Quantitative evaluation of computed tomography findings in patients with bronchial asthma: prediction of therapeutic response.

Introduction: To compare pretreatment quantitative CT parameters between patients with well-controlled and those with poorly controlled bronchial asthma after treatment.

Methods: We retrospectively reviewed 785 patients with clinical diagnosis of bronchial asthma from January 2009 to April 2015. Of these, 43 patients underwent high-resolution CT and pulmonary function tests at initial diagnosis. According to the Global Initiative for Asthma (GINA) 2015 guidelines, the patients were classified into two groups (well-controlled (GINA1), n = 18; poorly controlled (GINA2 and GINA3), n = 25). Quantitative measurements for airways (total cross-sectional area (TA), lumen area (LA), wall area (WA) and wall area percentage (WA%)), air trapping and emphysema were performed on initial pretreatment CT scans. We compared CT measurements for airways between well-controlled and poorly controlled groups and also compared those between ever-smokers and never-smokers. The significant quantitative CT parameters were evaluated with multiple regression analysis.

Results: The TA and the WA demonstrated significantly higher values in the poorly controlled than in the well-controlled patient group (TA in RB1 and LB1, each P < 0.05; WA in RB1 and RB8, each P < 0.05). Quantitative parameters for air trapping and emphysema did not show significant differences between the two patient groups. On multiple regression analysis, the TA and the WA were statistically significant in comparison of two patient groups with an adjustment for age, sex, body mass index and smoking history (each P < 0.05). Significantly higher values of the WA and the WA% were revealed in the asthmatics with smoking history comparing to non-smokers (P < 0.05).

Conclusion: Most of the quantitative CT measurements did not correlate significantly with clinical outcomes in patients with bronchial asthma. And, further research that supplements the limitations of this study is needed to support and validate the association between CT parameters and therapeutic response. This can be justified by the fact that a trend of higher values in airway measurements on initial pretreatment HRCT scan in the poorly controlled than in the well-controlled patient group.