Multicenter comparison using two AI stroke CT perfusion software packages for determining thrombectomy eligibility

BACKGROUND

Stroke AI platforms assess infarcted core and potentially salvageable tissue (penumbra) to identify patients suitable for mechanical thrombectomy. Few studies have compared outputs of these platforms, and none have been multicenter or considered NIHSS or scanner/protocol differences. Our objective was to compare volume estimates and thrombectomy eligibility from two widely used CT perfusion (CTP) packages, Viz.ai and RAPID.AI, in a large multicenter cohort.

METHODS

We analyzed CTP data of acute stroke patients with large vessel occlusion (LVO) from four institutions. Core and penumbra volumes were estimated by each software and DEFUSE-3 thrombectomy eligibility assessed. Results between software packages were compared and categorized by NIHSS score, scanner manufacturer/model, and institution.

RESULTS

Primary analysis of 362 cases found statistically significant differences in both software's volume estimations, with subgroup analysis showing these differences were driven by results from a single scanner model, the Canon Aquilion One. Viz.ai provided larger estimates with mean differences of 8cc and 18cc for core and penumbra, respectively (p<0.001). NIHSS subgroup analysis also showed systematically larger Viz.ai volumes (p<0.001). Despite volume differences, a significant difference in thrombectomy eligibility was not found. Additional subgroup analysis showed significant differences in penumbra volume for the Phillips Ingenuity scanner, and thrombectomy eligibility for the Canon Aquilion One scanner at one center (7 % increased eligibility with Viz.ai, p=0.03).

CONCLUSIONS

Despite systematic differences in core and penumbra volume estimates between Viz.ai and RAPID.AI, DEFUSE-3 eligibility was not statistically different in primary or NIHSS subgroup analysis. A DEFUSE-3 eligibility difference, however, was seen on one scanner at one institution, suggesting scanner model and local CTP protocols can influence performance and cause discrepancies in thrombectomy eligibility. We thus recommend centers discuss optimal scanning protocols with software vendors and scanner manufacturers to maximize CTP accuracy.

[Drug therapy for acute and elective stent angioplasty]

CLINICAL ISSUE

Carotid artery stenoses are constrictions of the common carotid artery and the internal carotid artery. They cause around 15% of all cerebral ischemia, which is why their detection and correct treatment play an important role in clinical practice.

PRACTICAL RECOMMENDATIONS

Depending on the severity and clinical symptoms, carotid artery stenosis is treated conservatively, surgically or endovascularly by means of stent angioplasty. In the case of stent angioplasty in particular, correct drug therapy plays an important role in avoiding/reducing thromboembolic complications.

A Simplified One-Size-Fits-All Approach to Carotid Stenting

BACKGROUND

Carotid artery stenosis causes up to 20% of ischemic strokes. Stenting is used as an alternative to endarterectomy in symptomatic patients. Each commercially available stent offers numerous stent diameters/lengths. Most centers thus carefully match each individual stenosis to a specific stent length/diameter stent size. However, this process can be time-consuming and costly while the relative benefit of a custom stent sizing versus one-size-fits-all approach has not been well evaluated yet. We hypothesized that a 'one-size-fits-all' default approach to carotid stenting results in comparable results to a customized approach.

METHODS

We conducted a descriptive retrospective cohort study on 154 patients who presented to our academic carotid revascularization clinic with symptomatic carotid artery stenosis who underwent carotid artery stenting for peri- and postprocedural carotid artery stenting complications. The primary outcomes were periprocedural (within 24 hours of the procedure) or postprocedural (within 30 days of the procedure) TIA, stroke, or death. The secondary outcome was the estimated degree of stenosis on follow-up ultrasound performed within 6 months of the procedure.

RESULTS

The complication rate within the first 24 hours was 4.5% while that during the first 30 days postprocedure was 6.5%. Age over 80 and degree of stenosis on postprocedural cerebral angiogram were associated with an increased risk of complications. Severe restenosis was reported in 16.8% of patients within 6 months postprocedure.

CONCLUSION

Our study suggests that using a simplified, one-size-fits-all, approach to carotid stenting results in safe and effective outcomes, suggesting an alternative to simplify a complex medical procedure.

Treatment of a posterior cerebral artery aneurysm in the context of complex cardio-cerebrovascular variations using the Tubridge flow diverter

We present a case of intracranial aneurysm located in the P1 segment of left posterior cerebral artery in the context of tetralogy of Fallot. Complex variations included right aortic arch with abnormal branching. Also, the bilateral vertebral arteries were absent, with a type I persistent proatlantal intersegmental artery of the left side. The aneurysm was treated with endovascular intervention with a Tubridge flow diverter and was noted to be completely cured on 6-month follow-up. We discuss the many considerations in this patient including developmental and modern-era treatment.

Artificial intelligence applied in acute ischemic stroke: from child to elderly

This review will summarize artificial intelligence developments in acute ischemic stroke in recent years and forecasts for the future. Stroke is a major healthcare concern due to its effects on the patient's quality of life and its dependence on the timing of the identification as well as the treatment. In recent years, attention increased on the use of artificial intelligence (AI) systems to help categorize, prognosis, and to channel these patients toward the right therapeutic procedure. Machine learning (ML) and in particular deep learning (DL) systems using convoluted neural networks (CNN) are becoming increasingly popular. Various studies over the years evaluated the use of these methods of analysis and prediction in the assessment of stroke patients, and at the same time, several applications and software have been developed to support the neuroradiologists and the stroke team to improve patient outcomes.

Ulnar artery access for intracranial mechanical thrombectomy procedure: A salvage option after failed trans-femoral and trans-radial access

84 years old gentle man with past medical history of hypertension and diabetes presented with sudden onset right sided weakness and aphasia for two hours. Initial neurological assessment revealed National Institute of Health Stroke Scale (NIHSS) 17. Computed tomography (CT) scan demonstrated minimal early ischemic changes along left insular cortex with occlusion of left middle cerebral artery (MCA). Based on clinical and imaging findings, decision was made to perform mechanical thrombectomy procedure. Initially, right common femoral artery approach was utilized. However, due to unfavorable type-III bovine arch, left internal carotid artery could not be engaged via this approach. Subsequently, access was switched to right radial artery. Angiogram revealed small caliber radial artery, with larger caliber ulnar artery. Attempt was made to advance the guide catheter through the radial artery, however significant vasospasm was encountered. Subsequently, ulnar artery was accessed and successful thrombolysis in cerebral infarction (TICI) III left MCA reperfusion was achieved with a single pass of mechanical thrombectomy via this approach. Post procedure neurological examination demonstrated significant clinical improvement. Doppler ultrasound 48 hours after the procedure demonstrated patent flow in radial and ulnar arteries with no evidence of dissection.

Small volume blood-brain barrier opening in macaques with a 1 MHz ultrasound phased array

The use of focused ultrasound to open the blood-brain barrier (BBB) has the potential to deliver drugs to specific regions of the brain. The size of the BBB opening and ability to localize the opening determines the spatial extent and is a limiting factor in many applications of BBB opening where targeting a small brain region is desired. Here we evaluate the performance of a system designed for small opening volumes and highlight the unique challenges associated with pushing the spatial precision of this technique. To achieve small volume openings in cortical regions of the macaque brain, we tested a custom 1 MHz array transducer integrated into a magnetic resonance image-guided focused ultrasound system. Using real-time cavitation monitoring, we demonstrated twelve instances of single sonication, small volume BBB opening with average volumes of 59 ± 37 mm3 and 184 ± 2 mm3 in cortical and subcortical targets, respectively. We found high correlation between subject-specific acoustic simulations and observed openings when incorporating grey matter segmentation (R2 = 0.8577), and the threshold for BBB opening based on simulations was 0.53 MPa. Analysis of MRI-based safety assessment and cavitation signals indicate a safe pressure range for 1 MHz BBB opening and suggest that our system can be used to deliver drugs and gene therapy to small brain regions.

