Fig 4 - uploaded by Ozcan Cakmak
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Frequency dependence of sound-power reflection coefficient for models with a main pipe of finite length. The 3 plots represent 3 different insert diameters, as shown inside the graph.
Source publication
The influence of nasal valve on acoustic rhinometry (AR) measurements was evaluated by using simple nasal cavity models. Each model consisted of a cylindrical pipe with an insert simulating the nasal valve. The AR-determined cross-sectional areas beyond the insert were consistently underestimated, and the corresponding area-distance curves showed p...
Context in source publication
Context 1
... one would expect consecutive minima and maxima to appear in the plots of both sound-power transmission and reflection coefficients vs. sound frequency. By combining Eqs. 3-6, we calculated the sound-power reflection coefficient r (1 t ) as a function of sound frequency for selected inner diameter values of the insert. The results are shown in Fig. 4, which, for clarity, shows only the data sets for three different inner diameters. For models with a constriction and main pipe of finite length, the sound-power reflection coefficient exhibits pronounced oscillations when the sound frequency is increased from 100 Hz to 10 kHz. As a consequence, the measured cross-sectional areas ...
Citations
... [6][7][8][9] Lateral and PA cephalometry being a 2D representation of 3D structures show superimposition, projection errors, and artifacts. Cankurtaran et al. 10 established that acoustic rhinometry is ineffective in calculating the volume of the posterior part of the nasal cavity, which was possible with CBCT especially in the midsagittal plane which was used in this study. Other methods of measurement, rhinomanometry, and CT have the disadvantage of being invasive and high radiation exposure, respectively, and also not readily available for dentists. ...
Aim and objective:
Mouth breathing is one of the most common deleterious habits prevalent in children which leads to various skeletal and dental malocclusions. Due to the close relationship between nasal and nasopharyngeal cavity volume and maxilla, transverse maxillary deficiency causes reduced nasal and nasopharyngeal cavity volume leading to mouth breathing. Therefore, knowledge of average nasal and nasopharyngeal cavity volume is essential to accurately diagnose mouth breathing and to evaluate underlying causative factors.
Materials and methods:
Cone-beam computed tomographic scans of 60 children were taken and nasal cavity and nasopharyngeal volumes were calculated using Planmeca Romexis 5.2.0.R software. Average volumes were computed using predetermined landmarks and compared among gender.
Results:
The nasal cavity and nasopharyngeal volume showed significant differences among the gender (p value < 0.001 and 0.018, respectively).
Conclusion and clinical significance:
Knowledge of the average nasal and nasopharyngeal cavity volumes can be a useful diagnostic aid for mouth breathing patients and also assess the causative factors and treatment outcomes in these patients.
How to cite this article:
Kalaskar R, Balasubramanian S, Kalaskar A. Evaluation of the Average Nasal and Nasopharyngeal Volume in 10-13-year-old Children: A Preliminary CBCT Study. Int J Clin Pediatr Dent 2021;14(2):187-191.
... Ware-Aki algorithm, which is used in acoustic rhinometry technique, however, has some assumptions regarding the ideal properties of airway. This algorithm assumes that the sound waves are plane waves, and it does not account for losses (airway wall nonrigidity, viscous losses) or nonplanar wave propagation effects (Celik et al. 2004 ;Cankurtaran et al. 2003 ;Cakmak et al. 2003a ). In order to understand the reasons of some artefacts and errors on acoustic rhinometry area-distance curves, these assumptions will be explained briefl y. ...
... This, in turn, causes additional delays in the refl ected waves, complicates the relation between incident and refl ected waves and eventually affects cross-sectional area and distance computations. In other words, planar wave assumption determines and limits the spatial resolution and the frequency bandwidth of the method and imposes limitations on the transverse sizes of an airway model (Celik et al. 2004 ;Cankurtaran et al. 2003 ;Cakmak et al. 2003a ). ...
... If there is a fi nite sudden jump in the acoustic impedance, the transformations and the potential functions used in the mathematical formulation of this algorithm are not well defi ned. In other words, the Ware-Aki algorithm is not suitable for calculating the area-distance function at locations where there are abrupt changes in the acoustic impedance (Celik et al. 2004 ;Cankurtaran et al. 2003 ;Cakmak et al. 2003aCakmak et al. , 2005b. ...
Acoustic rhinometry was introduced as an objective tool for the assessment of the nasal cavity geometry in 1989 by Hilberg et al. Acoustic rhinometry is potentially useful in the assessment of the nasal cavity geometry, nasal patency and the results of various medical and surgical therapies. However, interpretations that do not consider the limitations of the technique may easily lead to misinterpretations.
... The acoustic rhinometry was found to reasonably resolve the airways geometry of the plastinated casts. Concerning the specimen 2, characterized by pneumatised middle turbinate (i.e. a concha bullosa) in the right nasal cavity, the comparison of areas obtained by acoustic reflexion and by 3D reconstruction and then image analysis were previously described in [12]. ...
