Utility of Tc99m-Mebrofenin hepato-biliary scintigraphy (HIDA scan) for the diagnosis of biliary atresia.

AIM: To determine the utility of Tc99m-Mebrofenin hepato-biliary scintigraphy (HIDA scan) for diagnosis of biliary atresia in patients with neonatal cholestasis.

METHODS: Our study involves the retrospective analysis of 46 patients with neonatal cholestasis who underwent HIDA scans at the Pediatric Hepatobiliary Clinic, BJ Wadia Hospital for Children from May 2005 to July 2007. Biliary atresia (BA) was diagnosed on the basis of intra-operative cholangiogram. Non-BA patients were included in the neonatal hepatitis (NH) group. All patients received phenobarbitone and ursodeoxycholic acid for 5 days, prior to the HIDA scan. The HIDA scan was evaluated on the basis of uptake of the radioactive tracer by the liver at 5 minutes after intravenous injection; retention of radioactive tracer within the liver at 24 hours after injection and visualization of excretion of tracer into the intestine upto 24 hours after administration. The results of the HIDA scans were analyzed and correlated with the final diagnosis, gender and age of the patients. Chi-square test was employed for statistical analysis.

RESULTS: The age of presentation of our patients ranged from 5 days to 6 months. The male: female ratio was 37:9. Of the total 46 patients, 28 had BA and 18 had NH. All 28 (100%) patients diagnosed with BA showed persistent radiotracer in the liver at 24 hours whereas 17 (94.4%) of the 18 NH patients showed hepatic radiotracer retention (p = 0.207), the difference being statistically insignificant. Twenty two (78.6%) patients of BA showed no excretion of the radiotracer at 24 hours whereas only 7 (38.9%) of the NH group did not excrete the radiotracer (p = 0.007), which was statistically significant. Neither the sex nor the age of the child contributed to any difference on the hepatic retention (p = 0.618 and 0.235, respectively) or on the intestinal excretion (p = 0.307 and 0.9, respectively) of the radiotracer.

CONCLUSION: HIDA scan is a useful tool for screening of biliary atresia in patients with neonatal cholestasis. Non excretion of the radioactive radiotracer into the intestines even after 24 hours of radiotracer administration can suggest biliary atresia in majority of patients.