Ultrasound for the Diagnosis of Biliary Atresia: A Meta-Analysis

The purpose of this meta-analysis was to summarize the evidence on the accuracy of various ultrasound findings for excluding a diagnosis of biliary atresia.

We searched MEDLINE and the Web of Science databases for the period from January 1990 to May 2015. To be included, studies had to satisfy two criteria. First, the data needed to include 2 × 2 contingency data on the diagnostic accuracy of ultrasound in identifying biliary atresia in at least 10 patients with and 10 patients without disease. Second, the study needed to use surgery or biopsy for biliary atresia and surgery, biopsy, clinical follow-up, or some combination of the three as the reference standard for the exclusion of biliary atresia. The methodologic quality of each study was assessed with version 2 of the Quality Assessment of Diagnostic Accuracy Studies tool. Estimated sensitivity and specificity of each ultrasound characteristic were calculated using a random-effects model.

Twenty-three studies published during 1998-2015 were included. Summary sensitivity and specificity were 0.85 (95% CI, 0.76-0.91) and 0.92 (95% CI, 0.81-0.97), respectively, for gallbladder abnormalities in 19 studies; 0.74 (95% CI, 0.61-0.84) and 0.97 (95% CI, 0.95-0.99), respectively, for triangular cord sign in 20 studies; and 0.95 (95% CI, 0.70-0.99) and 0.89 (95% CI, 0.79-0.94), respectively, for the combination of the triangular cord sign and gallbladder abnormalities in five studies. Subgroup analysis of an absent gallbladder in 10 studies yielded a summary specificity of 0.99 (95% CI, 0.93-1.00).

The triangular cord sign and gallbladder abnormalities are the two most accurate and widely accepted ultrasound characteristics for diagnosing or excluding biliary atresia. Other ultrasound characteristics are less valuable for diagnosis or exclusion of biliary atresia.