Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: As compared to prior examination , lung volumes are decreased , accentuating the cardiac silhouette and bronchovascular structures . As seen on prior chest radiograph , the pulmonary artery is mildly enlarged , consistent with pulmonary arterial hypertension . There is persistent elevation of the right hemidiaphragm . There is no new focal consolidation , pleural effusion or pneumothorax .
    OUTPUT:
    
1 . Mildly enlarged pulmonary artery consistent with pulmonary arterial hypertension , seen on prior chest radiograph . 2 . Low lung volumes . No new focal consolidation .