Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Frontal and lateral views of the chest were performed . There is atelectasis of the left lung base . There is no pleural effusion or pneumothorax . The heart size is normal . Calcifications are seen within the aorta .
    OUTPUT:
    
Left lung base opacities are likely atelectasis , although , pneumonia should be considered .