Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lungs are less well expanded than seen on ___ , likely reflecting decreased inspiratory effort . Slight right lower lobe opacity may reflect atelectasis , although infection can not be excluded . The pleural surfaces , cardiac silhouette , and mediastinal contours are normal .
    OUTPUT:
    
Right lower lobe opacity , which may reflect atelectasis , although pneumonia can not be excluded .