The Renal Ultrasound shows the size of any blockages that may be present in the kidney’s arteries, which could reduce blood flow to the kidneys. This, in turn, results in an elevation of the body’s blood pressure. This ultrasound can also be used to monitor a blockage that has been recently treated with an angioplasty or stent, or to monitor the size of the kidneys. A smaller kidney size could indicate reduced blood flow as well.