Meckel’s diverticulum scan

What is a Meckel’s Diverticulum Scan?

A Meckel’s diverticulum scan is a specialized imaging test used to detect Meckel’s diverticulum, which is a small pouch or outpouching that occurs in the wall of the small intestine. This scan uses a radioactive tracer (Tc-99m pertechnetate) that is specifically attracted to gastric mucosa (stomach lining tissue) that may be present in the diverticulum.

What is Meckel’s Diverticulum?

Meckel’s diverticulum:

• Is present in approximately 2% of the population
• Forms during fetal development when part of the digestive tract doesn’t develop normally
• Often contains gastric tissue (stomach lining) that can secrete acid
• May cause no symptoms in many people, but can lead to complications in others
• Is the most common congenital (present at birth) abnormality of the digestive tract
• Is more commonly diagnosed in children but can be found in adults as well

Why Might I Need This Scan?

Your doctor may recommend this scan if you or your child has:

• Unexplained rectal bleeding (especially painless, maroon-colored, or bright red blood)
• Abdominal pain that has no clear cause
• Intestinal obstruction
• Symptoms that suggest Meckel’s diverticulum, such as vomiting, nausea, or abdominal distention

This scan is particularly useful for children with unexplained gastrointestinal bleeding, as Meckel’s diverticulum is one of the most common causes of significant intestinal bleeding in children.

How Does the Scan Work?

The scan works because:

1. The radioactive tracer (Tc-99m pertechnetate) is attracted to and accumulates in gastric tissue
2. Since Meckel’s diverticulum often contains gastric tissue, the tracer will concentrate in these areas
3. A special camera (gamma camera) detects the radiation emitted by the tracer
4. This creates images showing where the tracer has accumulated
5. Abnormal accumulation of the tracer in the right lower quadrant of the abdomen may indicate the presence of a Meckel’s diverticulum

Preparing for Your Scan

• You (or your child) will need to fast for 4-6 hours before the scan
  • For infants, this may be modified to 2-3 hours; your doctor will provide specific instructions
• Continue taking most regular medications with small sips of water
• You may be given medication called an H2 blocker (such as cimetidine, ranitidine, or famotidine) for 1-2 days before the test to improve the accuracy of the scan
• Inform your doctor if you:
  • Are pregnant or breastfeeding
  • Have had recent barium studies (these should be completed at least 3 days before the scan)
  • Have had recent endoscopy procedures
  • Have had recent abdominal surgery

What to Expect During the Procedure

Before the Scan

• You’ll be asked to change into a hospital gown or wear comfortable clothing without metal
• You’ll be positioned on an examination table lying on your back
• An IV line will be inserted into a vein in your arm or hand

During the Scan

1. The radioactive tracer will be injected through the IV
   • This injection is painless beyond the initial needle insertion
   • The tracer has no side effects and will not make you feel different
2. Immediate imaging:
   • The gamma camera will begin taking pictures right away to capture blood flow patterns
   • Then images will be taken every 5 minutes for the first 30 minutes
3. Delayed imaging:
   • At 60 minutes after injection, additional images will be taken from different angles
   • You’ll need to lie still during the imaging
4. Additional imaging (if needed):
   • If a suspicious area is identified, a three-dimensional scan (SPECT) may be performed
   • The camera will rotate around your body to capture images from all angles
   • A CT scan may also be performed and combined with the nuclear medicine images for better localization

For Children

• A parent or guardian may stay in the room for comfort
• Child-friendly distraction techniques may be used
• Infants may be swaddled to help them remain still
• The procedure is the same as for adults but may be adapted for comfort

After Your Scan

• You can resume normal activities and diet immediately
• The radioactive tracer will naturally leave your body within 24 hours, primarily through urine
• Drinking extra fluids will help flush the tracer from your body
• A nuclear medicine specialist will interpret the images and send a report to your doctor
• Your doctor will discuss the results with you at your next appointment

What Do the Results Mean?

• Positive scan: Shows abnormal accumulation of the tracer in an area separate from the stomach and bladder, suggesting the presence of a Meckel’s diverticulum
• Negative scan: No abnormal accumulation is seen, suggesting that symptoms are caused by something other than Meckel’s diverticulum

If a Meckel’s diverticulum is confirmed, surgical removal is often recommended, especially if it’s causing symptoms.

Are There Any Risks?

The Meckel’s scan uses a very small amount of radiation. The benefits of identifying the cause of symptoms far outweigh any potential risks from this minimal radiation exposure, especially when the patient is experiencing bleeding or other significant symptoms.

How Long Will the Entire Procedure Take?

The entire procedure typically takes about 1-2 hours:

• Initial preparation and IV placement: 15-20 minutes
• Initial dynamic imaging: 30 minutes
• Waiting period: 30 minutes
• Delayed imaging: 15-20 minutes
• Additional SPECT/CT imaging (if needed): 20-30 minutes

If you have any questions or concerns about the Meckel’s diverticulum scan, please discuss them with your healthcare provider.