Computer quantification of airway collapse on forced expiration to predict the presence of emphysema.
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ABSTRACT:
SUBMITTER: Topalovic M
PROVIDER: S-EPMC3870969 | biostudies-literature | 2013 Nov
REPOSITORIES: biostudies-literature
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Project description:RATIONALE:Expiratory central airway collapse is associated with respiratory morbidity independent of underlying lung disease. However, not all smokers develop expiratory central airway collapse, and the etiology of expiratory central airway collapse in adult smokers is unclear. Paraseptal emphysema in the paratracheal location, by untethering airway walls, may predispose smokers to developing expiratory central airway collapse. OBJECTIVES:To evaluate whether paratracheal paraseptal emphysema is associated with expiratory central airway collapse. METHODS:We analyzed paired inspiratory and expiratory computed tomography scans from participants enrolled in a multicenter study (Genetic Epidemiology of Chronic Obstructive Pulmonary Disease) of smokers aged 45 to 80 years. Expiratory central airway collapse was defined as greater than or equal to 50% reduction in cross-sectional area of the trachea during expiration. In a nested case-control design, participants with and without expiratory central airway collapse were included in a 1:2 fashion, and inspiratory scans were further analyzed using the Fleischner Society criteria for presence of centrilobular emphysema, paraseptal emphysema, airway wall thickening, and paratracheal paraseptal emphysema (maximal diameter???0.5 cm). RESULTS:A total of 1,320 patients were included, 440 with and 880 without expiratory central airway collapse. Those with expiratory central airway collapse were older, had higher body mass index, and were less likely to be men or current smokers. Paratracheal paraseptal emphysema was more frequent in those with expiratory central airway collapse than control subjects (16.6 vs. 11.8%; P?=?0.016), and after adjustment for age, race, sex, body mass index, smoking pack-years, and forced expiratory volume in 1 second, paratracheal paraseptal emphysema was independently associated with expiratory central airway collapse (adjusted odds ratio, 1.53; 95% confidence interval, 1.18-1.98; P?=?0.001). Furthermore, increasing size of paratracheal paraseptal emphysema (maximal diameter of at least 1 cm and 1.5 cm) was associated with greater odds of expiratory central airway collapse (adjusted odds ratio, 1.63; 95% confidence interval, 1.18-2.25; P?=?0.003 and 1.77; 95% confidence interval, 1.19-2.64; P?=?0.005, respectively). CONCLUSIONS:Paraseptal emphysema adjacent to the trachea is associated with expiratory central airway collapse. The identification of this risk factor on inspiratory scans should prompt further evaluation for expiratory central airway collapse. Clinical trial registered with ClinicalTrials.gov (NCT 00608764).
| S-EPMC5879141 | biostudies-literature
Project description:A recent estimate for the normal range of forced expiratory tracheal collapse differs substantially from that in an earlier study performed with comparable measurement methods. Given differences in subject characteristics between the two samples, we hypothesized that these discrepant findings may reflect a heretofore unrecognized association between forced expiratory tracheal collapse and age or sex.We enrolled 40 female and 41 male healthy volunteers between 25 and 75 years of age who were without respiratory symptoms or known risk factors for tracheomalacia. Subjects underwent low-dose CT scanning at total lung capacity (TLC) and during forced exhalation (Expdyn) with spirometric monitoring and coaching. Percentage forced expiratory collapse was regressed on age for the total sample and separately within sex.Mean tracheal cross-sectional area (CSA) was 2.54 cm(2) ± 0.57 cm(2) at TLC and 1.15 cm(2) ± 0.53 cm(2) at Expdyn. Mean percentage forced expiratory collapse (%collapse) was 54% ± 20%. Men aged 24 to 31 years (n = 12) had mean %collapse of 36% ± 19%, comparable to results previously reported for similarly aged men (35% ± 18%). Men, but not women, showed a significant positive correlation (R(2) = 0.40, P < .001) between %collapse and age. Older men had both greater CSA at TLC (P = .02) and smaller CSA at Expdyn (P = .001) than younger men.Men exhibit positive age dependence of forced expiratory tracheal collapse. The influence of age and sex on forced expiratory tracheal collapse should be considered in the diagnostic evaluation of expiratory dynamic airway collapse and/or tracheomalacia.
