Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The cardiac and mediastinal contours appear stable . Although less striking than on the last study , there is perihilar congestive change above that of an earlier baseline study from ___ . There are also patchy opacities at both lung bases , more prominent in the retrocardiac area than at the right lung base , decreased from ___ but retrocardiac opacity was not present in ___ so is not necessarily chronic .
    OUTPUT:
    
Findings suggest mild vascular congestion . Opacities at the lung bases , particularly the left lower lobe , which are indeterminate as to etiology and chronicity .