A DMSA renal scan is a specialized nuclear medicine test used to evaluate the physical shape, size, and structure of your kidneys, and check for any permanent scar tissue. DMSA stands for dimercaptosuccinic acid, a compound that binds to the outer layer of the kidneys.
During the scan, a tiny amount of a radioactive tracer is injected into your vein. After waiting a few hours for the kidneys to absorb the tracer, a specialized camera takes images. Areas of healthy kidney tissue will absorb the tracer and glow, while scarred or damaged areas will not.
Common Indications for a DMSA Renal Scan
- Checking for kidney scarring caused by recurrent urinary tract infections (UTIs) or kidney infections (pyelonephritis).
- Evaluating children with vesicoureteral reflux (VUR), where urine flows backward from the bladder to the kidneys.
- Investigating congenital kidney abnormalities (such as an ectopic or horseshoe kidney).
- Assessing the relative function of each kidney (determining if one kidney is doing more work than the other).
What exactly does a DMSA renal scan show?
The scan shows high-resolution images of your kidney tissue. It highlights the location, size, and severity of any kidney scarring. It also calculates the exact percentage of function contributed by each kidney (healthy kidneys should contribute about 50% each).
How should I prepare for a DMSA renal scan?
No fasting is required. You should drink plenty of fluids before the scan. For children, it is helpful to keep them well-hydrated to help flush the tracer out afterward. Bring books, toys, or tablet screens, as there is a long waiting time between the injection and the imaging session.
Do I need to stop taking medication?
No. Continue taking all your prescribed medications as normal. Let the scan team know if your child is taking antibiotics.
What happens when I arrive for my scan?
You will go to the nuclear medicine suite. A nurse will insert an IV line and inject the DMSA tracer. You will then have a 2 to 3 hour waiting period to allow the kidneys to absorb the tracer. You can leave the clinic during this wait, eat, and drink normally.
How is the procedure performed?
After the waiting period, you will return. You will lie flat on your back on a scan table. A large gamma camera will be positioned close to your abdomen and back. The camera will take images for about 15 to 20 minutes. You must lie completely still. The camera does not touch you or emit any radiation.
How long does a DMSA renal scan take?
The imaging part takes about 20 minutes. However, including the 2 to 3 hour waiting time after the injection, the entire process takes about 3 hours.
Is there any discomfort?
The scan itself is painless. You will feel a brief pinch from the IV needle during the injection. The tracer does not cause any side effects or sensations.
Are there risks?
The tracer exposes you to a small dose of radiation, similar to a standard X-ray. The tracer is quickly eliminated from your body in your urine. Drinking plenty of fluids after the scan helps flush it out.
Can children have this scan?
Yes. This scan is very commonly performed on young children who have had severe urinary tract infections. Pediatric teams are specially trained to insert IV lines gently and make children comfortable on the scan table.
Can I have this scan if I am pregnant?
Pregnancy Precaution
Tell your doctor or radiographer if you are pregnant or think you might be. Because this scan uses radioactive tracers, it is avoided during pregnancy to protect the unborn baby.
When will I get my results?
A nuclear medicine specialist will analyze the images. A report will be sent to your referring doctor (often a pediatrician or urologist) within 24 hours.
What if the scan finds something?
If the scan shows kidney scarring or reduced function in one kidney, your referring doctor will discuss management. This may involve long-term antibiotics to prevent infections, further urological testing, or surgery to correct urinary reflux.
Conclusion
A DMSA scan is a highly precise way to check for kidney damage and scarring. Remember to drink plenty of fluids before and after the scan, and prepare for the 2 to 3 hour waiting time between the injection and imaging.