Creation of a standardized geometry of the human nasal cavity

2009 ◽  
Vol 106 (3) ◽  
pp. 784-795 ◽  
Author(s):  
Y. Liu ◽  
M. R. Johnson ◽  
E. A. Matida ◽  
S. Kherani ◽  
J. Marsan
Keyword(s):  
Nasal Cavity ◽  
Three Dimensional ◽  
Ct Scans ◽  
Physical Parameters ◽  
Specific Procedure ◽  
Image Processing Algorithm ◽  
Cross Sectional ◽  
Nasal Airways ◽  
Numerical Studies ◽  
Inhaled Aerosols

A novel, standardized geometry of the human nasal cavity was created by aligning and processing 30 sets of computed tomography (CT) scans of nasal airways of healthy subjects. Digital three-dimensional (3-D) geometries of the 60 single human nasal cavities (30 right and 30 mirrored left cavities) were generated from the CT scans and measurements of physical parameters of each single nasal cavity were performed. A methodology was developed to scale, orient, and align the nasal geometries, after which 2-D digital coronal cross-sectional slices were generated. With the use of an innovative image processing algorithm, median cross-sectional geometries were created to match median physical parameters while retaining the unique geometric features of the human nasal cavity. From these idealized 2-D images, an original 3-D standardized median human nasal cavity was created. This new standardized geometry was compared against the original geometries of all subjects as well as limited existing data from the literature. The new model has potential for use as a geometric standard in future experimental and numerical studies of deposition of inhaled aerosols, as well as for use as a reference during diagnosis of unhealthy patients. The specific procedure developed could also be applied to build standard nasal geometries for different identifiable groups within the larger population.

Crown reconfiguration and trunk stress in deciduous trees

2008 ◽  
Vol 38 (6) ◽  
pp. 1275-1289 ◽  
Author(s):  
Brian Kane ◽  
Michael Pavlis ◽  
J. Roger Harris ◽  
John R. Seiler
Keyword(s):  
Factor Of Safety ◽  
Three Dimensional ◽  
Bending Moment ◽  
Modulus Of Rupture ◽  
Physical Parameters ◽  
Deciduous Trees ◽  
Cross Sectional ◽  
Tree Crowns ◽  
Wind Speeds ◽  
Crown Dimensions

In light of the risk of litigation following damage related to tree failure in urban and suburban settings, more empirical data related to tree risk assessment are needed. We measured drag and drag-induced bending moment (M) and calculated drag coefficient (CD) and trunk stress (σ) for three deciduous trees at wind speeds up to 22.4 m/s. We measured the modulus of rupture (MOR) of wood samples from trunks and calculated the factor of safety (SF = MOR / σ) for each tree. We also investigated which tree morphometric variables best predicted drag and M and whether simple two- and three-dimensional shapes accurately represented actual tree crowns. Drag, CD, M, σ, and SF differed among species in accordance with physical parameters. More massive trees experienced greater drag and M, but σ was greater for trees with smaller trunk diameters. Tree mass reliably predicted drag and M; crown dimensions, including crown area, were less reliable predictors. Crown reconfiguration varied only slightly among species, and CD values were similar to previously reported values for trees of similar size. Our study has important applications for practitioners who manage tree risk, particularly the critical wind speeds and percentage of trunk cross-sectional area that could be decayed before trunk failure.

The Identification of the Potential Limitations of Acoustic Rhinometery Using Computer-Generated, Three-Dimensional Reconstructions of Simple Models

1996 ◽  
Vol 10 (2) ◽  
pp. 77-82 ◽  
Author(s):  
A. Tomkinson ◽  
R. Eccles
Keyword(s):  
Nasal Cavity ◽  
Three Dimensional ◽  
Internal Surface ◽  
Three Dimensions ◽  
Gradual Change ◽  
Large Area ◽  
Cross Sectional ◽  
Wave Path ◽  
Acoustic Evaluation ◽  
Set Up

The internal surface of the nasal cavity is geometrically complicated and does not lend itself readily to direct measurement. Simple geometric shapes were used as a model for changes in the nasal cavity. Following the introduction of specific changes to a particular system, the effect of these changes on the acoustic evaluation of the space was studied. Cylinders were chosen, as the wave path could be assumed to be perpendicular to the model surface. The acoustic rhinometer's accuracy was assessed in the presence of small and large variations in cross sectional area, in the presence of a series of consecutive area changes, and a gradual change in diameter. The effect of the introduction of acoustic leak was also modelled. The acoustic data acquired from these models was used to reconstruct the model in three dimensions. These reconstructions were compared to the original model. The acoustic rhinometer was found to resolve with reasonable accuracy the dimensions of small spaces; however, if regions of sudden large area changes were present in the space, the data beyond these regions was highly unreliable. Furthermore, the presence of acoustic leak in a system had a similar effect. Unless precautions are taken in the set-up and operation of the acoustic rhinometer, the potential for misinterpretation of data and the introduction of bias is very high.

