Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A right PICC ends in the proximal right atrium . Bibasilar opacities are most consistent with atelectasis . Parenchymal opacity in the right upper lobe and bilateral lower lobes appears improved since the prior radiograph performed 1 day ago . Aortic knob is calcified . The heart is mildly enlarged . There is no pleural effusion or pneumothorax .
    OUTPUT:
    
1 . A right PICC ends in the proximal right atrium . For positioning in the low superior vena cava retraction of 3 cm is recommended . 2 . Parenchymal opacity in the right upper lobe and bilateral lower lobes appears improved since the prior radiograph performed 1 day ago . In the correct clinical setting these findings are consistent with aspiration , infection or asymmetric pulmonary edema .