Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Blunting of a posterior costophrenic angle is compatible with small pleural effusion , likely on the left . Lungs are otherwise clear besides mild right basilar atelectasis . The cardiomediastinal silhouette is within normal limits . No acute osseous abnormalities .
    OUTPUT:
    
Persistent small left pleural effusion . No superimposed acute cardiopulmonary process .