Measurement of total lung aerosol deposition as an index of lung abnormality

1988 ◽  
Vol 64 (4) ◽  
pp. 1527-1536 ◽  
Author(s):  
C. S. Kim ◽  
G. A. Lewars ◽  
M. A. Sackner
Keyword(s):  
Pulmonary Function Tests ◽  
Aerosol Deposition ◽  
Airway Disease ◽  
Forced Expiratory Volume ◽  
Chronic Obstructive ◽  
Small Airway Disease ◽  
Patient Screening ◽  
Chart Recorder ◽  
Strong Linear Correlation ◽  
Relationship Of

Total aerosol deposition in the lung was measured in 100 subjects with various lung conditions. The subjects consisted of 40 normals (N), 15 asymptomatic smokers (S), 10 smokers with small airway disease (SAD), 20 with chronic simple bronchitis (SB), and 15 with chronic obstructive bronchitis (COPD), and a relationship of total aerosol deposition to degree of lung abnormality was investigated. The subjects were categorized by medical history and a battery of pulmonary function tests, including spirometry, body plethysmography, and single and multiple N2 washout measurements. Subjects repeatedly breathed a monodisperse test aerosol (1.0 micron diam) from a collapsible rebreathing bag (0.5 liter volume) at a rate of 30 breaths/min, while inhaled and exhaled aerosol concentrations were continuously monitored by a laser aerosol photometer in situ and recorded on a strip-chart recorder. The number of rebreathing breaths resulting in 90% aerosol loss from the bag (N90) was determined, and percent predicted N90 values were then determined from the results of computer simulation and used as a deposition index. The percent predicted N90 values were 99.7 +/- 14, 86.5 +/- 15, 66.9 +/- 17, 51 +/- 12, and 30.9 +/- 9, respectively, for N, S, SAD, SB, and COPD. All of these values were significantly different from each other (P less than 0.05). There was no difference between male and female but percent predicted N90 values were slightly higher in young than in old normals. Percent predicted N90 values showed a strong linear correlation with spirometric measurements of forced expiratory volume in 1 s and maximum midexpiratory flow rate. However, many of the SAD and SB with normal spirometry showed abnormal N90. These results suggest that total lung aerosol deposition is a sensitive index of lung abnormality and may be of potential use for nonspecific general patient screening.

scholarly journals A 3D-CNN model with CT-based parametric response mapping for classifying COPD subjects

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Thao Thi Ho ◽  
Taewoo Kim ◽  
Woo Jin Kim ◽  
Chang Hyun Lee ◽  
Kum Ju Chae ◽  
...  
Keyword(s):  
Neural Network ◽  
Pulmonary Function Tests ◽  
Airway Disease ◽  
Chronic Obstructive ◽  
Respiratory Disorder ◽  
Obstructive Pulmonary Disease ◽  
Response Mapping ◽  
Small Airway Disease ◽  
3D Cnn ◽  
Parametric Response

AbstractChronic obstructive pulmonary disease (COPD) is a respiratory disorder involving abnormalities of lung parenchymal morphology with different severities. COPD is assessed by pulmonary-function tests and computed tomography-based approaches. We introduce a new classification method for COPD grouping based on deep learning and a parametric-response mapping (PRM) method. We extracted parenchymal functional variables of functional small airway disease percentage (fSAD%) and emphysema percentage (Emph%) with an image registration technique, being provided as input parameters of 3D convolutional neural network (CNN). The integrated 3D-CNN and PRM (3D-cPRM) achieved a classification accuracy of 89.3% and a sensitivity of 88.3% in five-fold cross-validation. The prediction accuracy of the proposed 3D-cPRM exceeded those of the 2D model and traditional 3D CNNs with the same neural network, and was comparable to that of 2D pretrained PRM models. We then applied a gradient-weighted class activation mapping (Grad-CAM) that highlights the key features in the CNN learning process. Most of the class-discriminative regions appeared in the upper and middle lobes of the lung, consistent with the regions of elevated fSAD% and Emph% in COPD subjects. The 3D-cPRM successfully represented the parenchymal abnormalities in COPD and matched the CT-based diagnosis of COPD.