Comparative verification of control methodology for robotic interventional neuroradiology procedures

PURPOSE

The use of robotics is emerging for performing interventional radiology procedures. Robots in interventional radiology are typically controlled using button presses and joystick movements. This study identified how different human-robot interfaces affect endovascular surgical performance using interventional radiology simulations.

METHODS

Nine participants performed a navigation task on an interventional radiology simulator with three different human-computer interfaces. Using Simulation Open Framework Architecture we developed a simulation profile of vessels, catheters and guidewires. We designed and manufactured a bespoke haptic interventional radiology controller for robotic systems to control the simulation. Metrics including time taken for navigation, number of incorrect catheterisations, number of catheter and guidewire prolapses and forces applied to vessel walls were measured and used to characterise the interfaces. Finally, participants responded to a questionnaire to evaluate the perception of the controllers.

RESULTS

Time taken for navigation, number of incorrect catheterisations and the number of catheter and guidewire prolapses, showed that the device-mimicking controller is better suited for controlling interventional neuroradiology procedures over joystick control approaches. Qualitative metrics also showed that interventional radiologists prefer a device-mimicking controller approach over a joystick approach.

CONCLUSION

Of the four metrics used to compare and contrast the human-robot interfaces, three conclusively showed that a device-mimicking controller was better suited for controlling interventional neuroradiology robotics.

Safety Evaluation of Primary Carotid Stenting: Transcranial Doppler and MRI

BACKGROUND AND PURPOSE

Cerebral emboli are generated by every step of standard carotid angioplasty and stenting. Primary carotid stenting (PCS) is a technique in which the use of balloon angioplasty (BA) is minimized to decrease the embolic load. The primary aim of this study is to establish the number of emboli generated by each step of primary stenting and determine the relationship to new diffusion (DWI) lesions on subsequent magnetic resonance imaging (MRI).

METHODS

Eighty-five patients with severe, symptomatic carotid stenosis were prospectively recruited and underwent carotid stenting. Intraoperative transcranial Doppler was performed in 77 patients. The number and size of microemboli for each of seven procedural steps were recorded. Correlation was made with the number and location of new DWI lesions.

RESULTS

PCS was performed in 73 patients. BA was required in 12 patients. The mean number of microemboli was 114, and most microemboli were generated by stent deployment, followed by BA. Balloon techniques generated significantly more emboli than primary stenting (p = 0.017). There was a significant relationship between total microemboli and new DWI lesions (p = 0.009), and between new DWI lesions in multiple territories and the severity of pretreatment stenosis (p = 0.002).

CONCLUSIONS

During PCS, more emboli are generated by stent deployment than during any other stage of the procedure. When BA is necessary, more malignant emboli are generated but total emboli are unchanged and there is no difference in new diffusion lesions on MRI. PCS is safe and is not inferior to historical controls for the generation of new DWI lesions.

Work-up and Management of Asymptomatic Extracranial Traumatic Vertebral Artery Injury

BACKGROUND

Non-penetrating head and neck trauma is associated with extracranial traumatic vertebral artery injury (eTVAI) in approximately 1-2% of cases. Most patients are initially asymptomatic but have an increased risk for delayed stroke and mortality. Limited evidence is available to guide the management of asymptomatic eTVAI. As such, we sought to investigate national practice patterns regarding screening, treatment, and follow-up domains.

METHODS

A cross-sectional, electronic survey was distributed to members of the Canadian Neurosurgical Society and Canadian Spine Society. We presented two cases of asymptomatic eTVAI, stratified by injury mechanism, fracture type, and angiographic findings. Screening questions were answered prior to presentation of angiographic findings. Survey responses were analyzed using descriptive statistics.

RESULTS

One hundred-eight of 232 (46%) participants, representing 20 academic institutions, completed the survey. Case 1: 78% of respondents would screen for eTVAI with computed topography angiography (CTA) (97%), immediately (88%). The majority of respondents (97%) would treat with aspirin (89%) for 3-6 months (46%). Respondents would follow up clinically (89%) or radiographically (75%), every 1-3 months. Case 2: 73% of respondents would screen with CTA (96%), immediately (88%). Most respondents (94%) would treat with aspirin (50%) for 3-6 months (35%). Thirty-six percent of respondents would utilize endovascular therapy. Respondents would follow up clinically (97%) or radiographically (89%), every 1-3 months.

CONCLUSION

This survey of Canadian practice patterns highlights consistency in the approach to screening, treatment, and follow-up of asymptomatic eTVAI. These findings are relevant to neurosurgeons, spinal surgeons, stroke neurologists, and neuro-interventionalists.

Treatment of Sub-Acute Intracranial Stent Occlusion with Rescue Stenting After Failed Aspiration and Stent Retriever Thrombectomy

We report a case of middle age man presented a subacute balloon-mounted stent occlusion placed for M1 segment occlusion stroke due to intracranial atherosclerotic stenosis after thrombectomy failure and treated with a second balloon-mounted stent within the first one. Successful recanalization and complete clinical recovery were achieved. The coronary balloon-mounted stent is s a useful tool as a rescue treatment in case of intracranial stent occlusion.

An off-label use of flow-diverter stent as a successful treatment of a postoperative middle cerebral artery pseudoaneurysm

A pseudoaneurysm or false aneurysm is the result of the disruption of the vessel wall and the formation of a hematoma in communication with the vascular lumen, restrained by perivascular connective tissue. Intracranial pseudoaneurysms represent a rare entity mainly because of trauma, iatrogenic causes, infectious disease, radiation exposure, connective tissue disease and sometimes spontaneous occurrence. We present a 35-year-old female patient with a history of multiple low-grade glioma debulking surgeries. During the last procedure, laceration of the left middle cerebral artery (MCA) occurred with diffuse subarachnoid hemorrhage. Imaging studies showed the formation of a pseudoaneurysm of the left MCA which was successfully treated with the implantation of a flow diverter across the lesion neck and excellent mid- to long- term results. Flow diverter implantation may be a promising technique for the therapeutic management of cerebral pseudoaneurysms.

The efficacy of postoperative middle meningeal artery embolization on chronic subdural hematoma - A multicentered randomized controlled trial

Background

Middle meningeal artery (MMA) embolization has recently emerged as a potential treatment for chronic subdural hematoma (cSDH). Numerous retrospective studies have suggested that it can potentially reduce the risk of hematoma recurrence following surgical evacuation. We have conducted a randomized controlled trial to investigate the effectiveness of postoperative MMA embolization in reducing recurrence rate, residual hematoma thickness as well as improving functional outcome.

Methods

Patients aged 18 or above were recruited. Following evacuation through burr hole or craniotomy, patients were randomly allocated to undergo either MMA embolization or standard care (monitoring). The primary outcome was symptomatic recurrence requiring redo evacuation. Secondary outcomes include residual hematoma thickness and modified Rankin Scale (mRS) at 6 weeks and 3 months.

Results

Thirty-six patients (41 cSDHs) were recruited between April 2021 and September 2022. Seventeen patients (19 cSDHs) were allocated to the embolization group and 19 patients (22 cSDHs) were in the control group. No symptomatic recurrence was observed in the treatment group while 3 control patients (15.8%) underwent repeat surgery for symptomatic recurrence, however, it was not statistically significant (P = 0.234). Furthermore, there was no significant difference in residual hematoma thickness at 6 weeks or 3 months between the two groups. All patients in the embolization group had a good functional outcome (mRS 0-1) at 3 months, which was significantly higher than the 53% observed in the control group. No complications related to MMA embolization were reported.

Conclusion

Further study with larger sample size is required to evaluate the efficacy of MMA embolization.

