Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Single AP upright portable view of the chest was obtained . There is mild elevation of the hemidiaphragm . Overlying right base linear opacity most likely represents subsegmental atelectasis . Subtle patchy left lower lung opacity is seen , difficult to discern whether lingular or left lower lobe on this single frontal view . No large pleural effusion or pneumothorax . The cardiac and mediastinal silhouettes are stable . External artifact is seen projecting over the medial lung fields .
    OUTPUT:
    
1 . Patchy left lower lung opacity , not definitely seen on the prior study concerning for infection and / or aspiration . Elevation of the right hemidiaphragm and right base atelectasis .