Ultrasonographic Triangular Cord Sign and Gallbladder Abnormality in Diagnosis of Biliary Atresia

Introduction: Early diagnosis of biliary atresia is very important for better outcome of treatment. Ultrasonography is one of the diagnostic tools for early differentiation of  biliary atresia from other causes of neonatal cholestasis. It has been reported that triangular cord sign  (TACS) in sonography is a reliable sign for diagnosis of biliary atresia. The aim of this study was to re-assess the accuracy of TACS alone and coupled with an abnormal gallbladder in the diagnosis of biliary atresia.   Methods: Infants with prolonged cholestatic jaundice underwent ultrasonography and liver biopsy. Results of ultrasound scans (TASC and gallbladder abnormality) were compared with histopathological findings. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy of Ultrasonographic findings for diagnosis of biliary atresia based on liver histopathology were studied.   Results: The sensitivity, specificity and accuracy of TACS for diagnosis of biliary atresia were 36%, 95% and 77% respectively. Positive predictive value and negative predictive value was 77%. The sensitivity and specificity of gallbladder abnormality for diagnosis of biliary atresia were 36% and 88% respectively. Positive predictive value of TACS coupled with gallbladder abnormality for diagnosis of biliary atresia was 100%.    Conclusion: The Ultrasonographic TACS is very specific for diagnosis of biliary atresia. Positive predictive value and accuracy of this sign is much higher than of gallbladder abnormality. The sensitivity of TACS for diagnosis of biliary atresia is very low.