Three-dimensional interactions between a finite-span synthetic jet and a crossflow

2011 ◽  
Vol 671 ◽  
pp. 254-287 ◽  
Author(s):  
ONKAR SAHNI ◽  
JOSHUA WOOD ◽  
KENNETH E. JANSEN ◽  
MICHAEL AMITAY
Keyword(s):  
Three Dimensional ◽  
Particle Image Velocimetry Data ◽  
Synthetic Jet ◽  
Synthetic Jets ◽  
Physical Parameters ◽  
Mean Flow ◽  
Cross Sectional ◽  
Finite Span ◽  
Blowing Ratio ◽  
Ratio Range

A complementary experimental and numerical investigation was performed to study the three-dimensional flow structures and interactions of a finite-span synthetic jet in a crossflow at a chord-based Reynolds number of 100,000 and a 0° angle of attack. Six blowing ratios in the range of 0.2–1.2 were considered. Experiments were conducted on a finite wing with a cross-sectional profile of NACA 4421, where particle-image velocimetry data were collected at the centre jet. To complement the experiments, three-dimensional numerical simulations were performed, where the numerical set-up matched not only the physical parameters (e.g. free stream) but also the physical dimensions (e.g. orientation and location of the jet. For the low blowing ratio cases, spatial non-uniformities developed, due to the finite span of the slit, which led to the formation of small and organized secondary structures or a streak-like pattern in the mean flow. On the other hand, for the high blowing ratio range, turbulent vortical structures were dominant, leading to larger spanwise structures, with a larger spanwise wavelength. Moreover, the phase-locked flow fields exhibited a train of counter-rotating coherent vortices that lifted off the surface as they advected downstream. In the mid-blowing ratio range, combined features of the low range (near the slit) and high range (in downstream locations) were found, where a pair of counter-rotating vortices issued in the same jet cycle collided with each other. In all cases, the spanwise extent of the secondary coherent structures reduced with downstream distance with a larger decrease at higher blowing ratios. Similar observations were made in earlier studies on finite-span synthetic jets in quiescent conditions.

Acoustic rhinometry: validation by three-dimensionally reconstructed computer tomographic scans

2000 ◽  
Vol 89 (3) ◽  
pp. 1013-1021 ◽  
Author(s):  
Hendrik Terheyden ◽  
Steffen Maune ◽  
Jürgen Mertens ◽  
Ole Hilberg
Keyword(s):  
Nasal Cavity ◽  
Linear Regression Analysis ◽  
Three Dimensional ◽  
Acoustic Rhinometry ◽  
Single Subject ◽  
Three Dimensional Model ◽  
Head Region ◽  
Cross Sectional ◽  
Air Volume ◽  
Ct Data

The aim of the present study was a validation of acoustic rhinometry (AR) by computed tomography (CT). Six healthy subjects were examined by CT and AR. The CT data were processed in a computer program (AutoCAD), and a virtual three-dimensional model of each nasal cavity was constructed. This model permitted an individual prediction of the center line of the sound wave propagation through the air volume of the nasal cavity with the cross-sectional areas oriented perpendicularly to this line. The area-distance curves derived from AR and CT were compared. Linear regression analysis revealed a reasonable agreement of AR and CT in the anterior nose below a mean of 6 cm distance from the nostrils [ r = 0.839, P < 0.01, m = 1.123, b= −0.113 (AR = m × CT + b)]. The measuring accuracy using CT as gold standard revealed a mean error at the nasal valve of <0.01 cm2 (4.52%) and at the nasal isthmus of 0.02 cm2 (1.87%). Beyond 6 cm, the correlation decreased ( r = 0.419), and overestimation of the true area occurred (>100%). In conclusion, the measurements were reasonably accurate for diagnostic use up to the turbinate head region. Certain factors induce an overestimation of the true areas beyond this region. However, these factors are constant and reproducible in a single subject, and intraindividual comparative measurements are possible beyond the turbinate head region.

