Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: PA and lateral views of the chest . No prior . Linear opacity at the left lung base in the frontal is most suggestive of atelectasis . Lungs are otherwise clear and there is no effusion . The cardiomediastinal silhouette is within normal limits , noting atherosclerotic calcifications at the aortic arch . Osseous and soft tissue structures are unremarkable .
    OUTPUT:
    
No acute cardiopulmonary process .