Prior Thrombectomy Does Not Affect the Surgical Complication Rate of Decompressive Hemicraniectomy in Patients with Malignant Ischemic Stroke.

BACKGROUND: Even though mechanical recanalization techniques have dramatically improved acute stroke care since the pivotal trials of decompressive hemicraniectomy for malignant courses of ischemic stroke, decompressive hemicraniectomy remains a mainstay of malignant stroke treatment. However, it is still unclear whether prior thrombectomy, which in most cases is associated with application of antiplatelets and/or anticoagulants, affects the surgical complication rate of decompressive hemicraniectomy and whether conclusions derived from prior trials of decompressive hemicraniectomy are still valid in times of modern stroke care. METHODS: A total of 103 consecutive patients who received a decompressive hemicraniectomy for malignant middle cerebral artery infarction were evaluated in this retrospective cohort study. Surgical and functional outcomes of patients who had received mechanical recanalization before surgery (thrombectomy group, n = 49) and of patients who had not received mechanical recanalization (medical group, n = 54) were compared. RESULTS: The baseline characteristics of the two groups did significantly differ regarding preoperative systemic thrombolysis (63.3% in the thrombectomy group vs. 18.5% in the medical group, p < 0.001), the rate of hemorrhagic transformation (44.9% vs. 24.1%, p = 0.04) and the preoperative Glasgow Coma Score (median of 7 in the thrombectomy group vs. 12 in the medical group, p = 0.04) were similar to those of prior randomized controlled trials of decompressive hemicraniectomy. There was no significant difference in the rates of surgical complications (10.2% in the thrombectomy group vs. 11.1% in the medical group), revision surgery within the first 30 days after surgery (4.1% vs. 5.6%, respectively), and functional outcome (median modified Rankin Score of 4 at 5 and 14 months in both groups) between the two groups. CONCLUSIONS: A prior mechanical recanalization with possibly associated systemic thrombolysis does not affect the early surgical complication rate and the functional outcome after decompressive hemicraniectomy for malignant ischemic stroke. Patient characteristics have not changed significantly since the introduction of mechanical recanalization; therefore, the results from former large randomized controlled trials are still valid in the modern era of stroke care.

The FRESH Study: Treatment of Intracranial Aneurysms with the New FRED X Flow Diverter with Antithrombotic Surface Treatment Technology-First Multicenter Experience in 161 Patients.

BACKGROUND AND PURPOSE: Flow diverters with antithrombotic coatings are increasingly used to improve the safety of flow diverter treatments of intracranial aneurysms. This study aimed to investigate the safety and short-term efficacy of the new FRED X flow diverter. MATERIALS AND METHODS: Medical charts and procedural and imaging data of a consecutive series of patients with intracranial aneurysms who were treated with the FRED X at 9 international neurovascular centers were retrospectively analyzed. RESULTS: One hundred sixty-one patients (77.6% women; mean age, 55 years) with 184 aneurysms (11.2% acutely ruptured) were included in this study. Most aneurysms were located in the anterior circulation (77.0%), most frequently at the ICA (72.7%). The FRED X was successfully implanted in all procedures. Additional coiling was performed in 29.8%. In-stent balloon angioplasty was necessary in 2.5%. The rate of major adverse events was 3.1%. Thrombotic events occurred in 7 patients (4.3%) with 4 intra- and 4 postprocedural in-stent thromboses, respectively (1 patient had both peri- and postprocedural thrombosis). Of these thrombotic events, only 2 (1.2%) led to major adverse events (ischemic strokes). Postinterventional neurologic morbidity and mortality were observed in 1.9% and 1.2%, respectively. The rate of complete aneurysm occlusion after a mean follow-up of 7.0 months was 66.0%. CONCLUSIONS: The new FRED X is a safe and feasible device for aneurysm treatment. In this retrospective multicenter study, the rate of thrombotic complications was low, and the short-term occlusion rates are satisfactory.

Material-Specific Roadmap Modes Can Improve the Visibility of Liquid Embolic Agents for Endovascular Embolization: A Systematic In Vitro Study.