Airway Development Relevant to Cranial Vault Suture Synostosis Subtype in Apert Syndrome

FACE ◽  
2020 ◽  
Vol 1 (2) ◽  
pp. 89-96
Author(s):  
Xiaona Lu ◽  
Antonio Jorge Forte ◽  
Kitae Eric Park ◽  
Omar Allam ◽  
Derek M. Steinbacher ◽  
...  
Keyword(s):  
Nasal Cavity ◽  
Cranial Base ◽  
Apert Syndrome ◽  
Ct Scans ◽  
Type I ◽  
Nasal Airway ◽  
Type Ii ◽  
Cross Sectional ◽  
Type Iii ◽  
Pharyngeal Airway

Introduction: Based on an established classification system of Apert syndrome subtypes, we aim to directly analyze the correlation between segmented airway volume changes and different skull suture synostosis, so as to provide individualized surgical planning for each subgroup of Apert patients. Methods: CT scans of 44 unoperated Apert syndrome and 53 controls were included and subgrouped as: type I. Bilateral coronal synostosis; type II. Pansynostosis; type III. Perpendicular combinations of cranial vault synostosis. CT scans were measured using Mimics and 3-matics software. Results: Type I developed a 41% ( P = .116) reduction in the nasal cavity, yet a normal sized pharyngeal airway. The reduced nasal airway was linked to the decreased cross sectional area ( r = 0.598, P = .001), vertical dimension ( r = 0.719, P < .001), and narrower width ( r = 0.727, P < .001). Type II developed proportionally reduced nasal airway and pharyngeal airway volumes (both 47%, P = .113 and P = .041), along with the proportionally restricted cross sectional areas at choana and condylion levels by 62 to 65%. This reduction is related to the cranial base length ( r = 0.712, P = .048), and also cranial base angulation ( r = 0.780, P = .023). Nasal and pharyngeal airway developed normal volume in type III. However, the cross sectional areas at the gonion level diminished by 74% ( P < .001). Conclusion: Airway development is influenced by subtype of Apert suture synostosis. Type II pansynostosis Apert patients developed synchronous reduced nasal and pharyngeal airways, which is correlated with the slightly flattened cranial base. Type I bicoronal patients have a smaller nasal cavity, but normally sized hypopharynx. Yet, type III patients developed normal nasopharyngeal airway volume overall.

scholarly journals Novel three-dimensional methods to analyze the morphology of the nasal cavity and pharyngeal airway

2021 ◽  
Author(s):  
Xiaowen Niu ◽  
Sivaranjani Madhan ◽  
Marie A. Cornelis ◽  
Paolo M. Cattaneo
Keyword(s):  
Nasal Cavity ◽  
Measurement Errors ◽  
Intraclass Correlation ◽  
Three Dimensional ◽  
The Novel ◽  
Cross Sectional ◽  
Pharyngeal Airway ◽  
Semiautomatic Segmentation ◽  
Bland Altman Method ◽  
Level Of Agreement

ABSTRACT Objectives To assess the intraexaminer and interexaminer reliabilities of novel semiautomatic methods to segment the nasal cavity (NC) and pharyngeal airway (PA) and to determine the minimal cross-sectional area (CS) and hydraulic diameter (HD) of the PA. Materials and Methods To test reproducibility, two examiners analyzed the NC and PA independently in 10 retrospectively selected cone beam computed tomography (CBCT) images using semiautomatic segmentation. The PA centerline was determined to assess the minimal CS and HD. The intraclass correlation coefficient (ICC) was used to calculate intraexaminer and interexaminer reliabilities. Measurement errors were assessed by Dahlberg's formula and paired t-tests. The level of agreement was assessed using the Bland-Altman method. Results Intraexaminer and interexaminer reliabilities were excellent (minimal ICC, 0.960). The error of the method was good except for interexaminer values for the oropharynx (P = .016). The minimal CS and HD measurements were reliable (minimal ICC, 0.993; narrow limits of agreement). Conclusions The novel methods for analysis of the NC and PA are reliable. The minimal CS and HD demonstrated excellent reliabilities, which are critical to detect the most constricted part of the PA. Separation of the oropharynx from the voids close to the retroglossal area is not trivial and should be considered with caution.

Changes in the parameters of nasal breathing and parameters of the upper respiratory tract during orthognathic operations in patients with II and III skeletal class of jaw anomalies

2020 ◽  
pp. 22-27
Author(s):  
S.Sh. Gammadaeva ◽  
M.I. Misirkhanova ◽  
A.Yu. Drobyshev
Keyword(s):  
Respiratory Tract ◽  
Nasal Cavity ◽  
Nasal Septum ◽  
Cross Sectional Area ◽  
Upper Respiratory Tract ◽  
Sectional Area ◽  
Nasal Breathing ◽  
Cross Sectional ◽  
Skeletal Class ◽  
Upper Respiratory

The study analyzed the functional parameters of nasal breathing, linear parameters of the nasal aperture, nasal cavity and nasopharynx, volumetric parameters of the upper airways in patients with II and III skeletal class of jaw anomalies before and after orthognathic surgery. The respiratory function of the nose was assessed using a rhinomanometric complex. According to rhinoresistometry data, nasal resistance and hydraulic diameter were assessed. According to the data of acoustic rhinometry, the minimum cross-sectional area along the internal valve, the minimum cross-sectional area on the head of the inferior turbinate and nasal septum and related parameters were estimated. According to the CBCT data, the state of the nasal septum, the inferior turbinates, the nasal aperture, the state of the nasal cavity, and the linear values of the upper respiratory tract (nasopharynx) were analyzed. The patients were divided into 4 groups according to the classification of the patency of the nasal passages by

