Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: Right Port - A - Cath terminates in the right atrium . Heart size is normal . Slight interval widening of the mediastinum may be accentuated by non-upright positioning and may reflect increased intravascular volume with mild distension of the mediastinal veins . The aortic knob contour is unchanged . Lungs are clear . Pleural surfaces are normal .
    OUTPUT:
    
Mild , interval widening of the mediastinum may reflect mediastinal venous distension . Aortic dissection can not be excluded radiographically , so if clinical concern for dissection exists , CTA chest is recommended for further evaluation .