Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The patient is status post CABG with intact sternotomy wires . The hilar and mediastinal contours appear to be stable with evidence of a tortuous aorta . There is stable mild cardiomegaly . There is no pleural effusion or pneumothorax . There appears to be a subtle increase in opacification in the retrocardiac region , superimposed on a stable mild background of interstitial abnormality , best seen on the lateral view .
    OUTPUT:
    
Stable diffuse increased interstitial markings with an interval increase in opacification in the retrocardiac region , best seen on the lateral view , which could be secondary to overlap of structures , however an acute infectious process is not excluded .