100 research outputs found
Towards Interactive Planning of Coil Embolization in Brain Aneurysms
The original publication is available at www.springerlink.comInternational audienceMany vascular pathologies can now be treated in a minimally invasive way thanks to interventional radiology. Instead of open surgery, it allows to reach the lesion of the arteries with therapeutic devices through a catheter. As a particular case, intracranial aneurysms are treated by filling the localized widening of the artery with a set of coils to prevent a rupture due to the weakened arterial wall. Considering the location of the lesion, close to the brain, and its very small size, the procedure requires a combination of careful planning and excellent technical skills. An interactive and reliable simulation, adapted to the patient anatomy, would be an interesting tool for helping the interventional neuroradiologist plan and rehearse a coil embolization procedure. This paper describes an original method to perform interactive simulations of coil embolization and proposes a clinical metric to quantitatively measure how the first coil fills the aneurysm. The simulation relies on an accurate reconstruction of the aneurysm anatomy and a real-time model of the coil for which sliding and friction contacts are taken into account. Simulation results are compared to real embolization procedure and exhibit good adequacy
A (Near) Real-Time Simulation Method of Aneurysm Coil Embolization
International audienceA (Near) Real-Time Simulation Method of Aneurysm Coil Embolizatio
A Comprehensive Numerical Approach to Coil Placement in Cerebral Aneurysms: Mathematical Modeling and In Silico Occlusion Classification
Endovascular coil embolization is one of the primary treatment techniques for
cerebral aneurysms. Although it is a well established and minimally invasive
method, it bears the risk of sub-optimal coil placement which can lead to
incomplete occlusion of the aneurysm possibly causing recurrence. One of the
key features of coils is that they have an imprinted natural shape supporting
the fixation within the aneurysm. For the spatial discretization our
mathematical coil model is based on the Discrete Elastic Rod model which
results in a dimension-reduced 1D system of differential equations. We include
bending and twisting responses to account for the coils natural curvature.
Collisions between coil segments and the aneurysm-wall are handled by an
efficient contact algorithm that relies on an octree based collision detection.
The numerical solution of the model is obtained by a symplectic semi-implicit
Euler time stepping method. Our model can be easily incorporated into blood
flow simulations of embolized aneurysms. In order to differentiate optimal from
sub-optimal placements, we employ a suitable in silico Raymond-Roy type
occlusion classification and measure the local packing density in the aneurysm
at its neck, wall-region and core. We investigate the impact of uncertainties
in the coil parameters and embolization procedure. To this end, we vary the
position and the angle of insertion of the microcatheter, and approximate the
local packing density distributions by evaluating sample statistics
Trends in Cerebrovascular Surgery and Interventions
This is an open access proceeding book of 9th European-Japanese Cerebrovascular Congress at Milan 2018. Since many experts from Europe and Japan had very important and fruitful discussion on the management of Cerebrovascular diseases, the proceeding book is very attractive for the physician and scientists of the area
Virtual endovascular treatment of intracranial aneurysms: models and uncertainty
Virtual endovascular treatment models (VETMs) have been developed with the view to aid interventional neuroradiologists and neurosurgeons to pre-operatively analyze the comparative efficacy and safety of endovascular treatments for intracranial aneurysms. Based on the current state of VETMs in aneurysm rupture risk stratification and in patient-specific prediction of treatment outcomes, we argue there is a need to go beyond personalized biomechanical flow modeling assuming deterministic parameters and error-free measurements. The mechanobiological effects associated with blood clot formation are important factors in therapeutic decision making and models of post-treatment intra-aneurysmal biology and biochemistry should be linked to the purely hemodynamic models to improve the predictive power of current VETMs. The influence of model and parameter uncertainties associated to each component of a VETM is, where feasible, quantified via a random-effects meta-analysis of the literature. This allows estimating the pooled effect size of these uncertainties on aneurysmal wall shear stress. From such meta-analyses, two main sources of uncertainty emerge where research efforts have so far been limited: (1) vascular wall distensibility, and (2) intra/intersubject systemic flow variations. In the future, we suggest that current deterministic computational simulations need to be extended with strategies for uncertainty mitigation, uncertainty exploration, and sensitivity reduction techniques. WIREs Syst Biol Med 2017, 9:e1385. doi: 10.1002/wsbm.138
In-silico clinical trials for assessment of intracranial flow diverters
In-silico trials refer to pre-clinical trials performed, entirely or in part, using individualised computer models that simulate some aspect of drug effect, medical device, or clinical intervention. Such virtual trials reduce and optimise animal and clinical trials, and enable exploring a wider range of anatomies and physiologies. In the context of endovascular treatment of intracranial aneurysms, in-silico trials can be used to evaluate the effectiveness of endovascular devices over virtual populations of patients with different aneurysm morphologies and physiologies. However, this requires (i) a virtual endovascular treatment model to evaluate device performance based on a reliable performance indicator, (ii) models that represent intra- and inter-subject variations of a virtual population, and (iii) creation of cost-effective and fully-automatic workflows to enable a large number of simulations at a reasonable computational cost and time.
Flow-diverting stents have been proven safe and effective in the treatment of large wide-necked intracranial aneurysms. The presented thesis aims to provide the ingredient models of a workflow for in-silico trials of flow-diverting stents and to enhance the general knowledge of how the ingredient models can be streamlined and accelerated to allow large-scale trials. This work contributed to the following aspects: 1) To understand the key ingredient models of a virtual treatment workflow for evaluation of the flow-diverter performance. 2) To understand the effect of input uncertainty and variability on the workflow outputs, 3) To develop generative statistical models that describe variability in internal carotid artery flow waveforms, and investigate the effect of uncertainties on quantification of aneurysmal wall shear stress, 4) As part of a metric to evaluate success of flow diversion, to develop and validate a thrombosis model to assess FD-induced clot stability, and 5) To understand how a fully-automatic aneurysm flow modelling workflow can be built and how computationally inexpensive models can reduce the computational costs
Time to Go Augmented in Vascular Interventional Neuroradiology?
International audienceThis editorial paper reports on our experience in introducing augmented reality (AR) in interventional neuroradiology environments. Our expectations about the next AR tools, in particular for more advanced visualization, are also put forward. For practical reasons, the references will be restricted to our contributions. For further information, the last recommendations concerning the medical management of aneurysm induced hemorrhages can be found in [connolly12
Focal Spot, Spring 2006
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