BACKGROUND AND PURPOSE: Endovascular embolization using liquid embolic agents is a safe and effective treatment option for AVMs and fistulas. Because reliable visibility of these liquid embolic agents is essential for intraprocedural visual control to prevent complications, novel angiographic systems are equipped with material-specific roadmap modes. The aim of this study was the systematic in vitro comparison of conventional and material-specific roadmap modes regarding the visibility of the most used liquid embolic agents. MATERIALS AND METHODS: A recently introduced in vitro model, resembling cerebral vessels, was embolized with Onyx 18, Squid 18, PHIL 25%, and n-BCA mixed with iodized oil (n = 4 for each liquid embolic agent), as well as with contrast medium and saline, both serving as a reference. Imaging was performed in conventional and material-specific roadmap modes. The visibility of the liquid embolic agents in both modes was compared quantitatively and qualitatively. RESULTS: Significant differences between conventional and material-specific roadmap modes regarding the visibility of the liquid embolic agents were observed for all study groups. All liquid embolic agents were better visible in the material-specific roadmap modes compared with the conventional mode in qualitative and quantitative analyses (eg, Onyx in conventional-versus-material-specific modes along the 1.0-mm sector: mean contrast-to-noise ratio, 5.69 [SD, 0.85] versus 47.18 [SD, 5.72]; P < .001, respectively). CONCLUSIONS: In this in vitro study, we demonstrated a better visibility of all investigated liquid embolic agents by using material-specific roadmap modes compared with the conventional roadmap technique. Especially in complex anatomic situations, these novel roadmap modes could improve the visual control and thus the safety and efficacy of embolization procedures in clinical practice.

Learning Curve for Flow Diversion of Posterior Circulation Aneurysms: A Long-Term International Multicenter Cohort Study.

BACKGROUND AND PURPOSE: Flow diversion has gradually become a standard treatment for intracranial aneurysms of the anterior circulation. Recently, the off-label use of the flow diverters to treat posterior circulation aneurysms has also increased despite initial concerns of rupture and the suboptimal results. This study aimed to explore the change in complication rates and treatment outcomes across time for posterior circulation aneurysms treated using flow diversion and to further evaluate the mechanisms and variables that could potentially explain the change and outcomes. MATERIALS AND METHODS: A retrospective review using a standardized data set at multiple international academic institutions was performed to identify patients with ruptured and unruptured posterior circulation aneurysms treated with flow diversion during a decade spanning January 2011 to January 2020. This period was then categorized into 4 intervals. RESULTS: A total of 378 procedures were performed during the study period. Across time, there was an increasing tendency to treat more vertebral artery and fewer large vertebrobasilar aneurysms (P = .05). Moreover, interventionalists have been increasingly using fewer overlapping flow diverters per aneurysm (P = .07). There was a trend toward a decrease in the rate of thromboembolic complications from 15.8% in 2011-13 to 8.9% in 2018-19 (P = .34). CONCLUSIONS: This multicenter experience revealed a trend toward treating fewer basilar aneurysms, smaller aneurysms, and increased usage of a single flow diverter, leading to a decrease in the rate of thromboembolic and hemorrhagic complications.

RAPID CT Perfusion-Based Relative CBF Identifies Good Collateral Status Better Than Hypoperfusion Intensity Ratio, CBV-Index, and Time-to-Maximum in Anterior Circulation Stroke.

