Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The heart is moderately enlarged . The mediastinal and hilar contours appear unchanged . There is no pleural effusion or pneumothorax . There is persistent posterior density in the left lower lobe , although decreased , suggesting improvement in atelectasis and pleural effusions although very small pleural effusions may persist . Upper zone redistribution of pulmonary vascularity suggests pulmonary venous hypertension , but without frank congestive heart failure on this study , which has improved .
    OUTPUT:
    
Improving patchy retrocardiac opacity and pleural effusions . Marked decrease in pulmonary vascular congestion with findings suggesting only pulmonary venous hypertension .