Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The lungs remain mildly hyperexpanded . Left lower lobe , retrocardiac streaky peribronchial opacities are not well evaluated on this portable radiograph . Mild obscuration of the left costophrenic angle likely reflects a trace pleural effusion . There is no lobar consolidation or large pneumothorax identified . The cardiomediastinal silhouette is unchanged from the prior examination .
    OUTPUT:
    
Nonspecific left retrocardiac opacity , which may be due to atelectasis , aspiration , or an early focus of pneumonia . Short - term followup radiographs may be helpful in this regard .