Meckel's Diverticulum Scan

Meckel’s Diverticulum Scan

Synonym/acronym: Ectopic gastric mucosa scan, Meckel’s scan, Meckel’s scintigraphy.

Common use

To assess, evaluate, and diagnose the cause of abdominal pain and gastrointestinal bleeding.

Area of application

Abdomen.

Contrast

IV radioactive technetium-99m pertechnetate.

Description

Meckel’s diverticulum scan is a nuclear medicine study performed to assist in diagnosing the cause of abdominal pain or occult gastrointestinal (GI) bleeding and to assess the presence and size of a congenital anomaly of the GI tract. After IV injection of technetium-99m pertechnetate, immediate and delayed imaging is performed, with various views of the abdomen obtained. The radionuclide is taken up and concentrated by parietal cells of the gastric mucosa, whether located in the stomach or in a Meckel’s diverticulum. Up to 25% of Meckel’s diverticulum is lined internally with ectopic gastric mucosal tissue. This tissue is usually located in the ileum and right lower quadrant of the abdomen; it secretes acid that causes ulceration of intestinal tissue, which results in abdominal pain and occult blood in stools.

This procedure is contraindicated for

  • high alert Patients who are pregnant or suspected of being pregnant, unless the potential benefits of a procedure using radiation far outweigh the risk of radiation exposure to the fetus and mother.

Indications

  • Aid in the diagnosis of unexplained abdominal pain and GI bleeding caused by hydrochloric acid and pepsin secreted by ectopic gastric mucosa, which ulcerates nearby mucosa
  • Detect sites of ectopic gastric mucosa

Potential diagnosis

Normal findings

  • Normal distribution of radionuclide by gastric mucosa at normal sites

Abnormal findings related to

  • Meckel’s diverticulum, as evidenced by focally increased radioactive uptake in areas other than normal structures

Critical findings

    N/A

Interfering factors

  • Factors that may impair clear imaging

    • Inability of the patient to cooperate or remain still during the procedure because of age, significant pain, or mental status.
    • Metallic objects (e.g., jewelry, body rings) within the examination field, which may inhibit organ visualization and cause unclear images.
    • Retained barium from a previous radiological procedure.
    • Other nuclear scans done within the preceding 24 hr.

  • Other considerations

    • Improper injection of the radio nuclide may allow the tracer to seep deep into the muscle tissue, producing erroneous hot spots.
    • Consultation with a health-care provider (HCP) should occur before the procedure for radiation safety concerns regarding younger patients or patients who are lactating. Pediatric & Geriatric Imaging Children and geriatric patients are at risk for receiving a higher radiation dose than necessary if settings are not adjusted for their small size. Pediatric Imaging Information on the Image Gently Campaign can be found at the Alliance for Radiation Safety in Pediatric Imaging (www.pedrad.org/associations/5364/ig/).
    • False-positive results may occur from nondiverticular bleeding, intussusception, duplication cysts, inflammatory bowel disease, hemangioma of the bowel, and other organ infections.
    • Inadequate amount of gastric mucosa within Meckel’s diverticulum can affect the ability to visualize abnormalities.
    • Inaccurate timing for imaging after the radionuclide injection can affect the results.
    • Failure to follow dietary restrictions before the procedure may cause the procedure to be canceled or repeated.
    • Risks associated with radiation overexposure can result from frequent x-ray or radionuclide procedures. Personnel working in the examination area should wear badges to record their level of radiation exposure.

Nursing Implications and Procedure

Pretest

  • Positively identify the patient using at least two unique identifiers before providing care, treatment, or services.
  • Inform the patient this procedure can assist in assessing gastrointestinal bleeding.
  • Obtain a history of the patient’s complaints or clinical symptoms, including a list of known allergens, especially allergies or sensitivities to latex, anesthetics, sedatives, or radionuclides.
  • Obtain a history of the patient’s gastrointestinal system, symptoms, and results of previously performed laboratory tests and diagnostic and surgical procedures.
  • Note any recent procedures that can interfere with test results.
  • Record the date of the last menstrual period and determine the possibility of pregnancy in perimenopausal women.
  • Obtain a list of the patient’s current medications, including anticoagulants, aspirin and other salicylates, herbs, nutritional supplements, and nutraceuticals, especially those known to affect coagulation (see Effects of Natural Products on Laboratory Values online at DavisPlus). Such products should be discontinued by medical direction for the appropriate number of days prior to a surgical procedure. Note the last time and dose of medication taken.
  • Review the procedure with the patient. Address concerns about pain and explain that some pain may be experienced during the test, but there may be moments of discomfort. Reassure the patient that the radionuclide poses no radioactive hazard and rarely produces side effects. Inform the patient that the procedure is performed in a nuclear medicine department by an HCP specializing in this procedure, with support staff, and takes approximately 60 min. Pediatric Considerations Preparing children for a Meckel's diverticulum scan depends on the age of the child. Encourage parents to be truthful about what the child may experience during the procedure (e.g., they may feel a pinch or minor discomfort when the IV needle is inserted) and to use words that they know their child will understand. Toddlers and preschool-age children have a very short attention span, so the best time to talk about the test is right before the procedure. The child should be assured that he or she will be allowed to bring a favorite comfort item into the examination room, and if appropriate, that a parent will be with the child during the procedure. Explain the importance of remaining still while the images are taken.
  • Sensitivity to social and cultural issues, as well as concern for modesty, is important in providing psychological support before, during, and after the procedure.
  • Explain that an IV line may be inserted to allow infusion of IV fluids such as normal saline, anesthetics, sedatives, radionuclides, medications used in the procedure, or emergency medications.
  • Instruct the patient to remove jewelry and other metallic objects from the area to be examined.
  • Instruct the patient to take a histamine blocker, as ordered, 2 days before the study to block GI secretion.
  • Make sure a written and informed consent has been signed prior to the procedure and before administering any medications.
  • Instruct the patient to fast and refrain from fluids for 8 hr prior to the procedure. Protocols may vary among facilities.

