Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There is increased retrocardiac opacity which could represent a left lower lobe pneumonia . Blunting of the left costophrenic angle is overall unchanged without obvious pleural effusion on the lateral view . The right lung is clear . The heart is top - normal and appears increased from the prior exam but may be secondary to lower lung volumes on today 's exam . Multilevel degenerative changes of the thoracic spine are unchanged . No pneumothorax or pulmonary edema .
    OUTPUT:
    
1 . Findings concerning for left lower lobe pneumonia . 2 . Persistent blunting of the left costophrenic angle . 3 . Top - normal heart size .