BACKGROUND AND PURPOSE: Information of collateral flow may help to determine eligibility for thrombectomy. Our aim was to identify CT perfusion-based surrogate parameters of good collateral status in acute anterior circulation ischemic stroke. MATERIALS AND METHODS: In this retrospective study, we assessed the collateral status of 214 patients who presented with acute ischemic stroke due to occlusion of the MCA M1 segment or the carotid terminus. Collaterals were assessed on dynamic CTA images analogous to the multiphase CTA score by Menon et al. CT perfusion parameters (time-to-maximum, relative CBF, hypoperfusion intensity ratio, and CBV-index) were assessed with RAPID software. The Spearman rank correlation and receiver operating characteristic analyses were performed to identify the parameters that correlate with collateral scores and good collateral supply (defined as a collateral score of ≥4). RESULTS: The Spearman rank correlation was highest for a relative CBF < 38% volume (ρ = -0.66, P < .001), followed by the hypoperfusion intensity ratio (ρ = -0.49, P < .001), CBV-index (ρ = 0.51, P < .001), and time-to-maximum > 8 seconds (ρ = -0.54, P < .001). Good collateral status was better identified by a relative CBF < 38% at a lesion size <27 mL (sensitivity of 75%, specificity of 80%) compared with a hypoperfusion intensity ratio of <0.4 (sensitivity of 75%, specificity of 62%), CBV-index of >0.8 (sensitivity of 60%, specificity of 78%), and time-to-maximum > 8 seconds (sensitivity of 68%, specificity of 76%). CONCLUSIONS: Automated CT perfusion analysis allows accurate identification of collateral status in acute ischemic stroke. A relative CBF < 38% may be a better perfusion-based indicator of good collateral supply compared with time-to-maximum, the hypoperfusion intensity ratio, and the CBV-index.

Periprocedural Safety and Feasibility of the New LVIS EVO Device for Stent-Assisted Coiling of Intracranial Aneurysms: An Observational Multicenter Study.

BACKGROUND AND PURPOSE: Stent-assisted treatment techniques can be an effective treatment option for intracranial aneurysms. The aim of this study was to evaluate the periprocedural feasibility and safety of the new LVIS EVO stent for the treatment of intracranial aneurysms. MATERIALS AND METHODS: Patients with intracranial aneurysms treated with the LVIS EVO in 11 European neurovascular centers were retrospectively reviewed. Patient and aneurysm characteristics, procedural parameters, immediate grade of occlusion, and technical and clinical complications were assessed. RESULTS: Fifty-seven patients with 59 aneurysms were treated with the LVIS EVO device; 57.6% of the aneurysms were incidental; 15.3% were acutely ruptured; 15.3% were recanalized or residual aneurysms; and 11.9% were treated for symptoms other than acute hemorrhage. The most frequent aneurysm locations were the middle cerebral artery (25.4%) and the anterior communicating artery (22.0%). The rate of immediate successful deployment was 93.2%. In 6.8% (n = 4) of cases, additional in-stent angioplasty was needed. The immediate complete occlusion rate was 54.2%, while there was a residual aneurysm in 35.6% and a residual neck in 10.2%. Periprocedural technical complications occurred in 7/59 treatments (11.9%; the most frequent technical complication [n = 3] was thrombus formation), which all resolved completely without clinical sequelae. Postprocedural neurologic complications occurred after 4/59 treatments (6.8%; 2 transient ischemic attacks, 1 minor stroke, 1 major stroke), of which only 1 persistent complication was directly related to the procedure (minor stroke in the vascular territory distal to the stent). CONCLUSIONS: The LVIS EVO stent is a safe, feasible device for the treatment of intracranial aneurysms.

Imaging Artifacts of Liquid Embolic Agents on Conventional CT in an Experimental in Vitro Model.

BACKGROUND AND PURPOSE: Endovascular embolization using liquid embolic agents is a safe and effective treatment option for AVMs and dural arteriovenous fistulas. The aim of this study was to assess the degree of artifact inducement by the most frequently used liquid embolic agents in conventional CT in an experimental in vitro model. MATERIALS AND METHODS: Dimethyl-sulfoxide-compatible tubes were filled with the following liquid embolic agents (n = 10, respectively): Onyx 18, all variants of Squid, PHIL 25%, PHIL LV, and n-BCA mixed with iodized oil. After inserting the tubes into a CT imaging phantom, we acquired images. Artifacts were graded quantitatively by the use of Hounsfield units in a donut-shaped ROI using a customized software application that was specifically designed for this study and were graded qualitatively using a 5-point scale. RESULTS: Quantitative and qualitative analyses revealed the most artifacts for Onyx 18 and the least artifacts for n-BCA, PHIL 25%, and PHIL LV. Squid caused more artifacts compared with PHIL, both for the low-viscosity and for the extra-low-viscosity versions (eg, quantitative analysis, Squid 18: mean ± SD, 30.3 ± 9.7 HU versus PHIL 25%: mean ± SD, 10.6 ± 0.8 HU; P < .001). Differences between the standard and low-density variants of Squid were observed only quantitatively for Squid 12. There were no statistical differences between the different concentrations of Squid and PHIL. CONCLUSIONS: In this systematic in vitro analysis investigating the most commonly used liquid embolic agents, relevant differences in CT imaging artifacts could be demonstrated. Ethylene-vinyl alcohol-based liquid embolic agents induced more artifacts compared with liquid embolic agents that use iodine as a radiopaque component.

