Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: One portable AP view of the chest . Right lung is clear . Left lower lobe opacity with blurring of the left hemidiaphragm and inferior positioning of the left hilum is consistent with left lower lobe collapse . No pleural effusion . No opacities concerning for pneumonia . Aortic arch calcifications are unchanged .
    OUTPUT:
    
New left lower lobe collapse . ___ be caused by aspiration . No evidence of pneumonia .