Korean J Med.  2007 Dec;73(6):631-637.

High resolution computed tomographic assessment of airway remodeling: comparison according to the severity of asthma

• Lim SY
• Kim YS
• Choi BW

Abstract

BACKGROUND: Airway remodeling is characterized by an increase in the airway wall thickness. We aimed to compare the airway wall thickness among asthmatic subjects with different severity and to examine its relation to pulmonary function and airway hyperresponsiveness.
METHODS
Thirty-seven adult asthmatics were assigned to mild (MA, n=17), moderate (MoA, n=11), and severe (SA, n=9) groups according to the Global Initiative for Asthma classification. Patients with more than 10 pack-years of smoking history were excluded. We measured the airway wall thickness (T) and internal diameter (d) using high-resolution computed tomography, and then calculated the external diameter (D). The T/D ratio was compared between the groups and correlations between the T/D ratio and pulmonary function (methacholine PC20) were assessed.
RESULTS
The mean T/D ratio was significantly higher in the MoA and the SA groups than in the MA group for the total airways (0.278+/-0.014, 0.281+/-0 .019 vs. 0.228+/-0.013; p=0.022, p=0.021, respectively). The mean T/D ratio was also higher in the SA group than the MA group for the small airways (0.313+/-0.018 vs. 0.253+/-0.013; p=0.009). However, there were no significant differences for the large airways. The mean T/D ratio negatively correlated with FEV1 (L) and FEV1 (% of predicted) in total airways (r=-0.519, p=0.001; r=-0.396, p=0.015), small airways (r=-0.567, p<0.001; r=-0.450, p=0.008) and large airways (r=-0.395, p=0.015; r=-0.351, p=0.033). The methacholine PC20 was not related to the T/D ratio.
CONCLUSIONS
This study suggests that patients with moderate to severe asthma have greater airway remodeling than those with mild asthma, and the degree of airway wall thickening correlates to the severity of airflow obstruction.

Keyword

Airway remodeling; Airway wall thickness; Bronchial asthma; High-resolution computed tomography; Pulmonary function

MeSH Terms

Adult
Airway Remodeling*
Asthma*
Classification
Humans
Methacholine Chloride
Smoke
Smoking
Methacholine Chloride
Smoke