Treatment of Ruptured Blister-Like Aneurysms with the FRED Flow Diverter: A Multicenter Experience.

BACKGROUND AND PURPOSE: Treatment of ruptured blister-like aneurysms is technically challenging. This study aimed at analyzing the safety and efficacy of the Flow-Redirection Endoluminal Device (FRED) in the treatment of ruptured blister-like aneurysms. MATERIALS AND METHODS: In a retrospective multicenter study, all patients treated with the FRED due to a ruptured intracranial blister-like aneurysm between January 2013 and May 2019 were analyzed. The primary end points for clinical safety were mRS 0-2 at 6 months after treatment and the absence of major ipsilateral stroke or death. The primary end points for efficacy were the absence of rebleeding after treatment and complete angiographic occlusion according to the O'Kelly-Marotta classification at 6 months after treatment. RESULTS: In total, 30 patients with 30 ruptured blister-like aneurysms were treated. Immediate complete aneurysm obliteration (O'Kelly-Marotta classification D) with the FRED was achieved in 10 patients (33%). Of the 26 patients with follow-up, complete obliteration was achieved in 21 patients (80%) after 6 months and in 24 patients (92%) in the final follow-up (median, 22 months). Twenty-three patients (77%) achieved mRS 0-2 at 6 months. Major stroke or death occurred in 17%. Two patients died due to pneumonia, and 2 patients died due to infarction following cerebral vasospasm. There was no case of rebleeding after FRED implantation. There was 1 case of delayed asymptomatic stent occlusion. CONCLUSIONS: Treatment of ruptured blister-like aneurysms with the FRED is safe and effective.

Topographic bone thickness maps to evaluate the intuitive placement of titanium miniplates for nasal prostheses.

The aim of this study was to evaluate the intuitive placement of titanium miniplates. The hypothesis was that virtual planning can improve miniplate placement. Twenty patients were included in the study. These patients were fitted with 21 titanium miniplates (16 y-plates, three t-plates, and two u-plates) to retain nasal prostheses between 2005 and 2017. Colour-coded topographic bone thickness maps (TBTMs) were created in fused pre- and postoperative computed tomography. Implants were virtually transposed at the position of highest bone thickness. The bone thickness index (BTI) was calculated as the sum of points assigned at each screw (1 point per millimetre up to 4 mm, and 5 points for greater values) divided by the number of screws. One plate broke after 2.8 years, thus plate survival after 5 years was 91% using the Kaplan-Meier method. The BTI for all 21 plates increased from 3.4 to 4.1 points using virtual transposition (P<0.001). No significant changes were observed in t- and u-plates, but the median BTI increased from 3.1 to 4.1 points (P<0.0005) in 16 y-plates. The change was substantial (≥0.5 points) in 9/16 y-plates. Therefore, the hypothesis that virtual planning improves implant placement was accepted.

Measurement of bone thickness at the site of titanium miniplates used to retain nasal prostheses in fused computed tomographic data.

Our aim was to investigate the bone thickness at the site of titanium miniplates inserted to retain nasal prostheses. We studied 13 patients who had had titanium miniplates inserted for retention of nasal prostheses with a total of 60 titanium bone screws. A trajectory along each bone screw was segmented in fused computed tomographic (CT) data. Bone thickness was measured along this trajectory on the preoperative CT. The median bone thickness at the positions of the screws implanted on the frontal process of the maxillary bone was 1.4 (range 0.2-6.9) mm (mean 1.8). The median (range) values for men and women were 1.4 (0.2-6.9) mm and 1.3 (0.2-3.3) mm, respectively. The thickest bone was at the cranial part of the frontal process of the maxilla with a median of 2.0 (range 0.3-4.1) mm. However, differences in sex and position were not significant. None of the implant miniplates lost osseointegration. Despite the low bone stock at the lateral aspect of the pyriform aperture, survival of implanted titanium miniplates was 100% in this study group.

