Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Since the prior radiograph , the previously seen opacity at the right base has returned , suggesting possible aspiration , although infectious process can not be excluded . Bibasilar atelectasis is unchanged . There is no pulmonary edema , pleural effusion , or pneumothorax . The cardiomediastinal silhouette is stable . Again noted is tortuosity of the aorta . Severe degenerative changes of the shoulder are stable .
    OUTPUT:
    
1 . Reappearance of right basilar opacification suggests ongoing aspiration , although infectious process can not be excluded . 2 . Stable bibasilar atelectasis .