Ultrasonographic triangular cord [TC] sign: a predictor of the type and outcome of biliary atresia

ABSTRACT

To study the accuracy of triangular cord [TC] sign in the diagnosis of biliary atresia [BA], and its validity in predicting the type and outcome of BA, patients treated for BA at the department of surgery. National Liver Institute, were included. Pre-operatively, the same radiologist examined all patients, with special emphasis on detecting the triangular cord [TC] sign if present. Operative findings included the presence or absence of fibrotic remnants at the porta-hepatis for correlation with the TC sign detected by ultrasound [US]. The type of biliary atresia [BA] was diagnosed and confirmed after intra-operative cholangiography. Postoperative data included routine laboratomy work-up, which was done weekly for a month, and monthly thereafter. The outcome was evaluated regarding achievement or not of restoration of bile drainage, frequency of postoperative cholangitic attacks, other morbidity and mortality. Thirty-eight patients treated for BA were included. They were 21 males and 17 females with a mean age of 8l.4 days [range 50-130]. The TC sign was detected in 93.3% of infants with type III BA, and absent in all cases of type II and I. The sensitivity and specificity of the TC sign in the diagnosis of type III BA were 93.3% and 100% respectively. The positive and negative predictive values were 100% and 80% respectively. The outcome of patients was categorized according to the achievement of bile flow restoration, and the presence or absence of jaundice into three groups group A; became non-icteric [n = 7], group B; stool became colored but remained icteric [n = 23], and group C; remained icteric with clay stool [n = 5].Attack of acute cholangitis were more frequent [17/2860.7%] among the icteric patients in groups B and C than the non-icteric patients in group A [2/728.6%]. Among the patients with type III BA, the TC sign usually indicates advanced fibrosis. All patients older than 60 days had a positive TC sign, and in whom, only 1 out of 2 7 patients [3.7%] achieved complete biliary drainage. Two of the 3 patients with a negative TC sign and type III BA achieved complete biliary flow restoration. Overall mortality was 16 out of 38 [42.1%]; four of them were lost during follow-up and considered as mortality. This study showed that detecting the triangular cord [TC] sign ultrasonographically might be a bad prognostic index, predicting failure of restoring biliary flow after surgery. Further large studies with longer follow-up period are recommended