Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: AP and lateral views of the chest are compared to previous exam from ___ . Linear opacities at the lung bases are suggestive of subsegmental atelectasis , especially given low lung volumes . Elsewhere , lungs are grossly clear without confluent consolidation or effusion . Cardiomediastinal silhouette is within normal limits . Osseous structures again notable for degenerative changes at the shoulder joints including evidence of prior surgery at the proximal left humerus . Large air - fluid level identified within the stomach .
    OUTPUT:
    
No acute cardiopulmonary process .