Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: PA and lateral views of the chest are provided . The right lung is clear . Vague opacity in the left infrahilar region is seen on the frontal radiograph , which could represent atelectasis versus less likely pneumonia . No pleural effusion or pneumothorax . Cardiomediastinal silhouette is stable . Bony structures are intact . Partially imaged cervical fusion hardware is noted in the lower neck .
    OUTPUT:
    
Probable atelectasis , less likely pneumonia in the left infrahilar region .