Utility of virtual stenting in treatment of cerebral aneurysms by flow diverter devices

Successful endovascular treatment by stenting of intracranial aneurysms requires proper placement of the device and appropriate choice of its diameter and length. To date, several methods have been employed to achieve these goals, although each has inherent critical issues. Recently developed stent planning software applications can be used to assist interventional neuroradiologists. Based on a 3D-DSA image acquired before stenting, these applications simulate and visualize the final placement of the deployed stent. In this single-centre retrospective study, 27 patients undergoing an intravascular procedure for the treatment of intracranial aneurysms from June 2019 to July 2020 were evaluated according to strict inclusion criteria. Stent virtualization was performed with Syngo 3D Aneurysm Guidance Neuro software. We compared the software-generated stent measurement and measurements taken by the interventional radiologist. Statistical analysis was performed using the STAC web platform. Mean and standard deviations of absolute and relative discrepancies between predicted and implanted stents were recorded. Friedman's nonparametric test was used to refute the null hypotheses, i.e. (I) discrepancies between the size of virtual and implanted stents would occur, and (II) operator influence does not affect the outcome of the virtual stenting process. Based on these observations, it is believed that the virtual stenting process can validly assist interventional neuroradiologists in selecting the appropriate device and reducing peri- and post-procedural complications. The results of our study suggest that virtual reality simulation of devices used for endovascular treatment of intracranial aneurysms is a useful, rapid, and accurate tool for interventional procedure planning.

Safety and feasibility of the Wahoo Hybrid Access System, a dual-mode guide catheter, in a range of neuroendovascular procedures

BACKGROUND

There is a clinical need for a guide catheter with combined stability and navigability, which can be used in a biaxial system for neuroendovascular procedures in place of triaxial systems.

OBJECTIVE

To assess the safety and feasibility of the Q'Apel Medical Wahoo Hybrid Access System, a dual-mode 0.072″ internal diameter guide catheter, in a range of neuroendovascular procedures.

METHODS

We performed a retrospective analysis of consecutive cases from a high-volume tertiary center in which the Wahoo Hybrid Access System was used as the guide catheter. Characteristics of the patients, vascular lesions, procedure, and procedural complications were assessed.

RESULTS

A total of 102 patients were included for analysis. Vascular lesions were in the anterior circulation in 90 of 102 (88%), and posterior circulation in 12 of 102 (12%). Eighty-four cases were ruptured or unruptured aneurysm embolization procedures, the majority being balloon-assisted coiling (42%) and flow diversion (42%). All cases, including flow diversion, were performed as a biaxial system. There were no instances of prolapse of the catheter beyond the arterial segment in which it was initially placed. The procedure was able to be performed to completion in 101 of 102 (99%) cases. Thromboembolic complications occurred in 5 of 102 (5%); causality in two cases was unrelated to the guide catheter, and three were indeterminate.

CONCLUSIONS

The Wahoo guide catheter is safe and feasible when used in a variety of neuroendovascular procedures. It can accommodate a range of devices, can be safely navigated into distal vasculature, and provides support for a range of procedures, including those which traditionally require triaxial support.

Rehearsals using patient-specific 3D-printed aneurysm models for simulation of endovascular embolization of complex intracranial aneurysms: 3D SIM study

BACKGROUND

In neurovascular treatment planning, endovascular devices to manage complex intracranial aneurysms requiring intervention are often selected based on conventional measurements and interventional neuroradiologist experience. A recently developed technology allows a patient-specific 3D-printed model to mimic the navigation experience. The goal of this study was to assess the effect of pre-procedure 3D simulation on procedural and clinical outcomes for wide-neck aneurysm embolization.

MATERIALS & METHODS

In this unblinded, non-randomized, prospective, multicenter study conducted from November 18 through December 20, patients with complex intracranial aneurysms (neck > 4 mm or ratio < 2¹) were treated by WEB or flow diverter stents (FDS). The primary endpoint was concordance between simulation and procedure, 3D-printed model accuracy as well as embolization outcomes including complications, procedure times, and radiation dose were also assessed. Secondary endpoint was to compare versus a retrospective WEB cohort.

RESULTS

Twenty-one patients were treated, 76% of cases by WEB and 24% by FDS. Concordance between post-simulation and real procedure efficiency was 0.85 [0.69 - 1.00] for size device selection and 0.93 [0.79 - 1.00] for wall-apposition/aneurysm neck closure. Geometrical accuracy of the 3D-printed model showed a mean absolute shift of 0.11 mm. Two complications without major clinical impact were reported with a post-operative mRS similar to pre-procedure mRS for all patients.

CONCLUSIONS

Rehearsal using accurate 3D-printed patient-specific aneurysm models enabled optimization of embolization strategy, resulting in reduced procedure duration and cumulative fluoroscopy time which translated to reduced radiation exposure compared to procedures performed without simulation.

Radiation dose and fluoroscopy time of aneurysm coiling in patients with unruptured and ruptured intracranial aneurysms as a function of aneurysm size, location, and patient age

PURPOSE

Endovascular treatment of unruptured intracranial aneurysms (UIAs) requires a risk-benefit analysis and adherence to diagnostic reference levels (DRLs). The national DRL (250 Gy·cm²) is only determined for intracranial aneurysm coiling in general, including ruptured intracranial aneurysms (RIAs). This study aims to investigate the dose in the treatment of UIAs and RIAs separately.

METHODS

In a retrospective study design, dose area product (DAP) and fluoroscopy time (FT) were assessed for all patients undergoing intracranial aneurysm coiling between 2010 and 2021. DRL was set as the 75th percentile of the dose distribution. A multivariable linear regression analysis was performed to investigate DAP and FT for the two groups, UIA and RIA adjusted for patient age, aneurysm size, and location.

RESULTS

583 (414 females, mean age 56.5 years, 311 UIAs) are included. In the overall population, DAP (median (IQR)) is 157 Gy·cm² (108-217) with a median FT of 32.7 min (IQR 24.0-47.0). Local DRL is 183 Gy·cm² for UIAs and 246 Gy·cm² for RIAs. After adjustment for the other variables, the UIA and RIA groups have a significant effect on both DAP (p < 0.001; 95% CI - 68.432 - - 38.040) and FT (p < 0.001; 95% CI - 628.279 - - 291.254). In general, both DAP and FT increase significantly with patient age and aneurysm size, whereas the location of the aneurysm did not significantly change neither DAP (p = 0.171; 95% CI - 5.537-31.065) nor FT (p = 0.136; 95% CI - 357.391-48.508).

CONCLUSION

Both aneurysm size and patient age were associated with increased DAP, whereas aneurysm location did not significantly change DAP or FT. The increased dose in patients with RIAs is likely equivalent to additional diagnostic cerebral four-vessel angiography performed in this group.

Single Centre Initial Experience with the Scepter Mini Balloon Microcatheter

BACKGROUND

The use of balloon microcatheters in interventional neuroradiology is well documented. However, their use is sometimes limited by the small diameter and excessive tortuosity of the vasculature. The Scepter Mini dual-lumen balloon microcatheter (SMBM) (Microvention, Aliso Viejo, CA) has been designed to address these challenges by decreasing the distal catheter profile, allowing distal access to the target vessel.

METHODS

This is a single-centre retrospective analysis of the initial cases performed using the Scepter Mini balloon microcatheter. The targeted conditions were vascular malformations. Patient clinical data, angiographic features of the vascular abnormalities and operation reports were reviewed and the procedural parameters, radiation doses, occlusion rates and complications were assessed.

RESULTS

A total of 15 SMBM were used in 11 cases. In all cases the procedure performed was balloon inflation and antegrade delivery of precipitating hydrophobic injectable liquid (PHIL) (Microvention, Aliso Viejo, CA) for embolisation of a targeted feeding vessel and cranial and spinal vascular malformations. Successful feeding vessel distal access and antegrade liquid embolisation was achieved in 100% of the cases. One of the 11 cases was an emergency procedure. One procedural target vessel rupture, likely due to overinflation, and three minor post-procedure complications were observed.

CONCLUSION

The SMBM represents a significant advance in the treatment of cerebrospinal vascular malformations, allowing balloon catheter access into tortuous and small calibre vessels.

