DMSA scan

A DMSA scan, also known as renal cortical scintigraphy, is a highly specialized and sensitive nuclear medicine imaging test used to evaluate the structure and function of the kidneys, especially the renal cortex. This scan is performed using a radiotracer called Technetium-99m dimercaptosuccinic acid (99mTc-DMSA), which selectively binds to functioning renal cortical tissue.  The DMSA scan is widely considered the gold standard for detecting renal scarring, acute pyelonephritis, congenital anomalies, and ectopic or malformed kidneys. It provides valuable insights that cannot be obtained by conventional ultrasound or intravenous urography, particularly in children and patients with suspected urinary tract infections (UTIs).

What is a DMSA Scan?

• The DMSA scan is a non-invasive nuclear medicine test that shows the functional anatomy of the kidneys, primarily the outer cortex, where most of the filtration occurs.
• It helps visualize renal parenchyma, detect scars, and confirm renal abnormalities, making it a key diagnostic tool in pediatric nephrology and urology.
• The radiotracer 99mTc-DMSA is injected intravenously and binds to functioning renal cortical cells. Images are then captured using a Gamma Camera to assess kidney function and structure.

Key Indications for a DMSA Scan

A DMSA scan is most commonly performed in the following clinical situations:

• Acute pyelonephritis – Identifying areas of acute inflammation in the kidney cortex
• Renal scarring – Evaluation of scarring due to repeated or untreated infections (chronic pyelonephritis)
• Congenital kidney anomalies – Including solitary kidneys, ectopic kidneys, and horseshoe kidneys
• Urinary tract infections (UTIs) – Especially in children, to assess damage caused by recurrent infections
• Functional evaluation of split renal function between both kidneys
• Assessment of renal tissue before surgery or kidney donation
• Follow-up imaging after treatment of kidney infections or surgery
• Pre-transplant renal evaluation in certain clinical settings

How is a DMSA Scan Performed?

Preparation:

• Usually, no fasting or special preparation is required.
• The patient should stay hydrated unless otherwise advised.
• Inform the technologist if you are pregnant or breastfeeding.

Procedure:

• Radiotracer Injection
• A small dose of 99mTc-DMSA is injected into a vein, typically in the arm.

Uptake Time

• A waiting period of 2 to 3 hours allows the tracer to be absorbed by functioning kidney tissue.

Imaging

• The patient lies still on a scanning table while a Gamma Camera captures detailed images of the kidneys from multiple angles.

Duration

• The entire test, including uptake and imaging, may take 3 to 4 hours.

Aftercare

• The patient can resume normal activities immediately after the scan.
• Drinking plenty of fluids helps flush the tracer from the body.

Why Choose a DMSA Scan Over Other Imaging Modalities?

• Highly sensitive – Detects twice as many cortical defects as ultrasound
• Superior accuracy – 4 times more effective than intravenous urography in identifying renal scars
• Functional imaging – Shows which areas of the kidney are working properly
• Pediatric friendly – Especially useful in diagnosing UTI complications in children
• Identifies abnormalities – Detects ectopic kidneys or renal duplication anomalies that are hard to find on ultrasound
• Helps guide treatment – Determines the extent of renal damage, aiding in prognosis and therapy planning

 What Conditions Can a DMSA Scan Detect?

The DMSA scan is ideal for diagnosing and monitoring:

• Acute pyelonephritis – Early inflammation detection before permanent damage
• Chronic pyelonephritis – Scarring from recurrent or poorly treated infections
• Congenital anomalies – Solitary kidney, horseshoe kidney, and ectopic renal tissue
• Vesicoureteral reflux (VUR) – Helps assess renal impact in children with VUR
• Kidney trauma – Assessment after blunt or penetrating renal injury
• Differential renal function – Measuring how each kidney contributes to overall function

Benefits of the DMSA Scan

• Non-invasive and safe procedure
• Minimal radiation exposure, especially with modern low-dose protocols
• Early detection of renal scarring and functional loss
• Helps prevent long-term kidney damage with early diagnosis and intervention
• Guides long-term treatment in children and adults with kidney disorders
• Accurate assessment of renal cortical defects even when other scans are inconclusive

Conclusion

The DMSA Scan (Renal Cortical Scintigraphy) is an essential diagnostic tool for evaluating the functional anatomy of the kidneys, particularly in cases of pyelonephritis, renal scarring, and congenital kidney abnormalities. It offers unmatched accuracy in detecting cortical defects, making it far superior to ultrasound or intravenous urography. This scan is especially beneficial in pediatric patients with recurrent urinary tract infections, as early detection and treatment can prevent permanent renal damage and preserve kidney function. With its safety, sensitivity, and non-invasive nature, the DMSA scan remains a gold standard for renal functional imaging.