Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: As compared to the prior examination dated ___ , there has been no significant interval change . Low lung volumes results in crowding of the bronchovascular structures . There is no lobar consolidation , pneumothorax , or overt pulmonary edema . The mediastinum is mildly widened , likely secondary to patient positioning . Allowing for differences in technique , the cardiac silhouette is stable . The cardiomediastinal silhouette is within normal limits . Significant degenerative changes are noted at the left acromioclavicular joint .
    OUTPUT:
    
Essentially normal chest radiograph