Clinical Research & Publications

Ischemic stroke is one of the leading causes of death and long-term disability in the West. Mechanical revascularization techniques are considered the standard of care for large vessel occlusive stroke. Traditional apprenticeship models involve doctors training their skills on patients. Simulation platforms have long been recognized as an alternative to this. There has however been very little robust assessment of the training outcomes achieved on some of these platforms.

To explore whether simulation-based endovascular training with focus on radiation safety could improve correct behavior without jeopardizing the learning of procedural skills.

Simulation training is a common method in many medical disciplines and is used to teach content knowledge, manual skills, and team skills without potential patient danger.

Likewise work experience, heart rate variability (HRV) has repeatedly been correlated with improved performance under real life and simulator conditions. Using HRV as a correlate of workload, it is meaningful to assess the impact of work experience. To understand the impact of work experience on HRV metrics, we examined differences in HRV among experts and beginners during simulated endovascular neuroradiological procedures.

Purpose: During follow-up of patients treated with WEB devices, shape changes have been observed. The quantitative three-dimensional measurement of the WEB shape modification (WSM) would offer useful information to be studied in association with the anatomical results and try to better understand mechanisms implicated in this modification phenomenon.

This study assessed the effectiveness of simulation-based training for neuroendovascular interventions using primary and secondary catheters via a transradial approach (TRA). Five neurosurgical residents participated, using the Mentice Visit G5 simulator. Results showed significant improvements in task completion time and knowledge of catheter techniques. The training was rated highly useful by the participants, demonstrating that simulator-based training is effective in enhancing residents' skills in neuroendovascular procedures using TRA.

The WEB Intra-saccular Therapy (WEB-IT) trial is an investigational device exemption study to demonstrate the safety and effectiveness of the WEB device for the treatment of wide-neck bifurcation aneurysms. The neurovascular replicator (Vascular Simulations, Stony Brook, New York, USA) creates a physical environment that replicates patient-specific neurovascular anatomy and hemodynamic physiology, and allows devices to be implanted under fluoroscopic guidance.

Simulators are increasingly used in the training of endovascular procedures; however, for the use of the Mentice vascular interventional system trainer (VIST) simulator in neuroradiology, the validity of the method has not yet been proven. The study was carried out to test the construct validity of such a simulator by demonstrating differences between beginner and expert neurointerventionalists and to evaluate whether a training effect can be demonstrated in repeated cases for different levels of experience.

Flow diverters are widely extended in clinical practice for intracraneal aneurysms treatment. They are formed by a dense mesh of braided wires that partially occludes the aneurysm neck and restores the blood flow into the parent vessel. The occlusion degree is highly dependant on the distribution of the wires under the aneurysm, which is affected by the vessel geometry. Nowadays, there are no clinical indicators of the covering ratio once the flow diverter is deployed.

We assessed the transfer of training (ToT) of virtual reality simulation training compared to invasive vascular experience training for carotid artery angiography (CA) for highly experienced interventionists but new to carotid procedures.

Flow diverter porosity directly influences the blood flow reduction at the aneurysm neck level and the anatomical result of the treatment. In this research, we present and compare three methodologies to determine the local porosity of deployed flow diverters.

Multiple studies have shown the benefit of simulator use for medical trainees. In the endovascular realm, this has been demonstrated in the cardiac, vascular and neurovascular literature with both computer simulation models and physical models of the vasculature. In this study, the authors investigate the feasibility of a customized 3D model, not for training purposes, but for rehearsal prior to an actual endovascular treatment procedure.

The example of university radiology/neuroradiology illustrates how high-tech angiography simulators can be used meaningfully in teaching, clinical training and research.

An important issue in the deployment of braided stents, such as flow diverters, is the change in length, also known as foreshortening, underwent by the device when is released from the catheter into a blood vessel. The position of the distal end is controlled by the interventionist, but knowing a priori the position of the proximal end of the device is not trivial.

Biplane angiography systems provide time resolved 2D fluoroscopic images from two different angles, which can be used for the positioning of interventional devices such as guidewires and catheters. The purpose of this work is to provide a novel algorithm framework, which allows the 3D reconstruction of these curvilinear devices from the 2D projection images for each time frame. This would allow creating virtual projection images from arbitrary view angles without changing the position of the gantries, as well as virtual endoscopic 3D renderings.

Intra-saccular devices (ID) are novel braided devices used for complex intracranial aneurysms treatment. Treatment success is associated with correct device size selection. A technique that predicts the ID size within the aneurysm before intervention will provide a powerful computational tool to aid the interventionist during device selection.

The use of simulators has been described in a variety of fields as a training tool to gain technical skills through repeating and rehearsing procedures in a safe environment. In cerebrovascular surgery, simulation of skull base approaches has been used for decades. The use of simulation in neurointervention to acquire and enhance skills before treating a patient is a newer concept, but its utilization has been limited due to the lack of good models and deficient haptics. The advent of 3D printing technology and the development of new training models has changed this landscape.

Flow-Diverter (FD) porosity has been pointed as a critical factor in the occlusion of cerebral aneurysms after treatment. Objective: Verification and Validation of computational models in terms of predictive capacity, relating FD porosity and occlusion after cerebral aneurysms treatment.

