Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The cardiac silhouette is within normal limits . The mediastinum is not widened and unremarkable in this frontal view . Opacity at the left lung base could reflect overlying costochondral calcifications . There is no large pleural effusion or pneumothorax . No focal consolidations concerning for pneumonia are identified . No definite fractures identified . External leads are seen overlying the chest .
    OUTPUT:
    
Mediastinum is not widened and appears unremarkable in this frontal view .