scholarly journals Three-dimensional modeling and automatic analysis of the human nasal cavity and paranasal sinuses using the computational fluid dynamics method

2020 ◽  
Author(s):  
Dmitry Tretiakow ◽  
Krzysztof Tesch ◽  
Jarosław Meyer-Szary ◽  
Karolina Markiet ◽  
Andrzej Skorek
Keyword(s):  
Fluid Dynamics ◽  
Computed Tomography ◽  
Computational Fluid Dynamics ◽  
Nasal Cavity ◽  
Paranasal Sinuses ◽  
Model Building ◽  
Cfd Simulation ◽  
Surface Model ◽  
Model Generation ◽  
Upper Airways

Abstract Purpose The goal of this study was to develop a complete workflow allowing for conducting computational fluid dynamics (CFD) simulation of airflow through the upper airways based on computed tomography (CT) and cone-beam computed tomography (CBCT) studies of individual adult patients. Methods This study is based on CT images of 16 patients. Image processing and model generation of the human nasal cavity and paranasal sinuses were performed using open-source and freeware software. 3-D Slicer was used primarily for segmentation and new surface model generation. Further processing was done using Autodesk® Meshmixer TM. The governing equations are discretized by means of the finite volume method. Subsequently, the corresponding algebraic equation systems were solved by OpenFOAM software. Results We described the protocol for the preparation of a 3-D model of the nasal cavity and paranasal sinuses and highlighted several problems that the future researcher may encounter. The CFD results were presented based on examples of 3-D models of the patient 1 (norm) and patient 2 (pathological changes). Conclusion The short training time for new user without a prior experience in image segmentation and 3-D mesh editing is an important advantage of this type of research. Both CBCT and CT are useful for model building. However, CBCT may have limitations. The Q criterion in CFD illustrates the considerable complication of the nasal flow and allows for direct evaluation and quantitative comparison of various flows and can be used for the assessment of nasal airflow.

Use of computational fluid dynamics to study the influence of the uncinate process on nasal airflow

2010 ◽  
Vol 125 (1) ◽  
pp. 30-37 ◽  
Author(s):  
G-X Xiong ◽  
J-M Zhan ◽  
K-J Zuo ◽  
L-W Rong ◽  
J-F Li ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Nasal Cavity ◽  
Paranasal Sinuses ◽  
Endoscopic Sinus Surgery ◽  
Uncinate Process ◽  
Functional Endoscopic Sinus Surgery ◽  
Sinus Surgery ◽  
Nasal Airflow ◽  
Before And After

AbstractBackground:Chronic rhinosinusitis is commonly treated by functional endoscopic sinus surgery involving excision of the uncinate process and opening of the osteomeatal complex.Methods:Computational fluid dynamics were used to compare nasal airflow after two different surgical interventions which involved opening the paranasal sinuses, excising the ethmoid sinus, and excising or preserving the uncinate process, in a cadaveric head model. Cross-sectional computed tomography images were obtained before and after the interventions. Imaging data were used to prepare computer simulations, which were used to assess the airflow characteristics of the nasal cavities and paranasal sinuses during inspiration and expiration, before and after intervention.Results:Significantly larger nasal cavity airflow velocity changes were apparent following the uncinate process excising procedure. Nasal cavity airflow distribution remained relatively unchanged following the uncinate process preserving procedure. There was a significantly greater increase in airflow volume following the uncinate process excising procedure, compared with the uncinate process preserving procedure.Conclusion:Preservation of the uncinate process may significantly reduce the alteration of nasal cavity airflow dynamics occurring after functional endoscopic sinus surgery for chronic rhinosinusitis.