| S-EPMC3418856 | biostudies-other
Project description:Intrapleural pressure during a forced vital capacity (VC) maneuver is often in excess of that required to generate maximal expiratory airflow. This excess pressure compresses alveolar gas (i.e., thoracic gas compression [TGC]), resulting in underestimated forced expiratory flows (FEFs) at a given lung volume. It is unknown if TGC is influenced by sex; however, because men have larger lungs and stronger respiratory muscles, we hypothesized that men would have greater TGC. We examined TGC across the "effort-dependent" region of VC in healthy young men (n = 11) and women (n = 12). Subjects performed VC maneuvers at varying efforts while airflow, volume, and esophageal pressure (POES ) were measured. Quasistatic expiratory deflation curves were used to obtain lung recoil (PLUNG ) and alveolar pressures (i.e., PALV = POES -PLUNG ). The raw maximal expiratory flow-volume (MEFVraw ) curve was obtained from the "maximum effort" VC maneuver. The TGC-corrected curve was obtained by constructing a "maximal perimeter" curve from all VC efforts (MEFVcorr ). TGC was examined via differences between curves in FEFs (?FEF), area under the expiratory curves (?AEX ), and estimated compressed gas volume (?VGC) across the VC range. Men displayed greater total ?AEX (5.4 ± 2.0 vs. 2.0 ± 1.5 L2 ·s-1 ; p < .001). ?FEF was greater in men at 25% of exhaled volume only (p < .05), whereas ?VGC was systematically greater in men across the entire VC (main effect; p < .05). PALV was also greater in men throughout forced expiration (p < .01). Taken together, these findings demonstrate that men display more TGC, occurring early in forced expiration, likely due to greater expiratory pressures throughout the forced VC maneuver.
| S-EPMC7090372 | biostudies-literature
Project description:BackgroundPulmonary function measurements are important when studying respiratory disease models. Both resistance and compliance have been used to assess lung function in mice. Yet, it is not always clear how these parameters relate to forced expiration (FE)-related parameters, most commonly used in humans. We aimed to characterize FE measurements in four well-established mouse models of lung diseases.MethodDetailed respiratory mechanics and FE measurements were assessed concurrently in Balb/c mice, using the forced oscillation and negative pressure-driven forced expiration techniques, respectively. Measurements were performed at baseline and following increasing methacholine challenges in control Balb/c mice as well as in four disease models: bleomycin-induced fibrosis, elastase-induced emphysema, LPS-induced acute lung injury and house dust mite-induced asthma.ResultsRespiratory mechanics parameters (airway resistance, tissue damping and tissue elastance) confirmed disease-specific phenotypes either at baseline or following methacholine challenge. Similarly, lung function defects could be detected in each disease model by at least one FE-related parameter (FEV0.1, FEF0.1, FVC, FEV0.1/FVC ratio and PEF) at baseline or during the methacholine provocation assay.ConclusionsFE-derived outcomes in four mouse disease models behaved similarly to changes found in human spirometry. Routine combined lung function assessments could increase the translational utility of mouse models.
