Synonym/Acronym
Biliary tract radionuclide scan, cholescintigraphy, hepatobiliary imaging, hepatobiliary scintigraphy, gallbladder scan, HIDA or hepatobiliary iminodiacetic scan.
Rationale
To visualize and assess the cystic and common bile ducts of the gallbladder toward diagnosing obstructions, stones, inflammation, and tumor.
Patient Preparation
There are no activity restrictions unless by medical direction. Instruct the patient to restrict food and fluids for 4 to 6 hr prior to the procedure. Explain that fasting for more than 24 hr before the procedure or receiving total parenteral nutrition may produce a false-positive result. Instruct the patient, as ordered, to discontinue use of opiate-based or morphine-based drugs 2 to 6 hr before the procedure. Protocols may vary among facilities.
Normal Findings
- Normal shape, size, and function of the gallbladder with patent cystic and common bile ducts; radionuclide should pass through the biliary system, and a significant amount should be visualized in the gallbladder within 15 to 30 min.
Study type: Nuclear scan; related body system: Digestive system.
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. A technetium-99 (Tc-99m)–labelled iminodiacetic acid analogue (e.g., tribromoethyl) is administered by IV injection 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.
Contraindications
Pregnancy is a general contraindication to procedures involving radiation.
Factors That May Alter the Results of the Study
- Bilirubin levels greater than or equal to 30 mg/mL, depending on the radionuclide used, indicate significant liver damage, which may decrease hepatic uptake.
- The use of opiate or morphine-based drugs 2 to 6 hr before the procedure may interfere with smooth muscle motility, affecting the passage of the radionuclide through the biliary system.
- Fasting for more than 24 hr before the procedure or receiving total parenteral nutrition may produce a false-positive result because the absence of the digestive process prevents the gallbladder from filling.
- Metallic objects (e.g., jewelry, body rings) within the examination field, other nuclear scans done within the previous 24 to 48 hr, or retained barium from a previous radiological procedure, which may inhibit organ visualization and cause unclear images.
- Improper injection of the radionuclide that allows the tracer to seep deep into the muscle tissue can produce erroneous hot spots.
- Inability of the patient to cooperate or remain still during the procedure, because movement can produce blurred or otherwise unclear images.
Abnormal Findings Related to
Uneven distribution of the radionuclide, deposited in concentrated “hot spots,” indicates areas where lesions, trauma, abnormal anatomy, or obstructions in the biliary system are located. Delayed visualization or absence of the radionuclide within 60 min or more is abnormal.
- Cholecystitis (acalculous, acute, chronic) (evidenced by visualization of the biliary tree and lack of visualization of the gallbladder related to obstruction of the cystic duct by gallstones)
- Common bile duct obstruction secondary to gallstones, tumor, or stricture (evidenced by visualization in the bile duct but absent visualization of the tracer in the small intestine, related to bile duct obstruction)
- Congenital biliary atresia or choledochal cyst (evidenced by delayed visualization of the tracer and low ejection fracture [less than 35%])
- Postoperative biliary leak, fistula, or obstruction
- Trauma-induced bile leak or cyst
Before the Study: Planning and Implementation
Teaching the Patient What to Expect
- Discuss how this procedure can assist in detecting inflammation or obstruction of the gallbladder or ducts.
- Explain that the procedure takes about 1 to 4 hr and is performed in a nuclear medicine department.
- Review the procedure with the patient.
- Explain that pregnancy testing may be required.
- Discuss how there may be moments of discomfort or pain when the IV line is inserted, allowing for infusion of fluids such as saline, anesthetics, sedatives, medications used in the procedure, or emergency medications.
- Reassure the patient that the radionuclide poses no radioactive hazard and rarely produces adverse effects.
Procedural Information
- Policies regarding breastfeeding before and after an imaging procedure may vary among facilities. For additional information see Appendix A: Patient Preparation and Specimen Collection, subsection: Potential Contraindications and Complications Associated with Diagnostic Procedures.
- Baseline vital signs are recorded and monitored throughout the procedure.
- Positioning for the study is in the supine position on a flat table with foam wedges to help maintain position and immobilization.
- After an IV radionuclide is administered, 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.
- When the gallbladder cannot be visualized, delayed views are taken in 2, 4, and 24 hr 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. This forces the radionuclide into the gallbladder, if the organ is not visualized within 1 hr of injection of the radionuclide.
- Imaging is done 20 to 50 min after administration of morphine to determine delayed visualization or nonvisualization of the gallbladder.
- When the study is requested to assess gallbladder function or bile reflux, the patient is given a fatty meal or cholecystokinin 60 min after the radionuclide is administered, after which the gall bladder is scanned continuously to determine the ejection fraction of the radionuclide.
- Once the study is completed, the needle is removed and a pressure dressing applied over the puncture site.
Potential Nursing Actions
Make sure a written and informed consent has been signed prior to the procedure and before administering any medications.
After the Study: Implementation & Evaluation Potential Nursing Actions
Avoiding Complications
- Establishing an IV site and injection of radionuclides are invasive procedures that can cause rare complications. For additional information see Appendix A: Patient Preparation and Specimen Collection, subsection: Potential Contraindications and Complications Associated with Diagnostic Procedures.
- Monitor the patient for complications related to the procedure.
- Complications are rare but 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 with known anticoagulant, antiplatelet, or thrombolytic properties), or infection (which might occur if bacteria from the skin surface is introduced at the puncture site).
- Discuss the importance of immediately reporting symptoms such as fast heart rate, difficulty breathing, skin rash, itching, or chest pain.
- Observe/assess the needle insertion site for bleeding, inflammation, or hematoma formation.
Treatment Considerations
- Follow post-procedure vital sign and assessment protocol.
- Explain that the radionuclide is eliminated from the body within 6 to 24 hr.
- Advise drinking increased amounts of fluids for 24 to 48 hr to eliminate the radionuclide from the body, unless contraindicated.
- Administer ordered antiemetics as needed.
- Resume usual diet, fluids, medications, and activity as directed by the HCP.
- Instruct the patient in the care and assessment of the injection site.
- Explain that application of cold compresses to the puncture site may reduce discomfort or edema.
- Evaluate pain and facilitate pain management with administration of ordered narcotics, anticholinergics, and alternative methods of pain management (relaxation, imagery, music, etc.).
Safety Considerations
- Refer to organizational policy for additional precautions that may include instructions on temporary suspension of breastfeeding, handwashing, toilet flushing, limited contact with others, and other aspects of nuclear medicine safety.
Clinical Judgement
- Consider which pain management strategies will provide the most relief.
Follow-Up and Desired Outcomes
- Acknowledges medical and surgical therapeutic options for disease management.