Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Ill - defined bibasilar airspace opacities may represent atelectasis , aspiration , , or early pneumonia , depending on the clinical setting . The left lung base is likely similar to the prior CT , wall the right lung base opacification is new . There is no pulmonary edema , pleural effusion , or pneumothorax . The cardiomediastinal silhouette , including a mildly tortuous descending aorta , is unchanged .
    OUTPUT:
    
Ill - defined bibasilar airspace opacities , similar on the left and new on the right , may represent atelectasis , aspiration , or early pneumonia , depending upon the clinical setting .