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Michele Pinelli - One of the best experts on this subject based on the ideXlab platform.
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Computational modelling of emboli travel trajectories in cerebral arteries: influence of microEmbolic Particle size and density
Biomechanics and Modeling in Mechanobiology, 2014Co-Authors: Dario Fabbri, Quan Long, Michele PinelliAbstract:Ischaemic stroke is responsible for up to 80 % of stroke cases. Prevention of the reoccurrence of ischaemic attack or stroke for patients who survived the first symptoms is the major treatment target. Accurate diagnosis of the emboli source for a specific infarction lesion is very important for a better treatment for the patient. However, due to the complex blood flow patterns in the cerebral arterial network, little is known so far of the Embolic Particle flow trajectory and its behaviour in such a complex flow field. The present study aims to study the trajectories of Embolic Particles released from carotid arteries and basilar artery in a cerebral arterial network and the influence of Particle size, mass and release location to the Particle distributions, by computational modelling. The cerebral arterial network model, which includes major arteries in the circle of Willis and several generations of branches from them, was generated from MRI images. Particles with diameters of 200, 500 and 800 $$\upmu \hbox {m}$$ μ m and densities of 800, 1,030 and 1,300 $$\hbox {kg/m}^{3}$$ kg/m 3 were released in the vessel’s central and near-wall regions. A fully coupled scheme of Particle and blood flow in a computational fluid dynamics software ANASYS CFX 13 was used in the simulations. The results show that heavy Particles (density large than blood or a diameter larger than 500 $$\upmu \hbox {m}$$ μ m ) normally have small travel speeds in arteries; larger or lighter Embolic Particles are more likely to travel to large branches in cerebral arteries. In certain cases, all large Particles go to the middle cerebral arteries; large Particles with higher travel speeds in large arteries are likely to travel at more complex and tortuous trajectories; emboli raised from the basilar artery will only exit the model from branches of basilar artery and posterior cerebral arteries. A modified Circle of Willis configuration can have significant influence on Particle distributions. The local branch patterns of internal carotid artery to middle cerebral artery and anterior communicating artery can have large impact on such distributions.
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Study of Embolic Particle Migration in Cerebral Arteries by Computational Modelling
ASME 2012 Summer Bioengineering Conference Parts A and B, 2012Co-Authors: Dario Fabbri, Quan Long, Saroj Das, Michele PinelliAbstract:As known, embolism is one of the major causes of stroke, which represents the rapid loss of brain functions. Two major sources of emboli which may cause ischemic attack were emboli formed in heart and from a ruptured arterial plaque in carotid arties. Due to the different characteristics of emboli formed from different mechanisms, the migration route of specific emboli in cerebral arteries may be different, so does the territory of the ischemic attack caused by them. Therefore, a good understanding of emboli migration in the complex cerebral arterial network may provide a good guidance for the diagnosis and treatment of stroke. Studies on the emboli motion in cerebral arteries so far were based on phantom models [1]. Although CFD simulation has been used on prediction of cerebral blood perfusion for many years, CFD Particle tracking technique is rarely applied on study emboli migration in cerebral arteries. The present study aims to demonstrate the feasibility of using CFD Particle tracking on emboli migration study with emphasis on the discussions of the Particle tracking result by different coupling algorithms between blood flow and Embolic Particles.Copyright © 2012 by ASME
Kimberley J. Hansen - One of the best experts on this subject based on the ideXlab platform.