We sought to develop a standardized curriculum capable of assessing key competencies in Interventional Neuroradiology by the use of models and simulators in an objective, quantitative, and efficient way. In this evaluation we analyzed the associations between the practical experience, theoretical knowledge, and the skills lab performance of interventionalists.

Intra-saccular devices (ID), developed for the treatment of bifurcation aneurysms, offer new alternatives for treating complex terminal and bifurcation aneurysms. In this work, a complete workflow going from medical images to post-treatment CFD analysis is described and used in the assessment of a concrete clinical problem.

Flow diverters are increasingly used to treat a broad category of cerebral aneurysms. We conducted an in vitro study to angiographically compare the flow diversion effect of Surpass Evolve from Stryker Neurovascular with the Pipeline Shield Embolization Device from Medtronic Neurovascular.

Likewise work experience, heart rate variability (HRV) has repeatedly been correlated with improved performance under real life and simulator conditions. Using HRV as a correlate of workload, it is meaningful to assess the impact of work experience. To understand the impact of work experience on HRV metrics, we examined differences in HRV among experts and beginners during simulated endovascular neuroradiological procedures.

Validate the use of a software-based simulation for pre-assessment of braided self-expanding stents in the treatment of wide-necked intracranial aneurysms

The increased adoption of endovascular neurosurgery procedures to treat cerebrovascular pathologies has led to the commercialization of a wide array of medical devices which, in turn, necessitates a more sophisticated training environment for physicians and fellows than the traditional “see one, do one, teach one” concept. Improvements in simulation technology and a changing healthcare culture are facilitating a wider assimilation of benchtop simulation models in lieu of cadaver or animal models in physician training as well as treatment planning. Medical device manufacturers as well as regulators are also increasingly utilizing such simulators for device development and assessment of efficacy.

Improvement in performance as measured by metric-based procedural errors must be demonstrated if virtual reality (VR) simulation is to be used as a valid means of proficiency assessment and improvement in procedural-based medical skills.

Sizing of flow diverters (FDs) stent in the treatment of intracranial aneurysms is a challenging task due to the change of stent length after implantation

Metric based virtual reality simulation training may enhance the capability of interventional neuroradiologists (INR) to perform endovascular thrombectomy. As pilot for a national simulation study we examined the feasibility and utility of simulated endovascular thrombectomy procedures on a virtual reality (VR) simulator.

Technical proficiency in carotid artery stent (CAS) procedures is paramount to ensure patient safety. If virtual reality (VR) simulation is to be used as a valid means for credentialing physicians for CAS procedures, the assessment parameters must be able to evaluate the performance during CAS and to differentiate level of CAS experience. The aim of this study was to validate assessment parameters of a commercially available VR simulator (VIST, Vascular Interventional Surgical Trainer, Mentice, Gothenburg, Sweden) during a CAS procedure in experienced interventionalists.

Flow diverter (FD) devices show severe shortening during deployment in dependency of the vessel geometry. Valid information regarding the geometry of the targeted vessel is therefore mandatory for correct device selection, and to avoid complications. But the geometry of diseased tortuous intracranial vessels cannot be measured accurately with standard methods. The goal of this study is to prove the accuracy of a novel virtual stenting method in prediction of the behavior of a FD in an individual vessel geometry.

Intrasaccular devices, like Woven EndoBridge (WEB), are novel braided devices employed for the treatment of aneurysms with a complex shape and location, mostly terminal aneurysms. Such aneurysms are often challenging or impossible to treat with other endovascular techniques such as coils, stents, flow diverter stents.

Different computational methods have been recently proposed to simulate the virtual deployment of a braided stent inside a patient vasculature. Those methods are primarily based on the segmentation of the region of interest to obtain the local vessel morphology descriptors. The goal of this work is to evaluate the influence of the segmentation quality on the method named "Braided Device Foreshortening" (BDF).

Many aspects of medical training take place on real patients in a live environment thus incurring risk. Apart from the obvious risks to patients there is the issue of X-ray exposure to both staff and trainees. Image quality used during interventional procedures is low to ensure minimum X-ray radiation dose. A virtual interventional system may be used to simulate the interventional cardiology training environment therefore reducing overall risk.

Flow diverters are widely extended in clinical practice for intracraneal aneurysms treatment. They are formed by a dense mesh of braided wires that partially occludes the aneurysm neck and restores the blood flow into the parent vessel. The occlusion degree is highly dependant on the distribution of the wires under the aneurysm, which is affected by the vessel geometry. Nowadays, there are no clinical indicators of the covering ratio once the flow diverter is deployed. We propose a novel method for the simulation of the flow diverter local porosity before its deployment into the parent vessel. We validate the method on curved silicon models, obtaining a correlation of 0.9 between the simulated values and the measured porosity on the deployed flow diverter.

Simulators are increasingly used in the training of endovascular procedures; however, for the use of the Mentice vascular interventional system trainer (VIST) simulator in neuroradiology, the validity of the method has not yet been proven. The study was carried out to test the construct validity of such a simulator by demonstrating differences between beginner and expert neurointerventionalists and to evaluate whether a training effect can be demonstrated in repeated cases for different levels of experience.