A hepatobiliary iminodiacetic acid scan is a test that uses 99mTc disofenin or mebrofenin to visualize the gallbladder and determine patency of the biliary system. It is also known as cholescintigraphy and hepatoscintigraphy. For pediatric patients, this test is done to differentiate biliary atresia from neonatal hepatitis and to assess liver trauma, right upper quadrant pain, and congenital malformations.
After injection, a series of images traces the excretion of the radionuclide. Through computer analysis, the activity in the gallbladder is quantitated, and the amount ejected (ejection fraction) is calculated.
To evaluate cholecystitis
To differentiate between obstructive and nonobstructive jaundice
To investigate upper abdominal pain
For biliary assessment after surgery
For evaluation of biliary atresia
Inject the radionuclide intravenously. For adults and older children, give medication to stimulate gallbladder contraction, such as sincalide. Morphine may also be given to better visualize the gallbladder. For infants, give phenobarbital to distinguish between biliary atresia and neonatal jaundice.
Start imaging immediately after injection. Take a series of images at 5-minute intervals for as long as it takes to visualize the gallbladder and small intestine.
In the event of biliary obstruction, obtain delayed views (2–24 hours).
Remember that if cholecystokinin (CCK) is administered, computer-assisted quantitative measurements can determine an ejection fraction.
See Chapter 1 guidelines for safe, effective, informed intratest care.
Abnormal concentration patterns reveal unusual bile communications.
Gallbladder visualization excludes the diagnosis of acute cholecystitis with a high degree of certainty.
Pretest Patient Care
Explain the purpose, procedure, benefits, and risks of the procedure.
Ensure that the patient has fasted for at least 4 hours (3–4 hours for pediatric patients) before testing. In case of prolonged fasting (more than 24 hours), notify the nuclear medicine department. Fasting does not apply when the indication is for biliary atresia or jaundice.
Discontinue opiate- or morphine-based pain medications 2–6 hours before the test to avoid interference with transit of the radiopharmaceutical.
Refer to standard NMI pretest precautions.
Follow guidelines in Chapter 1 for safe, effective, informed pretest care.
Posttest Patient Care
Review test results; report and record findings. Modify the nursing care plan as needed.
Refer to standard nuclear imaging posttest precautions.
Follow guidelines in Chapter 1 for safe, effective, informed posttest care.
Patients with high serum bilirubin levels (>10 mg/dL or >171 mmol/L) have less reliable test results.
Patients receiving total parenteral nutrition or with long-term fasting may not have gallbladder visualization.