Chest
Volume 136, Issue 3, September 2009, Pages 797-804
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Original Research
Asthma
The Use of Endobronchial Ultrasonography in Assessment of Bronchial Wall Remodeling in Patients With Asthma

https://doi.org/10.1378/chest.08-2759Get rights and content

Background

Endobronchial ultrasound (EBUS) is a new technique that enables the assessment of bronchial wall layers. The aim of the study was to verify the utility of EBUS for the assessment of bronchial wall remodeling in patients with asthma.

Methods

In 35 patients with asthma and 23 control subjects, high-resolution CT (HRCT) scanning and EBUS were used to measure bronchial wall thickness in the 10th segment of the right lung. With a radial 20-MHz probe, EBUS identified the 5-laminar structure of the bronchial wall. Layer 1 (L1) and layer 2 (L2) were analyzed separately, and layers 3 through 5 (L3–5), which corresponded to cartilage, were analyzed jointly. Digitalized EBUS images were used for the quantitative assessment of bronchial wall thickness and the wall area (WA) of the layers. Finally, bronchial biopsy specimens were taken for measuring the thickness of the reticular basement membrane (RBM). The thickness and WA of the bronchial wall layers, which were assessed using EBUS, were correlated with FEV1 and RBM.

Results

There was no significant difference in the measurements of total bronchial wall thickness using EBUS and HRCT scanning. The thickness and WA of the bronchial wall and its layers were significantly greater in patients with asthma than in the control subjects. A negative correlation among the thicknesses of L1, L2, and L3–5 and FEV1, and a positive correlation with RBM were observed only in the patients with asthma.

Conclusions

EBUS allows precise measurement of the thickness and WA of bronchial wall layers. The correlation of these parameters with asthma severity suggests implementation of EBUS in the assessment of bronchial wall remodeling in patients with asthma.

Section snippets

Patients

Thirty-five patients with bronchial asthma and 23 control subjects with clinical indications for bronchoscopy were enrolled in the study. The diagnosis of asthma was established according to Global Initiative for Asthma guidelines. Sixteen patients had mild asthma, 9 patients had moderate asthma, and the remaining 10 patients had severe asthma. In the control group, bronchofiberoscopy was performed to diagnosis hemoptysis and persistent cough or to exclude malignancy. The characteristics of the

Results

Bronchoscopy with EBUS was performed in 62 patients. In 4 patients, we did not obtain an ultrasonographic image that allowed assessment of the bronchial wall, so 58 patients were included in the final analysis. No complications were observed.

EBUS enabled us to measure the total bronchial wall thickness, its particular layers, and WA. The analysis of repeatability of the measurements performed by the two independent radiologists did not show significant discrepancies (L1, p = 0.6928; L2, p =

Discussion

Since EBUS was introduced in the 1990s, it has been continuously investigated for new clinical applications. Yamasaki et al4 have used EBUS to show the diminishing of subepithelial edema in patients with asthma after montelukast therapy. Miyazu et al5 applied this technique to the diagnosis of relapsing polychondritis with tracheobronchial malacia. Irani et al6 used the relative area of the layer measured with EBUS to detect lung transplant rejection or infection, and Murgu et al7 applied this

Conclusions

Besides the methods used to date, including HRCT scans and bronchial biopsies, EBUS may become a new technique for assessing asthma remodeling. In this preliminary study, EBUS was used in asthma research for the first time. Our results show greater thickness of the whole bronchial wall and its particular layers, which correlates positively with RBM and negatively with FEV1, and indicates the relationship between these parameters and asthma severity. Thus, our findings suggest the possibility of

Acknowledgments

Author contributions: Drs. Soja, Grzanka, Sładek, Niżankowska-Mogilnicka, and Szczeklik were responsible for conception and design of the study. Drs. Soja, Grzanka, Sładek, Okoń, Ćmiel, Mikoś, Mikrut, Pulka, Gross-Sondej, Niżankowska-Mogilnicka, and Szczeklik were responsible for analysis and interpretation of the data, manuscript preparation, and final approval of the article.

Financial/nonfinancial disclosures: The authors have reported to the American College of Chest Physicians that no

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Funding/Support: The study was funded by the Polish Scientific Research Committee (grant KBN 3 PO5B022 25).

Reproduction of this article is prohibited without written permission from the American College of Chest Physicians (www.chestjournal.org/site/misc/reprints.xhtml).

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