Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lung volumes are low , limiting evaluation of the lung bases . Bibasilar atelectasis is seen . Retrocardiac opacity most likely represents atelectasis , but a small focus of infection can not be excluded . Mild peribronchial cuffing and interstitial prominence is seen . No pleural effusion or pneumothorax is detected . There is no evidence for pulmonary edema . Heart and mediastinal contours are within normal limits .
    OUTPUT:
    
Low lung volumes with bibasilar atelectasis ; retrocardiac opacity likely represents atelectasis , but a small focus of consolidation can not be excluded . Peribronchial cuffing and interstitial prominence suggest small airways disease , which could be secondary to reactive airways and / or a viral process .