 mm; P = .06). Absolute volumes (mean, 456.1 ± 775.2 mm(3) versus 461.7 ± 789.9 mm(3); P = .31) and pulsatility (mean, 1.099 ± 0.088 mm(3) versus 1.095 ± 0.082 mm(3); P = .62) did not show a significant difference between iterative reconstruction and filtered back-projection images., Conclusions: CT images reconstructed with iterative reconstruction methods show a tendency toward shorter vessel edges but do not affect absolute aneurysm volumes or pulsatility measurements in vivo., (© 2014 by American Journal of Neuroradiology.)

Purpose: To evaluate a novel algorithm for correcting beam hardening artifacts caused by metal implants in computed tomography performed on a C-arm angiography system equipped with a flat panel (FP-CT)., Materials and Methods: 16 datasets of cerebral FP-CT acquisitions after coil embolization of brain aneurysms in the context of acute subarachnoid hemorrhage have been reconstructed by applying a soft tissue kernel with and without a novel reconstruction filter for metal artifact correction. Image reading was performed in multiplanar reformations (MPR) in average mode on a dedicated radiological workplace in comparison to the preinterventional native multisection CT (MS-CT) scan serving as the anatomic gold standard. Two independent radiologists performed image scoring following a defined scale in direct comparison of the image data with and without artifact correction. For statistical analysis, a random intercept model was calculated., Results: The inter-rater agreement was very high (ICC = 86.3 %). The soft tissue image quality and visualization of the CSF spaces at the level of the implants was substantially improved. The additional metal artifact correction algorithm did not induce impairment of the subjective image quality in any other brain regions., Conclusion: Adding metal artifact correction to FP-CT in an acute postinterventional setting helps to visualize the close vicinity of the aneurysm at a generally consistent image quality., (© Georg Thieme Verlag KG Stuttgart · New York.)

Introduction: To compare intra- and inter-observer reliability of aneurysm measurements obtained by a 3D computer-aided technique with standard manual aneurysm measurements in different imaging modalities., Methods: A total of 21 patients with 29 cerebral aneurysms were studied. All patients underwent digital subtraction angiography (DSA), contrast-enhanced (CE-MRA) and time-of-flight magnetic resonance angiography (TOF-MRA). Aneurysm neck and depth diameters were manually measured by two observers in each modality. Additionally, semi-automatic computer-aided diameter measurements were performed using 3D vessel surface models derived from CE- (CE-com) and TOF-MRA (TOF-com) datasets. Bland-Altman analysis (BA) and intra-class correlation coefficient (ICC) were used to evaluate intra- and inter-observer agreement., Results: BA revealed the narrowest relative limits of intra- and inter-observer agreement for aneurysm neck and depth diameters obtained by TOF-com (ranging between ±5.3 % and ±28.3 %) and CE-com (ranging between ±23.3 % and ±38.1 %). Direct measurements in DSA, TOF-MRA and CE-MRA showed considerably wider limits of agreement. The highest ICCs were observed for TOF-com and CE-com (ICC values, 0.92 or higher for intra- as well as inter-observer reliability)., Conclusion: Computer-aided aneurysm measurement in 3D offers improved intra- and inter-observer reliability and a reproducible parameter extraction, which may be used in clinical routine and as objective surrogate end-points in clinical trials.

Introduction: A fast and reproducible quantification of the recurrence volume of coiled aneurysms is required to enable a more timely evaluation of new coils. This paper presents two registration schemes for the semi-automatic quantification of aneurysm recurrence volumes based on baseline and follow-up 3D MRA TOF datasets., Methods: The quantification of shape changes requires a previous definition of corresponding structures in both datasets. For this, two different rigid registration methods have been developed and evaluated. Besides a state-of-the-art rigid registration method, a second approach integrating vessel segmentations is presented. After registration, the aneurysm recurrence volume can be calculated based on the difference image. The computed volumes were compared to manually extracted volumes., Results: An evaluation based on 20 TOF MRA datasets (baseline and follow-up) of ten patients showed that both registration schemes are generally capable of providing sufficient registration results. Regarding the quantification of aneurysm recurrence volumes, the results suggest that the second segmentation-based registration method yields better results, while a reduction of the computation and interaction time is achieved at the same time., Conclusion: The proposed registration scheme incorporating vessel segmentation enables an improved quantification of recurrence volumes of coiled aneurysms with reduced computation and interaction time.

The detection rate of intracranial aneurysms has increased with the improved availability of non-invasive imaging methods. Moreover, persons who have relatives with intracranial aneurysms increasingly demand imaging to rule out aneurysms. To deal with these problems, radiologists require basic knowledge regarding the detection and treatment of unruptured intracranial aneurysms. The prevalence of aneurysms in the normal population is 2 - 3 %. It increases to 4 - 10 % in persons with one relative with an aneurysm and to about 20 % in persons with two relatives with an aneurysm. The average natural rupture risk is estimated to be 5 % within 5 years of detection. In the individual case it depends on several variables that are discussed here. According to the literature, the risk of endovascular aneurysm treatment is about 5 %. On the basis of these data, the benefit of MRA screening needs to be discussed individually with the patient., (© Georg Thieme Verlag KG Stuttgart · New York.)

