Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Low lung volumes are somewhat improved . Left infrahilar atelectasis persists . There is no focal consolidation , pleural effusion or pneumothorax . Mild pulmonary edema is unchanged . Heart size is moderately enlarged and exaggerated by low lung volumes . Tracheostomy tube midline . Dual channel dialysis catheter ends in the right atrium .
    OUTPUT:
    
Mildly improved low lung volumes . No evidence of pneumonia .