Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Frontal and lateral chest radiographs were obtained , but evaluation is somewhat limited by patient rotation . Again seen is moderate cardiomegaly and extensive calcification of the thoracic aorta . Leftward shift of the mediastinum is similar in appearance to ___ and ___ , possibly related to left volume loss . There is persistent elevation of the left hemidiaphragm . Right base atelectasis is also persistent . A rounded retrocardiac opacity projecting posteriorly on lateral view is of unclear etiology . No definite focal consolidation is identified . Pleural fluid is seen within the fissure on the left . There is no pneumothorax . Chronic rib deformities are again noted .
    OUTPUT:
    
1 . Rounded mass - like opacity projecting over the posterior lung is of unclear etiology , and should be further evaluated with CT .