Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Moderate cardiomegaly is unchanged . There is new retrocardiac opacification which likely corresponds to left lower lobe collapse . There is moderate central vascular congestion and mild interstitial edema . Significantly calcified aortic arch is again noted . Elevation of the left mainstem bronchus is likely a function of left atrial enlargement . There is likely a small left pleural effusion .
    OUTPUT:
    
Moderate stable cardiomegaly Center vascular congestion and upper zone redistribution . Likely small left pleural effusion .