Adrenal Gland Scan

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Adrenal Gland Scan

 

Definition

The adrenal gland scan is a nuclear medicine evaluation of the medulla (inner tissue) of the adrenal gland.

Purpose

The adrenal glands are a pair of small organs located just above the kidney, which contain two types of tissue. The adrenal cortex produces hormones that affect water balance and metabolism in the body. The adrenal medulla produces adrenaline and noradrenaline (also called epinepherine and norepinepherine).
An adrenal gland scan is done when too much adrenaline and noradrenaline is produced in the body and a tumor in the adrenal gland is suspected. One such situation in which a tumor might be suspected is when high blood pressure (hypertension) does not respond to medication. Tumors that secrete adrenaline and noradrenaline can also be found outside the adrenal gland. An adrenal gland scan usually covers the abdomen, chest, and head.

Precautions

Adrenal gland scans are not recommended for pregnant women because of the potential harm to the developing fetus. A pregnant woman should discuss with her doctor the risks of the procedure against the benefits of the information it can provide in evaluating her individual medical situation.
People who have recently undergone tests that use barium must wait until the barium has been eliminated from their system in order to obtain accurate results from the adrenal gland scan.

Description

The adrenal gland scan takes several days. On the first day, a radiopharmaceutical is injected intravenously into the patient. On the second, third, and fourth day the patient is positioned under the camera for imaging. The scanning time each day takes approximately 30 minutes. It is essential that the patient remain still during imaging.
Occasionally, the scanning process may involve fewer than three days, or it may continue several days longer. The area scanned extends from the pelvis and lower abdomen to the lower chest. Sometimes the upper legs, thighs, and head are also included.

Preparation

For two days before and ten days after the injection of the radiopharmaceutical, patients are given either Lugol's solution or potassium iodine. This prevents the thyroid from taking up radioactive iodine and interfering with the scan.

Aftercare

The patient should not feel any adverse effects of the test and can resume normal activity immediately. Follow-up tests that might be ordered include a nuclear scan of the bones or kidney, a computed tomography scan (CT) of the adrenals, or an ultrasound of the pelvic area.

Risks

The main risk associated with this test is to the fetus of a pregnant woman.

Normal results

Normal results will show no unusual areas of hormone secretion and no tumors.

Abnormal results

Abnormal results will show evidence of a tumor where there is excessive secretion of adrenaline or noradrenaline. Over 90% of these tumors are in the abdomen.

Resources

Books

Fishback, Francis, editor. A Manual of Laboratory and Diagnostic Tests. 5th ed. Philadelphia: Lippincott, 1996.

Key terms

Adrenal cortex — The outer tissue of the adrenal gland. It produces a group of chemically related hormones called corticosteroids that control mineral and water balance in the body and include aldosterone and cortisol.
Adrenal medulla — The inner tissue of the adrenal gland. It produces the hormones adrenaline and noradrenaline.
Lugol's solution — A strong iodine solution.

Adrenal Gland Scan

Synonym/acronym: Adrenal scintiscan.

Common use

To assist in the diagnosis of Cushing’s syndrome and differentiate between adrenal gland cancer and infection.

Area of application

Adrenal gland.

Contrast

Intravenous radioactive NP-59 (iodomethyl-19-norcholesterol) or metaiodobenzylguanidine (MIBG).

Description

This nuclear medicine study evaluates the function of the adrenal glands. The secretory function of the adrenal glands is controlled primarily by the anterior pituitary, which produces adrenocorticotropic hormone (ACTH). ACTH stimulates the adrenal cortex to produce cortisone and secrete aldosterone. Adrenal imaging is most useful in differentiation of hyperplasia from adenoma in primary aldosteronism when computed tomography (CT) and magnetic resonance imaging (MRI) findings are equivocal. High concentrations of cholesterol (the precursor in the synthesis of adrenocorticosteroids, including aldosterone) are stored in the adrenal cortex and this allows the radionuclide, which attaches to the cholesterol, to be used in identifying pathology in the secretory function of the adrenal cortex. The uptake of the radionuclide occurs gradually over time and imaging is performed within 24 to 48 hr of radionuclide injection and continued daily for 3 to 5 days. Imaging can reveal increased uptake, unilateral or bilateral uptake, or absence of uptake in the detection of pathological processes. Following prescanning treatment with corticosteroids, suppression studies can also be done to differentiate the presence of tumor from hyperplasia of the glands.

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.
  • high alert Conditions associated with adverse reactions to contrast medium (e.g., asthma, food allergies, or allergy to contrast medium). Although patients are still asked specifically if they have a known allergy to iodine or shellfish, it has been well established that the reaction is not to iodine; in fact, an actual iodine allergy would be very problematic because iodine is required for the production of thyroid hormones. In the case of shellfish, the reaction is to a muscle protein called tropomyosin; in the case of iodinated contrast medium, the reaction is to the noniodinated part of the contrast molecule. Patients with a known hypersensitivity to the medium may benefit from premedication with corticosteroids and diphenhydramine; the use of nonionic contrast or an alternative noncontrast imaging study, if available, may be considered for patients who have severe asthma or who have experienced moderate to severe reactions to ionic contrast medium.