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Atheroembolism during percutaneous renal artery revascularization
Journal of vascular surgery, 2007Co-Authors: Matthew S. Edwards, Matthew A. Corriere, Timothy E. Craven, Xian Mang Pan, Joseph H. Rapp, Jeffrey D. Pearce, Nicholas B. Mertaugh, Kimberley J. HansenAbstract:Introduction Atheroembolization during renal artery angioplasty and stenting (RA-PTAS) has been postulated as a cause for the inferior renal function results observed when compared with those with surgical revascularization. To further characterize procedure-associated atheroembolism, we analyzed recovered atheroEmbolic debris and clinical data from patients undergoing RA-PTAS with distal Embolic protection (DEP). Methods RA-PTAS procedures were performed with DEP using a commercially available temporary balloon occlusion and aspiration catheter system between July 2005 and December 2006. Following RA-PTAS but prior to deflation of the distal occlusion balloon, the static column of blood proximal to the balloon was aspirated and submitted for Embolic Particle analysis. Angiograms, demographics, and laboratory data were reviewed. Glomerular filtration rate (eGFR) was estimated before RA-PTAS and at 4 to 8 weeks postintervention using the abbreviated Modification of Diet in Renal Disease formula. Associations between clinical factors, captured Particle counts, and changes in renal function were examined using univariate techniques and multiple linear regression. Results Twenty-eight RA-PTAS procedures were performed with DEP. Mean total number of Embolic Particles counted per procedure was 2033 ± 1553 for Particles 20-60 μm and 265 ± 132 for Particles >60 μm. Significant positive associations with quantity of captured Particles 20 to 60 μm were observed for African American race ( P = .002), predilation ( P = .005), and stent diameter ( P (P =.016). Quantity of captured Particles >60 μm was positively associated with ratio of stent to renal artery diameter ( P =.009). Change in eGFR was positively associated with preoperative aspirin use ( P = .006) and preoperative eGFR ( P 60 μm ( P = .015). Conclusion These results demonstrate the liberation of thousands of atheroEmbolic Particles during RA-PTAS. Clinical, anatomic, and device-related factors may be predictive of procedural embolization, and increasing captured Particle counts >60 μm were associated with inferior renal function results. Further investigation is warranted to establish relationships between atheroembolism, end organ functional impairment, and clinical responses.
Dario Fabbri - One of the best experts on this subject based on the ideXlab platform.
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Computational modelling of emboli travel trajectories in cerebral arteries: influence of microEmbolic Particle size and density
Biomechanics and Modeling in Mechanobiology, 2014Co-Authors: Dario Fabbri, Quan Long, Michele PinelliAbstract:Ischaemic stroke is responsible for up to 80 % of stroke cases. Prevention of the reoccurrence of ischaemic attack or stroke for patients who survived the first symptoms is the major treatment target. Accurate diagnosis of the emboli source for a specific infarction lesion is very important for a better treatment for the patient. However, due to the complex blood flow patterns in the cerebral arterial network, little is known so far of the Embolic Particle flow trajectory and its behaviour in such a complex flow field. The present study aims to study the trajectories of Embolic Particles released from carotid arteries and basilar artery in a cerebral arterial network and the influence of Particle size, mass and release location to the Particle distributions, by computational modelling. The cerebral arterial network model, which includes major arteries in the circle of Willis and several generations of branches from them, was generated from MRI images. Particles with diameters of 200, 500 and 800 $$\upmu \hbox {m}$$ μ m and densities of 800, 1,030 and 1,300 $$\hbox {kg/m}^{3}$$ kg/m 3 were released in the vessel’s central and near-wall regions. A fully coupled scheme of Particle and blood flow in a computational fluid dynamics software ANASYS CFX 13 was used in the simulations. The results show that heavy Particles (density large than blood or a diameter larger than 500 $$\upmu \hbox {m}$$ μ m ) normally have small travel speeds in arteries; larger or lighter Embolic Particles are more likely to travel to large branches in cerebral arteries. In certain cases, all large Particles go to the middle cerebral arteries; large Particles with higher travel speeds in large arteries are likely to travel at more complex and tortuous trajectories; emboli raised from the basilar artery will only exit the model from branches of basilar artery and posterior cerebral arteries. A modified Circle of Willis configuration can have significant influence on Particle distributions. The local branch patterns of internal carotid artery to middle cerebral artery and anterior communicating artery can have large impact on such distributions.