Quantitative CT Image-Based Structural and Functional Changes during Asthma Acute Exacerbations

2021 ◽  
Author(s):  
Joonwoo Park ◽  
Sujeong Kim ◽  
Jae-Kwang Lim ◽  
Kwang Nam Jin ◽  
Min Suk Yang ◽  
...  
Keyword(s):  
Pulmonary Function Tests ◽  
Quantitative Computed Tomography ◽  
Airway Disease ◽  
Forced Expiratory Volume ◽  
Imaging Features ◽  
Quantitative Ct ◽  
Functional Changes ◽  
Small Airway Disease ◽  
Acute Exacerbations ◽  
Residual Capacity

Asthma acute exacerbations (AE) have been investigated using quantitative computed tomography (QCT)-based imaging metrics, but QCT has not yet been used to investigate a comprehensive set of imaging metrics during AE. This study aims to explore imaging features, captured both at segmental and parenchymal scales, during asthma AE, compared to stable asthma (SA). Two sets of the QCT images at total lung capacity (TLC) and functional residual capacity (FRC) were captured for 14 subjects during asthma AE and in SA phase, respectively. We calculated airway wall thickness (WT), hydraulic diameter (Dh), and airway circularity (Cr) of the 36 segmental airways, percentage of functional small airway disease (fSAD%), percentage of emphysema, tissue fraction (βtiss), and coefficient of variation of βtiss (CV of βtiss). We performed Spearman correlation tests for changes in QCT metrics and pulmonary function tests, measured in AE and SA. During asthma AE, structural metrics, i.e., WT, Dh, and Cr, were not changed significantly. In functional metrics, CV of βtiss at FRC indicating the heterogeneity of lung tissue distribution was significantly increased, while the mean of βtiss at FRC did not change during AE. An increase of fSAD% during AE was most correlated with a decrease of forced expiratory volume in 1 second and forced vital capacity, especially in the lower lobes. This study demonstrates that the heterogeneous feature of βtiss measured at lower lobes is more noticeable during asthma AE, compared with other traditional imaging metrics. This metric could be utilized to identify unique features during asthma AE.

Physical Signs in Childhood Asthma

PEDIATRICS ◽  
1976 ◽  
Vol 58 (4) ◽  
pp. 537-541
Author(s):  
J. O. O. Commey ◽  
Henry Levison
Keyword(s):  
Pulmonary Function ◽  
Airway Obstruction ◽  
Pulmonary Function Tests ◽  
Severe Disease ◽  
Airway Disease ◽  
Chronic Obstructive ◽  
Scalene Muscle ◽  
Lung Capacity ◽  
Residual Capacity ◽  
Severe Airway Obstruction

In 62 children with bronchial asthma, the presence of subjective dyspnea and wheeze, and some physical signs commonly associated with chronic obstructive airway disease in older patients, were compared with results of routine pulmonary function tests. Overall, airway resistance and the relationships of residual volume and functional residual capacity to total lung capacity were increased and other measurements of pulmonary function were moderately decreased. The time-honored subjective dyspnea, wheeze, rhonchi, and prolonged expiration were least useful as indices of severity of disease. Most of the patients, particularly those in whom laboratory testing revealed marked impairment, had notable rhonchi, prolonged expiration, scalene muscle and sternocleidomastoid contraction, and supraclavicular indrawing. Only sternocleidomastoid contraction and supraclavicular indrawing clearly correlated with the severity of airway obstruction. A call is made for a search for these useful signs, whose presence may be the only clue to moderately severe disease; however, their absence does not guarantee absence of severe airway obstruction.

scholarly journals Does the nitrogen single-breath washout test contribute to detecting pulmonary involvement in rheumatoid arthritis? A pilot study

2019 ◽  
Vol 12 (1) ◽  
Author(s):  
Elizabeth Jauhar Cardoso Bessa ◽  
Felipe de Miranda Carbonieri Ribeiro ◽  
Geraldo da Rocha Castelar Pinheiro ◽  
Agnaldo José Lopes
Keyword(s):  
Rheumatoid Arthritis ◽  
Pulmonary Function Tests ◽  
Airway Disease ◽  
Pulmonary Involvement ◽  
Phase Iii ◽  
Ventilation Distribution ◽  
Lung Capacity ◽  
Single Breath ◽  
Small Airway Disease ◽  
Phase Iii Slope

Abstract Objective There has been growing interest in studying small airway disease through measures of ventilation distribution, thanks to the resurgence of the nitrogen single-breath washout (N2SBW) test. Therefore, this study evaluated the contribution of the N2SBW test to the detection of pulmonary involvement in patients with rheumatoid arthritis (RA). Results Twenty-one patients with RA underwent clinical evaluation, pulmonary function tests (PFTs), including the N2SBW test, and computed tomography (CT). The main tomographic findings were air trapping and bronchiectasis (57.1% and 23.8% of cases, respectively). According to the phase III slope of the N2SBW (phase III slope), 11 and 10 patients had values < 120% predicted and > 120% predicted, respectively. Five patients with limited involvement on CT had a phase III slope > 120%. The residual volume/total lung capacity ratio was significantly different between patients with phase III slopes < 120% and > 120% (P = 0.024). Additionally, rheumatoid factor positivity was higher in patients with a phase III slope > 120% (P = 0.021). In patients with RA and airway disease on CT, the N2SBW test detects inhomogeneity in the ventilation distribution in approximately half of the cases, even in those with normal conventional PFT results.

