Aerosol-Derived Airway Morphometry and Aerosol Bolus Dispersion in Patients With Lung Fibrosis and Lung Emphysema

doi:10.1378/chest.116.2.543

Chest

Volume 116, Issue 2, August 1999, Pages 543-548

https://doi.org/10.1378/chest.116.2.543 Get rights and content

Objective

Patients with lung emphysema show increased aerosol-derived dimensions of peripheral airspaces and increased aerosol bolus dispersion (AD). To apply these tests in epidemiologic studies, the objective of this pilot study was to investigate whether morphometric changes caused by lung fibrosis can be distinguished from those caused by emphysema.

Design

This study was designed as a cross-sectional study in which airspace dimensions and AD in patients with emphysema and in patients with fibrosis were compared. Forty patients participated in the study: 20 patients had high-resolution CT (HRCT)-proved lung emphysema and 20 patients had HRCT-proved lung fibrosis. All patients underwent conventional lung function tests, aerosol-derived airway morphometry (ADAM), and AD measurements.

Results

Patients with lung emphysema showed normal dimensions of small airways but enlarged airspace dimensions in the lung periphery. Patients with fibrosis showed in all lung depths increased airspace dimensions. AD was increased in patients with emphysema but was normal in patients with fibrosis.

Conclusions

These results show that when using ADAM and AD, morphometric changes caused by emphysema can be distinguished from those caused by fibrosis with high sensitivity and specificity.

Section snippets

Subjects

Twenty patients with chronic interstitial pulmonary fibrosis (IPF; 13 men, 7 women) and 20 patients with pulmonary emphysema (PE; 13 men, 7 women) participated in the study (Table 1). Anamnestic data were evaluated by a questionnaire based on American Thoracic Society recommendations.¹² The smoking habits of the patients were quantified by using the cumulative cigarette consumption expressed as pack-years.

The diagnosis of chronic IPF was based on clinical, histologic, and radiographic (CT of

Results

Patients with IPF and PE showed no differences in anthropometric data (age, weight, height; Table 1).

In patients with IPF, lung volumes VC and TLC were mild to moderately reduced. RV was relatively well preserved. Because 50% of the patients were current or former smokers, a moderate airflow obstruction with decreased FEV₁, MEF₂₅, and MEF₅₀ was observed. The Tlco was reduced.

Patients with PE showed chronic irreversible hyperinflation inferred from elevated levels of TLC and ITGV, clear signs of

Discussion

AD is increased in patients with PE, but is normal in patients with IPF. In both patient groups, ADAM showed increased airspace dimensions compared with the control group. However, the pattern of increased airspace dimensions was different between the two patient groups. Patients with PE showed normal EAD values in proximal lung depth. Inasmuch as this lung depth (Vp,r = 0.04) is, for the patients with PE, on average about 200 to 250 cm³, this likely represents the most peripheral parts of the

Conclusions

The presence of PE can be detected with ADAM and AD. IPF can be distinguished from PE by differences in AD and a different pattern of changes in ADAM. Therefore, in epidemiologic studies and in occupational medicine, both techniques seem to be useful for the detection of PE in humans. The specificity of the aerosol tests is not impaired by subjects with changes in lung morphometry caused by fibrosis. The practical value of these results should be confirmed by further prospective studies.

References (25)

T Beinert et al.
Peripheral airspace dimensions in patients with COPD
Chest
(1995)
FS Rosenthal
Aerosol recovery following breathholding derived from the distribution of chordlength in pulmonary tissue
J Aerosol Sci
(1989)
J Heyder et al.
The breathing of half-micron aerosols: III. Dispersion of particles in the respiratory tract
J Aerosol Sci
(1971)
A Nagai et al.
The National Institutes of Health Intermittent Positive-Pressure Breathing Trial: pathology studies; I. Interrelationship between morphologic lesions
Am Rev Respir Dis
(1985)
DA Schwartz et al.
The influence of cigarette smoking on lung function in patients with idiopathic pulmonary fibrosis
Am Rev Respir Dis
(1991)
JL Hankinson et al.
Pulmonary air space size in coal miners
Am Rev Respir Dis
(1979)
WD Bennett et al.
Use of aerosols to estimate mean air-space size in chronic obstructive pulmonary disease
J Appl Physiol
(1988)
FS Rosenthal et al.
Assessment of papain induced lung injury in isolated lungs by measurements of aerosol deposition and mixing
J Appl Physiol
(1992)
M Kohlha¨ufl et al.
Diagnosis of emphysema in patients with chronic bronchitis: a new approach
Eur Respir J
(1998)
FS Rosenthal
Aerosol deposition and dispersion characterize lung injury in a canine model of emphysema
J Appl Physiol
(1995)

M Kohlha¨ufl et al.