Blister-like internal carotid artery (ICA) aneurysms are known for their fragile and thin-walled morphology associated with a high risk of intraprocedural rupture. Neurosurgical and endovascular options are illustrated on three exemplary cases reviewing the diagnostic and therapeutic implications of these special aneurysms. A 49-year-old woman was admitted with subarachnoid hemorrhage (SAH) in which angiography showed a broad-based, small bulging ectasy of the terminal ICA segment. On the attempt of surgical clipping, the aneurysm ruptured leaving a tear in the ICA. After temporary clipping, the rims of the tear were approximated by sutures. Sufficient closure of the remaining leakage was achieved by circumferential wrapping which was secured by two clips. Postoperative angiography confirmed stenosis of the tightened ICA and patient recovered without neurological deficit. Surgical attempt on a second case with bulging of the C4-segment topped by a small aneurysm was fatal due to extensive laceration of the basal ICA intraoperatively. Endovascular stenting was the choice of treatment in a third SAH patient in which angiography was suspicious of a blister-like ICA aneurysm. Six-month follow-up was uneventful; the patient recovered well and further growth of bulging was not seen. Reviewing the literature, blister-like aneurysms tend to arise at uncommon sites not located at the arterial branches. Small and broad-based bulges with or without true saccular aneurysms have to be assessed as characteristic features of blister-like aneurysms. Rupture of the aneurysm involving the carrying artery has to be considered during therapeutic attempts, in which urgent strategies have to be kept in reserve preventing fatal outcome. Blister-like aneurysms is a hazardous affair for neurosurgeons and neuroradiologists as their fragile structure most likely will lead to intraoperative rupture. If endovascular treatment is not promising, wrapping and revascularization techniques come true to still be an important part of the neurosurgeons toolbox for reconstructing a vessel lumen and preserving a sufficient cerebral blood flow.

Introduction: New coils with unproven clinical benefit enlarge the armamentarium for endovascular aneurysm treatment continuously. Large patient numbers needed to detect benefits of such new techniques prevent timely evaluation of efficacy. We propose measuring the volume of aneurysm recurrences as surrogate endpoint for coil stability. We hypothesize that this method allows detecting effects of new materials with reduced sample sizes in comparison to conventional studies with dichotomous endpoints., Methods: Institutional review board approval and informed consent were obtained. Fifty-nine patients with decreasing aneurysm size and at least two available follow-up time-of-flight magnetic resonance angiographies (ToF-MRAs) were included. Newly developed software for measuring aneurysm volume differences based on ToF-MRA images was used. Based on the observed recurrence volumes and retreatment rates, the sample size for future studies comparing standard versus "new coils" were calculated., Results: Mean recurrence volume was 38.92 μl (SD110.85 μl). To show a 50% reduction of retreatment rate to control (p = 0.05; power 80%) in a regular study (dichotomous endpoint), the required sample size would be n = 356 compared with n = 78 if using the continuous surrogate endpoint "recurrence volume". When extrapolating our data to data given in the literature, sample sizes could be reduced from n = 948 to n = 74 without loss of statistical power., Conclusion: Further studies on new materials using volumetric analysis based on ToF-MRA as surrogate endpoint could substantially decrease sample size and allow a more timely assessment of possible benefit of new materials with a fraction of the cost.

Purpose: Evaluation of hospital resource allocation in intracranial aneurysm treatment in a medium-volume neurovascular center., Materials and Methods: Retrospective data analysis included 653 procedures performed on 598 patients with 667 aneurysms (A) from 1990 to 2004. 515 treatments were carried out in ruptured A (clip: n = 370; coil: n = 145) and 138 procedures in non-ruptured A (clip: n = 51, coil: n = 87). Patient management data included procedure time (min), length of stay in the intensive care unit (days), total length of hospital stay (days), and discharge to home ratio., Results: Clinical admission grade (rupt. A: Hunt and Hess grade 1 - 3: clip: 73 % coil: 72 %) and clinical outcome at discharge (good neurological outcome/mortality rate: rupt. A: clip: 51.1/13.8 % coil: 45.5 / 10.3 % non-rupt. A: 88.2/0 % coil: 88.5/1.3 %) were similar for both treatment modes. The coil procedure time was found to be significantly shorter (rupt. A: coil: 145 min; clip: 203 min; p < 0.01; non-rupt. A: coil: 164 min, clip: 200 min; p < 0.01). Coiling reduced the length of stay in the ICU (rupt. A: coil: 5.3 d; clip: 6 d, p < 0.01; non-rupt. A: coil: 1.5 d; clip: 2 d; p = 0.21) and coiling significantly reduced the length of hospital stay (rupt. A: coil: 21.4 d; clip: 26.8 d, p < 0.01; non-rupt. A: coil: 9.2 d; clip: 17.5 d; p = 0.01).The discharge to home ratio did not differ (rupt. A: clip: 31.6 % coil: 29.7 % non-rupt. A: clip: 74.5 % coil: 80.5 %)., Conclusion: In a medium-volume neurovascular center, coiling significantly reduced the procedure time, the stay in the ICU, and the length of hospital stay suggesting favorable resource allocation in endovascular therapy., (Georg Thieme Verlag KG Stuttgart-New York.)

