HIDA for Suspected Biliary Atresia
A sensitive rule-out test with limited specificity, and a clock that keeps running
Biliary atresia causes 25–40% of cholestatic jaundice in the first months of life, and the Kasai portoenterostomy works best when it is done early. Hepatobiliary scintigraphy answers one question well: does bile reach the bowel? If it does, biliary atresia is effectively excluded. If it does not, the differential stays wide.
Why the clock matters
- Kasai within the first 60 days of life: about 70% establish bile flow. After 90 days: under 25%.
- In 743 French patients, survival with the native liver was 57.1% at 2 years and 28.5% at 15 years. It fell steadily as age at surgery rose from 30 to 90 days.
- The authors estimated that operating on every child before 46 days would spare 5.7% of paediatric liver transplants in France each year.
Protocol and priming
- Use mebrofenin in the hyperbilirubinaemic neonate: 1.8 MBq/kg, with a minimum of 37 MBq.
- Phenobarbital 5 mg/kg/day in two divided doses for at least 3–5 days enhances biliary excretion.
- Ursodeoxycholic acid is the shorter alternative: 20 mg/kg/day in two doses for 2–3 days, continued until the study is over.
- Delayed images up to 24 hours are often needed before calling excretion absent.
- The paediatric hepatology guideline warns that 5 days of phenobarbital often delays the diagnosis and the operation unnecessarily.
What the scan can and cannot tell you
| Finding | Meaning |
|---|---|
| Tracer in the bowel, at any time up to 24 h | Biliary atresia excluded; false negatives are extremely rare |
| No bowel activity at 24 h | Consistent with biliary atresia, but also seen with hepatocellular disease, bile duct paucity, idiopathic neonatal hepatitis, low birth weight, parenteral nutrition and α1-antitrypsin ZZ |
- A meta-analysis of 81 studies: sensitivity 98.7%, specificity 70.4%. A later one gave 96% and 73%, against 98% and 93% for percutaneous liver biopsy.
- Specificity was higher with high-extraction tracers, phenobarbital priming, weight-based activity and a booster dose when there was no excretion.
- Single-centre results vary. In one comparison of 69 infants, specificity was only 45.7%, while liver biopsy reached 94.3%.
Its place in the work-up
- Ultrasound first. It excludes a choledochal cyst. A small or absent gallbladder or a triangular cord suggests biliary atresia, but a normal scan does not exclude it.
- Scintigraphy is selective. The joint NASPGHAN/ESPGHAN guideline: limited specificity rules it out as a stand-alone test, but clearly shown bile flow is of value in excluding biliary atresia.
- Liver biopsy read by an experienced pathologist gives the correct diagnosis in 90–95%.
- Intraoperative cholangiogram with histology of the duct remnant is the gold standard.
Pearl
Report the answer the surgeon needs: bowel activity seen, biliary atresia excluded; or no bowel activity at 24 hours, which does not separate atresia from severe intrahepatic cholestasis. Never let the scan or its priming delay biopsy or cholangiography.
Take home
- Bowel activity at any time up to 24 hours excludes biliary atresia; its absence is non-specific.
- Priming improves specificity, but 3–5 days of phenobarbital costs time the Kasai operation cannot spare.
- Scintigraphy supports, but never replaces, ultrasound, liver biopsy and intraoperative cholangiography.
Sources
- Tulchinsky M, Ciak BW, Delbeke D, et al. SNM practice guideline for hepatobiliary scintigraphy 4.0. J Nucl Med Technol. 2010;38(4):210-8.
- Fawaz R, Baumann U, Ekong U, et al. Guideline for the evaluation of cholestatic jaundice in infants: joint recommendations of the North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition and the European Society for Pediatric Gastroenterology, Hepatology, and Nutrition. J Pediatr Gastroenterol Nutr. 2017;64(1):154-68.
- Kianifar HR, Tehranian S, Shojaei P, et al. Accuracy of hepatobiliary scintigraphy for differentiation of neonatal hepatitis from biliary atresia: systematic review and meta-analysis of the literature. Pediatr Radiol. 2013;43(8):905-19.
- Serinet MO, Wildhaber BE, Broué P, et al. Impact of age at Kasai operation on its results in late childhood and adolescence: a rational basis for biliary atresia screening. Pediatrics. 2009;123(5):1280-6.
- Wang L, Yang Y, Chen Y, Zhan J. Early differential diagnosis methods of biliary atresia: a meta-analysis. Pediatr Surg Int. 2018;34(4):363-80.
- Yang JG, Ma DQ, Peng Y, et al. Comparison of different diagnostic methods for differentiating biliary atresia from idiopathic neonatal hepatitis. Clin Imaging. 2009;33(6):439-46.