Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The cardiac , mediastinal and hilar contours appear stable . Extensive parenchymal opacities have mostly resolved since the prior examination , primarily leaving bronchovascular opacity in the right lower lobe which can probably be attributed atelectasis , as well as suspected residual retrocardiac atelectasis . However , there is no further evidence for parenchymal edema or significant pleural effusions .
    OUTPUT:
    
Marked improvement in pulmonary opacities with suspected residual atelectasis in the posterior lower lobes , but no definite acute process .