Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Ill - defined opacities at the right lung base are nonspecific and may represent atelectasis . No pleural effusion or pneumothorax . Heart size and cardiomediastinal contours are normal .
    OUTPUT:
    
Ill - defined right lung base opacities may represent atelectasis but infection or aspiration can not be excluded in the appropriate clinical setting .