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.

scholarly journals Research on the Computed Tomography Pebble Flow Detecting System for HTR-PM

2017 ◽  
Vol 2017 ◽  
pp. 1-13
Author(s):  
Xin Wan ◽  
Ximing Liu ◽  
Jichen Miao ◽  
Peng Cong ◽  
Yuai Zhang ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Three Dimensional ◽  
Helical Ct ◽  
Design Parameters ◽  
Three Dimensional Model ◽  
Safe Operation ◽  
Cross Sectional ◽  
Ct System ◽  
Near Future ◽  
Pebble Flow

Pebble dynamics is important for the safe operation of pebble-bed high temperature gas-cooled reactors and is a complicated problem of great concern. To investigate it more authentically, a computed tomography pebble flow detecting (CT-PFD) system has been constructed, in which a three-dimensional model is simulated according to the ratio of 1 : 5 with the core of HTR-PM. A multislice helical CT is utilized to acquire the reconstructed cross-sectional images of simulated pebbles, among which special tracer pebbles are designed to indicate pebble flow. Tracer pebbles can be recognized from many other background pebbles because of their heavy kernels that can be resolved in CT images. The detecting principle and design parameters of the system were demonstrated by a verification experiment on an existing CT system in this paper. Algorithms to automatically locate the three-dimensional coordinates of tracer pebbles and to rebuild the trajectory of each tracer pebble were presented and verified. The proposed pebble-detecting and tracking technique described in this paper will be implemented in the near future.

A Comparison of the Nasal Cross-Sectional Areas and Volumes Obtained with Acoustic Rhinometry and Magnetic Resonance Imaging

1997 ◽  
Vol 117 (4) ◽  
pp. 349-354 ◽  
Author(s):  
Jacquelynne P. Corey ◽  
Anil Gungor ◽  
Robert Nelson ◽  
Jeff Fredberg ◽  
Vincent Lai
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Nasal Cavity ◽  
Acoustic Rhinometry ◽  
Resonance Imaging ◽  
Cross Sectional ◽  
Nasal Tip ◽  
Nasal Cycle ◽  
Volume Measurements ◽  
Mri Measurements

Acoustic rhinometry (AR) evaluates the geometry of the nasal cavity with acoustic reflections and provides information about nasal cross-sectional areas (CSA) and nasal volume within a given distance. The accuracy of the information obtained by AR was compared with that of magnetic resonance imaging (MRI) of the nasal cavity. Five healthy subjects were evaluated with AR and the MRI before and after the application of a long-acting nasal decongestant spray, to eliminate possible interference of the nasal cycle with both measurement techniques. The MRI images of 2 mm coronal sections of the nasal cavity were traced by three independent observers and the CSAs were calculated by computer-aided imaging digitization, to be compared with the calculated CSAs obtained with the AR at the corresponding distance from the nasal tip. Digitized data from the MRI images were also used to calculate the nasal volume within the first 6 cm from the nasal tip and compared with the AR volume measurements. The interobserver variation of digitized MRI data predecongestant and postdecongestant was not significant. The correlations of CSA and volume measurements between the AR and MRI were high (0.969) after the application of the decongestant. The correlation between the AR and MRI measurements before the decongestant was low (0.345). This may have been the result of interference of the nasal cycle during the long MRI measurements (1 hour) or other unknown factors. We conclude that AR measurements of nasal CSAs and volumes provide accurate information when compared with the MRI of the decongested nasal airway.

Influence of airflow dynamics on vortices in the human nasal cavity

2019 ◽  
Vol 36 (9) ◽  
pp. 3164-3179
Author(s):  
Punjan Dohare ◽  
Amol P. Bhondekar ◽  
Anupma Sharma ◽  
C. Ghanshyam
Keyword(s):  
Numerical Simulations ◽  
Nasal Cavity ◽  
Three Dimensional ◽  
Nasal Airflow ◽  
Nasal Valve ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Flow Rates ◽  
Content Type ◽  
Human Nose