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Study of Embolic Particle Migration in Cerebral Arteries by Computational Modelling
ASME 2012 Summer Bioengineering Conference Parts A and B, 2012Co-Authors: Dario Fabbri, Quan Long, Saroj Das, Michele PinelliAbstract:As known, embolism is one of the major causes of stroke, which represents the rapid loss of brain functions. Two major sources of emboli which may cause ischemic attack were emboli formed in heart and from a ruptured arterial plaque in carotid arties. Due to the different characteristics of emboli formed from different mechanisms, the migration route of specific emboli in cerebral arteries may be different, so does the territory of the ischemic attack caused by them. Therefore, a good understanding of emboli migration in the complex cerebral arterial network may provide a good guidance for the diagnosis and treatment of stroke. Studies on the emboli motion in cerebral arteries so far were based on phantom models [1]. Although CFD simulation has been used on prediction of cerebral blood perfusion for many years, CFD Particle tracking technique is rarely applied on study emboli migration in cerebral arteries. The present study aims to demonstrate the feasibility of using CFD Particle tracking on emboli migration study with emphasis on the discussions of the Particle tracking result by different coupling algorithms between blood flow and Embolic Particles.Copyright © 2012 by ASME
Matthew S. Edwards - One of the best experts on this subject based on the ideXlab platform.
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Atheroembolism during percutaneous renal artery revascularization
Journal of vascular surgery, 2007Co-Authors: Matthew S. Edwards, Matthew A. Corriere, Timothy E. Craven, Xian Mang Pan, Joseph H. Rapp, Jeffrey D. Pearce, Nicholas B. Mertaugh, Kimberley J. HansenAbstract:Introduction Atheroembolization during renal artery angioplasty and stenting (RA-PTAS) has been postulated as a cause for the inferior renal function results observed when compared with those with surgical revascularization. To further characterize procedure-associated atheroembolism, we analyzed recovered atheroEmbolic debris and clinical data from patients undergoing RA-PTAS with distal Embolic protection (DEP). Methods RA-PTAS procedures were performed with DEP using a commercially available temporary balloon occlusion and aspiration catheter system between July 2005 and December 2006. Following RA-PTAS but prior to deflation of the distal occlusion balloon, the static column of blood proximal to the balloon was aspirated and submitted for Embolic Particle analysis. Angiograms, demographics, and laboratory data were reviewed. Glomerular filtration rate (eGFR) was estimated before RA-PTAS and at 4 to 8 weeks postintervention using the abbreviated Modification of Diet in Renal Disease formula. Associations between clinical factors, captured Particle counts, and changes in renal function were examined using univariate techniques and multiple linear regression. Results Twenty-eight RA-PTAS procedures were performed with DEP. Mean total number of Embolic Particles counted per procedure was 2033 ± 1553 for Particles 20-60 μm and 265 ± 132 for Particles >60 μm. Significant positive associations with quantity of captured Particles 20 to 60 μm were observed for African American race ( P = .002), predilation ( P = .005), and stent diameter ( P (P =.016). Quantity of captured Particles >60 μm was positively associated with ratio of stent to renal artery diameter ( P =.009). Change in eGFR was positively associated with preoperative aspirin use ( P = .006) and preoperative eGFR ( P 60 μm ( P = .015). Conclusion These results demonstrate the liberation of thousands of atheroEmbolic Particles during RA-PTAS. Clinical, anatomic, and device-related factors may be predictive of procedural embolization, and increasing captured Particle counts >60 μm were associated with inferior renal function results. Further investigation is warranted to establish relationships between atheroembolism, end organ functional impairment, and clinical responses.
Shawn C. Shadden - One of the best experts on this subject based on the ideXlab platform.
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Inertial Particle dynamics in large artery flows – Implications for modeling arterial embolisms
Journal of biomechanics, 2016Co-Authors: Debanjan Mukherjee, Shawn C. ShaddenAbstract:Abstract The complexity of inertial Particle dynamics through swirling chaotic flow structures characteristic of pulsatile large-artery hemodynamics renders significant challenges in predictive understanding of transport of such Particles. This is specifically crucial for arterial embolisms, where knowledge of embolus transport to major vascular beds helps in disease diagnosis and surgical planning. Using a computational framework built upon image-based CFD and discrete Particle dynamics modeling, a multi-parameter sampling-based study was conducted on Embolic Particle dynamics and transport. The results highlighted the strong influence of material properties, embolus size, release instance, and embolus source on embolus distribution to the cerebral, renal and mesenteric, and ilio-femoral vasculature beds. The study also isolated the importance of shear-gradient lift, and elastohydrodynamic contact, in affecting Embolic Particle transport. Near-wall Particle re-suspension due to lift alters aortogenic Embolic Particle dynamics significantly as compared to cardiogenic. The observations collectively indicated the complex interplay of Particle inertia, fluid–Particle density ratio, and wall collisions, with chaotic flow structures, which render the overall motion of the Particles to be non-trivially dispersive in nature.