Detection of impaired intrapulmonary convective mixing by aerosol bolus dispersion in patients with emphysema

Eur J Med Res

(1997)

P Brand et al.

Aerosol derived airway morphometry in healthy subjects

Eur Respir J

(1995)

Cited by (17)

Monte-Carlo-Model for the Aerosol Bolus Dispersion in the Human Lung - Part 1: Theoretical Model Description and Application
2007, Zeitschrift fur Medizinische Physik
Die Aerosolbolusdispersion, welche in der Pneumologie aufgrund ihres möglichen Einsatzes als effizientes Werkzeug zur noninvasiven klinischen Diagnose der Lungenfunktion enormes Interesse erweckt hat, wurde mit Hilfe eines auf dem Konzept der effektiven Diffusivitäten beruhenden Monte-Carlo-Modells und unter Verwendung einer stochastischen Lungengeometrie simuliert. Die mathematische Näherung ermöglichte die Analyse essentieller Kenngrößen des exhalierten Bolus (Halbwertsbreite, Standardabweichung, Schiefe und Modusverschiebung) sowie die Abschätzung ihrer Abhängigkeit von der volumetrischen Lungentiefe (VLD) des inhalierten Bolus. Generell zeigen die Resultate des Bolusdispersionsmodells eine sehr gute Übereinstimmung mit bereits publizierten experimentellen Daten, wobei Halbwertsbreite und Standardabweichung des exhalierten Bolus nach spezifischen Funktionen mit der VLD zunehmen, Schiefe und Modusverschiebung jedoch gleichzeitig eine Abnahme zeigen. Während zwischen der Bolusdispersion und der Flussrate des inhalierten Luftstromes keine Korrelation mit dem Modell nachweisbar war, stieg die Dispersion linear mit der totalen Lungenkapazität (TLC) an.
Aerosol bolus dispersion, which has excited enormous interest in lung medicine due to its possible use as an efficient tool for the non-invasive clinical diagnosis of lung function, was simulated by a Monte Carlo model based on the concept of effective diffusivities and a stochastic lung geometry. The mathematical approach enabled the computation of essential characteristics of the exhaled bolus (half width, standard deviation, skewness, and mode shift) as well as the estimation of their dependence upon the volumetric lung depth (VLD) of the inhaled bolus. Results of the dispersion model generally show a very good correspondence with preliminary published experimental data. Half width and standard deviation of the exhaled bolus increase with VLD according to specific functions, whereas skewness and mode shift are subject to a decrease. While no correlation between bolus dispersion and flow rate could be worked out with the model, dispersion linearly increased with total lung capacity (TLC).
Chapter 12 Applications
2005, Interface Science and Technology
Particle transport in the respiratory tract has been a subject of intensive studies, because it has applications in health risk assessment of particulate pollutants, development of diagnostic procedures, and design of respiratory delivery devices and methodology for therapeutic agents. Advances in these applications as well as development of new applications can be expected as our understanding of inhaled particles improves.
Automated airway quantification associates with mortality in idiopathic pulmonary fibrosis
2023, European Radiology
Functional parameters of small airways can guide bronchodilator use in idiopathic pulmonary fibrosis
2020, Scientific Reports
Altered deposition of inhaled nanoparticles in subjects with chronic obstructive pulmonary disease
2018, BMC Pulmonary Medicine
Physiology of the lung in idiopathic pulmonary fibrosis
2018, European Respiratory Review

View all citing articles on Scopus

View full text

Chest

Preliminary ReportAerosol-Derived Airway Morphometry and Aerosol Bolus Dispersion in Patients With Lung Fibrosis and Lung Emphysema

Objective

Design

Results

Conclusions

Section snippets

Subjects

Results

Discussion

Conclusions

Chest

J Aerosol Sci

J Aerosol Sci

The National Institutes of Health Intermittent Positive-Pressure Breathing Trial: pathology studies; I. Interrelationship between morphologic lesions

Am Rev Respir Dis

The influence of cigarette smoking on lung function in patients with idiopathic pulmonary fibrosis

Am Rev Respir Dis

Pulmonary air space size in coal miners

Am Rev Respir Dis

Use of aerosols to estimate mean air-space size in chronic obstructive pulmonary disease

J Appl Physiol

Assessment of papain induced lung injury in isolated lungs by measurements of aerosol deposition and mixing

J Appl Physiol

Diagnosis of emphysema in patients with chronic bronchitis: a new approach

Eur Respir J

Aerosol deposition and dispersion characterize lung injury in a canine model of emphysema

J Appl Physiol

Detection of impaired intrapulmonary convective mixing by aerosol bolus dispersion in patients with emphysema

Eur J Med Res

Aerosol derived airway morphometry in healthy subjects

Eur Respir J

Preliminary Report
Aerosol-Derived Airway Morphometry and Aerosol Bolus Dispersion in Patients With Lung Fibrosis and Lung Emphysema