The diagnostic value of ultra-microangiography for biliary atresia

Color Doppler flow imaging (CDFI) has auxiliary diagnostic value for biliary atresia (BA), as it can detect positive blood flow signals under the liver capsule; however, it has low sensitivity and is easily affected by respiration. Ultra-microangiography (UMA) is a microvascular imaging technique that focuses on low-speed blood flow, and can display microvascular structures that traditional CDFI cannot. This study aimed to explore the application value of UMA in the diagnosis of BA by analyzing and comparing the microvascular detection capabilities of CDFI and UMA in infants with BA.

A retrospective study of 52 infants diagnosed with BA via intraoperative cholangiography or surgical exploration at Shandong Provincial Hospital Affiliated to Shandong First Medical University between January 2022 and February 2024 was conducted. An additional 105 newborns and infants with similar gender ratios and ages admitted to the hospital for jaundice were included in the study as control subjects. Prior to treatment, all subjects underwent two-dimensional ultrasonography, CDFI, and UMA to measure the microvascular color pixel percentage (CPP) under the liver capsule. The subjects' clinical laboratory information, including age, weight, gamma-glutamyl transpeptidase (GGT), total bilirubin (TB), and direct bilirubin (DB), was collected. The independent sample t-test was used for the normally distributed continuous variables, while the Mann-Whitney U-test was used for the non-normally distributed continuous variables, and Fisher's exact test was used for the categorical variables. Receiver operating characteristic curves were used to evaluate the diagnostic value of the CPP measured by UMA (CPP_UMA) in BA.

There was no significant difference between the two groups in terms of age and weight (P=0.057 and 0.613, respectively). The hepatic artery diameter, GGT, TB, and DB of the BA group were significantly higher than those of the control group (P=0.007, 0.005, 0.003, and 0.001, respectively). The maximum length and width of the gallbladder of the BA group were significantly lower than those of the control group (P=0.005 and 0.001, respectively). The CPP_UMA values of the control and BA groups were 60.7%±5.7% and 72.2%±5.6%, respectively, and were significantly higher than the CPPs measured by CDFI (CPP_CDFI), which were 22.1%±4.1% and 24.9%±4.4%, for the control and BA groups, respectively. Comparisons of the CPP_UMA values between the BA and control groups, as well as comparisons of the CPP_UMA and CPP_CDFI values within the BA group and within the control group, all showed statistically significant differences (all P=0.001), while there was no statistically significant difference in the CPP_CDFI values between the BA and control groups (P=0.055). The optimal cut-off value for the CPP_UMA in diagnosing BA was 66.28%, with a sensitivity of 92% and a specificity of 71%.

UMA better displayed the microvasculature than CDFI, and combined with other signs, it had better auxiliary diagnostic value for BA.