Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Single portable chest radiograph demonstrates unchanged exam . As before there is mild hyperinflation with relative hyperlucency of the bilateral upper lungs and paucity of vessels suggesting underlying emphysema . Stable retrocardiac opacification likely represents atelectasis though can not exclude infection in the correct clinical setting . Dense atherosclerotic calcifications are noted within the aortic arch . Prominence of the right pulmonary artery suggests a degree of pulmonsry arterial hypertension . Heart size is not enlarged .
    OUTPUT:
    
Unchanged exam . Stable retrocardiac opacification , most likely atelectasis though pneumonia not definitively excluded . Findings suggestive of pulmonary arterial hypertension .