A special nuclear medicine procedure called a Meckel's Diverticulum Study, also known as a Meckel diverticulum Scan, is a special nuclear medicine test that is performed to identify ectopic gastric mucosa in the small intestine, most commonly in a Meckel diverticulum.

It is a scan that can be particularly useful in the determination of the cause of unexplained bleeding of the gastrointestinal (GI) tract, specifically in children and adolescents. Meckel diverticulum is a hereditary pouch (true diverticulum) that occurs in about 2 percent of the general population. It may also harbor operative gastric mucosa secreting acid in other instances, causing ulceration and bleeding of the adjacent intestinal mucosa.

The test involves Technetium-99m pertechnetate (99mTc), which is a selective accumulation of a radiotracer in the gastric mucosa. This facilitates proper cell-location and identification of abnormal matter through a gamma camera.

What is Meckel’s Diverticulum?

• A birth defect, which is brought about by the incomplete closure of the vitelline (omphalomesenteric) duct.
• This is usually found at the close of the small intestine between 2 feet and the ileocecal valve area.
• In many cases, this does not display any symptoms, but it can lead to complications in the case of the presence of ectopic tissue.
• May will include gastric or pancreatic mucosa.
• Gastric mucosa has the ability to secrete acid, causing ulcers, inflammation, and bleeding.
• It is usually found in children below the age of 10 years and in adults.

Why is the Meckel’s Scan Performed?

• To identify gastric ectopic mucosa of a possible Meckel diverticulum.
• To determine the cause of unexplained GI bleeding.
• To determine melena (black stools) or hematochezia (fresh blood in stools)?
• Inconclusive endoscopy or colonoscopy.
• To prevent unnecessary invasive procedures.
• To help with pre-operative preparation.

Clinical Indications

• Repeated or idiopathic lower GI bleeding (in children).
• Iron-deficiency anemia is chronic.
• Constant abdominal pain with possible intestinal abnormality.
• Asymptomatic negative endoscopy /colonoscopy.
• There is rectal bleeding, but not due to a visible reason.

How is the Scan Performed?

It is a painless process that is relatively safe and normally finishes in 30-60 minutes:

• The patient is lying with a sense of comfort under a gamma camera.
• A pertechnetate of 99mTc is used intravenously.
• The tracer is concentrated in the gastric mucosa, both ectopic and non-ectopic.
• Immediately, dynamic imaging commences to follow the uptake of tracers.
• Oral images of the abdomen are taken in sequence.

Abnormal finding: One of the focal points of the enhanced tracer uptake is the right lower abdomen, which indicates a possible diverticulum of Meckel.

Other (possibly necessary) Measures: 

• The accuracy can be enhanced by using medications such as cimetidine, pentagastrin, or glucagon.
• In borderline cases, delayed imaging can be done.

Preparation for the Test

• Fasting: 3-4hours before scan.
• Some of the drugs (e.g., antacids, H2 blockers) might require discontinuation.
• Inform the doctor about:

Recent infections

Previous scans

Any known allergies

Distraction or mild sedation can be applied in the case of pediatric patients.

Benefits of Meckel’s Scan

• Non-invasive and painless
• surgery and anesthesia are unnecessary.
• Not functional gastric mucosa, but a structure.
• Able to detect minor or intermittent sources of bleeding.
• Helps assist in precise surgical treatment.
• Low radiation exposure
• Children are safe and repeat studies.

Limitations

• May produce false negatives when there is no gastric mucosa.
• False positives may occur in cases of bowel inflammation or urinary.
• Not able to identify non-functional or fibrotic diverticula.
• May should have more imaging when the results are inconclusive.

Results & Interpretation

A nuclear medicine specialist interprets the scan and examines:

• Abnormal uptake of tracers.
• Tether of a suspected Meckel/ diverticulum.
• Clinical symptoms: Correlation with clinical symptoms.

The reports will usually be made within 2 hours and be used to inform subsequent treatment or surgical choices.

Post-Test Instructions

• Restore regular diet and activities.
• Take ample fluids to get out the tracer.
• Unionize with your physician regarding outcomes and additional treatment.

Conclusion

The Meckel's Diverticulum Study is a diagnostic method of great efficiency and no invasiveness, designed to diagnose intermittent ectopic gastric mucosa, the leading barrier to unknown gastric bleeding of children and young adults.

Through its real-time functional imaging, it assists in the accurate location of the source of bleeding and assists in timely surgical intervention when necessary. This scan is also of much importance when other diagnostic measures fail, thus determining the correct diagnosis and enhancing patient outcomes.

A Meckel's scan can be used to detect if there is a complication and, hence, engage in better clinical management, particularly in children.

Test Information

• Fasting: Required (3–4 hours)
• Reporting Time: Within 2 hours*