| S-EPMC5477381 | biostudies-literature
Project description:PurposeTo assess forced expiratory tracheal collapsibility in healthy volunteers by using multidetector computed tomography and to compare the results with the current diagnostic criterion for tracheomalacia.Materials and methodsAn institutional review board approved this HIPAA-compliant study. After informed consent was obtained, 51 healthy volunteers (age range, 25-75 years) with normal spirometry results and no history of smoking or risk factors for tracheomalacia were prospectively studied. Volunteers were imaged with a 64-detector row scanner, with spirometric monitoring at total lung capacity and during forced exhalation, with 40 mAs, 120 kVp, and 0.625-mm detector collimation. Cross-sectional area and sagittal and coronal diameters of the trachea were measured 1 cm above the aortic arch and 1 cm above the carina. The percentage of expiratory collapse, the reduction in sagittal and coronal diameters, and the number of participants exceeding the current diagnostic criterion (>50% expiratory reduction in cross-sectional area) for tracheomalacia were calculated.ResultsThe final study population included 25 men and 26 women (mean age, 50 years). The mean percentage of expiratory reduction in tracheal lumen cross-sectional area was 54.34% +/- 18.6 (standard deviation) in the upper trachea and 56.14% +/- 19.3 in the lower trachea. Forty (78%) participants exceeded the current diagnostic criterion for tracheomalacia in the upper and/or lower trachea. Decreases in cross-sectional area of the upper and lower trachea correlated well with decreases in sagittal (r = 0.807 and 0.688, respectively) and coronal (r = 0.779 and 0.751, respectively) diameters (P < .001 for each correlation).ConclusionHealthy volunteers demonstrate a wide range of forced expiratory tracheal collapse, frequently exceeding the current diagnostic criterion for tracheomalacia.
| S-EPMC2797678 | biostudies-literature
Project description:There are multiple causes of dyspnea upon exertion in young, healthy patients to primarily include asthma and exercise-induced bronchospasm. Excessive dynamic airway collapse (EDAC) describes focal collapse of the trachea or main bronchi with maintained structural integrity of the cartilaginous rings. It is commonly associated with pulmonary disorders like bronchiectasis, chronic obstructive pulmonary disease and asthma. It is believed to result secondary to airway obstruction in these conditions. While uncommon in young, healthy adults, it has recently been found as a cause of dyspnea in this population. Inducible laryngeal obstruction (ILO) is an umbrella term that describes an induced, intermittent upper airway impediment. While ILO is found in 10% of young patients with exertional dyspnea, it is primarily inspiratory in nature due to paradoxical closure of the glottis or supraglottis. This report highlights the presentation of a United States Army soldier who after a deployment was given a diagnosis of asthma, later found to have ILO and was subsequently diagnosed with concurrent EDAC. We follow up with a literature review and discussion of symptomatology, diagnosis, exercise bronchoscopy, and treatment modalities for both EDAC and ILO.
| S-EPMC6446124 | biostudies-literature
Project description:BackgroundChronic obstructive pulmonary disease (COPD) and emphysema are common amongst patients with human immunodeficiency virus (HIV). We sought to determine the clinical factors that are associated with emphysema progression in HIV.Methods345 HIV-infected patients enrolled in an outpatient HIV metabolic clinic with ≥2 chest computed tomography scans made up the study cohort. Images were qualitatively scored for emphysema based on percentage involvement of the lung. Emphysema progression was defined as any increase in emphysema score over the study period. Univariate analyses of clinical, respiratory, and laboratory data, as well as multivariable logistic regression models, were performed to determine clinical features significantly associated with emphysema progression.Results17.4% of the cohort were emphysema progressors. Emphysema progression was most strongly associated with having a low baseline diffusion capacity of carbon monoxide (DLCO) and having combination centrilobular and paraseptal emphysema distribution. In adjusted models, the odds ratio (OR) for emphysema progression for every 10% increase in DLCO percent predicted was 0.58 (95% confidence interval [CI] 0.41-0.81). The equivalent OR (95% CI) for centrilobular and paraseptal emphysema distribution was 10.60 (2.93-48.98). Together, these variables had an area under the curve (AUC) statistic of 0.85 for predicting emphysema progression. This was an improvement over the performance of spirometry (forced expiratory volume in 1 second to forced vital capacity ratio), which predicted emphysema progression with an AUC of only 0.65.ConclusionCombined paraseptal and centrilobular emphysema distribution and low DLCO could identify HIV patients who may experience emphysema progression.
