Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Focal opacity in the left lower lobe is not from nipple shadow and on retrospective review was imaged in the CT abdomen and pelvis on ___ and likely represents atelectasis or focal scarring . No new focal opacity , pneumothorax , pleural effusion or pulmonary edema . Heart size , mediastinal contour and hila are normal . No bony abnormality .
    OUTPUT:
    
Focal opacity in the left lower lobe likely represents atelectasis or focal scarring .