Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Persistent low lung volumes with mild interval improvement in multiple ill - defined bilateral heterogeneous opacities . No cavitation noted . There is a crowded appearance of pulmonary vasculature at the bases and mild cardiac enlargement from low lung volumes . Mediastinal and hilar contours are normal . Stable mild bibasilar atelectasis , left greater than right . No pneumothorax or large pleural effusion .
    OUTPUT:
    
1 . Mild interval improvement in multifocal opacities suggestive of infectious process . 2 . No pulmonary edema .