Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Within the limitations of technique , although the heart has a left ventricular configuration , it is probably normal in size . The aorta is mildly tortuous . There is a retrocardiac nodular density which is probably due to summation shadow of converging ribs and pulmonary markings ; otherwise lung fields appear clear . There is no pleural effusion or pneumothorax .
    OUTPUT:
    
No evidence of acute cardiopulmonary disease . When clinically feasible repeat standard PA and lateral radiography is suggested in order to reassess the left lung base regarding artifact versus , less likely , nodular density .