Purpose The purpose of this paper is to understand the effect of airflow dynamics on vortices for different flow rates using the human nose three-dimensional model. Design/methodology/approach Olfaction originates with air particles travelling from an external environment to the upper segment of the human nose. This phenomenon is generally understood by using the nasal airflow dynamics, which enhances the olfaction by creating the vortices in the human nose. An anatomical three-dimensional model of the human nasal cavity from computed tomography (CT) scan images using the MIMICS software (Materialise, USA) was developed in this study. Grid independence test was performed through volume flow rate, pressure drop from nostrils and septum and average velocity near the nasal valve region using a four computational mesh model. Computational fluid dynamics (CFD) was used to examine the flow pattern and influence of airflow dynamics on vortices in the nasal cavity. Numerical simulations were conducted for the flow rates of 7.5, 10, 15 and 20 L/min using numerical finite volume methods. Findings At coronal cross-sections, dissimilar nasal airflow patterns were observed for 7.5, 10, 15 and 20 L/min rate of fluid flow in the human nasal cavity. Vortices that are found at the boundaries with minimum velocity creates deceleration zone in the nose vestibule region, which is accompanied by flow segregation. Maximum vortices were observed in the nasal valve region and the posterior end of the turbinate region, which involves mixing and recirculation and is responsible for enhancing the smelling process. Practical implications The proposed analysis is applicable to design the sensor chamber for electronic noses. Originality/value In this paper, the influence of airflow dynamics on vortices in the human nasal cavity is discussed through numerical simulations.

Effects of the Breathe Right Nasal Strips on Nasal Ventilation

1997 ◽  
Vol 11 (5) ◽  
pp. 399-402 ◽  
Author(s):  
Jan Gosepath ◽  
Wolf J. Mann ◽  
Ronald G. Amedee
Keyword(s):  
Nasal Cavity ◽  
Physical Performance ◽  
Cross Sectional Area ◽  
Acoustic Rhinometry ◽  
Sectional Area ◽  
Nasal Breathing ◽  
Cross Sectional ◽  
Subjective Impression ◽  
Breathe Right Nasal Strips ◽  
And Training

The Breathe Right nasal strips are more and more commonly used, mainly by athletes, who hope to enhance their physical performance in competition and training. The effect of the device in such situations is uncertain and perhaps somewhat controversial. To investigate the effects of the nasal strips on nasal ventilation, 20 Caucasian individuals were objectively assessed using anterior rhinomanometry and acoustic rhinometry. The results showed a significant increase in all subjects of transnasal airflow and in the average cross-sectional area of the nasal cavity that quantifies objectively the subjective impression of improved nasal breathing. In such patients where an improvement in nasal ventilation is desired, the use of the Breathe Right nasal strips seems to offer a beneficial treatment.

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.

Modeling of Solids and Gas Mixing Effects in Large-Scale CFB Combustors

2003 ◽  
Author(s):  
Karsten Luecke ◽  
Ernst-Ulrich Hartge ◽  
Joachim Werther
Keyword(s):  
Combustion Chamber ◽  
Residence Time ◽  
Large Scale ◽  
Control Volume ◽  
Combustion Process ◽  
Three Dimensional ◽  
Three Dimensional Model ◽  
Cross Sectional ◽  
Fuel Feed ◽  
Cross Section Area

In a CFB combustor the reacting solids are locally fed into the combustion chamber. These reactants have to be dispersed across the reactor’s cross-sectional area. Since the rate of mixing is limited this leads to a mal-distribution of the reactants and to locally varying reaction conditions. In order to describe the influence of mixing a three-dimensional model of the combustion chamber is suggested here. The model is divided into three sub-topics. First, the flow structure in terms of local gas and solids velocities and solids volume concentrations is described. Second, mixing of the solids and the gas phase has to be quantified by defining dispersion coefficients, and finally the combustion process itself, i.e. the reaction kinetics, has to be modeled. Employing the information of the three sub-models mass balances for the reactants at each finite control volume inside the CFB combustion chamber can be formulated. The model was validated against data from measurements in the large-scale combustor of Chalmers University of Technology in Go¨teborg/Sweden. Concentration gradients concerning the char phase are only moderate. However, the spatial distribution of the oxygen shows strong non-uniformities, especially under conditions of staged combustion. In further predictive calculations, the influence of the fuel supply arrangement on the emissions of industrial sized CFB boilers was studied. Furthermore, the influence of the fuel composition on the feeding technique has been examined. High volatile fuels tend to form plumes of unburned hydrocarbons near the fuel feed point, and might therefore need more feed points per square meter cross-section area. Since the average gas residence time in the primary cyclone of a CFB plant is about 30–40% of the total gas residence time, a considerable burn-off of not completely oxidized gas species may occur here. An effectively used cyclone may remedy to a certain extent the negative impacts of incomplete mixing in the combustion chamber.

scholarly journals Effect of rapid maxillary expansion on the dimension of the nasal cavity and on facial morphology assessed by acoustic rhinometry and rhinomanometry

