A methodological paradigm for patient-specific multi-scale CFD simulations: from clinical measurements to parameter estimates for individual analysis

2014 ◽  
Vol 30 (12) ◽  
pp. 1614-1648 ◽  
Author(s):  
S. Pant ◽  
B. Fabrèges ◽  
J-F. Gerbeau ◽  
I. E. Vignon-Clementel
Keyword(s):  
Patient Specific ◽  
Parameter Estimates ◽  
Cfd Simulations ◽  
Individual Analysis ◽  
Multi Scale ◽  
Clinical Measurements

scholarly journals Multi-Scale, Patient-Specific Computational Flow Dynamics Models Predict Formation of Neointimal Hyperplasia in Saphenous Vein Grafts

2019 ◽  
Author(s):  
Francesca Donadoni ◽  
Cesar Pichardo-Almarza ◽  
Shervanthi Homer-Vanniasinkam ◽  
Alan Dardik ◽  
Vanessa Díaz-Zuccarini
Keyword(s):  
Neointimal Hyperplasia ◽  
Flow Dynamics ◽  
Patient Specific ◽  
Growth Mechanisms ◽  
Cfd Simulations ◽  
Vein Grafts ◽  
Multi Scale ◽  
Computational Flow Dynamics ◽  
Computational Fluid Dynamics Cfd ◽  
Dynamics Models

AbstractBypass occlusion due to neointimal hyperplasia (NIH) is among the major causes of peripheral graft failure. Its link to abnormal hemodynamics in the graft is complex, and isolated use of hemodynamic markers insufficient to fully capture its progression. Here, a computational model of NIH growth is presented, establishing a link between computational fluid dynamics (CFD) simulations of flow in the lumen, with a biochemical model representing NIH growth mechanisms inside the vessel wall. For all 3 patients analyzed, NIH at proximal and distal anastomoses was simulated by the model, with values of stenosis comparable to the computed tomography (CT) scans.

Cyclic Breathing Simulations in Large Scale Models of the Lung Airway From the Oronasal Opening to the Terminal Bronchioles

2012 ◽  
Author(s):  
D. Keith Walters ◽  
Greg W. Burgreen ◽  
Robert L. Hester ◽  
David S. Thompson ◽  
David M. Lavallee ◽  
...  
Keyword(s):  
Steady State ◽  
Boundary Conditions ◽  
Large Scale ◽  
Whole Body ◽  
Patient Specific ◽  
Cfd Simulations ◽  
Reduced Order ◽  
Scale Models ◽  
Steady State Simulation ◽  
Conducting Zone

Computational fluid dynamics (CFD) simulations were performed for unsteady periodic breathing conditions, using large-scale models of the human lung airway. The computational domain included fully coupled representations of the orotracheal region and large conducting zone up to generation four (G4) obtained from patient-specific CT data, and the small conducting zone (to G16) obtained from a stochastically generated airway tree with statistically realistic geometrical characteristics. A reduced-order geometry was used, in which several airway branches in each generation were truncated, and only select flow paths were retained to G16. The inlet and outlet flow boundaries corresponded to the oronasal opening (superior), the inlet/outlet planes in terminal bronchioles (distal), and the unresolved airway boundaries arising from the truncation procedure (intermediate). The cyclic flow was specified according to the predicted ventilation patterns for a healthy adult male at three different activity levels, supplied by the whole-body modeling software HumMod. The CFD simulations were performed using Ansys FLUENT. The mass flow distribution at the distal boundaries was prescribed using a previously documented methodology, in which the percentage of the total flow for each boundary was first determined from a steady-state simulation with an applied flow rate equal to the average during the inhalation phase of the breathing cycle. The distal pressure boundary conditions for the steady-state simulation were set using a stochastic coupling procedure to ensure physiologically realistic flow conditions. The results show that: 1) physiologically realistic flow is obtained in the model, in terms of cyclic mass conservation and approximately uniform pressure distribution in the distal airways; 2) the predicted alveolar pressure is in good agreement with previously documented values; and 3) the use of reduced-order geometry modeling allows accurate and efficient simulation of large-scale breathing lung flow, provided care is taken to use a physiologically realistic geometry and to properly address the unsteady boundary conditions.

Vancomycin volume of distribution estimation in adults with class III obesity

2019 ◽  
Author(s):  
Ryan D Dunn ◽  
Ryan L Crass ◽  
Joseph Hong ◽  
Manjunath P Pai ◽  
Lynne C Krop
Keyword(s):  
Body Weight ◽  
Total Body Weight ◽  
Volume Of Distribution ◽  
Patient Specific ◽  
Pharmacokinetic Analysis ◽  
Pharmacokinetic Parameters ◽  
Parameter Estimates ◽  
Class Iii ◽  
Class Iii Obesity ◽  
Total Body

