Understanding a Shuntogram (Shunt Patency Study)

Shunt flow studies are tests used to check if the shunt—a medical device designed to manage hydrocephalus by diverting cerebrospinal fluid (CSF) —is working properly.  These studies help doctors assess how well CSF is flowing through the shunt system.  The test is often called a ‘shuntogram’ or a shunt patency study.

Shuntograms can use a radioactive medicine (‘nuclear shuntogram’) or a special medication that can be seen on X-rays or CT scans, that acts as a tracer and can be followed in the shunt.  The study can show if there is flow through the shunt, reveal a leak, and sometimes can help to show if there is a problem at the end of the shunt.

When Do You Need a Shuntogram?

Doctors might recommend a shuntogram if someone with hydrocephalus has symptoms that could mean the shunt isn’t working right, such as:

• Headaches
• Nausea and vomiting
• Trouble thinking or moving normally
• Feeling very tired
• Vision problems

These issues can happen if the shunt isn’t draining fluid the way it should, usually due to pressure increasing in the brain.  Sometimes these symptoms can be related to over-drainage, and defining if the shunt is open and flowing is important. 

How is a Shuntogram Performed?

A shuntogram is usually performed by a member of the neurosurgery team or a radiologist in a hospital or specialized imaging center.  The procedure typically involves the following steps:

1. Getting Ready: The patient lies down, and the area around the shunt is cleaned. The doctor may use a numbing medicine to make the procedure more comfortable.
2. Injecting the Dye:  The tracer (contrast dye or nuclear material) must be injected into the shunt.  A small needle is inserted in the shunt at a reservoir.  Sometimes the doctor will observe for any CSF that comes out before injecting a very small amount of the tracer into the shunt.
3. Taking Imaging: Depending on the tracer used, the radiologist will use X-rays, fluoroscopy, or a nuclear camera to follow the tracer through the shunt.  This can take some time (as long as 30 minutes) and occasionally the patient will be moved to a sitting position for a short time before repeating the imaging.
4. Reviewing Results: The images are checked to see whether the shunt is working.  Is the fluid moving through the shunt as expected?  Does it not get to the end?  Does it end up in a small area at the end of the shunt.

Risks and Considerations

A shuntogram is generally safe, but like any medical procedure, it has some risks, such as:

• Infection: There’s a very small chance of infection from inserting the needle.
• Allergic Reaction: Some patients may have an allergic reaction to the contrast dye; reaction to the nuclear material is extremely rare.
• Discomfort: Mild discomfort or soreness at the injection site may occur.

Before the test, patients should tell their doctor about any allergies, medical conditions, or medications they are taking.

What Happens After the Test?

After the shuntogram, the healthcare team will explain the results. If the test shows a problem with the shunt, the next steps might include:

• Additional imaging tests, such as a CT scan or MRI
• Watching symptoms closely
• A shunt revision (surgery) to repair or replace the shunt

Conclusion

Shuntograms are a helpful diagnostic test to check if a shunt is working properly. By showing how fluid flows through the shunt, this tests helps doctors decide the best next steps in your treatment. If you or a loved one experiences symptoms of a shunt malfunction, talk with your doctor about whether a shuntogram or other diagnostic tests might be needed.

Information you can trust! This article was produced by the Hydrocephalus Association, copyright 2025. We would like to thank Bruce A. Kaufman, MD for his valuable contribution and expert input.