Indications

  • Aid in the diagnosis of Cushing’s syndrome and aldosteronism
  • Aid in the diagnosis of gland tissue destruction caused by infection, infarction, neoplasm, or suppression
  • Aid in locating adrenergic tumors
  • Determine adrenal suppressibility with prescan administration of corticosteroid to diagnose and localize adrenal adenoma, aldosteronomas, androgen excess, and low-renin hypertension
  • Differentiate between asymmetric hyperplasia and asymmetry from aldosteronism with dexamethasone suppression test

Potential diagnosis

Normal findings

  • No evidence of tumors, infection, infarction, or suppression
  • Normal bilateral uptake of radionuclide and secretory function of adrenal cortex
  • Normal salivary glands and urinary bladder; vague shape of the liver and spleen sometimes seen

Abnormal findings related to

  • Adrenal gland suppression
  • Adrenal infarction
  • Adrenal tumor
  • Hyperplasia
  • Infection
  • Pheochromocytoma

Critical findings

    N/A

Interfering factors

  • Factors that may impair clear imaging

    • Retained barium from a previous radiological procedure.
    • Inability of the patient to cooperate or remain still during the procedure because of age, significant pain, or mental status.
  • Other considerations

    • Improper injection of the radionuclide 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/).
    • 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 radiation exposure level.

Nursing Implications and Procedure

Pretest

  • Positively identify the patient using at least two unique identifiers before providing care, treatment, or services.
  • Patient Teaching: Inform the patient this procedure can visualize and assess the function of the adrenal gland, which is located near the kidney.
  • Obtain a history of the patient’s complaints or clinical symptoms, including a list of known allergens, especially allergies or sensitivities to latex, anesthetics, contrast medium, or sedatives.
  • Obtain a history of the patient’s endocrine system, symptoms, and results of previously performed laboratory tests and diagnostic and surgical procedures.
  • Perform all adrenal blood tests before doing this test.
  • Record the date of last menstrual period and determine the possibility of pregnancy in perimenopausal women.
  • Obtain a list of the patient’s current medications, including herbs, nutritional supplements, and nutraceuticals (see Effects of Natural Products on Laboratory Values).
  • If iodinated contrast medium is scheduled to be used in patients receiving metformin (Glucophage) for non–insulin-dependent (type 2) diabetes, the drug should be discontinued on the day of the test and continue to be withheld for 48 hr after the test. Iodinated contrast can temporarily impair kidney function, and failure to withhold metformin may indirectly result in drug-induced lactic acidosis, a dangerous and sometimes fatal side effect of metformin (related to renal impairment that does not support sufficient excretion of metformin).
  • Review the procedure with the patient. Address concerns about pain and explain that there may be moments of discomfort and some pain experienced during the test. Inform the patient that the procedure is usually performed in a nuclear medicine department by a nuclear medicine technologist with support staff, and it takes approximately 1 to 2 hr each day. Inform the patient the test usually involves a prolonged scanning schedule over a period of days.
  • Administer saturated solution of potassium iodide (SSKI or Lugol iodine solution) 24 hr before the study to prevent thyroid uptake of the free radioactive iodine.
  • 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, contrast medium, or emergency medications.
  • Note that there are no food, fluid, or medication restrictions unless by medical direction.
  • Instruct the patient to remove jewelry and other metallic objects from the area to be examined.
  • Make sure a written and informed consent has been signed prior to the procedure and before administering any medications.

Intratest

  • Potential complications:
  • Injection of the contrast is an invasive procedure. Complications are rare but do include risk for: allergic reaction (related to contrast reaction), hematoma (related to blood leakage into the tissue following needle insertion), bleeding from the puncture site (related to a bleeding disorder, or the effects of natural products and medications known to act as blood thinners), or infection (which might occur if bacteria from the skin surface is introduced at the puncture site).

  • Avoid the use of equipment containing latex if the patient has a history of allergic reaction to latex.
  • Observe standard precautions, and follow the general guidelines in Patient Preparation and Specimen Collection. Positively identify the patient.
  • Ensure that the patient has removed external metallic objects from the area to be examined prior to the procedure.
  • 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.
  • Insert an IV line, and inject the radionuclide IV on day 1; images are taken on days 1, 2, and 3. Imaging is done from the urinary bladder to the base of the skull to scan for a primary tumor. Each image takes 20 min, and total imaging time is 1 to 2 hr per day.
  • Instruct the patient to cooperate fully and to follow directions. Instruct the patient to remain still throughout the procedure because movement produces unreliable results.

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.
  • Advise the patient to drink increased amounts of fluids for 24 to 48 hrs to eliminate the radionuclide from the body, unless contraindicated. Inform the patient that radionuclide is eliminated from the body within 24 to 48 hr.
  • Do not schedule other radionuclide tests 24 to 48 hr after this procedure.
  • Observe/assess the needle site for bleeding, hematoma formation, and inflammation.
  • Instruct the patient in the care and assessment of the injection site.
  • Instruct the patient to apply cold compresses to the puncture site as needed to reduce discomfort or edema.
  • If a woman who is breast-feeding must have a nuclear scan, she should not breast-feed the infant until the radionuclide has been eliminated. This could take as long as 3 days. Instruct her 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 48 hrs after the procedure.
  • Instruct all caregivers to wear gloves when discarding urine for 48 hrs after the procedure. Wash gloved hands with soap and water before removing gloves. Then wash ungloved hands after the gloves are removed.
  • Recognize anxiety related to test results. 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. Advise the patient that SSKI (120 mg/day) will be administered for 10 days after the injection of the radionuclide. 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 ACTH and challenge tests, aldosterone, angiography adrenal, catecholamines, CT abdomen, cortisol and challenge tests, HVA, MRI abdomen, metanephrines, potassium, renin, sodium, and VMA.
  • Refer to the Endocrine System table at the end of the book for related tests by body system.