Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Patchy left lower lobe opacity could be due to atelectasis or pneumonia . Subtle right apical opacity is stable to slightly decreased compared to the prior study . No right - sided consolidation is seen . Incidental note is made of an azygos lobe . No pleural effusion or pneumothorax is seen . The mediastinal contours are stable . The cardiac silhouette is top - normal to mildly enlarged .
    OUTPUT:
    
Patchy left lower lobe opacity may be due to pneumonia or atelectasis .