Hi, Thanks for writing in. A smaller right kidney with increase in cortical echogenicity can indicate decreased kidney function. FOr this the serum creatinine must be measured and glomerular filtration rate is also assessed. Disease in the right kidney might be in the initial stages. The most common cause of renal artery stenosis is a blockage in the arteries due to high cholesterol. This problem occurs when a sticky, fatty substance called plaque builds up on the inner lining of the arteries. When the arteries that carry blood to your kidneys become narrow, less blood flows to the kidneys. The kidneys mistakenly respond as if your blood pressure is low. As a result, they release hormones that tell the body to hold on to more salt and water. This causes your blood pressure to rise.