Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: The patient is status post median sternotomy and aortic valvular replacement . Mild cardiomegaly is re- demonstrated . Mediastinal and hilar contours are unchanged with dense atherosclerotic calcification of the aortic knob noted . Mild pulmonary vascular congestion is similar compared to the prior study . More focal patchy opacity in the retrocardiac region could reflect an area of atelectasis though infection is not completely excluded . No large pleural effusion or pneumothorax is identified . Marked degenerative changes of both acromioclavicular joints are seen . High riding right humeral head suggests underlying rotator cuff disease . Remote right eighth rib fracture is again seen .
    OUTPUT:
    
Mild pulmonary vascular congestion . Retrocardiac opacity likely reflects atelectasis but infection is not excluded in the correct clinical setting .