Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The cardiac , mediastinal and hilar contours appear stable . The lungs appear clear . There are no pleural effusions or pneumothorax . On this study , there is patchy retrocardiac opacity , streaky in nature , similar to earlier lateral radiographs . Streaky opacities in the lingula also suggest atelectasis . The patient is status post open reduction and internal fixation of the proximal humerus . The bones appear demineralized .
    OUTPUT:
    
Patchy left posterior opacities suggesting minor atelectasis .