Airway Morphology Research Articles

Epiglottis cross-sectional area and oropharyngeal airway length in male and female obstructive sleep apnea patients.

IntroductionObstructive sleep apnea (OSA) is a male-predominant condition, characterized by repeated upper-airway collapse with continued diaphragmatic efforts during sleep, and is accompanied by severe physiological consequences. Multiple morphological aspects, including epiglottis cross-sectional area (CSA) and oropharyngeal airway length (OPAL), can contribute to airway collapsibility in the condition. This study focused on the effects of OSA severity, sex, and race on OPA dimensions.Materials and methodsTwo high-resolution T1-weighted image series were collected from 40 mild-to-severe OSA subjects (age 46.9±9 years, body mass index 30.4±5.4 kg/m2, Apnea–Hypopnea Index score 32.8±22.5, 28 males) and 54 control subjects (47±9 years, 24.7±3.8 kg/m2, 32 males) using a 3 T magnetic resonance-imaging scanner. Caucasian, Asian, African-American, and “other” subjects constituted the study pool. Both image series were realigned and averaged, and reoriented to a common space. CSA and OPAL were measured, normalized for subject height, and compared between sexes and disease-severity levels in OSA and control subjects.ResultsSignificantly reduced epiglottis CSA appeared only in severe OSA vs controls (P=0.009). OPAL increased significantly with OSA severity vs controls (mild, P=0.027; moderate, P<0.001; severe, P<0.001). OSA males showed increased CSA and greater OPAL than OSA females, which may underlie the increased proportion of affected males with higher apnea–hypopnea index scores. However, no significant differences appeared between CSA and OPAL measures for male and female controls, suggesting that airway morphology may not be the sole contributor for airway collapse. No ethnic or racial differences appeared for CSA or OPAL measures.ConclusionSex-based reductions in epiglottis CSA and increased OPAL in OSA subjects may enhance airway-collapse vulnerability, more so with greater disease severity, and partially underlie male vs female susceptibility to the sleep disorder.

Three-dimensional analyses of palatal morphology and its relation to upper airway area in obstructive sleep apnea.

To evaluate the relationship between palatal morphology and pharyngeal airway morphology in patients who have obstructive sleep apnea (OSA) and compare with a nonsnoring and nonapneic control group. Three-dimensional maxillary dental cast measurements from 25 OSA patients (6 women, 19 men) with a mean age of 41.5 (4.8) years, and 25 control group participants (14 women, 11 men) without any symptom of OSA with a mean age of 38.3 (3.7) were correlated with an analysis of pharyngeal area evaluated with lateral cephalograms. Intermolar and intercanine widths and palatal volumes were calculated on the dental casts, and the upper airway area measurements were performed on lateral cephalograms. OSA patients had smaller oropharyngeal volume and upper airway when compared with controls (P < .001). Palatal area measurements were significantly smaller in OSA (P < .001). OSA patients had significantly narrower maxilla with smaller intermolar and intercanine widths (P < .001). A positive correlation was found between the palatal morphology and pharyngeal dimensions. A significant correlation exists between palatal morphology and pharyngeal airway.

The case for environmental etiology of malocclusion in modern civilizations—Airway morphology and facial growth

The impact of nasal respiration impairment on craniofacial growth and development remains a topic of interest for orthodontists in their daily encounter with mouth breathing patients. The aims of this article are to critically review the: (1) etiology of nasal obstruction, namely septal deviation, turbinate dysfunction, lymphoid tissue hypertrophy, and soft tissue alteration; (2) diagnostic methods to evaluate nasal obstruction; (3) role of mouth breathing in the development of characteristic malocclusions and associated patterns of facial growth (adenoid facies), with a focus on recent research data; (4) indications of medical and surgical treatments with the ongoing debate about removal of lymphoid tissues to avoid facial dysmorphology; (5) diagnosis and treatment of obstructive sleep apnea in growing subjects. Orthodontists play an important role in the early diagnosis of airway impairment. Early clearance of the airways, whether medically or surgically achieved, is gaining more ground between ENT specialists as they became aware of the potential effect on craniofacial development.