| S-EPMC5130231 | biostudies-literature
Project description:PurposeA single institutions experience with various surgical options in the treatment of severe suprastomal collapse (SSC).MethodsThe study included 18 tracheostomized children with SSC treated between January 2012 and December 2018. Data included: patient demography, initial airway lesions, comorbidities, indication and age at tracheostomy, prior airway surgery, stomal demography, type of surgery, postoperative management, complications and treatment outcomes.ResultsFour techniques were used to correct SSC. The surgical choice was dependent on stoma demography and associated airway lesions. Excision was done in eight patients and rib cartilage augmentation in five. Three patients had single stage tracheal resection and anastomosis. Two patients received stomal rigidification and temporary placement of Montgomery T tube. Three patients with anterior rib graft augmentation required additional lateral tracheal wall rigidification. Three patients (two with cartilage augmentation, and one with stomal rigidification) developed minimal granulation tissue in the postoperative period. Complete SSC resolution was seen in all except two patients who had a partial response to the treatment. All patients were successful decannulated and are currently asymptomatic.ConclusionDecannulation failures may be due to severe suprastomal collapse that could be either unique or associated with obstructing laryngotracheal lesions. Therefore, it is essential to select the most appropriate surgical treatment to obtain overall favorable outcomes.
| S-EPMC7647974 | biostudies-literature
Project description:Rodent models of retinal angiogenesis play a pivotal role in angiogenesis research. These models are a window to developmental angiogenesis, to pathological retinopathy, and are also in vivo tools for anti-angiogenic drug screening in cancer and ophthalmic research. The mouse model of oxygen-induced retinopathy (OIR) has emerged as one of the leading in vivo models for these purposes. Many of the animal studies that laid the foundation for the recent breakthrough of anti-angiogenic treatments into clinical practice were performed in the OIR model. However, readouts from the OIR model have been time-consuming and can vary depending on user experience. Here, we present a computer-aided quantification method that is characterized by (i) significantly improved efficiency, (ii) high correlation with the established hand-measurement protocols, and (iii) high intra- and inter-individual reproducibility of results. This method greatly facilitates quantification of retinal angiogenesis while at the same time increasing lab-to-lab reproducibility of one of the most widely used in vivo models in angiogenesis research.
| S-EPMC4005267 | biostudies-literature
Project description:BackgroundTracheal obstruction resulting from expiratory tracheal deformation has been associated with respiratory symptoms and severe airway exacerbations. In chronic obstructive pulmonary disease (COPD), acute exacerbations (AECOPD) create large intrathoracic pressure swings which may increase tracheal deformation. Excessive central airway collapse (ECAC) may be diagnosed when the tracheal area on expiration is less than 50% of that on inspiration. The prevalence of ECAC in AECOPD and its temporal course have not been systematically studied.MethodsWe prospectively recruited healthy volunteers (n = 53), stable outpatients with COPD (n = 40) and patients with hospitalised acute exacerbations of COPD (AECOPD, n = 64). 17 of the AECOPD group returned for repeat evaluation when clinically well at 6-12 weeks. All subjects underwent dynamic 320-slice computed tomography of the larynx and trachea during tidal breathing, enabling quantitation of tracheal area and dimensions (mean ± SD).ResultsNo healthy individuals had ECAC. The prevalence of ECAC in stable COPD and AECOPD was 35% and 39% respectively. Mean tracheal collapse did not differ between stable COPD (57.5 ± 19.8%), AECOPD (53.8 ± 19.3%) and in the subset who returned when convalescent (54.9 ± 17.2%). AECOPD patients with and without ECAC had similar clinical characteristics.ConclusionsTracheal collapse in both stable and AECOPD is considerably more prevalent than in healthy individuals. ECAC warrants assessment as part of comprehensive COPD evaluation and management. Further studies should evaluate the aetiology of ECAC and whether it predisposes to exacerbations.
| S-EPMC5574204 | biostudies-literature