Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Low lung volumes and mild elevation of the right hemidiaphragm are similar compared to the previous exam . The cardiac silhouette size is normal . The mediastinal contours are unremarkable . There is no pulmonary vascular congestion . Patchy opacities in the lung bases likely reflect atelectasis , similar compared to the previous exam . Small left pleural effusion remains unchanged . There is no pneumothorax . No acute osseous abnormalities detected .
    OUTPUT:
    
Bibasilar atelectasis and small left pleural effusion , relatively unchanged compared to the previous exam .