Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Heart size is top normal . The mediastinal and hilar contours are unremarkable . The pulmonary vasculature is not engorged . Streaky opacities in the lung bases likely reflect atelectasis in the setting of low lung volumes . No pleural effusion or pneumothorax is present . Bilateral shoulder prostheses are re - demonstrated .
    OUTPUT:
    
Mild bibasilar atelectasis . No evidence of pulmonary edema .