Intratest

  • Potential complications:

  • Although it is rare, there is the possibility of allergic reaction to the radionuclide. Have emergency equipment and medications readily available. If the patient has a history of allergic reactions to any substance or drug, administer ordered prophylactic steroids or antihistamines before the procedure.

  • Establishing an IV site and injecting radionuclides is an invasive procedure. Complications are rare but do include bleeding from the puncture site related to a bleeding disorder, or the effects of natural products and medications known to act as blood thinners; hematoma related to blood leakage into the tissue following needle insertion; infection that might occur if bacteria from the skin surface is introduced at the puncture site; or nerve injury that might occur if the needle strikes a nerve.

  • Observe standard precautions, and follow the general guidelines in Patient Preparation and Specimen Collection. Positively identify the patient.
  • Ensure that the patient has complied with dietary, fluid, and medication restrictions for 8 hr prior to the procedure.
  • Ensure that the patient has removed all external metallic objects from the area to be examined prior to the procedure.
  • Avoid the use of equipment containing latex if the patient has a history of allergic reaction to latex.
  • Have emergency equipment readily available.
  • Instruct the patient to void prior to the procedure and to change into the gown, robe, and foot coverings provided.
  • Record baseline vital signs and assess neurological status. Protocols may vary among facilities.
  • Establish an IV fluid line for the injection of saline, anesthetics, sedatives, radionuclides, or emergency medications.
  • Instruct the patient to cooperate fully and to follow directions. Instruct the patient to remain still throughout the procedure because movement produces unreliable results.
  • Place the patient in a supine position on a flat table with foam wedges, which help maintain position and immobilization.
  • IV radionuclide is administered, and the abdomen is scanned immediately to screen for vascular lesions. Images are taken in various positions every 5 min for the next hour.
  • Monitor the patient for complications related to the procedure (e.g., allergic reaction, anaphylaxis, bronchospasm).
  • Remove the needle or catheter and apply a pressure dressing over the puncture site.
  • Observe/assess the needle/catheter insertion site for bleeding, inflammation, or hematoma formation.

Post-Test

  • Inform the patient that a report of the results will be made available to the requesting HCP, who will discuss the results with the patient.
  • Unless contraindicated, advise the patient to drink increased amounts of fluids for 24 to 48 hr to eliminate the radionuclide from the body. Inform the patient that radionuclide is eliminated from the body within 6 to 24 hr.
  • No other radionuclide tests should be scheduled for 24 to 48 hr after this procedure.
  • Instruct the patient to resume usual diet, fluids, and medications, as directed by the HCP.
  • Monitor vital signs and neurological status every 15 min for 1 hr, then every 2 hr for 4 hr, and then as ordered by the HCP. Take temperature every 4 hr for 24 hr. Monitor intake and output at least every 8 hr. Compare with baseline values. Notify the HCP if temperature is elevated. Protocols may vary among facilities.
  • Observe for delayed allergic reactions, such as rash, urticaria, tachycardia, hyperpnea, hypertension, palpitations, nausea, or vomiting.
  • Instruct the patient to immediately report symptoms such as fast heart rate, difficulty breathing, skin rash, itching, chest pain, persistent right shoulder pain, or abdominal pain. Immediately report symptoms to the appropriate HCP.
  • Instruct the patient in the care and assessment of the injection site.
  • If a woman who is breastfeeding must have a nuclear scan, she should not breastfeed the infant until the radionuclide has been eliminated. This could take as long as 3 days. She should be instructed to express the milk and discard it during the 3-day period to prevent cessation of milk production.
  • Instruct the patient to immediately flush the toilet and to meticulously wash hands with soap and water after each voiding for 24 hr after the procedure.
  • Instruct all caregivers to wear gloves when discarding urine for 24 hr after the procedure. Wash gloved hands with soap and water before removing gloves. Then wash hands after the gloves are removed.
  • Nutritional Considerations: A low-fat, low-cholesterol, and low-sodium diet should be consumed to reduce current disease processes. High fat consumption increases the amount of bile acids in the colon and should be avoided.
  • Recognize anxiety related to test results, and be supportive of perceived loss of independent function. Discuss the implications of abnormal test results on the patient’s lifestyle. Provide teaching and information regarding the clinical implications of the test results, as appropriate.
  • Reinforce information given by the patient’s HCP regarding further testing, treatment, or referral to another HCP. Answer any questions or address any concerns voiced by the patient or family.
  • Depending on the results of this procedure, additional testing may be needed to evaluate or monitor progression of the disease process and determine the need for a change in therapy. Evaluate test results in relation to the patient’s symptoms and other tests performed.

Related Monographs

  • Related tests include barium swallow, colonoscopy, CT abdomen, CT pelvis, esophageal manometry, EGD, fecal analysis, gastric acid stimulation, gastric emptying scan, gastrin stimulation, GI blood loss, MRI abdomen, MRI pelvis, and upper GI series.
  • Refer to the Gastrointestinal System table at the end of the book for related tests by body system.