Practical use and underlying physics of the BENCHMARK™ BMX™ 96 for large-bore aspiration thrombectomy: Case report of initial institutional experience

Endovascular thrombectomy (EVT) is part of first-line intervention for acute ischemic stroke management. Recent technological advances have demonstrated that large-bore catheters are an attractive approach for EVT. A multitude of approaches such as A Direct Aspiration first Pass Technique (ADAPT) or in conjunction with stent retrieval (Solumbra technique) have been developed with increasingly large-bore catheters, demonstrating safety and efficacy. Furthermore, these techniques have demonstrated promise for the intervention of cerebral venous thrombosis as well as posterior circulation ischemic events. Recently, advances in neurointerventional catheters have focused on improved maneuverability to navigate the neurovasculature, as well as larger inner diameters for improved procedural versatility, including aspiration. We describe a case report highlighting our early institutional experience with the recently developed large-bore catheter, the BENCHMARK™ BMX™ 96. The case report entails near complete occlusion of the internal carotid artery from acute thrombus and the utility of the BMX™ 96 catheter for treatment of such extensive clot burden. The applicability of large-bore aspiration catheters, with an emphasis on recent advances, for mechanical thrombectomy in arterial as well as venous systems is discussed. To our knowledge, this is the first reported case of use of the BENCHMARK™ BMX™ 96 access system for EVT in acute ischemic stroke. Such new-generation large-bore catheters are a promising advance in neurointervention, and our early institution experience highlights the ease of use and versatility for neurointerventional procedures such as EVT.

Seeing the good in the bad: actual clinical outcome of thrombectomy stroke patients with formally unfavorable outcome

Purpose

Clinical outcome of stroke patients is usually classified into favorable (modified Rankin scale (mRS) 0–2) and unfavorable (mRS 3–5) outcome according to the modified Rankin scale. We took a closer look at the clinical course of thrombectomy stroke patients with formal unfavorable outcome and assessed whether we could achieve our treatment goals and/or neurological improvement in these patients.

Methods

We studied 107 patients with occlusions in the terminal carotid artery or the M1 segment of the middle cerebral artery, in whom complete recanalization (eTICI 3) could be achieved, and who had an mRS of 3–5 at 90 days. We analyzed whether an individual treatment goal (i.e., preventing aphasia) and neurological improvement (NIHSS) could be achieved. In addition, we examined whether there was clinical improvement on the mRS.

Results

The treatment goal was achieved in 52% (53/103) and neurological improvement in 65% (67/103). mRS 90 days post-stroke was better than mRS upon admission in 36% (38/107) and better than or equal to mRS upon admission in 80% (86/107). Of the 93 patients with known pre-stroke mRS, 18% (17/93) already had an mRS ≥ 3, with 15 of these 17 patients having a worse mRS on admission than before. Of these 17 patients, 18% regained baseline, and 24% improved from admission.

Conclusion

Dichotomizing the mRS into favorable and unfavorable outcome does not do justice to the full spectrum of stroke. Patients with formal unfavorable outcome after mRS can improve neurologically, achieve treatment goals, and even regain their admission or pre-stroke mRS.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00234-022-02920-1.

Radiation exposure in the endovascular therapy of cranial and spinal dural arteriovenous fistula in the last decade: a retrospective, single-center observational study

PURPOSE

This study aims to determine local diagnostic reference levels (DRLs) in the endovascular therapy (EVT) of patients with cranial and spinal dural arteriovenous fistula (dAVF).

METHODS

In a retrospective study design, DRLs and achievable dose (AD) were assessed for all patients with cranial and spinal dAVF undergoing EVT (I) or diagnostic angiography (II). All procedures were performed at the flat-panel angiography-system Allura Xper (Philips Healthcare). Interventional procedures were differentiated according to the region of fistula and the type of procedure.

RESULTS

In total, 264 neurointerventional procedures of 131 patients with dAVF (94 cranial, 37 spinal) were executed between 02/2010 and 12/2020. The following DRLs, AD, and mean values could be determined: for cranial dAVF (I) DRL 507.33 Gy cm2, AD 369.79 Gy cm2, mean 396.51 Gy cm2; (II) DRL 256.65 Gy cm2, AD 214.19 Gy cm2, mean 211.80 Gy cm2; for spinal dAVF (I) DRL 482.72 Gy cm2, AD 275.98 Gy cm2, mean 347.12 Gy cm2; (II) DRL 396.39 Gy cm2, AD 210.57 Gy cm2, mean 299.55 Gy cm2. Dose levels of EVT were significantly higher compared to diagnostic angiographies (p < 0.001). No statistical difference in dose levels regarding the localization of dAVF was found.

CONCLUSION

Our results could be used for establishing DRLs in the EVT of cranial and spinal dAVF. Because radiation exposure to comparably complex interventions such as AVM embolization is similar, it may be useful to determine general DRLs for both entities together.

Management of internal carotid artery injury sustained during routine endoscopic sinus surgery

A 49-year-old patient with a history of aspirin-exacerbated respiratory disease presented with carotid artery injury following revision functional endoscopic sinus surgery. Carotid artery injury is a rare but catastrophic complication of this surgery. The patient was transferred to our tertiary facility with interventional radiology for immediate management of the carotid artery injury. This case reaffirms that any surgery can have disastrous complications and highlights the importance of multidisciplinary management of complications such as carotid artery injury.

Radiation Exposure During Diagnostic and Therapeutic Angiography of Carotid-cavernous Fistula : A Retrospective Single Center Observational Study

Purpose

The aim of this study was to determine local diagnostic reference levels (DRLs) during endovascular diagnostics and therapy of carotid-cavernous fistulas (CCF).

Methods

In a retrospective study design, DRLs, achievable dose (AD) and mean values were assessed for all patients with CCF undergoing diagnostic angiography (I) or embolization (II). All procedures were performed with the flat-panel angiography system Allura Xper (Philips Healthcare). Interventional procedures were differentiated according to the type of CCF and the type of procedure.

Results

In total, 86 neurointerventional procedures of 48 patients with CCF were executed between February 2010 and July 2021. The following DRLs, AD and mean values could be determined: (I) DRL 215 Gy ∙ cm², AD 169 Gy ∙ cm², mean 165 Gy ∙ cm²; (II) DRL 350 Gy ∙ cm², AD 226 Gy ∙ cm², mean 266 Gy ∙ cm². Dose levels of embolization were significantly higher compared to diagnostic angiography (p < 0.001). No significant dose difference was observed with respect to the type of fistula or the embolization method.

Conclusion

This article reports on diagnostic and therapeutic DRLs in the management of CCF that could serve as a benchmark for the national radiation protection authorities. Differentiation by fistula type or embolization method does not seem to be useful.

Predictive value of DWI posterior-circulation lesion volume for 90-day clinical outcome after endovascular treatment of acute basilar artery occlusion: a retrospective single-center study

PURPOSE

The relationship between posterior-circulation lesion volume (PCLV) and clinical outcomes is poorly investigated. We aimed to analyze, in patients with acute basilar artery occlusion (ABAO), if pre-endovascular treatment (EVT) PCLV was a predictor of outcomes.

METHODS

We analyzed consecutive MRI selected, endovascularly treated ABAO patients. Baseline PCLV was measured in milliliters on apparent diffusion-coefficient map reconstruction. Univariable and multivariable logistic models were used to test if PCLV was a predictor of 90-day outcomes. After the received operating characteristic (ROC) analysis, the optimal cut-off was determined to evaluate the prognostic value of PCLV.

RESULTS

A total of 110 ABAO patients were included. The median PCLV was 4.4 ml (interquartile range, 1.3-21.2 ml). Successful reperfusion was achieved in 81.8% of cases after EVT. At 90 days, 31.8% of patients had a modified Rankin scale ≤ 2, and the mortality rate was 40.9%. PCLV was an independent predictor of functional independence and mortality (odds ratio [OR]:0.57, 95% confidence interval [CI], 0.34-0.93 and 1.84, 95% CI, 1.23-2.76, respectively). The ROC analysis showed that a baseline PCLV ≤ 8.7 ml was the optimal cut-off to predict the 90-day functional independence (area under the curve [AUC] = 0.68, 95% CI, 0.57-0.79, sensitivity 88.6%, and specificity 49.3%). In addition, a PCLV ≥ 9.1 ml was the optimal cut-off for the prediction of 90-day mortality (AUC = 0.71, 95% CI, 0.61-0.82, sensitivity 80%, and specificity 60%).

