HIDA scan


scan

 [skan] 1. to examine or map the body, or one or more organs or regions of it, by gathering information with a sensing device, such as a moving detector or a sweeping beam of radiation.2. the data or image so obtained, often designated according to the organ under examination, such as a brain scan, kidney scan, or thyroid scan.3. shortened form of scintiscan.A-scan display on a cathode ray tube of ultrasonic echoes, in which one axis represents the time required for return of the echo and the other corresponds to the strength of the echo.B-scan display on a cathode ray tube of ultrasonic echoes, in which the position of a bright dot on the tube corresponds to the time elapsed and the brightness of the spot to the strength of the echo; movement of the transducer across the skin surface yields a two-dimensional cross-sectional display.CAT scan (CT scan) the image generated by tomography" >computerized axial tomography.HIDA scan a type of scan using a technetium 99m complex to assess hepatobiliary function.thallium scan a scintiscan" >scintiscan involving use of thallium 201; see also thallium scan.ventilation-perfusion scan (V/Q scan) a scintigraphic technique for demonstrating perfusion defects in normally ventilated areas of the lung in the diagnosis of pulmonary embolism, consisting of the imaging of the distribution of an inhaled radionuclide followed by the imaging of the perfusion of the lungs by an injected radionuclide.

HIDA scan

An imaging procedure for evaluating diseases of the liver, gallbladder, and bile ducts. Hydroxy-iminodiacetic acid (HIDA), is injected into the bloodstream. Its excretion through the biliary tract is observed with a scintillation counter in a nuclear medicine laboratory. Normally HIDA travels from the bile ducts through the cystic duct and into the gallbladder, then out the common bile duct through the sphincter of Oddi into the duodenum. When the flow of bile is obstructed by disease (e.g., a stone, stricture, or malignancy), the passage of the tracer through the biliary tree is slowed or undetectable. See: cholescintigraphySee also: scan

Hepatobiliary Scan

Synonym/acronym: Biliary tract radionuclide scan, cholescintigraphy, hepatobiliary imaging, hepatobiliary scintigraphy, gallbladder scan, HIDA (a technetium-99m diisopropyl analogue) scan.

Common use

To visualize and assess the cystic and common bile ducts of the gall bladder toward diagnosing obstructions, stones, inflammation, and tumor.

Area of application

Bile ducts.

Contrast

IV contrast medium (iminodiacetic acid compounds), usually combined with technetium-99m.

Description

The hepatobiliary scan is a nuclear medicine study of the hepatobiliary excretion system. It is primarily used to determine the patency of the cystic and common bile ducts, but it can also be used to determine overall hepatic function, gallbladder function, presence of gallstones (indirectly), and sphincter of Oddi dysfunction. Technetium (Tc-99m) HIDA (tribromoethyl, an iminodiacetic acid) is injected IV and excreted into the bile duct system. A gamma camera detects the radiation emitted from the injected contrast medium, and a representative image of the duct system is obtained. The results are correlated with other diagnostic studies, such as IV cholangiography, computed tomography (CT) scan of the gallbladder, and ultrasonography. Gallbladder emptying or ejection fraction can be determined by administering a fatty meal or cholecystokinin to the patient. This procedure can be used before and after surgery to determine the extent of bile reflux.

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 acute and chronic cholecystitis
  • Aid in the diagnosis of suspected gallbladder disorders, such as inflammation, perforation, or calculi
  • Assess enterogastric reflux
  • Assess obstructive jaundice when done in combination with radiography or ultrasonography
  • Determine common duct obstruction caused by tumors or choledocholithiasis
  • Evaluate biliary enteric bypass patency
  • Postoperatively evaluate gastric surgical procedures and abdominal trauma

Potential diagnosis

Normal findings

  • Normal shape, size, and function of the gallbladder with patent cystic and common bile ducts

Abnormal findings related to

  • Cholecystitis (acalculous, acute, chronic)
  • Common bile duct obstruction secondary to gallstones, tumor, or stricture
  • Congenital biliary atresia or choledochal cyst
  • Postoperative biliary leak, fistula, or obstruction
  • Trauma-induced bile leak or cyst

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.
    • Retained barium from a previous radiological procedure.
    • Metallic objects (e.g., jewelry, body rings) within the examination field, which may inhibit organ visualization and cause unclear images.
    • Bilirubin levels greater than or equal to 30 mg/dL, depending on the radionuclide used, indicate significant liver damage, which may decrease hepatic uptake.
    • Other nuclear scans done within the previous 24 to 48 hr.
    • Fasting for more than 24 hr before the procedure, total parenteral nutrition, and alcoholism.
    • Ingestion of food or liquids within 2 to 4 hr before the scan.

