Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Right - sided PICC terminates in the low SVC . Cardiomediastinal silhouette is unchanged . There is a new opacity at the left lung base partially obscuring the left heart border and the left lateral hemidiaphragm . There is no pneumothorax or right pleural effusion .
    OUTPUT:
    
New opacity at the left lung base likely represents atelectasis , less likely secondary to aspiration .