Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lungs are hyper expanded and clear . The cardiomediastinal silhouette is stable . A prosthetic mitral valve is unchanged in position . Stable blunting of the bilateral costophrenic angles is possibly due to tiny pleural effusions or thickening . There is no pneumothorax , pulmonary edema , or focal airspace opacification .
    OUTPUT:
    
Stable blunting of the bilateral costophrenic angles , possibly tiny pleural effusions or thickening .