Low-density areas on high-resolution computed tomograms in chronic pediatric asthma

Objective: In children with chronic persistent asthma, we evaluated whether the presence of increased residual volume (RV) after anti-inflammatory treatment correlates with the detection of low-density areas on high-resolution computed tomography (HRCT), similar to those in emphysema. Methods: Children with a confirmed diagnosis of asthma (n = 32) were enrolled in a prospective study. All patients had reduction of airflow in the peripheral airways, increased RV, and increased serum eosinophil cationic protein (ECP) values indicating airway inflammation. All the children were treated with salmeterol (50 μg twice daily) and fluticasone (250 μg twice daily) for a 3-month period. Results: At the end of treatment, peripheral eosinophil counts, serum ECP, forced expiratory volume in 1 second (FEV 1 ), mean forced expiratory flow during the middle half of forced vital capacity (FEF 25-75 ), RV, and total lung capacity values improved in all the patients. HRCT was normal in 22 children (68.8%); in the remaining 10 subjects, low-density areas were found despite normalization of FEV 1 , FEF 25-75 , and significant reduction in ECP. A significant correlation was found between persistence of RV values >150% predicted and the presence of low-density areas on HRCT ( r = 0.84, P Conclusions: Structural changes similar to emphysema are also present in asthmatic children. Our findings suggest that the persistence of increased RV may be used to identify subjects with low-density areas on HRCT. (J Pediatr 2002;141:104-8)