Renal (kidney) ultrasound

Renal (kidney) ultrasound

Ultrasound is very useful for looking at soft tissue parts of the body such as the kidneys and bladder.

What is ultrasound (ultrasonography)?

Ultrasonography uses sound waves (ultrasound) rather than x-rays to create images of an object. These images are called scans. People usually refer to this test as an 'ultrasound' even though the official name is 'ultrasonography'.

Why is my child having an ultrasound scan?

Ultrasound is very useful for looking at soft tissue parts of the body such as the kidneys and bladder. Soft tissues do not show up well on x-ray.

Your baby or child may have a renal ultrasound to:

  • find out if there are any blockages in the urinary tract (kidney, ureter, bladder and urethra)
  • check if their kidneys are normal in shape, size and position
  • look at the blood vessels in the kidneys

All babies with their first UTI (urinary tract infection) should have an ultrasound scan of their urinary tract (urethra, ureter, bladder and kidneys).

Where is the test done?

The test is done in the x-ray (radiology) department of your hospital, or at another x-ray (radiology) centre.

What happens during the test?

  • the bladder should be full for this study
    • children who have bladder control should not empty their bladder for 2 to 3 hours before the ultrasound scan
    • infants who do not have bladder control should have as much fluid as they can tolerate about 30 minutes before the ultrasound scans
  • your child lies on a bed and an ultrasound technologist (sonographer) or an x-ray doctor (radiologist) smoothes a little warm gel on your child's skin and then slides a small instrument called a transducer (which looks a little like a microphone) over the area to be examined
  • this sends ultrasound, which cannot be heard by human ears, into the body
  • the sound waves cannot go through gas or bone so usually your child has to change positions on the bed during the study to get the best possible images
  • the sound waves are reflected by tissues in the body back to the transducer which converts them into an image of the body part
  • the images can be seen on a TV monitor during the study and they are recorded on video or x-ray film, or on a computer

How does it feel?

This is a simple and painless test, much like the scans that women have during pregnancy. Please reassure your child that there is no pain involved.

How can I prepare my child?

  • bring comforters or any toys that will reassure your child; a dummy (pacifier) for babies (if they normally suck on one) can be very soothing
  • see other suggestions in Helping your child manage their health care treatment / procedure
  • many hospitals have play specialists, whose job it is to help explain these tests to your child. Play specialists use play to show your child what is going to happen and ways to help them cope
  • you will be able to stay with your child for the test and your presence can help reassure them

Are there any side effects from ultrasound?

There are no known harmful effects from ultrasound.

How do I find out the results?

The x-ray doctor (radiologist) will examine and interpret the ultrasound scans and make a written report to your doctor.

The information can often be provided to you immediately after the scans.

You can find out more information about some common kidney conditions in children at the Kidney Health New Zealand website.

The Paediatric Society of New Zealand acknowledges the cooperation of the Starship Children's Hospital, Auckland District Health Board. The content on this page has been adapted from:

  • Starship Radiology Department. Starship Children's Health. 2004. Ultrasound examinations: Information for parents and families of children.

This page last reviewed 25 June 2015.
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