Differences of airway dimensions between patients with and without bronchiolitis obliterans syndrome after lung transplantation—Computer-assisted quantification of computed tomography

BackgroundThe aim of our retrospective study was to determine whether a dedicated software for assessment of airway morphology can detect differences in airway dimensions between patients with and without bronchiolitis obliterans syndrome (BOS), regarded as the clinical correlate of chronic lung allograft rejection. Methods12 patients with and 14 patients without diagnosis of BOS were enrolled in the study. Evaluation of bronchial wall area percentage (WA%) and bronchial wall thickness (WT) in all follow-up CT scans was performed using a semiautomatic airway assessment tool. We assessed temporal changes (ΔWA%, ΔWT) and compared these morphological parameters with forced expiratory volume in one second (ΔFEV1). ResultsIn patients with and without BOS, the temporal changes over the entire follow-up were 26.6% versus 16.2% for ΔFEV1 (p=0.034), 14.2% versus 5.4% for ΔWA% (p=0.003) and 0.212mm versus 0.064mm for ΔWT (p=0.011). ConclusionsWe detected significant differences of the temporal changes of airway dimensions (ΔWA%, ΔWT) between lung transplant recipients with and without BOS. We conclude that computer-assisted bronchial wall measurements in CT scans might complement the information from pulmonary function tests and establish as a non-invasive method to confirm BOS in lung transplant recipients in the future.

Th17 and Th1 play distinct roles in obliterative bronchiolitis pathogenesis after transplantation.

Abstract Development of obliterative bronchiolitis (OB) is the biggest obstacle that limits long-term allograft survival and clinical application of lung transplantation. Mouse orthotopic trachea or lung transplantations were utilized to examine roles of Th17 and Th1 during OB pathogenesis after transplantation. Allografts of wild type recipients displayed elevated levels of Th1 and Th17 cytokines IFNγ, IL-6 and IL-17 expression. Recipients deficient in Th1 key transcriptional factor T-bet resulted in decreased cell infiltration and improved airway integrity in orthotopic transplanted trachea grafts; Lack of Th2 transcriptional factor Stat6 had little effect; While absence of Th17 master transcriptional factor RORγt had striking effects in abolishing airway epithelial injury, a leading factor of OB pathogenesis. Administering anti-IL-6 or anti-IL-17 but not anti-IFNγ mAbs restored normal airway epithelial morphology. Furthermore, we found that anti-CD40L treatment resulted in increased FoxP3 and regulatory T cells, and decreased IFNγ expression; However it had very limited effect on IL-17 suppression and airway epithelial protection. While CTLA4-Ig treatment significantly inhibit IL-17 expression and reduced epithelial injury, and the combination of CTLA4-Ig and anti-CD40L markedly restored airway morphology of grafts. Together, our findings provide new insights for understanding Th17 and Th1 responses during OB pathogenesis and demonstrate the critical importance of suppressing Th17 for OB development after transplantation.

Cone Beam Computed Tomography (CBCT) Evaluation of Age-related Upper Airway Changes

Background: Upper airway morphology is associated with facial development and occlusion. Treatment of maxillofacial and occlusal disorders requires sufficient knowledge of related functional variables, including upper airway morphology. In order to determine upper airway obstruction and its exact site, three-dimensional (3D) reconstruction of the airway can be beneficial. The aim of the current study was to determine the age-related changes of upper airway morphology.Materials: The pharyngeal area of 87 patients was assessed using Cone Beam Computed Tomography (CBCT), and no artifacts were detected. The subjects were within the age range of 6-60 years, with normal body mass index (BMI) of 18-25 kg/m2. In the CBCTs, in addition to volumetric measurements of nasopharynx, oropharynx, and hypopharynx, distances between pharyngeal wall and posterior nasal spine, uvula, or valcula in anteroposterior and horizontal planes were measured (2D measurement). In addition, the shortest distance between tongue base and posterior pharyngeal wall was calculated in the anteroposterior plane. Data were analyzed in three age groups of 6-20, 21-40, and 41-60 years old via SPSS analysis.Results: Various values of upper airway and variables which measure anteroposterior dimensions of pharynx were significantly higher in the 21-40 years old group, compared to 6-20 years old group. Although these variables were higher in the 21-40 years old group, compared to the 41-60 years old group, the difference was statistically insignificant. The transverse variables had the highest value in the 21-40 years old group, but the difference with the other two groups was insignificant. No significant difference was observed between males and females.Conclusion: According to the results of the current study, upper airway changes in 2D and 3D models may be age-dependent and become more significant by the age of 20 years. In addition, gender has no effect on the development of upper airways.Bangladesh Journal of Medical Science Vol.15(1) 2016 p.78-83

Computed Tomography-based Subclassification of Chronic Obstructive Pulmonary Disease.

