MRI (Magnetic Resonance Imaging) Scan- MRI scan exposes the body to a strong magnetic field and creates images based on the molecular composition of different organs and tissues. The amount of fine detail in the pictures is greater than with either the ultrasound or CAT scan. However, the procedure, since it involves exposing the patient to a strong magnetic field, cannot be used in those who have metal devices in their bodies (such as pacemakers or defibrillators).
Ultrasound- Ultrasound uses sound waves to bounce off structures in the body and give images, in the same way as sonar is used by submarines to map the ocean floor, or as sound waves are used by flying bats. This test help to find the amount of scarring in a kidney, whether there is blockage to urine flow anywhere in the kidney, the ureters, or the bladder. Also, it helps to deter the kidney size and cyst size.
CAT (Computed Axial Tomography) Scan- CAT scan requires X-rays to produce pictures. It helps find kidney cysts, stones, blockage and other solid masses etc. CAT scans are sometimes done using contrast dye, which (as with IVPs) carries the risk of inducing an allergic reaction and/or causing renal failure, especially in people who already have reduced kidney function.
IVP (Intravenous pyelogram)- IVP uses x-rays to picture your kidneys, bladder and ureters. A substance called "contrast dye" is injected into a vein, circulates through the bloodstream, and is processed and excreted by the kidneys. But when you are in kidney function decline, this test are not done.
This technique produces two-dimensional black-and-white images and can provide fairly-detailed information about the size and shape of the kidneys, as well as the presence of kidney stones and sometimes cysts or tumors.