Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A dialysis catheter terminates in the right atrium , as before . The lung volumes are low . The cardiac , mediastinal and hilar contours appear unchanged . There is no definite pleural effusion or pneumothorax . There is mild persistent relative elevation of the left hemidiaphragm . Opacification in the left lower lobe along the hemidiaphragm has increased although similar to the earlier of two comparison studies . The pulmonary interstitium is minimally prominent , probably due to slight fluid overload .
    OUTPUT:
    
Increasing left lower lobe opacity , although similar to the earlier of two studies . Recurrence of pneumonia versus waxing and waning atelectasis could be considered . Findings also suggest very mild fluid overload .