Computed tomography (CT) is an obvious modality for subclassification of COPD. Traditionally, the pulmonary involvement of chronic obstructive pulmonary disease (COPD) in smokers is understood as a combination of deleterious effects of smoking on small airways (chronic bronchitis and small airways disease) and distal to the airways with destruction and loss of lung parenchyma (emphysema). However, segmentation of airways is still experimental; with contemporary high-resolution CT (HRCT) we can just see the "entrance" of small airways, and until now changes in airway morphology that have been observed in COPD are subtle. Furthermore, recent results indicate that emphysema may also be the essential pathophysiologic mechanism behind the airflow limitation of COPD. The definition of COPD excludes bronchiectasis as a symptomatic subtype of COPD, and CT findings in chronic bronchitis and exacerbations of COPD are rather unspecific. This leaves emphysema as the most obvious candidate for subclassification of COPD. Both chest radiologists and pulmonary physicians are quite familiar with the appearance of various patterns of emphysema on HRCT, such as centrilobular, panlobular, and paraseptal emphysema. However, it has not yet been possible to develop operational definitions of these patterns that can be used by computer software to automatically classify CT scans into distinct patterns. In conclusion, even though various emphysema patterns can be recognized visually, CT has not yet demonstrated a great potential for automated subclassification of COPD, and it is an open question whether it will ever be possible to achieve success equivalent to that obtained by HRCT in the area of interstitial lung diseases.

Effect of Head and Tongue Posture on the Pharyngeal Airway Dimensions and Morphology in Three-Dimensional Imaging: a Systematic Review.

ABSTRACTObjectivesNatural head position is recommended to be optimal at cone-beam computed tomography acquisition. For standardization purposes in control of treatment outcome, it is clinically relevant to discuss, if a change of posture from natural head position may have an effect on the pharyngeal airway dimensions and morphology, during computed tomography, cone-beam computed tomography or magnetic resonance imaging acquisition. This was the aim of the present literature review study for purposes of valid evidence, which was hypothesized, to be present.Material and MethodsThis systematic literature review has been registered in PROSPERO database with following number: CRD42015024567. A systematic literature search performed in PubMed, Embase and Cochrane was carried out in order to evaluate if the effect of human head or tongue posture has an effect on upper airway dimensions and morphology in CT, CBCT or MRI. Study quality assessment was performed. Predictor variable was head and tongue posture. Endpoints were numerical values of upper airway dimensions and morphology.ResultsOverall 1344 articles (Embase 1063, PubMed 269, and Cochrane 12) resulted in four included publications. Quality assessments revealed poor quality and low-level evidence by 46 - 67% of the maximum achievable score. Heterogeneous methodology made a meta-analysis impossible, consequently a narrative synthesis was performed.ConclusionsLimited, poor quality and low evidence level literature is available on the effect of head posture on upper airway dimensions and morphology in three-dimensional imaging. Valid evidence requires a standardized method of head and tongue posture during image acquisition in future studies.

Sleep-disordered breathing in orthodontic practice: Prevalence of snoring in children and morphological findings.

