Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There is mild retrocardiac atelectasis otherwise , the lungs are clear with no evidence of consolidations , effusions , or pneumothorax . The cardiomediastinal silhouette is normal . No acute fractures are identified . There is slight tortunosity of the aorta . An old right lateral eight rib fracture is noted . Additionally , there is widening of the Acromio - Clavicular interval to 18 mm suggestive of dissociation .
    OUTPUT:
    
There is widening of the acromio-clavicular joint to 18 mm which is suggestive of dissociation but may be chronic . There is also evidence of an old right - sided rib fracture . Correlation with exam is recommended . Otherwise , no acute cardiopulmonary process .