Airway Wall Thickness In Patients With Bronchial Asthma And Control Groups, Correlation With Lung Function: Assessment With High Resolution Computed Tomographic Scanning

Objective: Measure airway wall thickness at the segmental and subsegmental levels in 36 patients with asthma and 10 normal controls , assessment the relationship with lung function. Method :the subjects were prospectively divided into four age and sex matched groups : 13 patient with severe asthma (group 1),11 patient with moderate asthma (group 2), 12 patient with mild asthma (group3 ),and 10 normal controls, High resolution CT scans of the chest was performed in all subjects from top to bottom levels, measurement of total airway and lumen diameter, total airway cross sectional area and lumen area. Wall area as % total airway cross sectional area (WA%) and wall thickness to airway diameter ratio (T/D) were calculated for all airways clearly visualised with a transverse diameter of <2mm and 2-6mm. Measurement were related to forced expiratory volume in 1 second (FEV₁), optimal FEV1, forced mid expiratory flow(FEF25-75%), asthma severity, duration of asthma. Result: T/D and WA% were not significantly different between group 1 and 2. however, both groupl and 2 had higher WA% than group 3 and 4, statistically significant positive association were observed between WA% and asthma severity (r=0. 303 p=0.005, r=0. 299 P=0. 010), statistically significant negative association were observedbetween 2-6mm airway WA% and FEV,( r =-0.423P=0.010). No statistically association was identified with duration of asthma. Conclusion: the airway wall thickness and remodeling can be measured and accessed by HRCT, severe and moderate asthma had great airway wall thickening than the normal controls, the airway wall is thickened in more severe asthma and 2-6mm WA% is associated with FEV,%.