The purpose of this work was to evaluate the prevalence of snoring and its correlation with cranial and upper airway morphology in young individuals with orthodontic treatment need. Parents of 379 children were consecutively interviewed, using eight questions from a more comprehensive questionnaire about sleep behavior. A total of 100 patients (54 girls, 46 boys, average age 11.3 years) met the inclusion criteria. Based on the parents' interviews, the sample was divided into snorers (n = 53) and nonsnorers (n = 47). Using cephalograms obtained for initial orthodontic diagnostics, airway morphology was measured based on hyoid position and on the posterior airway space (PAS) dimensions at the maxillary, occlusal, and mandibular plane levels (PAS_NL, PAS_OCCL, PAS_ML). Mann-Whitney U testing, ANOVA, and Spearman's rank correlation coefficient were used for statistical analysis. Snoring was reported by 53 % of parents for 63 % (n = 29) of the boys and 44 % (n = 24) of the girls. Significant morphological differences were noted between snorers and nonsnorers. PAS dimensions were significantly reduced in the snorers compared to the nonsnorers at all three anatomical levels tested, which remained statistically significant when adjusted for age and gender. No differences between the two groups emerged for hyoid position or any of the vertical cranial parameters. A significant correlation between sagittal maxillary position (SNA) and PAS_NL was noted, indicating that larger SNA values were mildly associated with larger sagittal PAS dimensions at the maxillary level. This random sample of young patients with orthodontic treatment need was found to involve a high prevalence of parent-reported snoring. Characteristic features in cranial and upper airway morphology and thus differences between the snorers and nonsnorers were found.

Static craniofacial measurements and dynamic airway collapse patterns associated with severe obstructive sleep apnoea: a sleep MRI study.

Using sleep MRI, we aimed to identify static craniofacial measurements and dynamic upper airway collapse patterns associated with severe obstructive sleep apnoea (OSA) during natural sleep in age and BMI-matched patients. Nested case-control study. Sleep MRI images (3.0 Tesla scanner) and synchronised acoustic recording were used to observe patterns of dynamic airway collapse in subjects with mild and severe OSA. Midsagittal images were also used for static craniofacial measurements. Fifteen male subjects with severe OSA (mean AHI 70.3±23 events/h) were matched by age and BMI to 15 subjects with mild OSA (mean AHI 7.8±1.4 events/h). Subjects were selected from a consecutive sleep MRI study cohort. Static craniofacial measurements selected a priori included measurements that represent maxillomandibular relationships and airway morphology. Axial, sagittal and coronal views of the airway were rated for dynamic collapse at retropalatal, retroglossal and lateral pharyngeal wall regions by blinded reviewers. Bivariate analysis was used to correlate measures associated with severity of OSA using AHI. Statistical significance was set at P<0.01. Lateral pharyngeal wall collapse from dynamic sleep MRI (β=51.8, P<0.001) and upper airway length from static MRI images (β=27.2, P<0.001) positively correlated with severity of OSA. Lateral pharyngeal wall collapse and upper airway length are significantly associated with severe OSA based on sleep MRI. Assessment of these markers can be readily translated to routine clinical practice, and their identification may direct targeted surgical treatment.

Erratum to: Analysis of pediatric airway morphology using statistical shape modeling.

Erratum to: Analysis of pediatric airway morphology using statistical shape modeling.

Computed Tomographic Airway Morphology in Chronic Obstructive Pulmonary Disease. Remodeling or Innate Anatomy?

Computed tomographic measures of central airway morphology have been used in clinical, epidemiologic, and genetic investigation as an inference of the presence and severity of small-airway disease in smokers. Although several association studies have brought us to believe that these computed tomographic measures reflect airway remodeling, a careful review of such data and more recent evidence may reveal underappreciated complexity to these measures and limitations that prompt us to question that belief. This Perspective offers a review of seminal papers and alternative explanations of their data in the light of more recent evidence. The relationships between airway morphology and lung function are observed in subjects who never smoked, implying that native airway structure indeed contributes to lung function; computed tomographic measures of central airways such as wall area, lumen area, and total bronchial area are smaller in smokers with chronic obstructive pulmonary disease versus those without chronic obstructive pulmonary disease; and the airways are smaller as disease severity increases. The observations suggest that (1) native airway morphology likely contributes to the relationships between computed tomographic measures of airways and lung function; and (2) the presence of smaller airways in those with chronic obstructive pulmonary disease versus those without chronic obstructive pulmonary disease as well as their decrease with disease severity suggests that smokers with chronic obstructive pulmonary disease may simply have smaller airways to begin with, which put them at greater risk for the development of smoking-related disease.

Generation of Pig Airways using Rules Developed from the Measurements of Physical Airways.

