The value of bronchodilator administration in asthmatic patients before lung imaging

A 17-year-old boy with chest pain and severe bronchospasm underwent lung imaging to exclude pulmonary embolism. This showed widespread nonsegmental defects in both the ventilation and perfusion scans. A repeat study performed immediately after nebulized bronchodilator administration was normal apart from changes consistent with left lower lobe pneumonia and atelectasis which had subsequently evolved on the chest radiograph. Bronchodilator administration is valuable in improving the accuracy of lung scanning in asthmatic patients by reducing the perfusion and ventilation abnormalities caused by hypoxia-induced vasoconstriction.