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Numerical investigation of fluid–Particle interactions for Embolic stroke
Theoretical and Computational Fluid Dynamics, 2016Co-Authors: Debanjan Mukherjee, Jose Padilla, Shawn C. ShaddenAbstract:Roughly one-third of all strokes are caused by an embolus traveling to a cerebral artery and blocking blood flow in the brain. The objective of this study is to gain a detailed understanding of the dynamics of Embolic Particles within arteries. Patient computed tomography image is used to construct a three-dimensional model of the carotid bifurcation. An idealized carotid bifurcation model of same vessel diameters was also constructed for comparison. Blood flow velocities and Embolic Particle trajectories are resolved using a coupled Euler–Lagrange approach. Blood is modeled as a Newtonian fluid, discretized using the finite volume method, with physiologically appropriate inflow and outflow boundary conditions. The embolus trajectory is modeled using Lagrangian Particle equations accounting for embolus interaction with blood as well as vessel wall. Both one- and two-way fluid–Particle coupling are considered, the latter being implemented using momentum sources augmented to the discretized flow equations. It was observed that for small-to-moderate Particle sizes (relative to vessel diameters), the estimated Particle distribution ratio—with and without the inclusion of two-way fluid–Particle momentum exchange—were found to be similar. The maximum observed differences in distribution ratio with and without the coupling were found to be higher for the idealized bifurcation model. Additionally, the distribution was found to be reasonably matching the volumetric flow distribution for the idealized model, while a notable deviation from volumetric flow was observed in the anatomical model. It was also observed from an analysis of Particle path lines that Particle interaction with helical flow, characteristic of anatomical vasculature models, could play a prominent role in transport of Embolic Particle. The results indicate therefore that flow helicity could be an important hemodynamic indicator for analysis of embolus Particle transport. Additionally, in the presence of helical flow, and vessel curvature, inclusion of two-way momentum exchange was found to have a secondary effect for transporting small to moderate embolus Particles—and one-way coupling could be used as a reasonable approximation, thereby causing substantial savings in computational resources.
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Numerical investigation of fluid-Particle interactions for Embolic stroke
Theoretical and Computational Fluid Dynamics, 2015Co-Authors: Debanjan Mukherjee, Jose Padilla, Shawn C. ShaddenAbstract:Roughly one-third of all strokes are caused by an embolus traveling to a cerebral artery and blocking blood flow in the brain. The objective of this study is to gain a detailed understanding of the dynamics of Embolic Particles within arteries. Patient computed tomography image is used to construct a three-dimensional model of the carotid bifurcation. An idealized carotid bifurcation model of same vessel diameters was also constructed for comparison. Blood flow velocities and Embolic Particle trajectories are resolved using a coupled Euler–Lagrange approach. Blood is modeled as a Newtonian fluid, discretized using the finite volume method, with physiologically appropriate inflow and outflow boundary conditions. The embolus trajectory is modeled using Lagrangian Particle equations accounting for embolus interaction with blood as well as vessel wall. Both one- and two-way fluid–Particle coupling are considered, the latter being implemented using momentum sources augmented to the discretized flow equations. It was observed that for small-to-moderate Particle sizes (relative to vessel diameters), the estimated Particle distribution ratio—with and without the inclusion of two-way fluid–Particle momentum exchange—were found to be similar. The maximum observed differences in distribution ratio with and without the coupling were found to be higher for the idealized bifurcation model. Additionally, the distribution was found to be reasonably matching the volumetric flow distribution for the idealized model, while a notable deviation from volumetric flow was observed in the anatomical model. It was also observed from an analysis of Particle path lines that Particle interaction with helical flow, characteristic of anatomical vasculature models, could play a prominent role in transport of Embolic Particle. The results indicate therefore that flow helicity could be an important hemodynamic indicator for analysis of embolus Particle transport. Additionally, in the presence of helical flow, and vessel curvature, inclusion of two-way momentum exchange was found to have a secondary effect for transporting small to moderate embolus Particles—and one-way coupling could be used as a reasonable approximation, thereby causing substantial savings in computational resources.