CONCLUSIONS

Pre-treatment PCLV was an independent predictor of 90-day outcomes in ABAO. A PCLV ≤ 8.7 and ≥ 9.1 ml may identify patients with a higher possibility to achieve independence and a higher risk of death at 90 days, respectively.

Determinants of Leptomeningeal Collateral Status Variability in Ischemic Stroke Patients

BACKGROUND

Collateral status is an indicator of a favorable outcome in stroke. Leptomeningeal collaterals provide alternative routes for brain perfusion following an arterial occlusion or flow-limiting stenosis. Using a large cohort of ischemic stroke patients, we examined the relative contribution of various demographic, laboratory, and clinical variables in explaining variability in collateral status.

METHODS

Patients with acute ischemic stroke in the anterior circulation were enrolled in a multi-center hospital-based observational study. Intracranial occlusions and collateral status were identified and graded using multiphase computed tomography angiography. Based on the percentage of affected territory filled by collateral supply, collaterals were graded as either poor (0-49%), good (50-99%), or optimal (100%). Between-group differences in demographic, laboratory, and clinical factors were explored using ordinal regression models. Further, we explored the contribution of measured variables in explaining variance in collateral status.

RESULTS

386 patients with collateral status classified as poor (n = 64), good (n = 125), and optimal (n = 197) were included. Median time from symptom onset to CT was 120 (IQR: 78-246) minutes. In final multivariable model, male sex (OR 1.9, 95% CIs [1.2, 2.9], p = 0.005) and leukocytosis (OR 1.1, 95% CIs [1.1, 1.2], p = 0.001) were associated with poor collaterals. Measured variables only explained 44.8-53.0% of the observed between-patient variance in collaterals.

CONCLUSION

Male sex and leukocytosis are associated with poorer collaterals. Nearly half of the variance in collateral flow remains unexplained and could be in part due to genetic differences.

Is General Anesthesia for Endovascular Thrombectomy Helpful or Harmful?

Endovascular thrombectomy (EVT) has significantly improved outcomes for patients with acute ischemic stroke due to large vessel occlusion. However, despite advances, more than half of patients remain functionally dependent 3 months after their initial stroke. Anesthetic strategy may influence both the technical success of the procedure and overall outcomes. Conventionally, general anesthesia (GA) has been widely used for neuroendovascular procedures, particularly for the distal intracranial circulation, because the complete absence of movement has been considered imperative for procedural success and to minimize complications. In contrast, in patients with acute stroke undergoing EVT, the optimal anesthetic strategy is controversial. Nonrandomized studies suggest GA negatively affects outcomes while the more recent anesthesia-specific RCTs report improved or unchanged outcomes in patients managed with versus without GA, although these findings cannot be generalized to other EVT capable centers due to a number of limitations. Potential explanations for these contrasting results will be addressed in this review including the effect of different anesthetic strategies on cerebral and systemic hemodynamics, revascularization times, and periprocedural complications.

Stenting in High-Grade Internal Carotid Artery Stenosis: 2-Dimensional Operative Video

Carotid artery stenosis is implicated in up to 40% of all ischemic strokes. Accordingly, symptomatic, high-grade carotid artery stenosis portends an especially high risk of future stroke. Intervention via open or endovascular approaches drastically reduces this risk. Under the appropriate conditions, carotid artery stenting serves as a safe and effective alternative to carotid endarterectomy. We present the case of a 57-yr-old male with symptomatic, high-grade stenosis of his right internal carotid artery, for whom a history of radiation to the head and neck represented a relative contraindication to carotid endarterectomy, and thus endovascular treatment with angioplasty and stenting was performed. Informed consent was obtained prior to the procedure. Intraprocedurally, stent delivery past the area of stenosis proved somewhat challenging. However, by employing several nuanced maneuvers, we utilized our guiding catheter in a nonconventional manner in order to successfully perform the procedure. As the field of neuroendovascular surgery evolves, each case provides us unique lessons, which in turn expands our interventional capabilities and adds to the armamentarium of neuroendovascular techniques. We present this surgical video both as a means to provide a general overview of carotid artery stenting, and to share a lesson learned through the implementation of an interesting technical nuance.

Glue, Onyx, Squid or PHIL? Liquid Embolic Agents for the Embolization of Cerebral Arteriovenous Malformations and Dural Arteriovenous Fistulas

Background

Endovascular embolization is an effective treatment option for cerebral arteriovenous malformations (AVMs) and dural arteriovenous fistulas (DAVFs). A variety of liquid embolic agents have been and are currently used for embolization of AVMs and DAVFs. Knowledge of the special properties of the agent which is used is crucial for an effective and safe embolization procedure.

Material and Methods

This article describes the properties and indications of the liquid embolic agents which are currently available: cyanoacrylates (also called glues), and the copolymers Onyx, Squid and PHIL, as well as their respective subtypes.

Results

Cyanoacrylates were the predominantly used agents in the 1980s and 1990s. They are currently still used in specific situations, for example for the occlusion of macro-shunts, for the pressure cooker technique or in cases in which microcatheters are used that are not compatible with dimethyl-sulfoxide. The first broadly used copolymer-based embolic agent Onyx benefits from a large amount of available experience and data, which demonstrated its safety and efficacy in the treatment of cerebral vascular malformations, while its drawbacks include temporary loss of visibility during longer injections and artifacts in cross-sectional imaging. The more recently introduced agents Squid and PHIL aim to overcome these shortcomings and to improve the success rate of endovascular embolization. Novelties of these newer agents with potential advantages include extra-low viscosity versions, more stable visibility, and a lower degree of imaging artifacts.

Conclusion

All the available liquid embolic agents feature specific potential advantages and disadvantages over each other. The choice of the most appropriate embolic agent must be made based on the specific material characteristics of the agent, related to the specific anatomical characteristics of the target pathology.

[Spinal ozone therapy]

Klinisches/methodisches Problem

Technische Fortschritte auf dem Gebiet der spinalen interventionellen Neuroradiologie ermöglichen es, eine breite Palette an gezielten, minimal-invasiven Behandlungsoptionen einschließlich der spinalen Ozontherapie beim Rückenschmerz anzuwenden. Dieser Beitrag gibt eine Übersicht der biochemischen, molekularen, immunologischen und pharmazeutischen Mechanismen sowie Applikationstechniken der gezielten Ozontherapie.

Radiologische Standardverfahren

Zum Einsatz kommen die Computertomographie (CT) sowie konventionelle Röntgenaufnahmen (Durchleuchtung).

Leistungsfähigkeit

Die CT-gesteuerten Interventionen (epidural, periradikuläre, Facettengelenk und intradiskal) haben den höchsten Stellenwert und haben sich historisch durchgesetzt. Durchleuchtungsgesteuerte Verfahren können ebenfalls eingesetzt werden.

Schlussfolgerung

Die Ozontherapie liefert vielversprechende Ergebnisse. Der Beitrag soll dazu dienen, Informationen über die Grundlagen dieser Technik(en) zu vermitteln.

When Two Is Better than One : The Buddy-wire Technique in Flow-diversion Procedures

Background

Delivery of most flow diverters (FD) requires larger, and thus stiffer microcatheters (0.021–0.027in.) which can pose challenges to intracranial navigation. The concomitant use of two microwires within one microcatheter, also known as the buddy-wire technique, may be helpful for navigation and support in challenging situations.

Methods

We analyzed all flow diverter procedures in our prospectively collected database. We recorded all patient-related, anatomical and procedural information. We performed univariate statistics and technical descriptions.

