A DMSA scan, or Dimercaptosuccinic acid scan, is a type of renal (kidney) imaging test used in nuclear medicine. It helps in evaluating kidney function and structure, particularly focusing on kidney infections, scarring, or damage. Here’s how it works and what it involves:
- Procedure
- Radioactive Tracer: A small amount of a radioactive chemical, typically technetium-99m labeled DMSA, is injected into the bloodstream. DMSA is specifically absorbed by the kidney tissue.
- Distribution Phase: After the injection, there’s a waiting period (usually a few hours) to allow the DMSA to be absorbed by the kidneys.
- Imaging: The patient lies under a gamma camera, which detects the radiation emitted by the DMSA concentrated in the kidneys. This creates detailed images of the kidneys.
- Duration: The scan itself usually takes about 30 minutes to an hour.
- Uses
- Kidney Function: Assessing how well the kidneys are functioning.
- Infections: Identifying kidney infections or the extent of damage caused by infections.
- Scarring: Detecting scarring from previous infections or other kidney diseases.
- Congenital Abnormalities: Evaluating congenital abnormalities in children.
- Obstructions: Detecting obstructions or abnormalities in kidney structure.
- Advantages
- Detailed Imaging: Provides detailed images of the kidneys’ internal structure.
- Sensitive: More sensitive in detecting kidney scarring and chronic pyelonephritis than other imaging techniques.
- Safety and Considerations
- Radiation Exposure: Involves exposure to a small amount of radiation, but it’s generally considered safe.
- Preparation: Patients may need to be well-hydrated before the test.
- Pregnancy and Breastfeeding: Not usually recommended for pregnant women. If breastfeeding, women may be advised to take certain precautions after the scan.
- Interpretation
- Normal Result: Uniform uptake of the tracer indicates normal kidney function and structure.
- Abnormal Result: Irregular, reduced, or absent uptake in areas of the kidney may indicate scarring, infection, or other abnormalities.
- Context in Clinical Care
- A DMSA scan is a specialized test, typically ordered when there’s a need to closely examine the kidneys beyond what standard imaging (like ultrasounds or CT scans) can provide. It’s particularly useful in pediatrics for evaluating potential kidney damage from urinary tract infections.