What is a renal scan?

A renal or a kidney scan is a medical test to gain an idea of the well-working or functioning of your kidneys. It is also called renal imaging, renal scintigraphy, or a renogram. A renal scan is also performed through CT scans, ultrasounds, MRIs, X-rays. However, a renal scan can be termed as superior and more inquisitive than the other alternatives, since it offers information that other tests can’t generally provide. 

A radioactive material called a radioisotope is injected into your vein. The radioisotope releases gamma rays and a gamma camera or a scanner is used to detect these rays. It governs how the kidneys process the radioisotope. This camera is used to project images on the computer, which are used to determine the overall functioning of the kidneys in a detailed manner.

These images can show structural as well as functional abnormalities in the kidneys if any. If done at an early stage, a lot of kidney problems can be recognized and treated before they become too severe.

What is the procedure for a renal scan?

The procedure starts with getting an intravenous line (IV) in a vein in your hand or arm, through which a radioactive material (also called a tracer) is passed. This tracer will collect in your kidneys. 

During the entire procedure, you will be required to sit or lie on the scanning table and the camera will be moved around you. You might also be required to move in some angles for better images. This entire scanning could take anywhere from 30 minutes to as long as 2 hours. 

After the test is complete, your IV will be removed and you will be allowed to go home. The doctor might also give you certain instructions to follow, like taking in lots of fluids for the next 24 hours. Also, if you experience any kind of side effects on your skin, maybe any kind of swelling or pain, it is expedient to inform your doctor straight away. This happens when your body doesn’t respond well to the tracer used in the scanning procedure.

renal scan

What are the possible complications and risks associated with a renal scan?

Renal imaging is generally considered safe. The amount of radiation exposure is generally lesser in a renal scan, as compared to in an X-ray. The low doses of radiation exposure are generally not associated with any kind of long-term negative impacts on the body. 

However, it could pose risks to women in case they’re pregnant or breastfeeding and you must inform your doctor, to ensure there is no contamination of breast milk and they’re free of any possible risks.

As far as the needle stick for the IV is concerned, it might cause:

  • Redness
  • Bleeding
  • Swelling

The occurrence of these could mean an infection, and you must inform your doctor of this. However, a little dizziness or discomfort is normal and it generally passes after some time.

When is a renal scan needed?

The primary uses of the kidneys in our body are:

  • Removal of urea or liquid waste from the blood through urine
  • Maintenance of a balance of chemicals in the body, like sodium, potassium, etc.
  • Produce the hormone renin, which helps in regulating blood pressure levels in the body
  • Provide the hormone calcitriol, which supplies calcium to your bones

Routine blood tests and urine tests usually show the signs of reduced kidney function in most cases. A renal scan is an advanced option, which delves into identifying the cause of this decreased kidney function, which can be in the form of a disease, or maybe an injury to the kidneys.

During a renal scan, the flow of the radioisotope in the body and the ability of your kidneys to absorb and pass this radioisotope is monitored, which is used to measure the kidney function and accordingly determine the possible causes of it. 

The main uses of a renal scan include:

  1. To identify the decreased flow of blood to the kidneys
  2. To identify any tumors or cysts
  3. To recognize any kind of kidney disease
  4. To evaluate renovascular hypertension
DMSA renal scan

Abnormal results of the renal scan generally could indicate any of the following:

  1. Kidney disease, or a kidney failure in worse conditions
  2. Cysts or tumors
  3. Kidney infection, or inflammation associated with it
  4. Blockage, restricting the blood flow of urine from kidneys to the bladder
  5. Problems with a kidney transplant

How to prepare for a renal scan?

Undergoing a renal scan does not necessarily require any special preparations. Your doctor will already inform you about the things you need to take care of. You can take your normal diet.

You must also inform your doctor of any medications or prescriptions you’re taking since they could affect the renal scan. Your doctor, in such a case, would inform you of the precautions. 

Some common medications that tend to affect your renal scan, include:

  1. ACE inhibitors for high blood pressure or heart diseases
  2. Beta-blockers for high blood pressure or any heart disease
  3. Nonsteroidal anti-inflammatory drugs (NSAIDs), like aspirin or ibuprofen
  4. Diuretics or water pills

Further, the size and shape of our kidneys can also affect the readings of our renal imaging. If one’s kidney structure is abnormal, it can lead to an incorrect reading. In that case, your doctor might inform you to conduct some further tests to have a clear diagnosis of your condition. 

Additional tests might also be required because a renal scan cannot identify the difference between a cyst and a tumor. Hence, further tests are required to confirm the position and get a more definite diagnosis.

 A related term is DMSA Renal scan, which is a nuclear medicine test and mostly used in the case of children. 

This is all about a renal scan. We hope this article helped you understand everything that you need to know about it, the causes, uses, the risks associated with it, the procedure, and all the intricate details. Do visit your doctor if you have queries or feel the need for a renal scan.