A method for generating bronchial tree would be helpful when constructing models of the tree for benchtop experiments as well as for numerical modeling of flow or sound propagation in the airways. Early studies documented the geometric details of the human airways that were used to develop methods for generating human airway tree. However, methods for generating animal airway tree are scarcer. Earlier studies suggested that the morphology of animal airways can be significantly different from that of humans. Hence, using algorithms for the human airways may not be accurate in generating models of animal airway geometry. The objective of this study is to develop an algorithm for generating pig airway tree based on the geometric details extracted from the physical measurements. In the current study, measured values of branch diameters, lengths and bifurcation angles and rotation of bifurcating planes were used to develop an algorithm that is capable of generating a realistic pig airway tree. The generation relations between parent and daughter branches were found to follow certain trends. The diameters and the length of different branches were dependent on airway generations while the bifurcation angles were primarily dependent on bifurcation plane rotations. These relations were sufficient to develop rules for generating a model of the pig large airways. The results suggested that the airway tree generated from the algorithm can provide an approximate geometric model of pig airways for computational and benchtop studies.

Nasopharyngeal Dimensions From Computed Tomography of Pugs and French Bulldogs With Brachycephalic Airway Syndrome.

To describe the nasopharyngeal airway dimensions of two brachycephalic breeds and to localize the area of smallest airway dimensions. Prospective, descriptive, computed tomographic imaging study. Thirty pugs and 30 French bulldogs with brachycephalic upper airway syndrome. The thickness and length of the soft palate, cross-sectional area of the airway passage dorsal to the soft and hard palates, and cross-sectional area of the frontal sinus were measured and normalized to each dog's skull index and body weight before statistical comparison between breeds. Nasopharyngeal turbinates and surrounding airway space, and a possible relationship between the canine tooth angulation and the severity of airway obstruction were assessed. Pugs had significantly smaller cross-sectional areas of the airway dorsal to the soft and hard palates than French bulldogs. In both breeds, the smallest nasopharyngeal cross-sectional areas were located dorsal to the caudal end of the soft palate. The soft palate of pugs was significantly shorter than that of French bulldogs and also significantly thinner when normalized to each dog's skull index. Pugs more commonly exhibited nasopharyngeal turbinates. Pugs had significantly smaller air-filled cavities at the location of the frontal sinus. No correlation between the nasopharyngeal dimensions and canine tooth angulation was observed. Computed tomographic assessment of the upper airway morphology showed the smallest nasopharyngeal cross-sectional areas were located dorsal to the caudal end of the soft palate in both breeds. Pugs had a smaller nasopharyngeal cross-sectional area despite smaller soft palate dimensions than French bulldogs.

Volumes of Velopharyngeal and Glossopharyngeal Airway Were Not Changed after Uvulopalatopharyngoplasty: Report of Three Cases.

Objective. The aim of this study was to investigate the changes in velopharyngeal and glossopharyngeal airway morphology and volume after uvulopalatopharyngoplasty in three adult obstructive sleep apnea syndrome patients who had bilateral large tonsils using three-dimensional computed tomography. Case Report. All three patients (one male and two females) who presented with a history of heavy snoring and excessive daytime sleepiness were examined with overnight nocturnal polysomnography, which indicated moderate-to-severe obstructive sleep apnea syndrome. Because all patients had large tonsils, uvulopalatopharyngoplasty was expected to enlarge the pharyngeal airway. Polysomnography and three-dimensional computed tomography scanning were performed and compared, both before and 3 months after uvulopalatopharyngoplasty. Results. Unexpectedly, although the morphology of the glossopharyngeal airway clearly changed after UPPP, the volume changes in the velopharyngeal and glossopharyngeal airways were negligible.

