Diffusion Tensor Imaging for Evaluating Biliary Atresia in Infants and Neonates

Abstract

Background: Preliminary studies have shown that diffusion tensor imaging (DTI) is helpful in evaluating liver disorders. However, there is no published literature on the use of DTI in the diagnosis of biliary atresia (BA). This study aimed to investigate the diagnostic value of the liver average apparent diffusion coefficient (ADC) and fractional anisotropy (FA) measured using DTI for BA in neonates and infants.

Methods: Fifty-nine patients with infant jaundice were included in this study. DTI was performed with b factors of 0 and 1000 s/mm2. Liver fibrosis in the BA group was determined and graded (F0, F1, F2, F3, F4) based on the pathological findings. Statistical analyses were performed to determine the diagnostic accuracy of DTI for BA.

Results: The ADC value was significantly lower in the BA group [(1.262±0.127)×10-3 mm2/s] than in the non-BA group [(1.430±0.149)×10-3 mm2/s, (P<0.001)]. The area under the receiver operating characteristic curve was 0.805±0.058 (P<0.001) for ADC. With a cut-off value of 1.317×10-3 mm2/s, ADC achieved a sensitivity of 75% and a specificity of 81.5% for the differential diagnosis of BA and non-BA. In the BA group, the ADC value was significantly correlated with fibrotic stage. Further analysis showed that the ADC value of stage F0 was significantly higher than that of stages F1, F2, F3 and F4, whereas there were no significant differences among stages F1, F2, F3 and F4.

Conclusion: Hepatic ADC measured with DTI can be used as an adjunct to other noninvasive imaging methods in the differential diagnosis of BA and non-BA. ADC was helpful in detecting liver fibrosis but not in differentiating the fibrotic grades.

Fig 1. Measurement of the apparent diffusion coefficient and fractional anisotropy on diffusion tensor imaging reconstructed images.

A 165-day-old female infant with biliary atresia. Three regions of interest were drawn on each original image (b = 0), and three consecutive images (A1, B1 and C1) above the hepatic porta were included. The mean ADC values were obtained from the nine total ROIs on the ADC map (A2, B2 and C2), and the mean FA values were obtained from the FA maps (A3, B3 and C3).

Fig 2. Receiver operating characteristic curve of the average apparent diffusion coefficient for the detection of biliary atresia.

The area under the ROC curve was 0.805±0.058 (P<0.001) for ADC. With a cut-off value of 1.317×10⁻³ mm²/s, ADC reached a sensitivity of 75% and a specificity of 81.5% for the differential diagnosis of BA and non-BA.