Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Heart size is top normal with mild tortuosity of the thoracic aorta . Hilar contours are unremarkable . Pleural surfaces are clear without effusion or pneumothorax . Opacities in the posterior left lower lobe are suggestive of atelectasis .
    OUTPUT:
    
Left basilar opacities suggesting atelectasis . No potential nodules are visualized on this study , possibly due to decreased lung volumes , but please note the prior recommendation to follow - up with a PA view using nipple markers .