Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Frontal and lateral chest radiographs demonstrate unchanged cardiomediastinal and hilar contours . Streaky opacification in the retrocardiac space is not significantly changed compared to ___ and likely represents atelectasis . Small amount of left costophrenic angle blunting , similar to prior study without pleural effusion on lateral view suggests scarring . No pneumothorax evident .
    OUTPUT:
    
No acute intrathoracic process .