Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Right lower lobe density has improved a lot since the prior study . Left lower lobe opacities are stable since ___ . Mediastinal and cardiac contour is unchanged . There is no pneumothorax . Left - sided PICC line ends in mid SVC .
    OUTPUT:
    
1 . Left retrocardiac opacity is unchanged since ___ . It could represent only atelectasis ; however , pneumonia or aspiration can not be excluded . 2 . Right basilar opacities have resolved since prior exam .