The FRED for Cerebral Aneurysms of the Posterior Circulation: A Subgroup Analysis of the EuFRED Registry.

BACKGROUND AND PURPOSE: Flow diversion for the posterior circulation remains a promising treatment option for selected posterior circulation aneurysms. The Flow-Redirection Intraluminal Device (FRED) system has not been previously assessed in a large cohort of patients with posterior circulation aneurysms. The purpose of the present study was to assess safety and efficacy of FRED in this location. MATERIALS AND METHODS: Consecutive patients with posterior circulation aneurysms treated at 8 centers participating in the European FRED study (EuFRED) between April 2012 and January 2019 were retrospectively reviewed. Complication and radiographic and functional outcomes were evaluated. RESULTS: Eighty-four patients (median age, 54 years) with 84 posterior circulation aneurysms were treated with the FRED. A total of 25 aneurysms (29.8%) had previously ruptured, even though most aneurysms were diagnosed incidentally (45.2%). The intradural vertebral artery was the most common location (50%), and saccular, the most common morphology (40.5%). The median size was 7 mm. There were 8 (9.5%) symptomatic thromboembolic and no hemorrhagic complications. Thromboembolic complications occurred mostly (90.9%) in nonsaccular aneurysms. On last follow-up at a median of 24 months, 78.2% of aneurysms were completely occluded. Functional outcome at a median of 27 months was favorable in 94% of patients. All mortalities occurred in patients with acute subarachnoid hemorrhage and its sequelae. CONCLUSIONS: The largest cohort of posterior circulation aneurysms treated with the FRED to date demonstrated favorable safety and efficacy profiles of the device for this indication. Treatment in the setting of acute subarachnoid hemorrhage was strongly related to mortality, regardless of whether procedural complications occurred.

Endovascular Thrombectomy of Calcified Emboli in Acute Ischemic Stroke: A Multicenter Study.

BACKGROUND AND PURPOSE: Large intracranial vessel occlusion due to calcified emboli is a rare cause of major stroke. We assessed the prevalence, imaging appearance, the effectiveness of mechanical thrombectomy, and clinical outcome of patients with large-vessel occlusion due to calcified emboli. MATERIALS AND METHODS: We performed a retrospective analysis of clinical and procedural data of consecutive patients who underwent mechanical thrombectomy due to calcified emboli in 7 European stroke centers. RESULTS: We screened 2969 patients, and 40 patients matched the inclusion criteria, accounting for a prevalence of 1.3%. The mean maximal density of the thrombus was 327 HU (range, 150-1200 HU), and the mean thrombus length was 9.2 mm (range, 4-20 mm). Four patients had multiple calcified emboli, and 2 patients had an embolic event during an endovascular intervention. A modified TICI score of ≥2b was achieved in 57.5% (23/40), with minimal-to-no reperfusion (modified TICI 0-1) in 32.5% (13/40) and incomplete reperfusion (modified TICI 2a) in 10% (4/40). Excellent outcome (mRS 0-1) was achieved in only 20.6%, functional independence (mRS 0-2) in 26.5% and 90-day mortality was 55.9%. CONCLUSIONS: Acute ischemic stroke with large-vessel occlusion due to calcified emboli is a rare entity in patients undergoing thrombectomy, with considerably worse angiographic outcome and a higher mortality compared with patients with noncalcified thrombi. Good functional recovery at 3 months can still be achieved in about a quarter of patients.

The Influence of Angioarchitectural Features on the Success of Endovascular Embolization of Cranial Dural Arteriovenous Fistulas with Onyx.