Results

In total, 208 consecutive patients treated with a FD at our institution between July 2014 and August 2020 were retrospectively analyzed. In 17 patients the buddy-wire technique was used (mean age 63 years, range 31–87 years: 16 female). Aneurysms were located at the petrous, cavernous, supraophthalmic internal carotid artery, and a proximal M2 branch in 2, 7, 7 and 1 patient(s), respectively. In all cases a 0.027in. microcatheter was used for device deployment. In 14 patients with a wide-necked aneurysm the buddy-wire provided additional support to advance the microcatheter and mitigated the ledge between the aneurysm neck and the parent artery or a side branch. In two giant cavernous aneurysms treated with telescoping FDs, the buddy-wire was used to re-enter the proximal end of the foreshortened FD.

Conclusion

The buddy-wire is a useful technique in FD procedures to prevent herniation of the microcatheter into the aneurysm sack, in wide-necked aneurysms to mitigate the ledge effect between the aneurysm neck and the parent artery where the microcatheter tip may get stuck, or to enable re-entry into a foreshortened FD.

Acute Stenting and Concomitant Tirofiban Administration for the Endovascular Treatment of Acute Ischemic Stroke Related to Intracranial Artery Dissections: A Single Center Experience and Systematic Review of the Literature

BACKGROUND

Intracranial artery dissection is an uncommon cause of acute ischemic stroke. Although acute stenting of the dissected arterial segment is a therapeutic option, the associated antiplatelet regimen remains a matter of debate.

OBJECTIVES

To evaluate the efficacy and safety of acute intracranial stenting together with concomitant intravenous administration of tirofiban and to perform a systematic review of the literature.

MATERIALS AND METHODS

A single-center, retrospective study of the clinical and radiological records of all patients treated at our center by intracranial stenting in the setting of acute ischemic stroke between January 2010 and December 2020. A systematic review of the literature was conducted according to the PRISMA-P guidelines for relevant publications from January 1976 to December 2020 on intracranial artery dissection treated by stent.

RESULTS

Seven patients with intracranial artery dissections underwent acute stenting with concomitant tirofiban during the study period. Mid-term follow-up showed parent artery patency in 6/7 cases (85.7%). The modified Rankin Score was ≤ 0-2 at 3 months in 5/7 cases (71.4%). The literature review identified 22 patients with intracranial artery dissection treated with acute stenting in association with different antithrombotic therapies. Complete revascularization was obtained in 86.3% of cases with a modified Rankin Score of ≤ 0-2 in 68% of patients at 3-month follow-up.

CONCLUSIONS

Acute intracranial stenting together with intravenous tirofiban administration could be a therapeutic option in patients with intracranial artery dissection and a small ischemic core.

Management of Ruptured Intracranial Aneurysms in the Post-International Subarachnoid Aneurysm Trial Era: A Single-Centre Prospective Series

BACKGROUND

Aneurysmal subarachnoid haemorrhage (aSAH) is associated with significant morbidity and mortality. The International Subarachnoid Aneurysm Trial (ISAT) reported reduced morbidity in patients treated with endovascular coiling versus surgical clipping. However, recent studies suggest that there is no significant difference in clinical outcomes. This study examines the outcomes of either technique for treating aSAH during the 15 years post-ISAT at a Canadian quaternary centre.

METHODS

We reviewed prospectively collected data of patients admitted with aSAH from January 2002 to December 2017. Glasgow Outcome Scale (GOS) was compared at discharge, 6 months and 12 months' follow-up using univariate and multivariable ordinal logistic regression. Post-operative complications were assessed using binary logistic regression.

RESULTS

Two-hundred and eighty-seven patients were treated with coiling and 95 patients with clipping. The mean age of clipped patients was significantly younger, and hypertension was significantly commoner in coiled patients. A greater proportion of coiled aneurysms were located in the posterior circulation. No difference in the odds of having a favourable GOS was seen between patients who were clipped versus coiled at any of follow-up time points on univariate or multivariable analysis. In both treatment groups, patient recovery to independence (GOS 4-5) was seen from discharge to 6 months, but not from 6 to 12 months' follow-up, without difference between clipping and coiling.

CONCLUSION

These real-world findings suggest clipping remains an effective and important treatment option for patients with aSAH who do not meet ISAT inclusion criteria. The results can assist in clinical decision-making processes and understanding of the natural recovery progression of aSAH.

Use of radial access sheaths for transfemoral neuroendovascular procedures in children

PURPOSE

Pediatric neuroendovascular procedures require special considerations. Given small vessel sizes, risk for arterial injury must be weighed against use of larger devices, with the diameter of the sheath being a known association with arterial complications. We recently transitioned to using thin-walled radial sheaths for transfemoral angiography in children, given their lower profile. Here, we report on these sheaths' technical success and complications, comparing against a historical cohort where regular vascular sheaths were employed.

METHODS

We retrospectively recorded patient and procedural data from 168 consecutive procedures from September 2017 to January 2019 when radial-specific sheaths were exclusively used at our tertiary pediatric hospital. These results were compared to data from September 2015 to January 2017, when regular vascular sheaths were exclusively used in 152 consecutive procedures. Statistical analysis was performed using unpaired t test or chi-square test, with p < 0.05 considered statistically significant.

RESULTS

Patient characteristics (age, sex, weight) were not statistically different between the case and control group. No significant differences were found in the procedural data with the exception of heparin use which was higher in the radial-sheath cohort. There was a decrease in the rate of complications in the case group (1.2%) versus control group (2.6%), though not statistically different.

CONCLUSION

Radial-specific sheaths have numerous beneficial characteristics that make them well-suited to the pediatric population. In our study, we show that radial sheaths are equally effective and safe perioperatively. Follow-up research may show if radial sheaths used transfemorally decrease long-term complications such as limb-length discrepancy and mortality.

Ischemic stroke and retinal artery occlusion after carotid aneurysm embolization

We present the case of a 72-year-old male with a right carotid aneurysm incidentally discovered after an ischemic stroke. After management of the stroke, stent-assisted coil embolization was performed to treat the aneurysm. Two simultaneous and early complications occurred: new ischemic strokes and branch retinal artery occlusions, respectively in the right occipital lobe and in the right eye. Treatment of unruptured carotid aneurysm using stent-assisted coil embolization can lead to severe complications involving both the brain and the retina. Multidisciplinary and close surveillance of patients should be performed to diagnose adverse effects of this endovascular treatment.

Increased Rates of Hemorrhages after Endovascular Stroke Treatment with Emergency Carotid Artery Stenting and Dual Antiplatelet Therapy

BACKGROUND

While endovascular stroke treatment (EST) of large vessel occlusions in acute ischemic stroke (AIS) is proven to be safe and effective, there are subgroups of patients with increased rates of hemorrhages. Our goal was to identify risk factors for intracerebral hemorrhage and to assess whether acute carotid artery stenting (CAS) was associated with increased bleeding rates.

METHODS

We performed a retrospective analysis of our monocentric prospective stroke registry in the period from May 2010 to May 2018 and compared AIS patients receiving EST with (n = 73) versus without acute CAS (n = 548). Patients with intracranial stents, intra-arterial thrombolysis, or dissection of the carotid artery were excluded.

RESULTS

Parenchymal hemorrhage rates (PH2 according to the ECASS classification) and symptomatic hemorrhage (sICH) rates were increased in EST patients receiving CAS with odds being 6.3 (PH2) and 6.5 (sICH) times higher (PH2 17.8 vs. 3.3%, p < 0.001 and sICH: 16.4 vs. 2.9%, p < 0.001). Additional systemic thrombolysis with rtPA (IVRTPA) was no risk factor for cerebral hemorrhage (p = 0.213).

CONCLUSION

AIS patients receiving EST with acute CAS and consecutive tirofiban or dual antiplatelet therapy suffered from an increased risk of relevant secondary intracranial bleeding. After adjusting for confounders, tirofiban and dual antiplatelet therapy were associated with higher bleeding rates.

Cerebral angiography: Techniques and practice

As a refresher course on current techniques and practice of cerebral angiography, this chapter outlines the steps in effective angiography, incorporating modern quality and safety considerations. The format is step-by-step from preprocedure to intraprocedure to postprocedure for ease of reference. The chapter will serve as a framework for the fledgling angiographer, augmenting the important teaching provided by a seasoned angiographer.