... It is a reliable and non invasive mean in order to assess the first six centimetres of the nasal fossa anatomy [13]. Although this method has been used in clinical practice, some authors underline its potential limitations in the case of sudden large area changes in the space [14], or about the cross-sectional areas posterior to a significant constriction [12]. The acoustic rhinometry, performed on specimen 3, emphasized a perfect symmetry of right and left nasal cavities from the nostril to the ostium of maxillary sinus ( Fig 5). ...
For many years, researchers have been interested in investigating airflow and aerosol deposition in the nasal cavities. The nasal airways appear to be a complex geometrical system. Thus, in vitro experimental studies are frequently conducted with a more or less biomimetic nasal replica.
This study is devoted to the development of an anatomically realistic nose model with bilateral nasal cavities, i.e. nasal anatomy, airway geometry and aerodynamic properties as close as possible to in vivo behaviour.
A specific plastination technique of cephalic extremities was developed by the Anatomy Laboratory at the Saint-Etienne University in the last 10 years. The plastinated models obtained were anatomically, geometrically and aerodynamically validated using several techniques (endoscopy, CT scans, acoustic rhinometry and rhinomanometry).
Our plastination model exhibited a high level of anatomic quality, including a very good mucosa preservation. Aerodynamical and geometrical investigations highlighted a global behaviour of plastinated models perfectly in accordance with a nasal decongested healthy subject.
The present plastination model provides a realistic cast of nasal airways, and may be a useful tool for nasal flow, drug delivery and aerosol deposition studies.
... Nonetheless, while AR is a useful, objective tool, which correlates well with nasal obstruction, it is important to note that when the minimum cross-sectional area is <0.2 cm 2 , measurements beyond this site need to be considered with caution [24]. Indeed, Cankurtaran et al. [25] simulated nasal valve morphology and suggested that AR does not provide reliable information posterior to a significant constriction, such as narrowing in the nasal valve area. Therefore, our results are taken from within 6 cm of the anterior nares, as Numminen et al. [26] suggest that the reliability of AR is very good in the anterior and middle parts of the nasal cavities, while evaluations based on the posterior regions are less accurate. ...
... Nonetheless, while AR is a useful, objective tool, which correlates well with nasal obstruction, it is important to note that when the minimum cross-sectional area is <0.2 cm 2 , measurements beyond this site need to be considered with caution [24]. Indeed, Cankurtaran et al. [25] simulated nasal valve morphology and suggested that AR does not provide reliable information posterior to a significant constriction, such as narrowing in the nasal valve area. Therefore, our results are taken from within 6 cm of the anterior nares, as Numminen et al. [26] suggest that the reliability of AR is very good in the anterior and middle parts of the nasal cavities, while evaluations based on the posterior regions are less accurate. ...
To determine the effects of a nasal dilation appliance on 3-D nasopharyngeal airway patency. The sample comprised 187 adults (98 males, 89 females) with a history of sleep-disordered breathing. Acoustic rhinometry readings were taken from all patients before and after the intra-oral placement of a nasal dilation appliance (OASYS). The mean left and right nasopharyngeal airways were reconstructed in 3-D, and the data from the right and left nostrils were subjected to principal components analysis (PCA) and finite-element scaling analysis (FESA). Comparing the pre- and post-treatment 3-D mean, left nasopharyngeal airways using PCA, the first two eigenvalues accounted for 96% of the total shape change, and statistical differences were found (p < 0.01). Similarly, for the right side, significant differences were detected between the mean pre- and post-treatment 3-D nasopharyngeal airways (p < 0.01) using PCA. Using FESA to quantify and localize changes after the placement of the nasal dilation appliance, the 3-D mean, normalized, left nasopharyngeal airway was found to be 14% wider in the anterior nasal valve region and 28% wider in the distal regions, while the 3-D mean, normalized, right nasopharyngeal airway was 13% wider in the anterior nasal valve region and 27% wider further distally. The use of an intra-oral nasal dilation appliance may be useful in the management of nasopharyngeal conditions, such as snoring, upper airway resistance syndrome, sleep-disordered breathing, and obstructive sleep apnea, especially in cases where nasal obstruction is demonstrable.
... Nonetheless, all of these AR findings have been uncritically accepted and were included in the most recent "Consensus Report on Acoustic Rhinometry and Rhinomanometry." 4 However, even for healthy humans, there is no clear consensus on the interpretation of these AR results. Moreover, the contributors to this consensus report did not consider the results of recent experimental and theoretical studies of the effects of the nasal valve 5,6 and the paranasal sinuses 7 on the AR area-distance curves for models simulating the nasal cavity. ...