Validation of Forced Expiratory Volume at 6 Seconds of Exhalation (FEV 6 ) in the Detection of Small Airway Disease

CHEST Journal ◽  
2015 ◽  
Vol 148 (4) ◽  
pp. 894A
Author(s):  
Edgardo Tiglao ◽  
Teresita DeGuia ◽  
Maria Encarnita Limpin ◽  
Aileen Guzman-Banzon
Keyword(s):  
Airway Disease ◽  
Forced Expiratory Volume ◽  
Small Airway ◽  
Small Airway Disease

scholarly journals The Diagnostic Value of Forced Expiratory Time

2011 ◽  
Vol 1 (1) ◽  
pp. 39-42
Author(s):  
Siraj O. Wali
Keyword(s):  
Tertiary Care ◽  
Airway Disease ◽  
Diagnostic Value ◽  
Forced Expiratory Volume ◽  
Small Airway ◽  
Airflow Limitation ◽  
Forced Expiration ◽  
Care Hospital ◽  
Expiratory Time ◽  
Small Airway Disease

Objective: Airway obstruction can be clinically quantified at the bedside by measuring the time taken for forced expiration. The aim of this study was to examine the accuracy of the forced expiratory time in detecting airflow limitation, and small airway disease when compared with simple spirometry as a gold standard test. Method: Simple spirometry and forced expiratory time were performed on 201 subjects (age range; 12-81 years), referred to a pulmonary function laboratory at a tertiary care hospital. The diagnostic accuracy of forced expiratory time and its correlation with spirometric parameters were tested. Forced expiratory time > 6 seconds was regarded as abnormal, and the ratio of forced expiratory volume in the first second to forced vital capacity of < 70% was considered indicative of an airflow limitation. Results: Forced expiratory time was found to correlate weakly with spirometric parameters. Forced expiratory time at a cut-off value of => 6 seconds had a sensitivity of 61% and a specificity of 79% in predicting obstructive airway disease when compared with simple spirometry. On the other hand, the sensitivity and the specificity of forced expiratory time in predicting small airway disease were 47% and 86%, respectively. Conclusion: Forced expiratory time does not correlate well with all parameters of a simple spirometry. Its sensitivity and specificity for detecting airflow limitation and small airway disease were not high enough to be used as a diagnostic test. However, it may be effective enough to be utilized to confirm the diagnosis of small airway disease.

scholarly journals Pulmonary Emphysema Regional Distribution and Extent Assessed by Chest Computed Tomography Is Associated With Pulmonary Function Impairment in Patients With COPD

2021 ◽  
Vol 8 ◽  
Author(s):  
Plácido Gomes ◽  
Hélder Novais e Bastos ◽  
André Carvalho ◽  
André Lobo ◽  
Alan Guimarães ◽  
...  
Keyword(s):  
Pulmonary Function ◽  
Lung Volume ◽  
Pulmonary Emphysema ◽  
Regional Distribution ◽  
Airway Disease ◽  
Forced Expiratory Volume ◽  
Chronic Obstructive ◽  
Total Lung Volume ◽  
Emphysema Severity ◽  
Function Impairment

Objective: This study aimed to evaluate how emphysema extent and its regional distribution quantified by chest CT are associated with clinical and functional severity in patients with chronic obstructive pulmonary disease (COPD).Methods/Design: Patients with a post-bronchodilator forced expiratory volume in one second (FEV1)/forced vital capacity (FVC) &lt; 0.70, without any other obstructive airway disease, who presented radiological evidence of emphysema on visual CT inspection were retrospectively enrolled. A Quantitative Lung Imaging (QUALI) system automatically quantified the volume of pulmonary emphysema and adjusted this volume to the measured (EmphCTLV) or predicted total lung volume (TLV) (EmphPLV) and assessed its regional distribution based on an artificial neural network (ANN) trained for this purpose. Additionally, the percentage of lung volume occupied by low-attenuation areas (LAA) was computed by dividing the total volume of regions with attenuation lower or equal to −950 Hounsfield units (HU) by the predicted [LAA (%PLV)] or measured CT lung volume [LAA (%CTLV)]. The LAA was then compared with the QUALI emphysema estimations. The association between emphysema extension and its regional distribution with pulmonary function impairment was then assessed.Results: In this study, 86 patients fulfilled the inclusion criteria. Both EmphCTLV and EmphPLV were significantly lower than the LAA indices independently of emphysema severity. CT-derived TLV significantly increased with emphysema severity (from 6,143 ± 1,295 up to 7,659 ± 1,264 ml from mild to very severe emphysema, p &lt; 0.005) and thus, both EmphCTLV and LAA significantly underestimated emphysema extent when compared with those values adjusted to the predicted lung volume. All CT-derived emphysema indices presented moderate to strong correlations with residual volume (RV) (with correlations ranging from 0.61 to 0.66), total lung capacity (TLC) (from 0.51 to 0.59), and FEV1 (~0.6) and diffusing capacity for carbon monoxide DLCO (~0.6). The values of FEV1 and DLCO were significantly lower, and RV (p &lt; 0.001) and TLC (p &lt; 0.001) were significantly higher with the increasing emphysema extent and when emphysematous areas homogeneously affected the lungs.Conclusions: Emphysema volume must be referred to the predicted and not to the measured lung volume when assessing the CT-derived emphysema extension. Pulmonary function impairment was greater in patients with higher emphysema volumes and with a more homogeneous emphysema distribution. Further studies are still necessary to assess the significance of CTpLV in the clinical and research fields.

