Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Right - sided Port - A - Cath tip terminates in the proximal right atrium . Lung volumes are low . The heart size is mildly enlarged but unchanged . The mediastinal and hilar contours are stable . There is no pulmonary edema , pleural effusion or pneumothorax . Minimal patchy opacity in the retrocardiac region likely reflects atelectasis . There are no acute osseous abnormalities .
    OUTPUT:
    
Minimal retrocardiac atelectasis . Low lung volumes .