Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Compared to the prior chest radiograph there is little change in , left greater than right , lower lobe opacities which may represent atelectasis or pneumonia . There is no pulmonary edema , pleural effusion or pneumothorax . The cardiac silhouette is top normal in size . The mediastinal and pulmonary vascular are not dilated . There is no free air beneath the right hemidiaphragm .
    OUTPUT:
    
Left greater than right , lower lobe opacities are unchanged since ___ and may represent atelectasis or pneumonia .