Healthy Living

What Is Renal Ultrasound Used For?

What Is Renal Ultrasound Used For?

A renal ultrasound is actually a diagnostic procedure, wherein high-frequency sound waves are transmitted through the body tissues that are inaudible to the human ear. The echoes recorded into videos or images of the internal structures of the body.

A wide range of diseases and conditions can be diagnosed using ultrasound imaging. Moreover, ultrasound imaging can also detect blocked blood vessels. This type of imaging is used to produce images of structures of soft tissues such as the liver, kidneys, heart, gallbladder, and female reproductive organs, including fetuses in the womb. Sometimes, they are used alone or with other diagnostic procedures. According to studies, an ultrasound has no harmful side effects.

The three necessary parts of the renal system are:

  • Kidneys - They filter blood and eliminate toxins from the body through urination. 
  • Ureters - They transport urine from the kidneys to the bladder.
  • Bladder - A urinary organ that stores urine and allows voluntary or infrequent urination. 

The normal functions of the renal system are:

  • Prevents the accumulation of wastes and extra fluid in the body
  • Helps regulate blood pressure
  • Secretes important hormones
  • Helps create red blood cells
  • Keeps the bones strong
  • Stabilizes the levels of electrolytes such as potassium and phosphate

Renal Ultrasound

A renal ultrasound is a noninvasive diagnostic imaging test that helps assess the condition of the renal system. The size, location, and shape of the ureters, kidneys, and bladder can be assessed by a renal ultrasound. It is the safest test to obtain images of the parts of the renal system. 

The kidneys are two bean-shaped organs, which are located at the back of the abdominal cavity. The removal of wastes through the creation of urine is their primary function. Urine is transported by the ureters from the kidney to the urinary bladder. Urine is then excreted out of the body through the urethra.

An ultrasound machine works by sending sound waves into the kidney region. The images, which appear as black and white areas, are then recorded on a computer. The images vividly show the internal structure of the kidneys and other related organs.

To detect and diagnose conditions within the kidneys, bladder, and ureters, a renal ultrasound is used. By identifying the changes in the tension of the bladder walls or by identifying the changes in the overall size and structure of the kidneys, certain conditions such as cysts, masses, kidney stones, and infection can be detected.

A renal ultrasound provides a quick way of detecting or ruling out problems in the renal system. As part of the examination, a blood test is combined with a urinalysis to help doctors reach an accurate diagnosis.

The Importance of a Renal Ultrasound

The renal system can still function when the body is under stress or other tough situations. The renal system, like other body systems, is resilient and durable. However, there are still millions of Americans who are at risk of developing chronic kidney disease. Thus, regular testing is highly recommended. 

Purpose of a Renal Scan

Doctors usually recommend a renal scan when a patient's blood and urine tests show certain abnormalities in the renal system. A renal scan can detect tumors, stones, and cysts. 

A renal scan can also detect and evaluate:

  • Kidney problems
  • Low blood flow to the kidneys
  • Renal hypertension
  • Abscesses
  • Success or failure of renal transplants

A renal ultrasound is also used to assess the location, size, and shape of the kidney and other renal organs such as the ureters and urinary bladder.


  • Hematuria (blood in urine)
  • Flank pain
  • Abnormal renal function
  • Dilated upper urinary tract assessment
  • Renal and perirenal mass assessment
  • Postoperative assessment following renal and ureteral surgery
  • Assessment of the upper urinary tract dynamics and urinary effects
  • Urolithiasis monitoring and evaluation
  • Evaluation of blood in urine in individuals who are not candidates for an intravenous pyelogram (IVP), CT scan, or an MRI scan. 
  • Guide to cyst aspiration, transcutaneous or renal biopsies, and ablation of masses
  • Urinary tract stones 
  • Ureter changes

In the emergency department, a relatively common complaint is acute flank pain and abdominal pain with hematuria. Although a urinary obstruction is a likely diagnosis, life-threatening disease processes are included in the differential diagnosis.

The diagnosis of an acute urinary obstruction can be rapidly confirmed by an emergency sonography, which can also help exclude life-threatening disease processes. Obstructive uropathy is a structural impediment to the flow of urine. Typically, this type of obstruction is painful unless it develops slowly. If it causes pain, then it is known as renal colic.

Usually, when kidney and bladder issues are suspected, doctors may recommend a renal ultrasound. A renal ultrasound may reveal:

  • The size of the kidneys
  • Renal abnormalities present since birth
  • Kidney stones or any other blockages
  • Kidney damage 
  • Cysts or tumors
  • Any complications related to the urinary tract

Risks Associated with a Renal Ultrasound

In a renal ultrasound, radiation is not used. By applying the ultrasound transducer on the skin, no general discomfort can be experienced. However, depending on the patient's specific medical condition, there could be risks as everything cannot be ruled out. If you have any concerns, speak with your doctor before undergoing the procedure. Certain factors may interfere with a renal ultrasound, and they include:

  • Intestinal gas
  • Severe obesity
  • Presence of barium in the intestine after a recent barium procedure

What is expected from a renal ultrasound?

A renal ultrasound is usually performed as an outpatient procedure. It can also be one of the tests performed when you are admitted to a hospital. 

In a renal ultrasound, an ultrasound gel is placed in your abdomen. The doctor or technician uses an ultrasound probe to scan the organs in your body. The result of your renal scan will be available within 12-48 hours. A renal ultrasound lasts for about 20-30 minutes. 

How a Renal Ultrasound Is Done


Before the procedure, you may be required to have a full bladder. In general, there are no required preparations such as fasting or sedation prior to the procedure. 

The procedure will be explained by the doctor and may give you the chance to ask questions before undergoing the procedure. Next, a consent form will be given asking your permission for the procedure. Carefully read the consent form and ask questions if there are some things you want to clarify. 

During the Procedure

Generally, a renal ultrasound is done with the following process:

  • You may be asked to wear a hospital gown. Any clothing, accessories, and metal items that may interfere with the scan are removed.
  • On the examination table, you may have to lie down with your stomach facing down.
  • A water-soluble clear gel is applied to the area that will be examined.
  • A transducer is pressed against the skin and around the area to be examined.
  • After the examination of the bladder, you may be told to empty your bladder. After that, any other scan may be performed when needed.
  • After the procedure, the gel is completely wiped off.

After the Procedure

No specialized type of care is needed after the procedure. You can continue doing your normal activities and resume on your normal diet unless otherwise advised by the physician. However, in certain renal conditions, the doctor may give additional or alternative instructions.