With hyperpolarized 3He MRI regional differences in airflow can be assessed. We sought to evaluate the changes in regional ventilation following bronchodilator therapy in patients with asthma. Baseline and post-treatment 3He/1H scans were co-registered, and normalized to enable serial comparison. Linear binning quantification was applied to the ventilation scan data to obtain quantitative metrics. Baseline and post-treatment scans were compared for regions of ventilation improvement or worsening. Lobar analysis was performed to identify ventilation abnormalities in each lobe. It was found that in asthmatics with bronchodilator response, ventilation improved globally, with most significant improvement in the upper and middle lobes.