Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Right - sided Port - A - Cath terminates in the low SVC without evidence of pneumothorax . No pleural effusion is seen . There are low lung volumes , which accentuate the bronchovascular markings . Subtle left base retrocardiac patchy opacity could be due to atelectasis , aspiration , or pneumonia .
    OUTPUT:
    
Subtle patchy left base retrocardiac opacity could be due to atelectasis , aspiration , or pneumonia .