Renal Ultrasound (U/S)

What is a Renal U/S?

It is a diagnostic test to evaluate the size, shape and position of kidneys. It is performed  with an ultrasound device that has a special fixed probe for investigating the kidneys. Most ultrasound devices today have also Doppler technology integrated for evaluating renal blood flow.  The examination procedure is performed by a Radiologist or Urologist trained in Urinary Tract Ultrasonography. 

When is a Renal U/S performed?

Your physician may recommend a Renal Ultrasound for various reasons:

  • In case you suffer from urinary tract symptoms, such as hematuria or renal colic. U/S can diagnose pathological renal conditions, such as stones, abscesses, obstructions, fluid collection around kidneys and tumors.
  • In some cases , U/S can help obtain renal biopsies or place a tube (catheter) through the skin into the kidney to drain urine (percutaneous nephrostomy).
  • In case of febrile UTI (urinary tract infection with fever), to avoid any potentially occurring renal obstruction.
  • In injuries of the renal region (car accidents, falls from height), so as to rule out any renal hematoma or rupture.

What preparation is needed for a Renal U/S?

No special preparation is needed. You should though be aware that some factors or conditions may affect the results of a Renal U/S.  Such factors are:

  • Severe obesity.
  • Presence of large amounts of gases or stool in the bowel.
  • Recent barium intake for some other radiological examination.

U/S has no radiation, and is absolutely safe for pregnant women and children.

How is a Renal U/S performed?

You may need to undergo a Renal U/S either as an outpatient or as a hospital inpatient. Your physician will explain the procedure and answer any questions related to the test you may potentially have. The procedure is as follows:

  • You will be asked to remove your clothes from the renal region and lie on an examination bed.  Your physician will determine your body position (supine, prone, on the side).
  • A clear viscous gel will be applied on the region to be examined. You should be aware that clothes do not get stained by any potentially remaining gel residues.
  • Then your physician will place the ultrasound probe on the gel and start scanning the region. You will feel only a light pressure without any pain at all. You may be asked to take a deep breath and keep it.
  • Should renal hematoma be identified, a rushing sound (like wind blowing) will be heard.
  • In some cases, you will be asked to go urinate and come back in order to have the test repeated.
  • Once the procedure is completed, the physician will remove the gel from the examined region.

Following the U/S procedure, you can right away resume to your everyday activities without any restrictions. 

How are the results of a Renal U/S interpreted?

Should there be any abnormal finding, the physician will inform you about this. You will be given further instructions and information about therapeutic options that are appropriate for you. In case of doubts, you may be recommended to undergo more specific screening (MRI, CT scan etc).