Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Frontal and lateral chest radiograph demonstrates well expanded lungs with mild left lower lobe atelectasis . New ill - defined opacity is seen within the left lower lobe on frontal projection . No pleural effusion or pneumothorax . Heart size , mediastinal contour , and hila are unremarkable . Limited assessment of the osseous structures are unremarkable and visualized upper abdomen is within normal limits .
    OUTPUT:
    
New ill - defined opacity within the left lower lobe on frontal projection may represent focal atelectasis however given clinical history this is concerning for an early pneumonia . It may alternatively represent superimposed shadows including overlying costochondral this cartilage . No definite abnormality seen on the lateral view . If desired and shallow obliques could help further clarify .