Relationship between malocclusion, soft tissue profile, and pharyngeal airways: A cephalometric study

Background and objectiveThe recent years have been marked by a search for new interrelations between the respiratory function and the risk of the development of malocclusions, and algorithms of early diagnostics and treatment have been developed. The aim of the study was to evaluate the relationships between hard and soft tissues and upper airway morphology in patients with normal sagittal occlusion and Angle Class II malocclusion according to gender. Materials and methodsAfter the evaluation of clinical and radiological data, 114 pre-orthodontic patients with normal or increased ANB angle, were randomly selected for the study. The cephalometric analysis was done by using the Dolphin Imaging 11.8 computer software. ResultsComparison of the cephalometric values of soft tissue and airway measurements performed statistically significant negative correlation between the width of the upper pharynx and the ANB angle was found: the ANB angle was decreasing with an increasing width of the upper pharynx. The airways showed a statistically significant negative correlation between the width of the lower pharynx and the distance from the upper and the lower lips to the E line. Logistic regression analysis was performed to evaluate significant factors that could predict airway constriction. The upper pharynx was influenced by the following risk factors: a decrease in the SNB angle, an increase in the nose tip angle, and younger age; while the lower pharynx was influenced by an increase in the distance between the upper lip and the E line and by an increase in the upper lip thickness. ConclusionsDuring critical period of growth and development of the maxillofacial system, the patients with oral functional disturbances should be monitored and treated by a multidisciplinary team consisting of a dentist, an orthodontist, a pediatrician, an ENT specialist, and an allergologist. Cephalometric analysis applied in our study showed that Angle Class II patients with significantly decreased facial convexity angle, increased nasomental, upper lip-chin, and lower lip-chin angles, and upper and lower lips located more proximally to the E line more frequently had constricted airways.

The revolution of overground respiratory video-endoscopy in exercising horses

The revolution of overground respiratory video-endoscopy in exercising horses

骨格性開咬患者における顎矯正手術前後の舌骨位置と気道形態の変化について

骨格性開咬患者における顎矯正手術前後の舌骨位置と気道形態の変化について

Analysis of pediatric airway morphology using statistical shape modeling.

Traditional studies of airway morphology typically focus on individual measurements or relatively simple lumped summary statistics. The purpose of this work was to use statistical shape modeling (SSM) to synthesize a skeleton model of the large bronchi of the pediatric airway tree and to test for overall airway shape differences between two populations. Airway tree anatomy was segmented from volumetric chest computed tomography of 20 control subjects and 20 subjects with cystic fibrosis (CF). Airway centerlines, particularly bifurcation points, provide landmarks for SSM. Multivariate linear and logistic regression was used to examine the relationships between airway shape variation, subject size, and disease state. Leave-one-out cross-validation was performed to test the ability to detect shape differences between control and CF groups. Simulation experiments, using tree shapes with known size and shape variations, were performed as a technical validation. Models were successfully created using SSM methods. Simulations demonstrated that the analysis process can detect shape differences between groups. In clinical data, CF status was discriminated with good accuracy (precision=0.7, recall=0.7) in leave-one-out cross-validation. Logistic regression modeling using all subjects showed a good fit (ROC AUC=0.85) and revealed significant differences in SSM parameters between control and CF groups. The largest mode of shape variation was highly correlated with subject size (R=0.95, p<0.001). SSM methodology can be applied to identify shape differences in the airway between two populations. This method suggests that subtle shape differences exist between the CF airway and disease control.

The nasal septum deviation index (NSDI) based on CBCT data

To assess whether three-dimensional morphometric parameters could be useful in nasal septal deviation (NSD) diagnosis and, secondarily, whether CBCT could be considered an adequate imaging technique for the proposed task. We analysed images of 46 subjects who underwent CBCT for reasons not related to this study. Two experienced operators divided all the images into healthy and NSD subjects. Subsequently, the images were segmented using ITK Snap in order to obtain the three-dimensional model of the nasal airways and compute four morphological parameters: septal deviation angle (SDA), percentage of volume difference between right and left side of the nasal airways, nasal airway total volume and a new synthetic septal deviation index (SDI). Principal component analysis (PCA) was used to unveil relationships between each variable and the global nasal airway variability. Differences between the groups were found in SDA (p < 0.001), in volume percentage difference (p < 0.05) and in SDI (p < 0.001). PCA showed high correlation between the SDI and the first principal component (0.97, p < 0.001). Among the analysed parameters, SDI seemed to be the most suitable for the quantitative assessment of NSD, and CBCT allowed accurate assessment of airway morphology.