A NEW DIAGNOSTIC-APPROACH TO BILIARY ATRESIA WITH EMPHASIS ON THE ULTRASONOGRAPHIC TRIANGULAR CORD SIGN - COMPARISON OF ULTRASONOGRAPHY, HEPATOBILIARY SCINTIGRAPHY, AND LIVER NEEDLE-BIOPSY IN THE EVALUATION OFINFANTILE CHOLESTASIS

Background/Purpose: The authors evaluated prospectively the utility of ultrasonography, Tc-99m-DISIDA hepatobiliary scintigraphy, and liver needle biopsy in differentiating biliary atresia (BA) from intrahepati c cholestasis in 73 consecutive infants who had cholestasis. Methods: Sixty three ultrasonographic examinations of 61 infants with 7.0-MHz t ransducer were carried out, focusing on the fibrous tissue al the port a hepatis. The authors defined the triangular cord (TC) as visualizati on of a triangular or tubular shaped echogenic density just cranial to the portal vein bifurcation on a transverse or longitudinal scan. Res ults: Although 17 of 20 ultrasonographic examinations from infants who had BA denoted TC, 43 ultrasonographic examinations from infants with either neonatal hepatitis (NH) or other causes of cholestasis denoted no TC, showing a diagnostic accuracy of 95% with 85% sensitivity and 100% specificity. Investigation with Tc-99m-DISIDA hepatobiliary scint igraphy showed that 24 of 25 infants who had BA had no gut excretion, and 16 of 46 infants who had either NH or other causes of cholestasis had gut excretion, showing a diagnostic accuracy of 56% with 96% sensi tivity and 35% specificity. Therefore, gut excretion of tracer exclude d BA, but no gut excretion of tracer needed further investigations as liver needle biopsy. Forty-four liver needle biopsies were carried out in 19 infants who had BA and 24 infants who had either NH or other ca uses of cholestasis. Although 18 of 20 biopsy findings in infants who had BA were correctly interpreted as having BA, 23 of 24 biopsy result s in infants who had either NH or other causes of cholestasis were cor rectly diagnosed, showing a diagnostic accuracy of 93% with 90% sensit ivity and 96% specificity. Conclusions: Since the introduction of ultr asonographic TC sign in the diagnosis of BA by our institution, we hav e found that it seemed to be a simple, time-saving, highly reliable, a nd non-invasive tool in the diagnosis of BA from other causes of chole stasis. The authors propose a new diagnostic strategy in the evaluatio n of infantile cholestasis with emphasis on ultrasonographic TC sign a s first priority of investigations. When the TC is visualized, prompt exploratory laparotomy is mandatory without further investigations. Wh en the TC is not visualized, hepatobiliary scintigraphy is the next st ep. Excretion of tracer into the small bowel actually rules out BA. Li ver needle biopsy is reserved only for the infants with no excretion o f tracer. The authors believe that a correct decision regarding the ne ed for surgery can be made in almost all cases with infantile cholesta sis by this multidisciplinary approach. Copyright (C) 1997 by W.B. Sau nders Company.