Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: PA and lateral views of the chest are compared to previous exam from ___ . There is subtle increased opacity at the left lung base laterally . This could be due to atelectasis ; however , developing infiltrate is also possible . Lungs are otherwise clear . There is no effusion or pneumothorax . The cardiomediastinal silhouette is within normal limits , noting a mildly tortuous aorta . Osseous and soft tissue structures are unremarkable .
    OUTPUT:
    
Left basilar opacity , potentially due to atelectasis ; however , early infiltrate is not excluded . Clinical correlation is suggested .