Transabdominal Ultrasound Evaluation of Pancreaticobiliary Maljunction in Children

The development of high-frequency ultrasound made the diagnosis of pancreaticobiliary maljunction (PBM) possible. However, no study has been performed to clarify the sensitivity and specificity of transabdominal ultrasound (TAUS) in the diagnosis of PBM. The purpose of this study was to evaluate the accuracy of TAUS in the diagnosis of pediatric PBM and to assess factors that may influence the accuracy of ultrasound. This was a prospective study and 43 patients with suspected PBM were enrolled. All of these patients underwent TAUS examination to detect the pancreaticobiliary ductal union. Final diagnoses were determined by endoscopic retrograde cholangiopancreatography or intraoperative cholangiography. Sensitivity and specificity were calculated. Fisher exact test was used to analyze the difference of sonographic features between false-negative group and true-positive group. Transabdominal ultrasound demonstrated 77.4% (95% confidence interval, 58.5%-89.7%) sensitivity and 100% (95% confidence interval, 69.9%-100%) specificity for PMB diagnosis. In the false-negative group, infant patients (71.4% vs 16.7%, P = 0.012), cystic dilatation of the common bile duct (CBD) (71.4% vs 16.7%, P = 0.012), and stenosis of the distal CBD (71.4% vs 16.7%, P = 0.012) were more frequently observed than in the true-positive group. On the other hand, the true-positive group showed a higher incidence of protein plugs than the false-negative group (62.5% vs 0%, P = 0.007). Transabdominal ultrasound may serve as a potential alternative detection modality for pediatric patients with suspected PBM. Nondetection of the anomaly may be attributed to factors, such as younger age, cystic dilatation of the CBD, and stenosis of the distal CBD.