BACKGROUND AND PURPOSE: Endovascular embolization can be an effective treatment for cranial dural arteriovenous fistulas. However, a considerable number of dural arteriovenous fistulas still cannot be treated sufficiently. The purpose of this study was to report our single-center experience of endovascular embolization of dural arteriovenous fistulas with Onyx, including the investigation of the influence of angioarchitectural features on the treatment success. MATERIALS AND METHODS: Clinical data, angioarchitectural features, complications, treatment success (defined as complete symptom remission for low-grade dural arteriovenous fistulas and complete occlusion for high-grade dural arteriovenous fistulas), and occlusion rates were assessed. The influence of various angioarchitectural features (including location, pattern of venous drainage, and quantity and origin of feeding arteries) was investigated using multivariable backward logistic regression. RESULTS: One hundred four patients with 110 dural arteriovenous fistulas were treated in 132 treatment procedures. Treatment success and complete occlusion rates were 81.8% and 90.9%, respectively. After a mean follow-up of 23.6 months, 95.5% of the patients showed complete symptom remission or symptom relief. The overall complication rate was 8.3% (4.5% asymptomatic, 2.3% transient, and 1.5% permanent complications). Logistic regression showed that ≥10 feeding arteries (P = .041) and involvement of the ascending pharyngeal artery (P = .039) significantly lowered the probability of treatment success. Treatment success tended to be lower for low-grade dural arteriovenous fistulas, Cognard type I dural arteriovenous fistulas, and dural arteriovenous fistulas with involvement of dural branches of the internal carotid artery, however without reaching statistical significance in the multivariable model. CONCLUSIONS: The presence of multiple feeding arteries and involvement of the pharyngeal artery negatively influence the treatment success of endovascular embolization of cranial dural arteriovenous fistulas with Onyx.

Clinical Outcome after Thrombectomy in Patients with Stroke with Premorbid Modified Rankin Scale Scores of 3 and 4: A Cohort Study with 136 Patients.

BACKGROUND AND PURPOSE: We aimed to analyze the clinical outcome after mechanical thrombectomy in patients with premorbid mRS 3 and 4 because there are currently no data on this patient group. MATERIALS AND METHODS: Between January 2009 and November 2017, all patients with premorbid mRS 3 or 4 undergoing mechanical thrombectomy due to anterior circulation stroke were selected. Good outcome was defined as a clinical recovery to the status before stroke onset (ie, equal premorbid mRS and mRS at 90 days). In addition, mortality at discharge and at 90 days was analyzed. RESULTS: One hundred thirty-six patients were included, of whom 81.6% presented with premorbid mRS 3; and 18.4%, with premorbid mRS 4; 24.0% of patients with premorbid mRS 4 achieved clinical recovery compared with 20.7% of patients with premorbid mRS 3 (P = .788). However, the proportion of hospital mortality and mortality at 90 days was nonsignificant, but markedly higher in patients with premorbid mRS 4. Multivariate analysis identified low NIHSS scores (OR, 0.92; 95% CI, 0.85-0.99; P = .040), high ASPECTS (OR, 1.45; 95% CI, 1.02-2.16; P = .049), and TICI 2b-3 (OR, 7.11; 95% CI, 1.73-49.90; P = .017) as independent predictors of good outcome. CONCLUSIONS: Good outcome in patients with premorbid mRS 3 and 4 is less frequent compared with premorbid mRS 0-2. Nevertheless, about 20% of the patients return to their premorbid mRS, which may justify endovascular treatment. The most important predictor of good outcome is successful recanalization.

[Intracranial vascular malformations]. / Intrakranielle Gefäßmalformationen.

Intracranial vascular malformations range from incidental asymptomatic vascular alterations up to life-threatening vascular disorders. Arteriovenous malformations and dural arteriovenous fistulas are cerebral vascular malformations with arteriovenous shunting of blood. In the majority of cases they are accompanied by an elevated risk of intracerebral hemorrhage and can cause severe symptoms. They can be treated conservatively or interventionally via microneurosurgery, endovascular embolization and radiation therapy. Cavernous malformations, developmental venous anomalies (DVA) and capillary telangiectasia are cerebral vascular malformations without arteriovenous shunting. Cavernous malformations are rarely symptomatic in the form of cerebral hemorrhage, headache or seizures and in such cases an operative treatment can be indicated. The DVA and capillary telangiectasia are usually asymptomatic and do not require treatment.

Value of Contrast-Enhanced MRA versus Time-of-Flight MRA in Acute Ischemic Stroke MRI.

