Joint Program in Nuclear Medicine

Conjugated Bilirubinemia in a Neonate

Gaurav M. Patel, MD
Leonard P. Connolly, MD

November 4, 2003

Presentation

A 5 week old male who presented with jaundice and hepatomegaly. Total bilirubin = 8.0 (direct = 4.9), alkaline phosphatase = 567, AST = 174, ALT = 116. Abdominal U/S showed no evidence of a gallbladder.

Imaging Findings

Initial dynamic images performed over one hour show uptake of tracer into the hepatic parenchyma. There is no visualization of the biliary tree, nor is tracer seen in the small bowel during the initial hour of imaging. Enhanced renal excretion and urinary bladder collection of tracer is seen.

Delayed static images performed at 4.5 and 24 hours show no evidence of tracer excretion into the small bowel.

Diagnosis

Suggestive but not diagnostic of biliary atresia.

Discussion

Scintigraphic evaluation of biliary atresia is most commonly performed with (-IDA) agents. DISIDA, which has greater hepatic uptake than HIDA is used at Children's Hospital of Boston. Initial dynamic images are taken over 1 hour centered on the abdomen. Delayed imaging is performed at 4 hours and 24 hours.

Early diagnosis of biliary atresia is important because the results of surgical intervention are most successful during the first 2 months of life. The key finding is lack of tracer excretion into the bowel by 24 hours of imaging. There are various other etiologies that could result in a "non-draining" scan, but the most common is neonatal hepatitis.

In a study of 86 patients less than four months of age with documented conjugated hyperbilirubinemia, Gilmour et al found that 53 had "non-draining" scans and 33 had "draining" scans. Of the 53 non-draining scans, 40 (75%) were subsequently found to have biliary atresia. Of the 33 draining scans, 24(75%) were subsequently found to have neonatal hepatitis. A key finding was that no patient with extrahepatic biliary atresia had a draining hepatobiliary scan. However, 25% of patients with neonatal hepatitis had “non-draining” scans.

The patient in these images underwent an intraoperative cholangiogram which demonstrated the patency of the distal common bile duct into the duodenum with no proximal ducts. Further exploration demonstrated a very atretic common hepatic duct going up to the portal plate. A Kasai procedure was successfully performed and the patient was discharged seven days later.

Conclusions:

Hepatobiliary scintigraphy can rule out biliary atresia when it demonstrates passage of radiotracer into the bowel.
If passage of tracer is not seen, a suspected diagnosis of biliary atresia is supported but not established.

References

1. Treves ST. Pediatric Nuclear Medicine. Second Edition. Springer-Verlag. New York. 1995. 466-476.

2. Gilmour SM, Hershkop M, Reifen R, Gilday D, Roberts EA. Outcome of Hepatobiliary Scanning in Neonatal Hepatitis Syndrome. J Nucl Med. 1997; 38:1279-1282.

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J. Anthony Parker, MD PhD, Tony_Parker@CareGroup.Harvard.edu