Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Cardiomediastinal silhouette is within normal limits . Lung volumes are low . Retrocardiac opacity likely represent atelectasis . There is no focal consolidation , pleural effusion , or pneumothorax
    OUTPUT:
    
In the setting of low lung volumes , retrocardiac opacities likely represent atelectasis however consolidation can not be excluded .