  • Other considerations

    • Failure to follow dietary restrictions before the procedure may cause the procedure to be canceled or repeated.
    • Improper injection of the radionuclide that allows the tracer to seep deep into the muscle tissue can produce erroneous hot spots.
    • Inaccurate timing of imaging after the radionuclide injection can affect the results.
    • 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 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.
  • Patient Teaching: Inform the patient this procedure can assist in detecting inflammation or obstruction of the gallbladder or ducts.
  • 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 hepatobiliary system, symptoms, and results of previously performed laboratory tests and diagnostic and surgical procedures.
  • Note any recent procedures that can interfere with test results, including examinations using iodine-based contrast medium.
  • 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 herbs, nutritional supplements, and nutraceuticals (see Effects of Natural Products on Laboratory Values online at DavisPlus).
  • Review the procedure with the patient. Address concerns about pain and explain that some pain may be experienced during the test, or there may be moments of discomfort. Reassure the patient that the radionuclide poses no radioactive hazard and rarely produces side effects. Inform the patient the procedure is performed in a nuclear medicine department by an HCP specializing in this procedure, with support staff, and takes approximately 30 to 60 min.
  • 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.
  • Sensitivity to social and cultural issues, as well as concern for modesty, is important in providing psychological support before, during, and after the procedure.
  • Instruct the patient to remove jewelry and other metallic objects from the area to be examined prior to the procedure.
  • Instruct the patient to restrict food and fluids for 4 to 6 hr prior to the procedure. Protocols may vary among facilities.
  • Make sure a written and informed consent has been signed prior to the procedure and before administering any medications.

Intratest

  • Potential complications:

  • Although it is rare, there is the possibility of allergic reaction to the radionuclide.

  • Establishing an IV site and injection of 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, fluids, and medication restrictions for 4 to 6 hr prior to the procedure.
  • Ensure that the patient has removed all external metallic objects prior to the procedure.
  • Administer ordered prophylactic steroids or antihistamines before the procedure if the patient has a history of allergic reactions to radionuclides or medications.
  • 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.
  • 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 cooperate fully and to follow directions. Instruct the patient to lie still during the procedure because movement produces unclear images.
  • Administer sedative to a child or to an uncooperative adult, as ordered.
  • Place the patient in a supine position on a flat table with foam wedges to help maintain position and immobilization.
  • IV radionuclide is administered, and the upper right quadrant of the abdomen is scanned immediately, with images then taken every 5 min for the first 30 min and every 10 min for the next 30 min. If the gallbladder cannot be visualized, delayed views are taken in 2, 4, and 24 hr in order to differentiate acute from chronic cholecystitis or to detect the degree of obstruction.
  • IV morphine may be administered during the study to initiate spasms of the sphincter of Oddi, forcing the radionuclide into the gallbladder, if the organ is not visualized within 1 hr of injection of the radionuclide. Imaging is then done 20 to 50 min later to determine delayed visualization or nonvisualization of the gallbladder.
  • If gallbladder function or bile reflux is being assessed, the patient will be given a fatty meal or cholecystokinin 60 min after the injection.
  • Remove the needle or catheter and apply a pressure dressing over the puncture site.
  • Observe 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.
  • Instruct the patient to resume usual diet, fluids, medications, and activity as directed by the 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 ungloved hands after the gloves are removed.
  • 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 amylase, bilirubin, CT abdomen, lipase, liver and spleen scan, MRI abdomen, radiofrequency ablation liver, US abdomen, and US liver and bile ducts.
  • Refer to the Hepatobiliary System table at the end of the book for related tests by body system.