Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The inspiratory lung volumes are appropriate . Retrocardiac opacification with corresponding streaky opacities on the lateral view most likely represents overlapping thoracic aorta , pulmonary vascular structures and degenerative changes at the thoracic spine , although superimposed infection is not entirely excluded . Trace fluid is seen in the major fissure on the lateral view . There is no significant pleural effusion or pneumothorax . The pulmonary vasculature is essentially within normal limits . The cardiac silhouette is top normal in size , as before . Mild calcification of the aortic arch is redemonstrated with tortuosity of the descending thoracic aorta . The mediastinal and hilar contours are within normal limits .
    OUTPUT:
    
1 . No pulmonary edema . Small amount of fluid in major fissure on the lateral view . 2 . Retrocardiac opacity corresponding to the left lower lobe likely represents atelectasis and / or superimposed structures , although pneumonia can not be entirely excluded in the appropriate clinical context .