Overview of Different Flow Diverters and Flow Dynamics

Over the past decade, flow diverter technology for endocranial aneurysms has seen rapid evolution, with the development of new devices quickly outpacing the clinical evidence base. However, flow diversion has not yet been directly compared to surgical aneurysm clipping or other endovascular procedures. The oldest and most well-studied device is the Pipeline Embolization Device (PED; Medtronic), recently transitioned to the Pipeline Flex (Medtronic), which still has sparse data regarding outcomes. To date, other flow diverting devices have not been shown to outperform the PED, although information comes primarily from retrospective studies with short follow-up, which are not always comparable. Because of this lack of high-quality outcome data, no reliable recommendations can be made for choosing among flow diversion devices yet. Moreover, the decision to proceed with flow diversion should be individualized to each patient. In this work, we wish to provide a comprehensive overview of the technical specifications of all flow diverter devices currently available, accompanied by a succinct description of the evidence base surrounding each device.

Critical Evaluation of Interventional Neuroradiology Fellowship Program Websites in North America

OBJECTIVE

To investigate the accessibility and content of interventional neuroradiology (INR) fellowship program websites in North America.

METHODS

We obtained a list of INR/endovascular surgical neuroradiology (ESN) fellowship programs from the Accreditation Council for Graduate Medical Education, the Committee on Advanced Subspecialty Training, the Society of NeuroInterventional Surgery, and the Neurosurgical Fellowship Training Program Directory websites. Individual program websites were evaluated for 27 different fellow recruitment and education criteria. U.S. programs were grouped based on census region and national ranking, and differences between these groups with regard to fellow recruitment and education characteristics were analyzed using nonparametric statistics.

RESULTS

A total of 79 INR/ESN fellowship websites were evaluated for presence of fellow recruitment and education features. Approximately one third of all features pertinent to recruitment (32.11%) and approximately 1 in 5 features regarding education (19.11%) were described in these websites. Program description (69.6%), program coordinator/administrator contact e-mail (59.5%), program director's name (59.5%), program eligibility requirements (51.9%), research opportunities (40.5%), and faculty listing (39.2%) were among the most frequently described features, whereas details about parking (1.3%), interview day itinerary (1.3%), meal allowance (2.5%), retirement and benefits (3.8%), and call schedule (5.1%) were the least frequently described features. There was no significant difference between surveyed features and programs when stratified by U.S. census region, neurosurgery/neurology hospital rankings, or accreditation status.

CONCLUSIONS

INR/ESN fellowship website content is variable across North America and there is room for improvement to develop and enhance comprehensiveness of program website content.

[Treatment of intracranial aneurysms with flow diverters]

CLINICAL ISSUE

The clinical picture of a subarachnoid haemorrhage (SAH) is associated with a high morbidity and mortality, due to the associated complications. Therefore, both unruptured and ruptured aneurysms are to be treated based on an individual and interdisciplinary treatment concept. Several endovascular procedures are already available for the treatment of intracranial aneurysms. A more recent concept is the treatment with vessel-reconstructive stents so-called flow diverters.

PRACTICAL RECOMMENDATIONS

Due to the continuous development and revision of flow diverters, the initial complication rates have been significantly reduced, which now effectively and efficiently justifies their clinical use. After careful patient selection and risk-benefit assessment, the implantation of a flow diverter can also be considered for the treatment of ruptured aneurysms and is often the only therapy option in such situations.

Estimation of radiation exposure of children undergoing superselective intra-arterial chemotherapy for retinoblastoma treatment: assessment of local diagnostic reference levels as a function of age, sex, and interventional success

PURPOSE

This study aims to determine local diagnostic reference levels (LDRLs) of intra-arterial chemotherapy (IAC) procedures of pediatric patients with retinoblastoma (RB) to provide data for establishing diagnostic reference levels (DRLs) in pediatric interventional radiology (IR).

METHODS

In a retrospective study design, LDRLs and achievable dose (AD) were assessed for children undergoing superselective IAC for RB treatment. All procedures were performed at the flat-panel angiography systems (I) ArtisQ biplane (Siemens Healthineers) and (II) Allura Xper (Philips Healthcare). Patients were differentiated according to age (A1: 1-3 months; A2: 4-12 months; A3: 13-72 months; A4: 73 months-10 years; A5: > 10 years), sex, conducted or not-conducted chemotherapy.

RESULTS

248 neurointerventional procedures of 130 pediatric patients (median age 14.5 months, range 5-127 months) with RB (68 unilateral, 62 bilateral) could be included between January 2010 and March 2020. The following diagnostic reference values, AD, and mean values could be determined: (A2) DRL 3.9 Gy cm², AD 2.9 Gy cm², mean 3.5 Gy cm²; (A3) DRL 7.0 Gy cm², AD 4.3 Gy cm², mean 6.0 Gy cm²; (A4) DRL 14.5 Gy cm², AD 10.7 Gy cm², mean 10.8 Gy cm²; (A5) AD 8.8 Gy cm², mean 8.8 Gy cm². Kruskal-Wallis-test confirmed a significant dose difference between the examined age groups (A2-A5) (p < 0.001). There was no statistical difference considering sex (p = 0.076) and conducted or not-conducted chemotherapy (p = 0.627). A successful procedure was achieved in 207/248 cases.

CONCLUSION

We report on radiation exposure during superselective IAC of a pediatric cohort at the German Retinoblastoma Referral Centre. Although an IAC formally represents a therapeutic procedure, our results confirm that radiation exposure lies within the exposure of a diagnostic interventional procedure. DRLs for superselective IAC are substantially lower compared with DRLs of more complex endovascular interventions.

Optimization of resources and modifications in acute ischemic stroke care in response to the global COVID-19 pandemic

Background

The COVID-19 pandemic has presented unprecedented challenges to healthcare organizations worldwide. A steadily rising number of patients requiring intensive care, a large proportion from racial and ethnic minorities, demands creative solutions to provide high-quality care while ensuring healthcare worker safety in the face of limited resources. Boston Medical Center has been particularly affected due to the underserved patient population we care for and the increased risk of ischemic stroke in patients with COVID-19 infection.

Methods

We present protocol modifications developed to manage patients with acute ischemic stroke in a safe and effective manner while prioritizing judicious use of personal protective equipment and intensive care unit resources.

Conclusion

We feel this information will benefit other organizations facing similar obstacles in caring for the most vulnerable patient populations during this ongoing public health crisis.

Long-term Kinetic Papilledema Improvement After Venous Sinus Stenting in Idiopathic Intracranial Hypertension

BACKGROUND AND PURPOSE

The aim of this study was to assess the safety and effectiveness of lateral sinus stenosis (LSS) stenting in patients with idiopathic intracranial hypertension (IIH) who are refractory to medical treatment, particularly focusing on visual outcomes including papilledema.

MATERIAL AND METHODS

Retrospective study of consecutive patients with IIH refractory to medical treatment who underwent LSS stenting. Clinical features, visual fields and optical coherence tomography (OCT) retinal nerve fiber layer (RNFL) and ganglion cell layer (GCL) thicknesses were assessed before stenting, at 1 month poststenting and at last follow-up. Complications were also recorded.

RESULTS

A total of 16 women were included, with a mean age of 39 ± 11 years. All patients had papilledema while 15/16 (94%) had headaches. Mean visual acuity was 0.036 logMAR, range (+0.4 to +0.0 logMAR). The mean RNFL thickness prior to stenting was 121.7 µm (±34.7 µm) and mean GCL thickness was 80.2 µm (±8.9 µm). Mean follow-up was 19.7 months (±11.8 months). After stenting, acetazolamide was discontinued in 15/16 (94%) patients. Papilledema improved in 14/16 (88%) of patients. The mean RNFL thickness was significantly decreased 1 month after stenting (96.3 ± 15.6 µm; p < 0.001) and at last visit (93.4 ± 15.3 µm; p < 0.001). The GCL thickness after LSS stenting was moderately decreased at the last visit examination: 80.2 ± 8.9 µm vs. 78.0 ± 10.7 µm; (p < 0.01). No stent-related complication occurred, while there was one case of restenosis.