Abstract Purpose To compare methods of estimating vancomycin volume of distribution (V) in adults with class III obesity. Methods A retrospective, multicenter pharmacokinetic analysis of adults treated with vancomycin and monitored through measurement of peak and trough concentrations was performed. Individual pharmacokinetic parameter estimates were obtained via maximum a posteriori Bayesian analysis. The relationship between V and body weight was assessed using linear regression. Mean bias and root-mean-square error (RMSE) were calculated to assess the precision of multiple methods of estimating V. Results Of 241 patients included in the study sample, 159 (66.0%) had a BMI of 40.0–49.9 kg/m2, and 82 (34.0%) had a BMI of ≥50.0 kg/m2. The median (5th, 95th percentile) weight of patients was 136 (103, 204) kg, and baseline characteristics were similar between BMI groups. The mean ± S.D. V was lower in patients with a BMI of 40.0–49.9 kg/m2 than in those with a BMI of ≥50.0 kg/m2 (72.4 ± 19.6 L versus 79.3 ± 20.6 L, p = 0.009); however, body size poorly predicted V in regression analyses (R2 < 0.20). A fixed estimate of V (75 L) or use of 0.52 L/kg by total body weight yielded similar bias and error in this population. Conclusion Results of the largest analysis of vancomycin V in class III obesity to date indicated that use of a fixed V value (75 L) and use of a TBW-based estimate (0.52 L/kg) for estimation of vancomycin V in patients with a BMI of ≥40.0 kg/m2 have similar bias. Two postdistribution vancomycin concentrations are needed to accurately determine patient-specific pharmacokinetic parameters, estimate AUC, and improve the precision of vancomycin dosing in this patient population.

Experimental and Numerical Flow Visualization in Patient Specific Pre Operative Human Airway Geometry

2011 ◽  
Author(s):  
Mathias Vermeulen ◽  
Cedric Van Holsbeke ◽  
Tom Claessens ◽  
Jan De Backer ◽  
Peter Van Ransbeeck ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Particle Image ◽  
Patient Specific ◽  
Lung Volume Reduction ◽  
Cfd Simulations ◽  
Piv Measurements ◽  
Image Velocimetry ◽  
Specific Geometry ◽  
Computational Fluid Dynamics Cfd ◽  
Human Airways

An experimental and numerical platform was developed to investigate the fluidodynamics in human airways. A pre operative patient specific geometry was used to create an identical experimental and numerical model. The experimental results obtained from Particle Image Velocimetry (PIV) measurements were compared to Computational Fluid Dynamics (CFD) simulations under stationary and pulsatile flow regimes. Together these results constitute the first step in predicting the clinical outcome of patients after lung surgeries such as Lung Volume Reduction.

SU-E-T-256: Optimizing the Combination of Targeted Radionuclide Therapy Agents Using a Multi-Scale Patient-Specific Monte Carlo Dosimetry Platform

2014 ◽  
Vol 41 (6Part15) ◽  
pp. 282-282
Author(s):  
A Besemer ◽  
B Titz ◽  
J Grudzinski ◽  
J Weichert ◽  
L Hall ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Radionuclide Therapy ◽  
Patient Specific ◽  
Targeted Radionuclide Therapy ◽  
Multi Scale

scholarly journals Multi-scale computational models of the airways to unravel the pathophysiological mechanisms in asthma and chronic obstructive pulmonary disease (AirPROM)

2013 ◽  
Vol 3 (2) ◽  
pp. 20120057 ◽  
Author(s):  
K. S. Burrowes ◽  
J. De Backer ◽  
R. Smallwood ◽  
P. J. Sterk ◽  
I. Gut ◽  
...  
Keyword(s):  
Chronic Obstructive Pulmonary Disease ◽  
Pulmonary Disease ◽  
Heart Function ◽  
Scale Model ◽  
Patient Specific ◽  
Chronic Obstructive ◽  
Disease Heterogeneity ◽  
Obstructive Pulmonary Disease ◽  
Pathophysiological Mechanisms ◽  
Multi Scale

The respiratory system comprises several scales of biological complexity: the genes, cells and tissues that work in concert to generate resultant function. Malfunctions of the structure or function of components at any spatial scale can result in diseases, to the detriment of gas exchange, right heart function and patient quality of life. Vast amounts of data emerge from studies across each of the biological scales; however, the question remains: how can we integrate and interpret these data in a meaningful way? Respiratory disease presents a huge health and economic burden, with the diseases asthma and chronic obstructive pulmonary disease (COPD) affecting over 500 million people worldwide. Current therapies are inadequate owing to our incomplete understanding of the disease pathophysiology and our lack of recognition of the enormous disease heterogeneity: we need to characterize this heterogeneity on a patient-specific basis to advance healthcare. In an effort to achieve this goal, the AirPROM consortium ( Air way disease Pr edicting O utcomes through patient-specific computational M odelling) brings together a multi-disciplinary team and a wealth of clinical data. Together we are developing an integrated multi-scale model of the airways in order to unravel the complex pathophysiological mechanisms occurring in the diseases asthma and COPD.

scholarly journals Multi-Scale Modeling of Patient-Specific Ventricular Geometry, Fiber Structure, and Biomechanics

2012 ◽  
Vol 102 (3) ◽  
pp. 351a
Author(s):  
Adarsh Krishnamurthy ◽  
Chris Villongco ◽  
Roy Kerckhoffs ◽  
Andrew McCulloch
Keyword(s):  
Patient Specific ◽  
Fiber Structure ◽  
Multi Scale ◽  
Ventricular Geometry ◽  
Scale Modeling ◽  
Multi Scale Modeling
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