Acoustic Analysis of Detailed Three-Dimensional Shape of the Human Nasal Cavity and Paranasal Sinuses

2017 ◽  
Author(s):  
Tatsuya Kitamura ◽  
Hironori Takemoto ◽  
Hisanori Makinae ◽  
Tetsutaro Yamaguchi ◽  
Kotaro Maki
Keyword(s):  
Nasal Cavity ◽  
Paranasal Sinuses ◽  
Acoustic Analysis ◽  
Three Dimensional ◽  
Dimensional Shape ◽  
Three Dimensional Shape

scholarly journals Accuracy and Reproducibility of Facial Measurements of Digital Photographs and Wrapped Cone Beam Computed Tomography (CBCT) Photographs

Diagnostics ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 757
Author(s):  
Maged Sultan Alhammadi ◽  
Abeer Abdulkareem Al-mashraqi ◽  
Rayid Hussain Alnami ◽  
Nawaf Mohammad Ashqar ◽  
Omar Hassan Alamir ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Soft Tissue ◽  
Cone Beam Computed Tomography ◽  
High Reliability ◽  
Three Dimensional ◽  
Cone Beam ◽  
Cross Sectional ◽  
Facial Profile ◽  
Digital Photographs ◽  
Gonial Angle

The study sought to assess whether the soft tissue facial profile measurements of direct Cone Beam Computed Tomography (CBCT) and wrapped CBCT images of non-standardized facial photographs are accurate compared to the standardized digital photographs. In this cross-sectional study, 60 patients with an age range of 18–30 years, who were indicated for CBCT, were enrolled. Two facial photographs were taken per patient: standardized and random (non-standardized). The non-standardized ones were wrapped with the CBCT images. The most used soft tissue facial profile landmarks/parameters (linear and angular) were measured on direct soft tissue three-dimensional (3D) images and on the photographs wrapped over the 3D-CBCT images, and then compared to the standardized photographs. The reliability analysis was performed using concordance correlation coefficients (CCC) and depicted graphically using Bland–Altman plots. Most of the linear and angular measurements showed high reliability (0.91 to 0.998). Nevertheless, four soft tissue measurements were unreliable; namely, posterior gonial angle (0.085 and 0.11 for wrapped and direct CBCT soft tissue, respectively), mandibular plane angle (0.006 and 0.0016 for wrapped and direct CBCT soft tissue, respectively), posterior facial height (0.63 and 0.62 for wrapped and direct CBCT soft tissue, respectively) and total soft tissue facial convexity (0.52 for both wrapped and direct CBCT soft tissue, respectively). The soft tissue facial profile measurements from either the direct 3D-CBCT images or the wrapped CBCT images of non-standardized frontal photographs were accurate, and can be used to analyze most of the soft tissue facial profile measurements.

scholarly journals A Numerical Study of Sub-Millisecond Integrated Mix-and-Inject Microfluidic Devices for Sample Delivery at Synchrotron and XFELs

2021 ◽  
Vol 11 (8) ◽  
pp. 3404
Author(s):  
Majid Hejazian ◽  
Eugeniu Balaur ◽  
Brian Abbey
Keyword(s):  
Molecular Dynamics ◽  
Flow Rate ◽  
Numerical Study ◽  
Three Dimensional ◽  
Microfluidic Devices ◽  
Liquid Jets ◽  
Mixing Efficiency ◽  
X Ray Diffraction ◽  
Cross Sectional ◽  
Time Required

Microfluidic devices which integrate both rapid mixing and liquid jetting for sample delivery are an emerging solution for studying molecular dynamics via X-ray diffraction. Here we use finite element modelling to investigate the efficiency and time-resolution achievable using microfluidic mixers within the parameter range required for producing stable liquid jets. Three-dimensional simulations, validated by experimental data, are used to determine the velocity and concentration distribution within these devices. The results show that by adopting a serpentine geometry, it is possible to induce chaotic mixing, which effectively reduces the time required to achieve a homogeneous mixture for sample delivery. Further, we investigate the effect of flow rate and the mixer microchannel size on the mixing efficiency and minimum time required for complete mixing of the two solutions whilst maintaining a stable jet. In general, we find that the smaller the cross-sectional area of the mixer microchannel, the shorter the time needed to achieve homogeneous mixing for a given flow rate. The results of these simulations will form the basis for optimised designs enabling the study of molecular dynamics occurring on millisecond timescales using integrated mix-and-inject microfluidic devices.

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