Incremental Value of MR Cholangiopancreatography in Diagnosis of Biliary Atresia.

To evaluate the incremental value of a combination of magnetic resonance cholangiopancreatography (MRCP) and ultrasonography (US), compared to US alone, for diagnosing biliary atresia (BA) in neonates and young infants with cholestasis.The institutional review board approved this retrospective study. The US and MRCP studies were both performed on 64 neonates and young infants with BA (n = 41) or without BA (non-BA) (n = 23). Two observers reviewed independently the US alone set and the combined US and MRCP set, and graded them using a five-point scale. Diagnostic performance was compared using pairwise comparison of the receiver operating characteristics (ROC) curve. The sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value were assessed.The diagnostic performance (the area under the ROC curve [Az]) for diagnosing BA improved significantly after additional review of MRCP images; Az improved from 0.688 to 0.901 (P = .015) for observer 1 and from 0.676 to 0.901 (P = .011) for observer 2. The accuracy of MRCP combined with US (observer 1, 95% [61/64]; observer 2 92% [59/64]) and PPV (observer 1, 95% [40/42]; observer 2 91% [40/44]) were significantly higher than those of US alone for both observers (accuracy: observer 1, 73% [47/64], P = 0.003; observer 2, 72% [46/64], P = 0.004; PPV: observer 1, 76% [35/46], P = 0.016; observer 2, 76% [34/45], P = 0.013). Interobserver agreement of confidence levels was good for US alone (ĸ = 0.658, P < .001) and was excellent for the combined set of US and MRCP (ĸ = 0.929, P < .001).Better diagnostic performance was achieved with the combination of US and MRCP than with US alone for the evaluation of BA in neonates and young infants with cholestasis

Biliary atresia in a 65-day-old girl.

<p>(A) US image in transverse plane shows negative triangular cord sign (arrow). (B) US image in oblique subcostal plane shows atretic gallbladder measuring 0.8 cm (asterisk) and enlarged hepatic artery measuring 1.5 mm (arrow). US confidence level using a five-point scale is 3 (equivocal biliary atresia) by both observers. (C) 3D MRCP image shows no visible extrahepatic biliary tree and small gallbladder (asterisk). Biliary atresia was diagnosed with certainty by both observers after additional review of MRCP images. (D) Surgical cholangiography shows small gallbladder (asterisk) and a patent but extremely hypoplastic common bile duct (arrowheads), suggesting type 2 biliary atresia.</p

US and MRCP findings in patients with BA and non-BA.

<p>US and MRCP findings in patients with BA and non-BA.</p

Neonatal hepatitis in a 54-day-old girl.

<p>(A) US image in transverse plane shows echogenic thickening anterior to the right portal vein measuring 4.2 mm in thickness (positive triangular cord sign) (arrow). Diameter of right hepatic artery is 0.7 mm (arrowhead). (B) US image in oblique subcostal plane shows atretic gallbladder measuring 0.9 cm (arrowhead). US confidence level using a five-point scale is 3 (equivocal biliary atresia) by both observers. (C) 3D MRCP image shows the common hepatic and common bile ducts (arrows), the confluence of the right and left hepatic ducts (arrowheads), and normal gallbladder (asterisk). Non-biliary atresia was diagnosed correctly by both observers after additional review of MRCP images.</p

Clinical profile and laboratory data.

<p>Clinical profile and laboratory data.</p

Interobserver cross-classification of results before and after MRCP interpretation.

<p>Interobserver cross-classification of results before and after MRCP interpretation.</p

Comparison of diagnostic performance of US alone and US with MRCP for discrimination between BA and non-BA.

<p>Comparison of diagnostic performance of US alone and US with MRCP for discrimination between BA and non-BA.</p