Relationships Between High-Resolution Computed Tomographic Features and Lung Function Trajectory in Patients With Asthma

PURPOSE: A subset of asthmatics suffers from persistent airflow limitation, known as remodeled asthma, despite optimal treatment.

Typical quantitative scoring methods to evaluate structural changes of airway remodeling on high-resolution computed tomography (HRCT) are time-consuming and laborious.

Thus, easier and simpler methods are required in clinical practice.

We evaluated the clinical usefulness of a simple, semi-quantitative method based on 8 HRCT parameters by comparing asthmatics with a persistent decline of post-bronchodilator (BD)-FEV1 to those with a BD-FEV1 that normalized over time and evaluated the relationships of the parameters with BD-FEV1.

METHODS: Asthmatics (n = 59) were grouped into 5 trajectories (Trs) according to the changes of BD-FEV1 over 1 year.

After 9–12 months of guideline-based treatment, HRCT parameters including emphysema, bronchiectasis, anthracofibrosis, bronchial wall thickening (BWT), fibrotic bands, mosaic attenuation on inspiration, air-trapping on expiration, and centrilobular nodules were classified as present (1) or absent (0) in 6 zones.

RESULTS: The Tr5 group (n = 11) was older and exhibited a persistent decline in BD-FEV1.

The Tr5 and Tr4 groups (n = 12), who had a lower baseline BD-FEV1 that normalized over time, had longer durations of asthma, frequent exacerbations, and higher doses of steroid use compared to the Tr1–3 groups (n = 36), who had a normal baseline BD-FEV1.

The Tr5 group had higher emphysema and BWT scores than the Tr4 (P = 8.25E-04 and P = 0.044, respectively).

Scores for the other 6 parameters were not significantly different among the Tr groups.

BD-FEV1 was inversely correlated with the emphysema and BWT scores in multivariate analysis (P = 1.70E-04, P = 0.006, respectively).

CONCLUSIONS: Emphysema and BWT are associated with airway remodeling in asthmatics.

Our simple, semi-quantitative scoring system based on HRCT may be an easy-to-use method for estimating airflow limitation.