Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Cardiac silhouette size is normal . The aorta remains tortuous . Mediastinal and hilar contours are otherwise unchanged . Pulmonary vasculature is not engorged . Patchy bibasilar opacities likely reflect areas of atelectasis without focal consolidation . No pleural effusion or pneumothorax is present . There are mild degenerative changes seen in the imaged thoracolumbar spine .
    OUTPUT:
    
Mild bibasilar atelectasis .