Summarize the radiology report findings into an impression within 3 sentences.
    INPUT: A left - sided pacer unit demonstrates leads in the right atrium , right ventricle , and coronary sinus . A coronary stent is present . The heart size is at the upper limits of normal . The mediastinal contours demonstrate calcified atherosclerotic disease of the aortic knob . The lungs are clear of consolidation . In the lateral lower portion of the right lung , the previously described ill - defined nodular opacity is less apparent and sits over the intersection of tubes and bronchovascular structure , likely reflecting the superimposition of normal structures .
    OUTPUT:
    
The previously described nodular opacity is less conspicuous on the current exam and most likely reflects the summation of normal overlapping structures .