scholarly journals Treatable traits in an English cohort: Prevalence and predictors of future decline in lung function and quality of life in COPD

2021 ◽  
pp. 00934-2020
Author(s):  
Muhammad Rehan Sarwar ◽  
Vanessa Marie McDonald ◽  
Michael John Abramson ◽  
Eldho Paul ◽  
Johnson George
Keyword(s):  
Quality Of Life ◽  
Lung Function ◽  
Precision Medicine ◽  
Airway Disease ◽  
Forced Expiratory Volume ◽  
Chronic Obstructive ◽  
Obstructive Pulmonary Disease ◽  
Lifestyle Risk Factors ◽  
The Core

Background“Treatable traits (TTs)” is a precision medicine approach for facilitating multidimensional assessment of every patient with chronic airway disease to determine the core traits associated with disease outcomes, where targeted treatments are applied.ObjectivesTo determine the prevalence of TTs in chronic obstructive pulmonary disease (COPD) and which traits predict future decline in lung function and quality of life (QoL).MethodsA 4 year longitudinal evaluation was conducted using data from 3726 participants in the English Longitudinal Study of Ageing (ELSA). TTs were identified based on published recommendations. Traits that predicted decline in lung function and QoL were analysed using generalised estimating equations.ResultsOverall, 21 TTs, including pulmonary (n=5), extra-pulmonary (n=13) and behavioural/lifestyle risk-factors (n=3) were identified. In multivariate analyses, traits of chronic bronchitis (β=−0.186; 95%CI=−0.290 to −0.082), breathlessness (β=−0.093; 95%CI=−0.164 to −0.022), underweight (β=−0.216; 95%CI=−0.373 to −0.058), sarcopaenia (β=−0.162; 95%CI=−0.262 to −0.061), and current smoking (β=−0.228; 95%CI=−0.304 to −0.153), predicted decline in forced expiratory volume in 1 s (FEV1). Of the seven traits that predicted decline in QoL, depression (β=−7.19; 95%CI=−8.81 to −5.57) and poor family and social support (β=−5.12; 95%CI=−6.65 to −3.59) were the strongest.ConclusionThe core TTs of COPD associated with a decline in lung function and QoL were identified. Targeting these impactful traits and individualised treatment using a precision medicine approach may improve outcomes in people with COPD.

scholarly journals The Diagnostic Value of Forced Expiratory Time

2011 ◽  
Vol 1 (1) ◽  
pp. 39-42
Author(s):  
Siraj O. Wali
Keyword(s):  
Tertiary Care ◽  
Airway Disease ◽  
Diagnostic Value ◽  
Forced Expiratory Volume ◽  
Small Airway ◽  
Airflow Limitation ◽  
Forced Expiration ◽  
Care Hospital ◽  
Expiratory Time ◽  
Small Airway Disease

Objective: Airway obstruction can be clinically quantified at the bedside by measuring the time taken for forced expiration. The aim of this study was to examine the accuracy of the forced expiratory time in detecting airflow limitation, and small airway disease when compared with simple spirometry as a gold standard test. Method: Simple spirometry and forced expiratory time were performed on 201 subjects (age range; 12-81 years), referred to a pulmonary function laboratory at a tertiary care hospital. The diagnostic accuracy of forced expiratory time and its correlation with spirometric parameters were tested. Forced expiratory time > 6 seconds was regarded as abnormal, and the ratio of forced expiratory volume in the first second to forced vital capacity of < 70% was considered indicative of an airflow limitation. Results: Forced expiratory time was found to correlate weakly with spirometric parameters. Forced expiratory time at a cut-off value of => 6 seconds had a sensitivity of 61% and a specificity of 79% in predicting obstructive airway disease when compared with simple spirometry. On the other hand, the sensitivity and the specificity of forced expiratory time in predicting small airway disease were 47% and 86%, respectively. Conclusion: Forced expiratory time does not correlate well with all parameters of a simple spirometry. Its sensitivity and specificity for detecting airflow limitation and small airway disease were not high enough to be used as a diagnostic test. However, it may be effective enough to be utilized to confirm the diagnosis of small airway disease.

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