... Hence, superposition of the sound waves traveling in opposite directions within the nasal cavity generates a complicated pattern of standing waves. 5 Taking into account the CT-determined actual size (effective diameter and length) of the portion of the nasal cavity from the nasal valve to the choana, we estimated the fundamental resonant frequency of the nasal cavity to be approximately 2,260 Hz before decongestion and approximately 2,240 Hz after decongestion. Thus, the fundamental frequency and the first 3 overtones of the nasal cavity fall within the frequency bandwidth of the acoustic rhinometer. ...
... The opening to a paranasal sinus causes a significant change in the acoustic impedance of the nasal passage at that site; however, the average sound energy loss to the sinus is negligible. The results of our present and previous 9 clinical studies of healthy humans and previous model studies [5][6][7]25 reveal that the complex acoustic impedances of the nasal cavity and paranasal sinuses (and, hence, the effects of acoustic resonances in the nasal cavity and sinuses) are not accounted for in the current AR algorithms. Consequently, AR does not provide quantitative information about paranasal sinus volume or ostium size in either non-decongested or decongested nasal cavities, and it considerably overestimates crosssectional areas in the nasal passage beyond the paranasal sinus ostia. ...
We evaluated the accuracy of acoustic rhinometry (AR) measurements in healthy humans and assessed the ability of AR in quantifying the dimensions of the paranasal sinuses and certain anatomic structures in the nasal cavity.
Twenty nasal passages of 10 healthy adults were examined by AR and computed tomography (CT) before and after decongestion. Actual cross-sectional areas of the nasal cavity and actual locations of the nasal valve, the head of the inferior turbinate, the head of the middle turbinate, the ostia of the frontal and maxillary sinuses, and the choana were determined from CT sections perpendicular to the curved acoustic axis of the nasal passage.
The AR-measured cross-sectional areas in the anterior nasal cavity were in reasonable agreement with the corresponding areas determined from CT, whereas AR consistently overestimated the passage areas at locations posterior to the paranasal sinus ostia. The nasal valve was identified as a pronounced minimum on the AR area-distance curve. However, AR did not discretely identify the head of the inferior turbinate, the head of the middle turbinate, or the choana.
The local minima on the AR area-distance curve beyond the nasal valve are caused by acoustic resonances in the nasal cavity, and do not correspond to any anatomic structure. The AR area overestimation beyond the paranasal sinus ostia is due to the interaction between the nasal cavity and the paranasal sinuses, rather than to sound loss into the sinuses. Acoustic rhinometry provides no quantitative information on ostium size or sinus volume in either non-decongested or decongested nasal cavities.
... Poetker et al. (2004) call this CT reconstruction the “nasal base view” and confirm the possible exact measurement of the angle of the nasal valve [25]. The disadvantage of acoustic rhinometry is that, in case of a severe constriction of the area of the nasal aperture, no valid findings regarding posterior regions can be made [26]. Furthermore, voluminous paranasal sinuses with large ostia seem to cause false results [27]. ...
The nasal valve area is not a singular structure, but a complex three-dimensional construct consisting of several morphological structures. From the physiologic point of view, it is the place of maximum nasal flow resistance ("flow limiting segment"). Therefore, according to Poiseuille's law, even minor constrictions of this area result in a clinically relevant impairment of nasal breathing for the patient. This narrow passage, also called "ostium internum nasi", is formed by the mobile lateral nasal wall, the anterior septum with the swell body, the head of the inferior turbinate and the osseous piriform aperture. Within the framework of aetiology, static and dynamic disorders of the nasal valve area have to be distinguished since they result in different therapeutic measures. In the context of diagnosis, the exploration of the case history for assessing the patient's extent of suffering and the clinical examination are very important. In addition to the presentation of the basics of disorders of the nasal valves, this paper focuses on the treatment of dynamic disorders that mainly constitute the more important therapeutic issue. In this context, we distinguish between stabilisation techniques through grafts or implants and stabilising suture techniques. Following a thorough analysis, the correction of static nasal valve disorders requires various plastic-reconstructive measures using transposition grafting and skin or composite grafts.
... Acoustic rhinometry is a well-established method for evaluation of nasal patency, 8 but may not provide reliable information about the cross-sectional areas of the nasal cavity posterior to a significant constriction. 9 Because the nasal cavity has a complex three-dimensional geometry, a detailed experimental study of nasal airflow is limited and rather difficult. The anterior part of the nasal cavity, which consists of the nasal valve area and the head of the inferior turbinate, is responsible for most of the nasal resistance. ...
To evaluate the practicability of Odiosoft-Rhino (OR), a new experimental method for assessing the nasal airflow and resistance, in normal subjects and to compare the results with acoustic rhinometry (AR) findings.
