A renal scan, also known as renal scintigraphy, is a medical imaging test that uses radioactive material to assess the function and appearance of the kidneys. The objective of this examination is to assess the efficiency of the kidneys and identify any possible renal disorders or damages in their early stages.
During the examination, a small amount of radioactive material is injected into a vein, and a scanner locates the material in the kidneys, sending images to a computer for analysis. Renal scans are also useful for monitoring the progress of patients after kidney transplants. This medical procedure can help healthcare providers diagnose and treat kidney-related conditions more effectively.
When is a renal scan recommended?
A renal scan is usually ordered by healthcare providers when they suspect that a patient's kidneys may not be functioning properly. This concern may arise after observing reduced kidney function levels during blood and urine tests or on an X-ray. In such cases, a renal scan can help confirm a diagnosis and provide valuable information to help guide treatment.
- Renal scans may be ordered for patients allergic to the X-ray dye, as this test uses radioactive material instead.
- Patients who have undergone a kidney transplant may require a renal scan to ensure the new kidney functions properly.
- Individuals with high blood pressure (hypertension) may be ordered a renal scan to assess the health of their kidneys, which are involved in regulating blood pressure.
- Renal scans may also be ordered for patients who have blocked urinary drainage from their kidneys, as this can lead to kidney damage or infection.
A scan to assess the kidneys may also be ordered by the doctor if:
How does a renal scan work?
A nuclear medicine technologist performs a kidney test to capture images of a patient's kidneys. These images display blood flow in and out of the kidneys and urine flow through the ureters and bladder. By analyzing these images, healthcare providers can determine if there is reduced kidney function or blockage, aiding in diagnosis and treatment planning.
What are the types of renal scans?
Renal scans are performed by nuclear medicine technologists in four ways:
- ACE inhibitor renal scintigraphy : This medical examination aims to determine if there is any narrowing in the renal arteries, which can cause hypertension. The procedure involves taking images of the kidneys before and after the patient takes an ACE inhibitor, a medication that helps lower blood pressure. These images are then reviewed by a healthcare professional.
- Diuretic renal scintigraphy : This nuclear scan detects blockages in the kidneys or difficulties with urine flow. By taking images before and after patients take a diuretic, the healthcare professional can see how urine flows through the kidneys.
- Renal cortical scintigraphy : This kidney scan examines the functioning of the renal cortical tissue (tissue in the outer part of the kidneys). Around two hours after receiving an IV with a radioactive substance, a camera takes photographs.
- Renal perfusion : This nuclear medicine test examines blood flow to the kidneys. The renal scan assesses the diameter of the renal arteries and the function of the kidneys. During the procedure, a camera captures many photographs for a 20- to 30-minute period.
How to prepare for a kidney scan?
Before undergoing a renal scan, it is essential to provide a comprehensive list of all medications, including vitamins and herbal supplements, to your healthcare provider. They may advise you to discontinue certain medications several days before the procedure, such as nonsteroidal anti-inflammatory drugs (NSAIDs), as these can impact the accuracy of the kidney scan results.
Inform the doctor if you are:
- Individuals allergic to certain medications or latex should inform their healthcare provider before undergoing a renal scan.
- Claustrophobic individuals may find the scan uncomfortable, as the camera may come close to them during the procedure.
- Nursing mothers should not undergo a renal scan, as the radioactive material used during the procedure could enter their breast milk.
- Pregnant women, or those who suspect they may be pregnant, should not undergo a renal scan, as the procedure could harm the developing fetus.
In preparation for a nuclear scan, a healthcare provider may instruct the patient to increase their water intake. Additionally, the patient may need to empty their bladder before the start of the exam.
To ensure the accuracy of the scan, it is important to remove all jewelry and metal objects before the procedure or leave them at home, as they can cause interference.
