Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: There is severe cardiomegaly , with widening of the mediastinal contour . Additionally , there is a 3 .5 - cm additional rounded contour at the apical lateral aspect of the aortic knob , which appears to be vascular , but is unusual in size and location . The hilar contours show some prominence of central pulmonary vasculature . Trace effusions are present with mild vascular congestion . Incidental note is made of an azygos fissure . There is no pneumothorax .
    OUTPUT:
    
1 . Severe cardiomegaly with mild pulmonary vascular congestion . 2 . 3 .5 - cm additional rounded contour at the apical lateral aspect of the aortic knob , which is of unclear etiology . Further evaluation with a dedicated chest CT with contrast is recommended . Results were uploaded to the online ___ critical results database .