Effect of inhaled steroid therapy on distribution of Tc-99m DTPA radioaerosol in asthmatic children

The aim of this study was to evaluate the effect of inhaled steroid therapy on the distribution of inhaled Tc-99m DTPA in asthmatic children. Twenty-o ne asthmatic children and 15 healthy controls were entered in this study. T he distribution of radioaerosols was scored by using a modified standardize d score system over both lungs and expressed as homogeneity score/patient T he baseline homogeneity score war calculated before the inhalation therapy of budesonide (400 mug/day) for six months. The homogeneity score was repea ted at the end of the the second and sixth months of therapy therapy. Asthm atic symptom scores and peak-flow rate variability, which were observed to improve throughout the study, were also recorded Although homogeneity score s of the controls demonstrated no abnormality, mean baseline homogeneity sc ores of asthmatics was significantly high, 1.7 +/- 0.4/patient, ai rd decre ased to 0.6 +/- 0.2 and 0.3 +/- 0.1/patient at the end of second and sixth months, respectively (p < 005). These results revealed significant improvem ent in the radioaerosol distribution after inhaled steroid therapy. It was concluded that the lack of homogeneity in the distribution of Tc99m-DTPA in the lung, as an indicator for ventilation defects, may be accepted as a us eful, noninvasive tool to monitor the efficacy of the therapy with inhaled agents in childhood asthma.