Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Left basilar opacity has improved since the prior study , with similar appearance of bilateral interstitial opacities . Medial right lung base opacity is likely atelectasis . The cardiomediastinal silhouette is unchanged . There is no pneumothorax or large pleural effusion .
    OUTPUT:
    
1 . Right basilar opacity , likely atelectasis , has slightly increased ; and left basilar opacity has improved since the prior study . 2 . Bilateral interstitial opacities persist , most likely edema , however PCP pneumonia could be considered in the appropriate clinical setting , as it can have a similar radiographic appearance .