Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There is blunting of posterior costophrenic angles suggestive of small effusions . In addition , there is retrocardiac opacity silhouetting the medial portion of the left hemidiaphragm , potentially due to atelectasis or developing infiltrate . Elsewhere , the lungs are clear . Cardiac silhouette is at upper limits of normal for technique . The osseous and soft tissue structures are unremarkable .
    OUTPUT:
    
Small bilateral effusions . Retrocardiac opacity could be due to left lower lobe atelectasis given the relatively lower lung volumes , however , infectious process such as pneumonia is also possible .