Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lung volumes are low . Heart size is mildly enlarged but unchanged . Mediastinal and hilar contours are normal . There is crowding of the bronchovascular structures without overt pulmonary edema . Streaky opacities are seen within the lung bases , likely reflective of atelectasis . No focal consolidation , pleural effusion or pneumothorax is seen . There are no acute osseous abnormalities . Clips from prior cholecystectomy are noted in the right upper quadrant of the abdomen .
    OUTPUT:
    
Mild bibasilar atelectasis . No evidence of pneumonia .