Look for blocked urine flow in a kidney. If needed, a kidney ultrasound can find out the size of the kidneys, detect a mass, or detect fluid surrounding the kidneys. It can also look for causes of bladder infections that won't go away. Or it can check how the kidneys are doing after a transplant.
Find out if a mass in a belly organ is a solid tumor or a fluid-filled cyst.
Guide the placement of a needle or other tool during a biopsy.
Look for fluid buildup in the belly cavity. This problem is called ascites. An ultrasound also may be done to guide the needle during a paracentesis. This is a procedure to remove fluid from the belly cavity.
How To Prepare
Tell your doctor if you have had a barium enema or upper GI (gastrointestinal) tests within the past 2 days. Barium that stays in the intestines can affect the results of the ultrasound.
You may need to prepare in other ways too. It depends on what test you are having. For example:
If you are having your liver, gallbladder, spleen, and pancreas checked, you may need to eat a fat-free meal on the evening before the test. Then you may need to avoid eating for 8 to 12 hours before the test.
For a test of the kidneys, you may be asked to drink 4 to 6 glasses of liquid about an hour before the test. This is to fill your bladder. You may need to avoid eating for 8 to 12 hours before the test to avoid gas buildup in the intestines. Gas could affect the results of the kidney ultrasound.
If you are having your aorta checked, you may need to avoid eating for 8 to 12 hours before the test.