Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The right lung and left upper lung are clear . The heart is not enlarged . Left pigtail projects in the posterior costophrenic sulcus . There has been substantial improvement in left basilar empyema since the CT of ___ . Residual opacity blunting the left posterior costophrenic sulcus likely reflects small residual effusion and atelectasis . There is persistent elevation of the left hemidiaphragm . The mediastinal and hilar contours are normal . Progression of dilation of colon in the left mid and upper abdomen possibly reflects ileus .
    OUTPUT:
    
1 . Substantial improvement in left basilar empyema . 2 . Progression of colonic dilation may reflect ileus . Consider radiograph of the abdomen for followup evaluation