Meckel's diverticulum scanning is a nuclear study performed to assist in diagnosing the presence and size of this congenital anomaly of the gastrointestinal tract. The condition can become symptomatic in children and adults, causing bleeding, diverticulitis, volvulus, or intussusception. The radionuclide 99mTc as technetium Tc 99m pertechnetate is administered IV, and immediate and delayed imaging are performed of the abdominal lower right quadrant (LRQ). The radionuclide is taken up and concentrated by gastric mucosa, a type of tissue found in Meckel's diverticulum, and a focal increase in activity is associated with an abnormality.

• Normal distribution of radionuclide by gastric mucosa at normal sites; no ectopic gastric mucosa revealed by uptake activity in abnormal structures

• Inability of client to remain still during the procedure
• Barium in the bowel from previous radiologic studies

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Indications

• Unexplained abdominal pain and gastrointestinal bleeding in adults and children as a result of hydrochloric acid and pepsin secretions by ectopic gastric mucosa causing ulceration of nearby mucosa⁴⁸
• Detecting sites of ectopic gastric mucosa revealed by focal increased activity in areas other than normal structures

Contraindications

• Pregnancy, unless the benefits of performing the procedure greatly outweigh the risks to the fetus

[Section Outline]

• Indications
• Contraindications

Nursing Care Before the Procedure

Client teaching and physical preparation are the same as for any nuclear scan study (see section under "Brain Scanning").

• Inform the client of the scanning schedule and explain that the study takes 1 hour.
• Instruct the client to restrict food for 6 to 8 hours and to restrict water and medications according to agency policy or physician preference.
• Advise that a nasogastric (NG) tube may be inserted and medications administered during the procedure to enhance imaging.
• A histamine H2 antagonist, cimetidine (Tagamet), in doses of 300 mg four times per day, is administered 2 days before the scan to block acid secretion and to keep the radionuclide from gastric mucosa. This practice improves the lesion-background ratio in the scan.⁴⁹
• History should include information about signs, symptoms, and conditions associated with Meckel's diverticulum, such as pain, bleeding, intussusception, volvulus, and diverticulitis, and results of diagnostic tests and procedures.

The client is placed on the examining table in a supine position and the radiopharmaceutical is administered IV. Initial anterior abdominal images are obtained for 1 minute to screen for a vascular lesion that could cause bleeding. The client is requested to remain still during the scanning and is informed that positions are changed to obtain different views. Delayed imaging of the left upper portion of the abdomen to obtain stomach views and of a lower field of view of the bladder is performed. Imaging takes place every 5 minutes for 1 hour in anterior, oblique, and lateral views, including a postvoiding view. Modifications can be made to facilitate the study, such as positioning the client on the left side with the table tilted 45 to 90 degrees to decrease emptying of the radiopharmaceutical from the stomach into the bowel. Another modification is insertion of an NG tube into the stomach to decrease peristalsis and emptying of the radiopharmaceutical from the stomach into the bowel. Also, glucagon or pentagastrin, or both, can be administered to control uptake of the radionuclide.⁵⁰

Nursing Care After the Procedure

Care and assessment after the procedure are the same as for any nuclear scan study (see section under "Brain Scanning").