Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The cardiac , mediastinal , and hilar contours appear unchanged . Streaky right basilar opacity suggests minor atelectasis associated with low lung volumes . Otherwise , the lungs appear clear . There are no pleural effusions or pneumothorax . Small degenerative changes are noted along the mid thoracic spine . There is no evidence for recent fracture . Irregularity along the course of the anterolateral right fourth rib suggests there may be a remote prior fracture , however , unchanged since the prior study .
    OUTPUT:
    
No radiographic evidence of injury .