Mechanical effect of friction and stretching on endothelium denudation

Peer reviewed: NoNRC publication: Ye

Finite Element Prediction of Elastic Recoil after Stent Implantation

Peer reviewed: YesNRC publication: Ye

Mechanical effect of friction on endothelium denudation

Peer reviewed: NoNRC publication: Ye

A novel 3D segmentation method of the lumen from intravascular ultrasound images

In this paper a novel method that automatically detects the lumen-intima border on an intravascular ultrasound sequence (IVUS) is presented. First, a 3D co-occurrence matrix was used to efficiently extract the texture information of the IVUS images through the temporal sequence. By extracting several co-occurrence matrices a complete characterization feature space was determined. Secondly, using a k-means algorithm, all the pixels in the IVUS images were classified by determining if they belong to either the lumen or the other vessel tissues. This enables automatic clustering and therefore no learning step was required. The classification of the pixels within the feature space was obtained using 3 clusters: two clusters for the vessel tissues, one cluster for the lumen, while the remaining pixels are labeled as unclassified. Experimental results show that the proposed method is robust to noisy images and yields segmented lumen-intima contours validated by an expert in more than 80% of a total of 300 IVUS images.Peer reviewed: YesNRC publication: Ye

Constitutive Modelling of Endothelium Denudation for Finite Element Simulation of Angioplasty

This study aims at characterizing and modelling the effect of mechanical factors on endothelial denudation during angioplasty, such as normal force between balloon and artery, stretching of arterial walls, and relative displacement between contacting surfaces. Friction damage was applied to porcine aorta samples with different contact forces, relative displacements, and biplanar stretching conditions. After the tests, endothelium denudation was quantified by isolating and counting the remaining endothelial cells. Using multiple-regression analysis, a constitutive model is proposed for integration in finite element software. This model will help optimize balloon and stent deployment conditions to minimize the amount of damage to the endothelium, and eventually to reduce the occurrence of restenosis.Peer reviewed: YesNRC publication: Ye

Mechanical Characterization of Arteries: Comparison of Square and Cruciform Biaxial Tests Using Inverse Modeling Technique

Peer reviewed: NoNRC publication: Ye

Computer-Based Simulation of Cardiovascular Stent Implantation

Peer reviewed: NoNRC publication: Ye

Modeling the Thermal Effect of the Bipolar Electrocautery for Neurosurgery Simulation

Real-time surgical simulation requires computationally-fast models describing the interaction between surgical instrument and tissues. In this study, a model for predicting the temperature distribution in brain tissue when using a bipolar electrocautery is proposed and validated against experimental in vitro animal data. Joule heat generation and heat conduction in the tissue are considered. The agreement between simulated temperature distributions and experimental data could be improved by modeling the output power as a function of electrical resistance between the electrodes, and by considering the heat exchange with surrounding air and bipolar tips.Peer reviewed: NoNRC publication: Ye

Endoscopic third ventriculostomy on a microneurosurgery simulator

Endoscopic third ventriculostomy is a procedure used to treat hydrocephalus by making a perforation in the floor of the third ventricle of the brain under endoscopic guidance. We report on our initial experience in developing an endoscopic third ventriculostomy simulator for neurosurgery residents, including the definition of the simulation content and integration on NeuroTouch, a simulator for microneurosurgery training. The simulator includes exercises in which the trainee is asked to choose the location of the burr hole and the orientation of the trajectory to the foramen of Monro, or is required to find the third ventricle with a neuro-endoscope and perforate its floor. The simulator provides feedback on trainee performance either graphically or using quantitative metrics. The simulator allows easily switching from endoscopic third ventriculostomy mode to microscopic craniotomy mode using a retractable stereoscope based on a single screen and mirrors, detachable plastic heads, and quick-connect tool handles to give more realistic haptic feedback. \ua9 2013 National Research Council Canada, Crown copyright.Peer reviewed: YesNRC publication: Ye

Modelling Polymer Balloons for Angioplasty : from Fabrication to Deployment

Peer reviewed: YesNRC publication: Ye