Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Linear opacities within the left lung base most likely represent atelectasis . There is no focal consolidation , vascular congestion , pleural effusion , or pneumothorax . Elevation of the left hemidiaphragm is unchanged since ___ . Normal heart size . The mediastinal contours are normal . There is no free air beneath the right hemidiaphragm .
    OUTPUT:
    
No pneumonia or evidence of congestive heart failure .