What are ventilation defects in asthma?

Svenningsen, Sarah; Kirby, Miranda; Starr, Danielle; Coxson, Harvey O.; Paterson, Nigel A. M.; McCormack, David G.; Párraga, Grace

doi:10.1136/thoraxjnl-2013-203711

Cited by 99 publications

(102 citation statements)

References 44 publications

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“…Although case misclassification may account for some of this group, it is unlikely to be the sole cause as four of these cases had asthma shown as the primary cause of death on their death certificate. Interestingly, the study by Svenningsen and co-workers 10 regional ventilation abnormalities were also absent in 35% of the asthma patients, and was associated with less airway hyperresponsiveness, inflammation and airway remodelling. It is possible that this may be related to sampling, or that in these cases, excessive airway narrowing may result from factors other than ASM remodelling, such as excessive production of mucus or altered contractile properties of the ASM.…”

Section: Discussionmentioning

confidence: 99%

“…The detection of airway remodelling (increased wall area and reduced luminal area) has been shown in asthma by using CT and MRI. 7,10,11 These studies, however, while showing evidence of regional remodelling are limited as they cannot determine structural differences that are present (e.g. increased ASM, mucous glands or reticular basement membrane thickness) and have difficulty measuring images beyond the 5th or 6th generation of airways.…”

Section: Discussionmentioning

confidence: 99%

“…7,8 Computed tomography (CT) scans have been used to investigate the structure-function relationships that exist between spirometry, airways inflammation and disease severity, 9 but are limited in their ability to visualize airways with diameters less than 2 mm. A recent study by Svenningsen et al, 10 using hyperpolarized 3 He magnetic resonance imaging (MRI), showed that 65% of asthma patients studied had regional ventilation defects. Compared with asthmatics without ventilation defects, this group had worse airway hyperresponsiveness, increased inflammation and airway remodelling.…”

Section: Introductionmentioning

confidence: 99%

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Distribution of airway smooth muscle remodelling in asthma: Relation to airway inflammation

et al. 2014

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Background and objective: Pathological phenotypes of asthma have been based predominantly on inflammation, rather than airway wall remodelling. Differences in the distribution of airway smooth muscle (ASM) remodelling between large and small airways may affect clinical outcomes in asthma. The aim of this study was to examine the distribution of ASM remodelling and its relation to airway inflammation. Methods: Post-mortem cases of asthma (n = 68) were categorized by the distribution of increased thickness of the ASM layer (relative to nonasthmatic controls, n = 37), into 'large only' (LO, n = 15), 'small only' (SO, n = 4) 'large/small' (LS, n = 24) or no increase (NI, n = 25). Subject characteristics, ASM and airway wall dimensions and inflammatory cell numbers were compared between groups. Results: Apart from reduced clinical severity of asthma in NI cases (P = 0.002), subject characteristics did not distinguish asthma groups. Compared with control subjects, ASM cell number, reticular basement membrane thickness, airway wall thickness, percent muscle shortening and eosinophil number were increased (P < 0.05) in both large and small airways in LS cases and only the large airways in LO cases. Increased numbers of neutrophils were observed only in the small airways of LO cases. Conclusions: Distinct distributions of ASM remodelling are seen in asthma. Pathology limited to the small airways was uncommon. Increased thickness of the ASM layer was associated with airway remodelling and eosinophilia, but not neutrophilia. These data support the presence of distinct pathological phenotypes based on the site of increased ASM.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Distribution of airway smooth muscle remodelling in asthma: Relation to airway inflammation

et al. 2014

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“…Evaluating the fraction of lung volume containing ventilation defects is an established method of evaluating overall lung ventilation (33)(34)(35)(36)(37). Lung defect calculations-total and segmental defect percentages-were performed by evaluating the percentage of voxels whose signal intensity was below a threshold of 60% of the total lung mean signal intensity.…”

Section: Defect Analysismentioning

confidence: 99%

Regional Ventilation Changes in Severe Asthma after Bronchial Thermoplasty with³He MR Imaging and CT

Thomen¹,

Sheshadri²,

Quirk³

et al. 2015

Radiology

121

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).q RSNA, 2014 Purpose:To quantify regional lung ventilation in healthy volunteers and patients with severe asthma (both before and after thermoplasty) by using a combination of helium 3 ( 3 He) magnetic resonance (MR) imaging and computed tomography (CT), with the intention of developing more effective image-guided treatments for obstructive lung diseases. Materials andMethods:With approval of the local institutional review board, informed consent, and an Investigational New Drug Exemption, six healthy volunteers and 10 patients with severe asthma were imaged in compliance with HIPAA regulations by using both multidetector CT and 3He MR imaging. Individual bronchopulmonary segments were labeled voxel by voxel from the CT images and then registered to the Results:Ventilation measures for healthy volunteers yielded smaller segment-to-segment variation (mean SVP, 100% 6 18 [standard deviation]) than did the measures for patients with severe asthma (mean SVP, 97% 6 23). Patients with asthma also demonstrated larger segmental defect percentages (median, 13.5%; interquartile range, 8.9%-17.8%) than healthy volunteers (median, 6%; interquartile range, 5.6%-6.3%). These quantitative results confirm what is visually observed on the 3 He images. A Spearman correlation of r = 20.82 was found between the change in whole-lung defect percentage and the number of days between final treatment and second 3 He imaging. Conclusion:Regional quantification of lung ventilation is indeed feasible and may be a useful technique for image-guided treatment of obstructive lung diseases, such as bronchial thermoplasty for severe asthma. In these patients, ventilation defects decreased as a function of time after treatment.q RSNA, 2014

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“…Hyperpolarized 3 He magnetic resonance imaging (MRI) ventilation heterogeneity has been shown in patients with pulmonary diseases such as COPD (4,5), asthma (6,7), and cystic fibrosis (8). At the same time, however, preclinical or subclinical 3 He ventilation heterogeneity has also been observed in volunteers without clinical signs or symptoms of lung disease such as healthy elderly never-smokers (9), ex-smokers without airflow limitation (10), in second-hand smoke exposed adults (11), and current-smokers without disease (12).…”

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Ventilation Heterogeneity in Ex-smokers without Airflow Limitation

et al. 2015

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What are ventilation defects in asthma?

Cited by 99 publications

References 44 publications

Distribution of airway smooth muscle remodelling in asthma: Relation to airway inflammation

Distribution of airway smooth muscle remodelling in asthma: Relation to airway inflammation

Regional Ventilation Changes in Severe Asthma after Bronchial Thermoplasty with³He MR Imaging and CT

Ventilation Heterogeneity in Ex-smokers without Airflow Limitation

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What are ventilation defects in asthma?

Cited by 99 publications

References 44 publications

Distribution of airway smooth muscle remodelling in asthma: Relation to airway inflammation

Distribution of airway smooth muscle remodelling in asthma: Relation to airway inflammation

Regional Ventilation Changes in Severe Asthma after Bronchial Thermoplasty with3He MR Imaging and CT

Ventilation Heterogeneity in Ex-smokers without Airflow Limitation

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Regional Ventilation Changes in Severe Asthma after Bronchial Thermoplasty with³He MR Imaging and CT