CT Urogram

A computed tomography (CT) urogram is a useful diagnostic tool for detecting conditions that affect your urinary system. It uses a series of X-rays and a computer to produce three-dimensional images of your soft tissues and bones. CT urograms are painless and have minor risks to your overall health. Most people get their results in a few days.


What is a CT urogram?

Medical professionals use a computed tomography (CT) urogram to examine your urinary system, including your kidneys, bladder and ureters (yer-IT-ters), which are the two thin tubes that carry urine (pee) from your kidneys to your bladder. A CT urogram uses a special contrast dye, X-rays and computers to produce images of your abdomen, pelvis and lower back. It takes pictures that show thin “slices” of your bones, muscles, organs and blood vessels. The pictures allow your healthcare provider to see your urinary system in greater detail.

Traditional X-ray machines use a fixed tube to take two-dimensional (2D) images. CT urograms use a doughnut-shaped tube that rotates the X-ray 360 degrees around your body. A computer takes the images and organizes them into a three-dimensional (3D) view of the inside of your body.


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Why would a urologist order a CT urogram?

Your urologist may order a CT urogram if you have symptoms of a condition that affects your urinary system. A CT urogram helps your healthcare provider see your urinary system. CT urograms can help diagnose:

Who performs a CT urogram?

Radiologic technologists perform CT urograms. A radiologic technologist conducts imaging procedures that help your healthcare provider diagnose a condition.


Test Details

How do I prepare for a CT urogram?

Before your CT urogram, your healthcare provider will check your vitals (temperature, pulse and blood pressure). They’ll also ask you questions, including:

You may need to take a blood test before your CT urogram. A blood test will ensure your healthcare provider uses the right contrast dye.

If you’re allergic to a contrast dye, you may need to take a steroid medication the night before and the morning of your procedure. You will also likely take an antihistamine before the CT urogram. Your healthcare provider can order these medications for you.

Your healthcare provider will also give you instructions on how to prepare for your CT urogram.

What to expect before a CT urogram

You may have to drink water before your CT urogram and hold your pee until after the test. Drinking water and holding your pee will cause your bladder to expand, making it easier for your healthcare provider to assess.

It’s also a good idea to wear comfortable clothes. You may need to change into a gown before the CT urogram and remove your watch and other jewelry, including piercings. You may need to remove your dentures or hearing aids as well. Metal objects can obstruct the scan.


What to expect during a CT urogram

During a CT urogram, you will lie on your back on a table (like a bed), though you may also lie on your sides and stomach. Your healthcare provider may ask you to lie on cushions. Cushions help keep your body in the best, most comfortable position during the scan.

A healthcare provider will use a small needle and tube to deliver the contrast dye directly into a vein in your arm or hand (intravenously). It usually isn’t painful, but you will feel a slight pinch as the needle goes through your skin.

As the contrast dye flows through your veins, you may feel warm or flushed, almost like you’re embarrassed. Some people feel nauseous or develop a headache. You may also have a salty or metallic taste in your mouth, and you may suddenly feel like you have to pee. These feelings should go away after a few moments.

When the scan begins, the bed slowly moves into the doughnut-shaped tube. It’s important to stay as still as possible — movement can create blurry images. Let your healthcare provider know if you have to move because you’re uncomfortable or have an itch.

The scanner takes pictures of the areas that your healthcare provider needs to see. The scanner is relatively quiet as it takes pictures. Some people find the process relaxing and may fall asleep.

However, the bed may be slightly noisy as it gradually moves in and out of the scanner while taking images.

How long does a CT urogram last?

Typically, you should plan for an hour for a CT urogram. You and your healthcare providers need time to prepare. The entire session takes between 10 and 30 minutes in order for your body to process the contrast material. Each scan takes between 10 and 30 seconds to complete. You must have several scans to complete the full exam.

What to expect after a CT urogram

Once the scan is complete and your radiologic technologist verifies that the images are clear, they’ll remove the IV from your vein and bandage the area. If you changed into a gown before the scan, you can put your clothes back on.

What are the risks of a CT urogram?

CT urograms are generally safe. However, CT urograms, like other diagnostic imaging procedures, use a small amount of ionizing radiation to capture images. Some risks associated with CT urograms include:

  • Cancer risk. All imaging that uses radiation causes a small increase in your risk of developing cancer. The increase is too small to measure effectively.
  • Allergic reactions. Occasionally, some people have a minor or more serious allergic reaction to the contrast dye.
  • Bruising or angioedema (swelling). Bruising or swelling around the needle injection site may occur.

If you have any concerns about the risks associated with a CT urogram, talk to your healthcare provider. They will listen to your concerns and help you make an informed decision.

Care at Cleveland Clinic

Results and Follow-Up

When should I know the results of a CT urogram?

The results of your CT urogram may take 1 to 3 days. A physician who specializes in reading and interpreting radiologic images (radiologist) will review your scan and prepare a report that explains their findings. They’ll then discuss their report with you, either over the phone or at another appointment.

In an emergency setting, such as a hospital or emergency room (ER), the results of your CT urogram may take an hour or less.

When should I call my healthcare provider?

Waiting for the results of your CT urogram can be stressful. You should get the results of your CT urogram after a few days, but if you haven’t heard back or if you have any questions or concerns, reach out to your healthcare provider.

Additional Common Questions

Is a CT urogram painful?

No, a CT urogram isn’t painful. You will only feel a slight pinch when your healthcare provider administers the IV.

What is the difference between a CT scan and a CT urogram?

A CT urogram is a type of CT scan. A CT urogram examines your urinary system. CT scans may examine any of the structures in your body, though they may not all use a contrast dye.

What is the difference between a CT urogram and a cystoscopy?

A cystoscopy is a more invasive procedure than a CT urogram. During a cystoscopy, your healthcare provider will insert a lubricated, pencil-sized lighted tube with a camera (cystoscope) through your urethra (where pee comes out of your body) to your bladder. They’ll then inject sterile saltwater into your bladder to make it expand and look at the inside of your bladder and your urethra.

A note from Cleveland Clinic

CT urograms are helpful tests that help your healthcare provider look at your urinary system. They help your healthcare provider accurately diagnose health conditions and provide the proper treatment for you.

You may feel nervous if your healthcare provider orders a CT urogram. However, it’s safe, noninvasive and low-risk. Talk to your healthcare provider if you have any questions or concerns.

Medically Reviewed

Last reviewed by a Cleveland Clinic medical professional on 09/21/2022.

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