Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Patient is status post median sternotomy and CABG . Low lung volumes are present . Heart size is moderately enlarged . Mediastinal contours appear unchanged . Crowding of bronchovascular structures is noted with probable mild pulmonary vascular congestion . Elevation of the right hemidiaphragm appears to be chronic . Patchy opacities in the lung bases may reflect areas of atelectasis . No pleural effusion or pneumothorax is demonstrated . The osseous structures are diffusely demineralized .
    OUTPUT:
    
Low lung volumes with patchy opacities in the lung bases , likely atelectasis . Mild pulmonary vascular engorgement .