Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A retrocardiac opacity is present in the left lung base . There is mild pulmonary vascular congestion and interstitial edema . The cardiac silhouette is mildly enlarged . There are small bilateral pleural effusions . There is no pneumothorax . The visualized upper abdomen is unremarkable . A VP shunt is partially visualized . Median sternotomy wires and surgical clips are noted projecting over the mediastinum . Osseous structures are grossly intact .
    OUTPUT:
    
1 . Retrocardiac opacity , which may be due to atelectasis , however superimposed pneumonia can not be excluded . 2 . Mild cardiomegaly with pulmonary vascular congestion and interstitial edema . 3 . Bilateral small pleural effusions .