Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Lung volumes are low . There is diffuse interstitial opacity with engorgement of the central vasculature , consistent with moderate pulmonary edema . Heart is moderately enlarged but unchanged . There is a small right pleural effusion . A retrocardiac opacity presumably reflects a component of pleural effusion and overlying atelectasis and appears similar to ___ . A superimposed infection be difficult to exclude . Sternotomy wires and an aortic valve prosthesis are constant .
    OUTPUT:
    
1 . Moderate pulmonary edema . 2 . Retrocardiac opacity is presumably component of pleural effusion and overlying atelectasis . A superimposed infection would be difficult to exclude .