Effect of Nasal Valve Shape on Downstream Volume, Airflow, and Pressure Drop: Importance of the Nasal Valve Revisited

2018 ◽  
Vol 127 (11) ◽  
pp. 745-753 ◽  
Author(s):  
John P. Naughton ◽  
Andrew Y. Lee ◽  
Eric Ramos ◽  
David Wootton ◽  
Howard D. Stupak
Keyword(s):  
Fluid Dynamics ◽  
Computed Tomography ◽  
Computational Fluid Dynamics ◽  
Pressure Drop ◽  
Nasal Cavity ◽  
Physical Model ◽  
Nasal Obstruction ◽  
Nasal Valve ◽  
Cross Sectional ◽  
Computational Fluid Dynamics Analysis

Objectives: The relative importance of the nasal valve relative to the remainder of the nasal airway remains unknown. The goal of this article was to objectively measure the shape of the nasal inlet and its effect on downstream airflow and nasal cavity volume using a physical model and a physiologic flow model. Methods: A patient who had isolated nasal valve surgery and had pre- and postoperative computed tomography scans available for analysis was studied. Nasal inlet shape measurements, computational fluid dynamics, and nasal volume analysis were performed using the computed tomography data. In addition, a physical model was used to determine the effect of nasal obstruction on downstream soft tissue. Results: The postoperative shape of the nasal inlet was improved in terms of length and degree of tortuosity. Whereas the operated-on region at the nasal inlet showed an only 25% increase in cross-sectional area postoperatively, downstream nonoperated sites in the nasal cavity revealed increases in area ranging from 33% to 51%. Computational fluid dynamics analysis showed that airway resistance decreased by 42%, and pressure drop was reduced by 43%. Intraluminal mucosal expansion was found with nasal obstruction in the physical model. Conclusion: By decreasing the degree of bending and length at the nasal valve, inspiratory downstream nonoperated sites of the nasal cavity showed improvement in volume and airflow, suggesting that the nasal valve could play an oversized role in modulating the aerodynamics of the airway. This was confirmed with the physical model of nasal obstruction on downstream mucosa.

Computational fluid dynamics simulation of air flow in the normal nasal cavity and paranasal sinuses

2012 ◽  
Vol 22 (6) ◽  
pp. 664-664 ◽  
Author(s):  
Guan-xia Xiong ◽  
Jie-Min Zhan ◽  
Hong-Yan Jiang ◽  
Jian-Feng Li ◽  
Liang-Wan Rong ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Nasal Cavity ◽  
Paranasal Sinuses ◽  
Air Flow ◽  
Dynamics Simulation ◽  
Computational Fluid Dynamics Simulation

Development and Verification of a High-Fidelity Computational Fluid Dynamics Model of Canine Nasal Airflow

2009 ◽  
Vol 131 (9) ◽  
Author(s):  
Brent A. Craven ◽  
Eric G. Paterson ◽  
Gary S. Settles ◽  
Michael J. Lawson
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Nasal Cavity ◽  
Regional Distribution ◽  
Small Time ◽  
High Fidelity ◽  
Grid Refinement ◽  
Nasal Airflow ◽  
Time Step ◽  
Upper Airways

The canine nasal cavity contains a complex airway labyrinth, dedicated to respiratory air conditioning, filtering of inspired contaminants, and olfaction. The small and contorted anatomical structure of the nasal turbinates has, to date, precluded a proper study of nasal airflow in the dog. This study describes the development of a high-fidelity computational fluid dynamics (CFD) model of the canine nasal airway from a three-dimensional reconstruction of high-resolution magnetic resonance imaging scans of the canine anatomy. Unstructured hexahedral grids are generated, with large grid sizes ((10–100)×106 computational cells) required to capture the details of the nasal airways. High-fidelity CFD solutions of the nasal airflow for steady inspiration and expiration are computed over a range of physiological airflow rates. A rigorous grid refinement study is performed, which also illustrates a methodology for verification of CFD calculations on complex unstructured grids in tortuous airways. In general, the qualitative characteristics of the computed solutions for the different grid resolutions are fairly well preserved. However, quantitative results such as the overall pressure drop and even the regional distribution of airflow in the nasal cavity are moderately grid dependent. These quantities tend to converge monotonically with grid refinement. Lastly, transient computations of canine sniffing were carried out as part of a time-step study, demonstrating that high temporal accuracy is achievable using small time steps consisting of 160 steps per sniff period. Here we demonstrate that acceptable numerical accuracy (between approximately 1% and 15%) is achievable with practical levels of grid resolution (∼100×106 computational cells). Given the popularity of CFD as a tool for studying flow in the upper airways of humans and animals, based on this work we recommend the necessity of a grid dependence study and quantification of numerical error when presenting CFD results in complicated airways.