OR and AR were carried out in 72 healthy subjects. Their visual analogue scales of nasal obstruction, minimal cross sectional areas (MCA(1) and MCA(2)), and nasal expiration sounds were analyzed and noted for both nasal cavities.
Statistically significant correlations (P < 0.05) were found between OR and AR in 2,000 to 4,000 Hz and 4,000 to 6,000 Hz with MCA(1) and MCA(2).
OR is a noninvasive and rapid test. It is easy to carry out and requires little patient cooperation. It seems that it may give compatible results with other reliable methods that assess nasal airflow.
We assume that OR is a sensitive method for evaluating nasal airflow in normal subjects in an easy way. EBM rating: A-1b.
... In our present clinical study, we found that both the area overestimation and oscillation of the AR-derived area-distance curve beyond the paranasal sinus ostia were common to all 20 nasal passages investigated. This suggests that these two AR phenomena are inherent to the physics of sound-wave transmission through the human nasal cavity (1,4,5). ...
A comprehensive study that compared acoustic rhinometry (AR) data to computed tomography (CT) data was performed to evaluate the accuracy of AR measurements in estimating nasal passage area and to assess its ability of quantifying paranasal sinus volume and ostium size in live humans. Twenty nasal passages of 10 healthy adults were examined by using AR and CT. Actual cross-sectional areas of the nasal cavity, sinus ostia sizes, and maxillary and frontal sinus volumes were determined from CT sections perpendicular to the curved acoustic axis of the nasal passage. Nasal cavity volume (from nostril to choana) calculated from the AR-derived area-distance curve was compared with that from the CT-derived area-distance curve. AR measurements were also done on pipe models that featured a side branch (Helmholtz resonator of constant volume but two different neck diameters) simulating a paranasal sinus. In the anterior nasal cavity, there was good agreement between the cross-sectional areas determined by AR and CT. However, posterior to the sinus ostia, AR overestimated cross-sectional area. The difference between AR nasal volume and CT nasal volume was much smaller than the combined volume of the maxillary and frontal sinuses. The results suggest that AR measurements of the healthy adult nasal cavity are reasonably accurate to the level of the paranasal sinus ostia. Beyond this point, AR overestimates cross-sectional area and provides no quantitative data for sinus volume or ostium size. The effects of paranasal sinuses and acoustic resonances in the nasal cavity are not accounted for in the present AR algorithms.
... However, certain factors inherent to the physics and algorithms used in AR limit the accuracy of this method. One potential problem in using AR to study the geometry of the nasal cavity is that the area of a region beyond a severe constriction may not be measured accurately (Cakmak et al 2001, Cankurtaran et al 2003, Hilberg et al 1989, Hilberg and Pedersen 2000. This means that, when considering AR accuracy in relation to the complex anatomy of the nasal passage, special attention must be paid to the influence of the anterior narrow segment, the nasal valve. ...
... Various researchers have suggested that the nasal valve may cause loss of energy from the incident sound wave, which would lead to underestimation of AR-measured area beyond the narrowed site (Hamilton et al 1995, Hilberg et al 1989, Hilberg and Pedersen 2000, Terheyden et al 2000. However, the specific physical cause of the area underestimation in this portion of the nasal passage was clarified only recently by Cankurtaran et al (2003). These authors examined the effects of nasal valve passage area on accuracy of AR measurements using simple pipe models with a constriction. ...
... The passage areas of the inserts used matched those of the actual human nasal valve, in order to imitate the normal anatomy and pathologies of the nasal valve region (Cakmak et al 2003b, Hilberg and Pedersen 2000, Tomkinson and Eccles 1998. These diameters also matched those tested in pipe models by previous investigators (Buenting et al 1994, Cakmak et al 2001, Cankurtaran et al 2003. All the dimensions of the five-stage stepped-tube model fitted with an insert of 0.7 cm inner diameter were approximately the same as the model used by Hilberg and Pedersen (2000). ...
Stepped-tube models with a constriction in the anterior section were used to evaluate the effects that nasal valve passage area and nasal cavity shape have on acoustic rhinometry (AR) measurements. The AR-determined cross-sectional areas beyond a constriction of small passage area were consistently underestimated, and the corresponding area-distance curves showed pronounced oscillations. Also, the AR technique did not accurately reproduce abrupt changes in passage area. The results suggest that, regardless of the particular shape of the nasal cavity model, AR does not provide reliable information about cross-sectional areas posterior to a severe constriction. The experimental results are discussed in terms of theoretically calculated acoustic input impedance for the models studied, the physical limitations of AR, and assumptions made in AR algorithms. The study demonstrated that energy losses and sound wave attenuation due to air viscosity do not significantly affect AR measurements. It was also shown that passage area beyond a severe constriction is underestimated because the barrier created by the constriction reflects most of the incident sound power. The results also indicate that the oscillations in area-distance curves are due to low-frequency acoustic resonances in the nasal cavity model.
