Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There is a peripheral left lower lobe opacity . No pleural effusion or pneumothorax is seen . The cardiac and mediastinal silhouettes are unremarkable .
    OUTPUT:
    
A peripheral left lower lobe opacity may represent pneumonia or pulmonary infarct . If there is clinical concern for pulmonary embolism , CTA chest should be obtained .