Adjunctive value of 3D MRCP in biliary atresia: a retrospective two-center analysis of cholestatic infants.

OBJECTIVES: To evaluate the adjunctive diagnostic value of three-dimensional MR cholangiopancreatography (3D MRCP) for identifying biliary atresia (BA) in infants with cholestasis. MATERIALS AND METHODS: This retrospective two-center study evaluated the adjunctive diagnostic performance of 3D MRCP beyond ultrasound (US) using receiver operating characteristic (ROC) analysis. The cohort from center 1 was divided into training (n = 770) and validation (n = 330) sets, with center 2 as the test set (n = 252). The optimal cut-off for the MR triangular cord thickness (MR-TCT) was derived from the area under the ROC curve (AUC) calculated from all cases. Extrahepatic bile ducts visualization on 3D MRCP was validated against surgical findings. Image quality metrics were assessed for their diagnostic value on BA detection. RESULTS: One thousand three hundred fifty-two eligible cholestatic infants undergoing 3D MRCP (February 2012 to June 2023) were enrolled, including 363 BA and 989 non-BA. ROC analysis identified 3.75 mm as the optimal cut-off MR-TCT for BA diagnosis (AUC = 0.828). The combination of MR-TCT, 3D MRCP, and US yielded superior diagnostic performance, achieving AUCs of 0.967 in the training set, 0.958 in the validation set, and 0.972 in the test set (all p < 0.001). Image quality scores (p < 0.001), signal-to-noise ratio (SNR) (p < 0.001), contrast ratio (p = 0.012), and contrast-to-noise ratio (CNR) (p < 0.001) of 3D MRCP significantly differed between correct and incorrect diagnosis groups. CONCLUSIONS: 3D MRCP is a valuable diagnostic adjunct tool in diagnosing BA, particularly when combined with MR-TCT and US. Optimizing 3D MRCP image quality enhances diagnostic accuracy. CRITICAL RELEVANCE STATEMENT: 3D MRCP enhances BA diagnosis when combined with MR-TCT and US. Importantly, in cases with strong clinical suspicion but negative US findings, MRCP should be utilized as an adjunct diagnostic modality to reduce false-negative rates. KEY POINTS: The diagnostic efficacy of 3D-MRCP in BA remains to be fully characterized. MR-TCT, 3D-MRCP, and US combined achieved optimal diagnostic accuracy for BA. For high-suspicion BA with negative US, adjunct 3D-MRCP reduces false-negative diagnoses.