Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Linear opacity in the bibasilar , left greater than right , lower lobe appear relatively stable over multiple prior studies and most likely represents atelectasis . No overt pulmonary edema , pleural effusion or pneumothorax identified . The cardiac and mediastinal contours are stable .
    OUTPUT:
    
Bibasilar , left greater than right , lower lobe opacities appear stable over multiple prior studies and most likely represent atelectasis , however superimposed infection can not be excluded .