The current gold standard for imaging to rule out extra-hepatic biliary atresia (EHBA) is hepatobiliary scintigraphy (HBS), which involves visually assessing the tracer appearance in the bowel. However, in cases where hepatic function is impaired, biliary-to-bowel transit may not be observable, even in neonatal hepatitis (NH) cases. This study aims to assess the utility of semi-quantitative parameters on HBS to distinguish biliary atresia (BA) from NH when there is a lack of biliary-to-bowel transit for up to 24 h.

The study involved retrospective analysis of patients with the diagnosis of neonatal cholestasis where HBS failed to differentiate BA and NH. Histopathological examination was taken as the gold standard. Semiquantitative parameters calculated include: Liver: blood pool (LBR) and liver: kidney ratios (LKR) at 5 min, 30 min, 1 h and 24 h. Mean values for the two groups were calculated. Student’s t-test was employed to assess the statistical significance of difference of mean between the two groups. Receiver operating characteristic (ROC) curve was also drawn to determine a cut-off of these ratios to differentiate between the two groups using SPSS v26.0. P-value < 0.05 was considered statistically significant.

The study included 53 patients (37 males) with a median age of 3 months (range: 24 days to 10 months). Of these, 32 patients had a histopathological diagnosis of BA, while 21 had NH. Mean LBR and LKR at 24 h were statistically different in the two groups (p-value < 0.05). Receiver operating characteristic (ROC) curve analyses showed highest AUC for LBR at 24 h 0.683 (CI:0.532–0.834, p-value 0.017) and LKR at 24 h − 0.669 (CI: 0.511–0.827, p-value:0.036). For diagnosis of BA a cut-off value of ≤ 4.18 for LBR at 24 h (sensitivity and specificity of 62.5% and 61.9% respectively) and ≤ 4.64 for LKR at 24 h (sensitivity and specificity of 68.8% and 66.7% respectively) were found to be pertinent.

HBS serves as non-invasive imaging of choice to rule out EHBA. Semi-quantitative indices LBR and LKR at the 24-hour can differentiate between EHBA and NH even in cases with compromised hepatic function where traditional visual interpretation of tracer transit proves inadequate.