HRCT Findings of Asthmatic Children under Maintenance Therapy

Hong, Hyun Sook; Park, Jai Soung; Goo, Dong Erk; Lee, Hae Kyung; Kwon, Kui Hyang; Choi, Deuk Lin; Pyun, Bok Yang

Abstract

PURPOSE: The purpose of this study was to evaluate the HRCT findings of bronchial asthma during maintenance bronchodilator therapy and to determine whether there were irreversible bronchial changes occurred in pediatric patients with this condition. MATERIALS AND METHODS: HRCT findings of the lung in 21 asthmatic children [14 boys and 7 girls aged between 3.5 and 13.8 (mean : 7.7) years] who were receiving maintenance bronchodilator therapy were retrospectively studied. At the time of CT examination, 16 were receiving nonsteroid bronchodilator therapy only, and five were receiving both bronchodilator and steroid therapy. Thirteen patients were defined as allergic and eight were nonallergic. The clinical severity of chronic asthma was graded as severe in seven cases, and moderate in 14. The duration of the disease ranged from 4 months to 6 years (mean 3.2 years). HRCT was performed in 19 cases for evalvation of the atelectasis, hyperinflation, and prominent bronchovascular bundles seen on plain radiographs, and in two cases for evaluation following acute exacerbation. A CT W-2000 scanner (Hitachi Medical Co. Tokyo, Japan) was used during the end inspiratory phase, and in addition, ten patients were scanned during the expiratory phase. Scans were reviewed for evidence of bronchial thickening, bronchiectasis, emphysema, abnormal density, mucus plugs, and other morphological abnormalities. The presence of bronchial wall thickening or air trapping was evaluated according to the duration, severity and type of asthma. RESULTS: Among the 21 patients, 7(33.3%) had normal HRCT findings, while in 14 (66.7%), bronchial wall thickening was demonstrated. Eleven of the 14 patients with bronchial wall thickening (78.6%) also had air trapping. No patient was suffering from bronchiectasis or emphysema. There were no statistically significant correlations between the presence of bronchial wall thickening or air trapping and the duration of the disease, its severity, or type of asthma. There was, however, a statistically significant correlation between bronchial wall thickening and air trapping (p < . 0 5 ). CONCLUSION: In asthmatic children who were under maintenance therapy, the most frequent HRCT findings were bronchial wall thickening and air trapping, with significant correlation between the presence of these two phenomena. No destructive lesion such as bronchiectasis or emphysema was found in these asthmatic children, however, and this is probably due to the short duration of the disease, and different disease processes.