CONCLUSION

Improvement of papilledema appears to occur relatively rapidly after the LSS stenting. The results further support the role of LSS stenting in the treatment of IIH, especially with respect to visual symptoms.

International Survey on Criteria for Training and Accreditation in Interventional Neuroradiology

Purpose

With the rapid expansion of the field of interventional neuroradiology (INR) and the diverse background of aspiring neuro-interventionists, there is an ever increasing need to establish consensus criteria for training and accreditation in INR.

Materials and Methods

We performed a survey to explore the current state of criteria for training and accreditation in INR. The questionnaire consisting of 11 questions was emailed to the members of World Federation of Interventional and Therapeutic Neuroradiology (WFITN) worldwide. It was focused on the training charter, training program, qualifying examination, and education after training program as perceived by practitioners in each country.

Results

A total of 52 WFITN members in 19 countries responded to the questionnaire. There was a huge variation internationally and nationally due to the unique situation and challenges in each country and institution. Criteria for training and accreditation in INR were well established in some countries of Europe, North America, and Asia but not specified in other countries.

Conclusion

It is critical to establish consensus criteria for training and accreditation in INR in order to ensure safe practice and continued expansion and development of INR as a specialty.

An experience-based review of HIFU in functional interventional neuroradiology: transcranial MRgFUS thalamotomy for treatment of tremor

Tremor is a common and very disabling symptom in patients with essential tremor and Parkinson's disease. In the recent years, transcranial ablation of thalamic nuclei using magnetic resonance guided high-intensity focused ultrasound has emerged as a minimally invasive treatment for tremor. The aim of this review is to discuss, in the light of our single-center experience, the technique, current applications, results, and future perspectives of this novel technology.

Safety and efficacy of a pre-treatment antiplatelet regimen of unruptured intracranial aneurysms: a single-center experience

PURPOSE

Endovascular treatment of unruptured intracranial aneurysms with stent-assisted coiling or flow diverter stents requires a prophylactic antiplatelet premedication to avoid thrombo-embolic complications. Guidelines for optimal antiplatelet regimens are poorly defined. The aim of this study is to report our experience using a high dosage antiplatelet premedication regimen for patients with unruptured intracranial aneurysms undergoing endovascular treatment by stent-assisted coiling or flow diverter stents.

METHODS

From a retrospective analysis of a prospectively maintained database, we collected clinical and angiographic data of 400 procedures in 362 patients treated by stent-assisted coiling or flow diverter stents for 419 unruptured intracranial aneurysms. Descriptive and analytic statistics were performed to report morbidity, mortality, and complication rates and to demonstrate associations between variables and outcomes. Logistic multivariable regression was performed to rule out confounding factors between subgroups.

RESULTS

Thrombo-embolic complications occurred in 23/400 procedures (5.75%) and hemorrhagic complications in 19/400 procedures (4.75%). The majority of complications were minor and transient with overall procedure-related morbidity and mortality rates of 1.75% (n = 7/400) and 1.25% (n = 5/400) respectively. The co-existence of multiple cardiovascular risk factors among smoking, hypertension, dyslipidemia, and age > 65 years old was significantly associated with permanent procedure-related morbidity (p = 0.006) and thrombo-embolic complications occurrence (p = 0.034). Age alone was associated with higher permanent morbidity (p = 0.029) and was the only variable associated with higher hemorrhagic complication (p = 0.024).

CONCLUSION

In this study, the use of a high dosage antiplatelet premedication was safe and effective for the treatment of unruptured intracranial aneurysms with stent-assisted coiling or flow diverter stents. Mortality and morbidity rates compare favorably with the current literature. The thrombo-embolic complications rate is low and most of them were clinically silent. However, the hemorrhagic complications rate was substantial and a significant proportion of them were associated with mortality.

Endovascular Treatment of Acute Ischemic Stroke

PURPOSE OF REVIEW

Endovascular thrombectomy (ET), the standard of treatment for emergent large vessel occlusion (ELVO) strokes, has been subject to rigorous efforts to further improve its usage and delivery for optimised patient outcomes. This review aims to provide an outline and discussion about the recently established and emerging recommendations regarding endovascular treatment of stroke.

RECENT FINDINGS

The indications for ET have expanded continually, with perfusion imaging now enabling selection of patients presenting 6-24 h after last-known-well, and improved device and operator proficiency allowing treatment of M2-MCA occlusions and tandem occlusions. Further inclusion of paediatric patients and patients with larger infarct core or milder stroke symptoms for ET has been proposed; however, this remains unproven. This growing applicability is supported by more efficient systems of care, employing modern techniques such as telemedicine, mobile stroke units and helicopter medical services. Ongoing debate exists regarding thrombolytic agent, thrombectomy technique, anaesthesia method and the role of advanced neuroimaging, with upcoming RCTs expected to provide clarification. The journey to further improving the efficacy of ET has advanced and diversified rapidly over recent years, involving improved patient selection, increased utility of advanced neuroimaging and ongoing device redevelopment, within the setting of more efficient, streamlined systems of care. This dynamic and ongoing influx of evidence-based refinements is key to further optimising outcomes for ELVO patients.

First Line Onyx Embolization in Ruptured Pediatric Arteriovenous Malformations : Safety and Efficacy

PURPOSE

Brain arteriovenous malformations (bAVM) are the main cause of pediatric intracerebral hemorrhage (pICH). Embolization with Onyx (ev3, Irvine, CA, USA) in children with ruptured bAVM has been infrequently reported. The aim of this study was to assess the safety and efficacy profile of Onyx embolization as first line endovascular treatment of ruptured pediatric bAVMs.

METHODS

Children with non-traumatic pICH due to bAVM rupture at a pediatric quaternary care center were prospectively enrolled in a registry and retrospectively analyzed between 2013 and 2018. Clinical and demographic data, treatment modalities and clinical imaging follow-up were retrieved, and detailed procedural data were retrospectively assessed by two investigators. The safety (procedural morbidity and mortality) and efficacy (obliteration and interval rebleeding) were evaluated.

RESULTS

In this study 29 children treated for a bAVM by Onyx embolization were included (14 girls, 48%; median age 11.1 years, interquartile range, IQR 8.1-12.7 years) with a total of 72 endovascular sessions (median of 2 sessions per patient IQR 1-3). The AVMs were deeply located in 23 patients (79%). No systemic complications occurred, and no child experienced embolization-related persistent neurological deficits. Non-clinically relevant complications were observed during five procedures, unrelated to Onyx. After a mean follow-up of 31 months from rupture complete obliteration rates were 100%, 89%, 29%, 14% in bAVM Spetzler Martin grades I, II, III and IV-V, respectively.

CONCLUSION

It was found that Onyx embolization is safe and represents a good option for an initial treatment approach, in a sequential treatment strategy for pediatric ruptured brain AVMs. Younger age may not be an argument to deny Onyx embolization.

Number needed to treat: A primer for neurointerventionalists

BACKGROUND

The number needed to treat is a commonly used statistical term in modern neurointerventional practice. It represents the number of patients that need to be treated for one patient to benefit from an intervention. Given its growing popularity in reflecting study results, understanding the basics behind this statistic is of practical value to the neurointerventionalist.

METHODS

Here, we review the basic theory and calculation of the number needed to treat, its application to stroke interventions, and its limitations. In addition, we demonstrate several simple methods of calculating the number needed to treat utilizing recent thrombectomy trial results. By presenting the number needed to treat as a universal metric, we provide a comprehensive comparative of the number needed to treat for key stroke therapies, including mechanical thrombectomy, tissue plasminogen activator, carotid endarterectomy, and prevention with antiplatelet and statin drugs.

CONCLUSIONS

In comparison with available stroke therapies, mechanical thrombectomy stands out as the most effective acute intervention in patients with emergent large-vessel occlusions. Understanding how the number needed to treat is derived and its implications helps provide perspective to clinical trial data, identify health-care resource priorities, and improve communication with patients, health-care providers, and additional key stakeholders.