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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Sensitivity of nasal airflow variables computed via computational fluid dynamics to the computed tomography segmentation threshold

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Author(s):
Cherobin, Giancarlo B. [1] ; Voegels, Richard L. [1] ; Gebrim, Eloise M. M. S. [2] ; Garcia, Guilherme J. M. [3, 4, 5]
Total Authors: 4
Affiliation:
[1] Univ Sao Paulo, Dept Ophtalmol & Otorhinolaryngol, Sao Paulo - Brazil
[2] Univ Sao Paulo, Hosp Clin, Fac Med, Dept Radiol, Sao Paulo - Brazil
[3] Med Coll Wisconsin, Milwaukee, WI 53226 - USA
[4] Marquette Univ, Dept Biomed Engn, Milwaukee, WI 53233 - USA
[5] Med Coll Wisconsin, Dept Otolaryngol & Commun Sci, Milwaukee, WI 53226 - USA
Total Affiliations: 5
Document type: Journal article
Source: PLoS One; v. 13, n. 11 NOV 16 2018.
Web of Science Citations: 0
Abstract

Computational fluid dynamics (CFD) allows quantitative assessment of transport phenomena in the human nasal cavity, including heat exchange, moisture transport, odorant uptake in the olfactory cleft, and regional delivery of pharmaceutical aerosols. The first step when applying CFD to investigate nasal airflow is to create a 3-dimensional reconstruction of the nasal anatomy from computed tomography (CT) scans or magnetic resonance images (MRI). However, a method to identify the exact location of the air-tissue boundary from CT scans or MRI is currently lacking. This introduces some uncertainty in the nasal cavity geometry. The radiodensity threshold for segmentation of the nasal airways has received little attention in the CFD literature. The goal of this study is to quantify how uncertainty in the segmentation threshold impacts CFD simulations of transport phenomena in the human nasal cavity. Three patients with nasal airway obstruction were included in the analysis. Pre-surgery CT scans were obtained after mucosal decongestion with oxymetazoline. For each patient, the nasal anatomy was reconstructed using three different thresholds in Hounsfield units (-800HU, -550HU, and -300HU). Our results demonstrate that some CFD variables (pressure drop, flowrate, airflow resistance) and anatomic variables (airspace cross-sectional area and volume) are strongly dependent on the segmentation threshold, while other CFD variables (intranasal flow distribution, surface area) are less sensitive to the segmentation threshold. These findings suggest that identification of an optimal threshold for segmentation of the nasal airway from CT scans will be important for good agreement between in vivo measurements and patient-specific CFD simulations of transport phenomena in the nasal cavity, particularly for processes sensitive to the transnasal pressure drop. We recommend that future CFD studies should always report the segmentation threshold used to reconstruct the nasal anatomy. (AU)

FAPESP's process: 12/20823-9 - Rhinomanometry using computational fluid dynamics
Grantee:Richard Louis Voegels
Support Opportunities: Regular Research Grants