BACKGROUND AND PURPOSE: Vessel imaging in acute ischemic stroke is essential to select patients with large-vessel occlusion for mechanical thrombectomy. Our aim was to compare the diagnostic accuracy of time-of-flight MR angiography and contrast-enhanced MR angiography for identification of vessel occlusion and collateral status in acute ischemic stroke. MATERIALS AND METHODS: One hundred twenty-three patients with stroke with large-vessel occlusion before thrombectomy were included in this retrospective study. Before thrombectomy, 3T MR imaging, including conventional 3D TOF-MRA of the intracranial arteries and contrast-enhanced MRA of intra- and extracranial arteries, was performed. Both techniques were assessed independently by 2 neuroradiologists for location of the occlusion, imaging quality, and collateral status. Findings were compared, with subsequent DSA as the reference standard. RESULTS: Both techniques had good interrater agreement of κ = 0.74 (95% CI, 0.66-0.83) for TOF-MRA and κ = 0.72 (95% CI, 0.63-0.80) for contrast-enhanced MRA. Occlusion localization differed significantly on TOF-MRA compared with DSA (P < .001), while no significant difference was observed between DSA and contrast-enhanced MRA (P = .75). Assessment of collaterals showed very good agreement between contrast-enhanced MRA and DSA (94.9% with P = .25), but only fair agreement between TOF-MRA and DSA (23.2% with P < .001). CONCLUSIONS: Contrast-enhanced MRA offers better diagnostic accuracy than TOF-MRA in acute ischemic stroke. Contrast-enhanced MRA was superior in localizing vessel occlusion within a shorter acquisition time while providing a larger coverage, including extracranial vessels, and a more accurate assessment of collateral status. These results support inclusion of contrast-enhanced MRA in acute stroke MR imaging, perhaps making TOF-MRA superfluous.

Investigation of a New Version of the Liquid Embolic Agent PHIL with Extra-Low-Viscosity in an Endovascular Embolization Model.

BACKGROUND AND PURPOSE: The type and composition of an embolic agent have a relevant influence on the performance of endovascular embolization. The aim of this study was to investigate a new version of the liquid embolic agent precipitating hydrophobic injectable liquid (PHIL) with extra-low-viscosity in an in vivo embolization model. MATERIALS AND METHODS: Twenty-four embolization procedures were performed in the porcine rete mirabile. Eight embolizations were performed with PHIL 25% low viscosity, Squid 12, and standard PHIL 25%, respectively. Procedure time, required volume of embolic agent, visibility of the embolic agent, embolization control, embolization extent (ie, penetration of the rete mirabile), amount of reflux, and degree of embolization distal to the rete mirabile were assessed. RESULTS: All embolic agents were adequately visible. The embolization extent was not significantly different among the 3 investigated agents; however, there was a tendency toward a higher embolization extent for PHIL 25% low viscosity (median embolization extent: 88% [PHIL 25% low viscosity]; 65% [Squid 12]; 60% [PHIL 25%]; P = .146). The amount of reflux was significantly lower for the extra-low-viscosity agents PHIL 25% low viscosity and Squid 12 compared with the standard PHIL 25% (median reflux distance: 8 mm [PHIL 25% low viscosity]; 6 mm [Squid 12]; 17 mm [PHIL 25%]; P = .011). All other embolization features did not differ among agents. CONCLUSIONS: PHIL 25% low viscosity is a promising liquid embolic agent for endovascular embolization, featuring effective distal penetration, adequate visibility, a low amount of reflux, and good flow control.

Endovascular Treatment of Dural Arteriovenous Fistulas Using Transarterial Liquid Embolization in Combination with Transvenous Balloon-Assisted Protection of the Venous Sinus.