Computational Fluid Dynamics Simulation of Airflow in the Normal Nasal Cavity and Paranasal Sinuses

2008 ◽  
Vol 22 (5) ◽  
pp. 477-482 ◽  
Author(s):  
Guan-Xia Xiong ◽  
Jie-Min Zhan ◽  
Hong-Yan Jiang ◽  
Jian-Feng Li ◽  
Liang-Wan Rong ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Nasal Cavity ◽  
Paranasal Sinuses ◽  
Dynamics Simulation ◽  
Computational Fluid Dynamics Simulation

scholarly journals Agreement between rhinomanometry and computed tomography-based computational fluid dynamics

2021 ◽  
Author(s):  
Manuel Berger ◽  
Aris I. Giotakis ◽  
Martin Pillei ◽  
Andreas Mehrle ◽  
Michael Kraxner ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computed Tomography ◽  
Computational Fluid Dynamics ◽  
Lattice Boltzmann ◽  
Univariate Analysis ◽  
Error Rates ◽  
Bland Altman Method ◽  
Nasal Side ◽  
Computational Fluid Dynamics Cfd ◽  
Side Error

Abstract Purpose Active anterior rhinomanometry (AAR) and computed tomography (CT) are standardized methods for the evaluation of nasal obstruction. Recent attempts to correlate AAR with CT-based computational fluid dynamics (CFD) have been controversial. We aimed to investigate this correlation and agreement based on an in-house developed procedure. Methods In a pilot study, we retrospectively examined five subjects scheduled for septoplasty, along with preoperative digital volume tomography and AAR. The simulation was performed with Sailfish CFD, a lattice Boltzmann code. We examined the correlation and agreement of pressure derived from AAR (RhinoPress) and simulation (SimPress) and these of resistance during inspiration by 150 Pa pressure drop derived from AAR (RhinoRes150) and simulation (SimRes150). For investigation of correlation between pressures and between resistances, a univariate analysis of variance and a Pearson’s correlation were performed, respectively. For investigation of agreement, the Bland–Altman method was used. Results The correlation coefficient between RhinoPress and SimPress was r = 0.93 (p < 0.001). RhinoPress was similar to SimPress in the less obstructed nasal side and two times greater than SimPress in the more obstructed nasal side. A moderate correlation was found between RhinoRes150 and SimRes150 (r = 0.65; p = 0.041). Conclusion The simulation of rhinomanometry pressure by CT-based CFD seems more feasible with the lattice Boltzmann code in the less obstructed nasal side. In the more obstructed nasal side, error rates of up to 100% were encountered. Our results imply that the pressure and resistance derived from CT-based CFD and AAR were similar, yet not same.

scholarly journals Computational Fluid Dynamics (CFD) Simulation on Mixing in T-Shaped Micromixer

2020 ◽  
Vol 932 ◽  
pp. 012006
Author(s):  
S N A Ahmad Termizi ◽  
C Y Khor ◽  
M A M Nawi ◽  
Nurlela Ahmad ◽  
Muhammad Ikman Ishak ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Cfd Simulation ◽  
Computational Fluid Dynamics Cfd

A Study on the Performance of Stratified Air Conditioning Design in Assembly Halls – A Case Study at the Dazhi Cultural Center in Taiwan

2013 ◽  
Vol 368-370 ◽  
pp. 599-602 ◽  
Author(s):  
Ian Hung ◽  
Hsien Te Lin ◽  
Yu Chung Wang
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Indoor Air ◽  
Air Conditioning ◽  
Cfd Simulation ◽  
Indoor Temperature ◽  
Cultural Center ◽  
Computational Fluid Dynamics Cfd

This study focuses on the performance of air conditioning design at the Dazhi Cultural Center and uses a computational fluid dynamics (CFD) simulation to discuss the differences in wind velocity and ambient indoor temperature between all-zone air conditioning design and stratified air conditioning design. The results have strong implications for air conditioning design and can improve the indoor air quality of assembly halls.

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