Asthma CT

Overview
In asthmatics, high-resolution CT may reveal several structural changes related to small-airway disease including cylindrical bronchiectasis, bronchial wall thickening, and air trapping. CT markers valid for small-airway disease can be derived from quantitative lung density measurements and these markers correlate with clinical severity, lung function test results and are also sensitive to demonstrate therapeutic effects. An FEV1/FVC ratio of 75% or more has been shown to be an important predictor of bronchial wall thickening and bronchiectasis; but has a low discriminatory utility for patients without structural airway changes (sensitivity, 67%; specificity, 65%). Thereby, suggesting the importance of radiological assessment of bronchial wall changes in patients with severe asthma.

CT findings in Asthma

 * Bronchial wall thickening,


 * Patients with mild asthma have one or more dilated bronchi,


 * Cylindrical bronchiectasis with the bronchoarterial-diameter ratio is less than 1.5,


 * Bronchiolar mucus statis and constrictive bronchiolitis,
 * Centrilobular opacities subsequent to bronchiolar mucus stasis or peri-bronchiolar inflammation,
 * Areas of decreased attenuation and vascularity, as demonstrated at end-inspiration,
 * Air trapping, as demonstrated after maximal expiration.