Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There is slightly low lung volumes . Heart size is top normal . There are aortic calcifications . There are no pleural effusions or pneumothorax . There is probable mild pulmonary vascular congestion . There is a retrocardiac opacity that may represent pneumonia or atelectasis .
    OUTPUT:
    
Mild pulmonary vascular congestion . Retrocardiac opacity is likely atelectasis however can not rule out infection . Recommend clinical correlation .