BACKGROUND AND PURPOSE: Sinus-preserving endovascular embolization was described as a promising treatment technique for dural arteriovenous fistulas. Our aim was to report our single-center experience in patients with dural arteriovenous fistulas who were treated with transarterial liquid embolization in combination with transvenous balloon-assisted protection of the affected venous sinus. MATERIALS AND METHODS: A retrospective analysis of a prospectively collected data base was performed. Demographic and clinical data, angiographic features of the dural arteriovenous fistulas, procedural parameters, complications, treatment success, follow-up imaging, and clinical outcome were assessed. RESULTS: Twenty-two patients were treated in 25 procedures. All patients were symptomatic, of whom 81.8% presented with tinnitus; 9.1%, with ocular symptoms; and 9.1%, with headache. Most fistulas were located at the transverse and/or sigmoid sinus. The most frequent fistula type was Cognard IIa+b (40.9%), followed by Cognard I (31.8%) and Cognard IIa (27.3%)/Borden I (59.1%), followed by Borden II (40.9%). The affected sinus could be preserved in all except for 1 patient in whom it was sacrificed in a second treatment procedure by coil embolization. The overall complete occlusion rate was 86.4%. The overall complication rate was 20%, with transient and permanent morbidity and mortality of 8%, 0%, and 0%, respectively. After a mean follow-up of 18 months, most patients (68.2%) achieved complete symptom remission, 27.3% showed symptom relief, and 4.6% had stable symptoms. CONCLUSIONS: Transarterial liquid embolization of dural arteriovenous fistulas in combination with transvenous balloon-assisted protection of the venous sinus is feasible and safe and offers high rates of occlusion and of symptom remission.

European Multicenter Study for the Evaluation of a Dual-Layer Flow-Diverting Stent for Treatment of Wide-Neck Intracranial Aneurysms: The European Flow-Redirection Intraluminal Device Study.

BACKGROUND AND PURPOSE: Endoluminal reconstruction with flow-diverting stents represents a widely accepted technique for the treatment of complex intracranial aneurysms. This European registry study analyzed the initial experience of 15 neurovascular centers with the Flow-Redirection Intraluminal Device (FRED) system. MATERIALS AND METHODS: Consecutive patients with intracranial aneurysms treated with the FRED between February 2012 and March 2015 were retrospectively reviewed. Complications and adverse events, transient and permanent morbidity, mortality, and occlusion rates were evaluated. RESULTS: During the defined study period, 579 aneurysms in 531 patients (median age, 54 years; range, 13-86 years) were treated with the FRED. Seven percent of patients were treated in the acute phase (≤3 days) of aneurysm rupture. The median aneurysm size was 7.6 mm (range, 1-36.6 mm), and the median neck size 4.5 mm (range, 1-30 mm). Angiographic follow-up of >3 months was available for 516 (89.1%) aneurysms. There was progressive occlusion witnessed with time, with complete occlusion in 18 (20%) aneurysms followed for up to 90 ± 14 days, 141 (82.5%) for 180 ± 20 days, 116 (91.3%) for 1 year ± 24 days, and 122 (95.3%) aneurysms followed for >1 year. Transient and permanent morbidity occurred in 3.2% and 0.8% of procedures, respectively. The overall mortality rate was 1.5%. CONCLUSIONS: This retrospective study in real-world patients demonstrated the safety and efficacy of the FRED for the treatment of intracranial aneurysms. In most cases, treatment with a single FRED resulted in complete angiographic occlusion at 1 year.

First Experiences with the New Enterprise2® Stent.

INTRODUCTION: Stent-assisted coiling of wide-necked intracranial aneurysms has become an established treatment and has significantly benefited from the introduction of compliant, self-expanding devices, such as the Enterprise VRD (EP-VRD). We report our experiences with the successor model, the Enterprise2 (EP2) stent in stent-assisted coiling as well as in the treatment of atherosclerotic stenosis. MATERIALS AND METHODS: In 11 consecutive patients 12 EP2 were used to treat 9 intracranial aneurysms and 2 stenoses. RESULTS: All stents could easily be delivered including partial or complete recapturing when necessary. In two cases with sharp angled curves in the carotid siphon there was kinking and flattening of the stent resulting in incomplete wall apposition of the stent. Moreover, when vascular anatomy showed curves with angles >50° it was regularly observed that the proximal stent markers were asymmetrically arranged along the vessel circumference without influence on the stent apposition. Both findings could be reproduced in a silicone flow model. CONCLUSION: The EP2 performed well in our small patient cohort; however, above a critical acute angle there may be incomplete wall apposition of the stent.