Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A single portable frontal view of the chest was performed . Opacification is seen in adjacent to the left heart border . The heart size is mildly enlarged . There is no pleural effusion or pneumothorax . The mediastinal structures are normal . Small amount of calcifications within the aortic arch . The imaged upper abdomen is unremarkable .
    OUTPUT:
    
Left lower lung opacification which may represent atelectasis , although pneumonia can not be excluded . Mild cardiomegaly .