2012 ◽  
Vol 17 (4) ◽  
pp. 129-133 ◽  
Author(s):  
Carla Enoki Itikawa ◽  
Fabiana Cardoso Pereira Valera ◽  
Mírian Aiko Nakane Matsumoto ◽  
Wilma Terezinha Anselmo Lima
Keyword(s):  
Nasal Cavity ◽  
Nasal Bone ◽  
Inferior Turbinate ◽  
Rapid Maxillary Expansion ◽  
Mouth Breathing ◽  
Acoustic Rhinometry ◽  
Facial Morphology ◽  
Nasal Resistance ◽  
Maxillary Expansion ◽  
Cross Sectional

OBJECTIVE: To assess the effects of rapid maxillary expansion on facial morphology and on nasal cavity dimensions of mouth breathing children by acoustic rhinometry and computed rhinomanometry. METHODS: Cohort; 29 mouth breathing children with posterior crossbite were evaluated. Orthodontic and otorhinolaryngologic documentation were performed at three different times, i.e., before expansion, immediately after and 90 days following expansion. RESULTS: The expansion was accompanied by an increase of the maxillary and nasal bone transversal width. However, there were no significant differences in relation to mucosal area of the nose. Acoustic rhinometry showed no difference in the minimal cross-sectional area at the level of the valve and inferior turbinate between the periods analyzed, although rhinomanometry showed a statistically significant reduction in nasal resistance right after expansion, but were similar to pre-treatment values 90 days after expansion. CONCLUSION: The maxillary expansion increased the maxilla and nasal bony area, but was inefficient to increase the nasal mucosal area, and may lessen the nasal resistance, although there was no difference in nasal geometry. Significance: Nasal bony expansion is followed by a mucosal compensation.

Acoustic Rhinometry in the Diagnosis of Occupational Rhinitis

1996 ◽  
Vol 10 (6) ◽  
pp. 393-398 ◽  
Author(s):  
Maija L Hytönen ◽  
Eeva L Sala ◽  
Henrik O Malmberg ◽  
Henrik Nordman
Keyword(s):  
Nasal Cavity ◽  
Provocation Test ◽  
Acoustic Rhinometry ◽  
Cross Sectional ◽  
Occupational Rhinitis ◽  
Limit Value ◽  
Provocation Tests ◽  
Calculated Parameter ◽  
Essential Change ◽  
The Mean

Acoustic rhinometry (ARM) has been used to study the nasal cavity geometry and the response in nasal provocations. However, the use of ARM in the diagnosis of occupational rhinitis (OR) has not been reported. The purpose of this study was to find an ARM parameter and a limit value that could be used in provocation tests to express an objective change in the nasal cavity geometry. We used a new calculated parameter, Volume MCA%, for describing the change in the nasal geometry. Volume MCA% is the mean of the percentile changes of nasal volumes and minimal cross-sectional areas in a provocation test. We recommend a decrease of at least 15% in Volume MCA% for the limit of an essential change in the nasal cavity.

Robot Guided Sheaths (RoGS) for Percutaneous Access to the Pediatric Kidney: Patient-Specific Design and Preliminary Results

2013 ◽  
Author(s):  
Tania K. Morimoto ◽  
Michael H. Hsieh ◽  
Allison M. Okamura
Keyword(s):  
Three Dimensional ◽  
The Body ◽  
Surrounding Tissue ◽  
Patient Specific ◽  
Three Dimensional Model ◽  
Specific Design ◽  
Surgical Access ◽  
Minimally Invasive Surgical ◽  
Area Of Interest ◽  
Ct Data

Robot-guided sheaths consisting of pre-curved tubes and steerable needles are proposed to provide surgical access to locations deep within the body. In comparison to current minimally invasive surgical robotic instruments, these sheaths are thinner, can move along more highly curved paths, and are potentially less expensive. This paper presents the patient-specific design of the pre-curved tube portion of a robot-guided sheath for access to a kidney stone; such a device could be used for delivery of an endoscope to fragment and remove the stone in a pediatric patient. First, feasible two-dimensional paths were determined considering workspace limitations, including avoidance of the ribs and lung, and minimizing collateral damage to surrounding tissue by leveraging the curvatures of the sheaths. Second, building on prior work in concentric-tube robot mechanics, the mechanical interaction of a two-element sheath was modeled and the resulting kinematics was demonstrated to achieve a feasible path in simulation. In addition, as a first step toward three-dimensional planning, patient-specific CT data was used to reconstruct a three-dimensional model of the area of interest.

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