Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lungs are well - expanded . Again noted is a vague retrocardiac opacity , stable since the prior chest radiographs . Prominent interstitial lung markings may reflect mild pulmonary vascular congestion , which is not significantly different from prior examination . The cardiac silhouette is mildly enlarged , similar to prior examination .
    OUTPUT:
    
No definite acute intrathoracic process .