Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The heart size is mild to moderately enlarged . Aortic knob is prominent , suggesting dilatation of the thoracic aorta . Atherosclerotic calcification of the aortic arch is present . Opacification within the retrocardiac region may reflect a combination of a small pleural effusion with adjacent atelectasis . Hazy opacification within the mid lung fields is noted . There is no right - sided pleural effusion pneumothorax . No acute osseous abnormality seen .
    OUTPUT:
    
1 . Left basilar opacification likely reflects a combination of a small pleural effusion and adjacent atelectasis . Infection , however , is not excluded . 2 . Hazy opacification within the mid lung fields bilaterally is nonspecific , and could reflect an infectious or inflammatory process . Mild pulmonary edema is considered less likely .