Background and Purpose: The purpose of this study was to estimate the safety and efficacy of abciximab treatment in combination with prophylactic heparin, acetylsalicylic acid (ASA), and clopidogrel application in cases of thrombus formation complicating endovascular coil embolization in cerebral aneurysms., Methods: Thromboembolic incidents during endovascular management of 515 consecutive cerebral aneurysms were observed in 48 cases (9.3%). Eight incidents were observed during embolization of incidental aneurysms (8/174; 4.6%, 95% CI: 2.0 to 8.9%). All patients underwent anticoagulation with heparin and platelet-inhibition with ASA during treatment procedure. In addition, clopidogrel orally was applied 3 days preoperatively in patients with incidental aneurysms. In case of thrombus formation, glycoprotein IIb-IIIa inhibitor abciximab was given in 42 cases. No coagulation-effective rescue treatment was conducted in 5 cases. One patient was treated with r-tPA. End points were infarction on follow-up cranial CT and the rate of intracranial hemorrhages., Results: No infarcts on follow-up CT were observed after treatment with abciximab in 29/42 patients (69.0%, 95% CI: 52.9 to 82.4%). No coagulant rescue therapy was applied in 5 patients because of a small nonocclusive thrombus or good collateral blood supply, showing consecutive infarction on follow-up CT in 3 cases as did the 1 patient treated with r-tPA. No periprocedural bleedings or rebleedings were observed in any case., Conclusions: Abciximab was safe as rescue treatment in cases of thrombus formation during endovascular aneurysm coiling. In our study the use of Abciximab, in combination with prophylactic anticoagulation and antiaggregation, does not lead to additional intracranial hemorrhages or any extracranial bleeding complications.

Purpose of Review: This brief review highlights some factors affecting the short-term and long-term outcomes after endovascular treatment (EVT) of patients with intracranial aneurysms., Recent Findings: The principal procedural risks associated with EVT are symptomatic thromboembolic events affecting 2.4-5.2% of treatments, and aneurysm perforation which occurs in 0.5-2.4% of the patients with unruptured aneurysms and 2.3-6.5% of patients with subarachnoid haemorrhage. The risk of subsequent aneurysm recurrence requiring retreatment is about 10% and does not negate the morbidity advantage (relative to surgical clipping) of the initial EVT. This risk is about three-fold greater in aneurysms with a neck width more than 4 mm and sac maximum diameter greater than 10 mm. The incidence of rebleeding after EVT is 0.11-0.32% per annum and is probably lower if EVT achieves complete occlusion., Summary: EVT dramatically reduces the risk of rebleeding in patients with subarachnoid haemorrhage. Treatment risks and rates of incomplete occlusions are increased in ruptured in comparison with unruptured aneurysms. Large aneurysms have higher risk of procedural thromboembolism, incomplete treatment and rate of recurrences with strong interdependence between these variables. The low risk of rebleeding in patients with subarachnoid haemorrhage is probably increased in incompletely treated aneurysms and in patients revealing aneurysm growth over time.

Background and Purpose: The purpose of this study was to analyze angiographic and clinical results before and after additional endovascular therapy in patients with previously coiled but reopened cerebral aneurysms and to identify possible risk factors for retreatment of an aneurysm., Materials and Methods: Follow-up with selective digital subtraction angiography was performed in 323/596 (54.2%) patients harboring 342 aneurysms with a mean follow-up time of 28.6 months. The patients were divided into 3 groups: group A, who remained stable after initial treatment; group B, who showed minor morphologic changes; and group C, who underwent repeat treatment. Univariate and multivariate regression analyses were performed to determine possible risk factors for aneurysmal retreatment., Results: Single or multiple retreatment was performed in 33 of 323 (10.2%) patients. Retreatment of small aneurysms (< or =10 mm) with small necks (< or =4 mm) was performed in 6 of 214 aneurysms. When summarizing all other aneurysms as a "risk group" (n = 128), the odds ratio (OR) for retreatment in the "risk group" was 3.11 (95% CI: 1.43-6.75; P = .004). In patients with residual aneurysm after the first treatment, OR for retreatment was 3.96 (95% CI: 1.48-10.65; P = .006), whereas a neck remnant, clinical presentation, and aneurysmal localization were not predictive. We observed no resulting morbidity and mortality from the 33 retreatment procedures., Conclusion: In our series, the retreatment of aneurysmal recurrences was a safe procedure. The best single predictors of aneurysmal recurrence were aneurysmal anatomy (neck width >4 mm and diameter >10 mm) and the presence of a residual aneurysm after initial treatment. A limitation in our study was the significant number of patients lost to follow-up (22.7%).