弥散张量成像诊断新生儿和婴儿胆道闭锁

Diffusion tensor imaging in diagnosis of biliary atresia in neonates and infants

目的探讨弥散张量成像(DTI)对新生儿和婴儿胆道闭锁(BA)的诊断价值。方法收集疑诊为BA或其他胆道疾病的患儿46例,以手术探查、腹腔镜探查、术中造影、病理检查或临床治疗结果作为金标准,将患儿分为BA组与非BA组(non-BA组)。对所有患儿应用1.5T MR扫描仪,采用单次激发自旋回波平面成像DTI序列(b值为1 000s/mm^2)行肝脏扫描,经后处理获得平均扩散系数(AvgDC)图及FA图,测量AvgDC值及FA值。结果 46例中,BA组24例,non-BA组22例,BA组的AvgDC值显著低于non-BA组[(1.27±0.16)×10^(-3) mm^2/s vs(1.43±0.15)×10^(-3) mm^2/s,P=0.001)]。在BA组中,不同肝脏纤维化分级患儿间AvgDC值、FA值的差异均无统计学意义(P>0.05);INF1~INF3级炎症分级患儿AvgDC值逐渐降低,但差异无统计学意义(F=2.15,P=0.14),FA值差异有统计学意义(F=5.51,P=0.01)。应用AvgDC、FA值诊断BA的ROC曲线下的面积分别为0.80±0.07、0.60±0.09;AvgDC界限值为1.33×10^(-3) mm^2/s时,诊断敏感度为75.00%(18/24),特异度为77.27%(17/22)。结论 DTI的AvgDC值可用于诊断新生儿和婴儿BA,但其诊断敏感度与特异度仍有待提高。

Objective To explore the diagnostic value of diffusion tensor imaging （DTI） for biliary atresia （BA） in neo- nates and infants. Methods Totally 46 patients with clinical suspicion of BA or other biliary diseases were collected. The patients were divided into BA group and non-BA group according to the surgical exploration, laparoscopic exploration, intr- aoperative cholangiography, pathological examination or clinical therapy results. All participants were examined with a 1.5T MRI unit. DTI was performed using a single-shot spin echo echo-planar-imaging sequence with b factors of 1 000 s/mmz. The liver average diffusion coefficient （AvgDC） and fractional anisotropy （FA） values were obtained by measuring on the reconstructed AvgDC and FA maps, respectively. Results In 46 patients, there were twenty-four BA pa- tients and twenty-two non-BA patients. The AvgDC value in the BA group （[1.27：k0. 16IX 10 3 mm2/s） was significantly lower than that in the non-BA group （[1.43±0.15I×10 3 mm2/s, P=0.01）. In the BA group, there was no statistically significant difference in the AvgDC or FA values among different fibrotic stages （P〉0.05）. Among different inflammatory grades, there was no statistically significant difference in the AvgDC values, although showing a decreasing trend with the inflammatory grade increasing （F= 2.15, P= 0.14）, while there was significant difference in the FA values （F= 5.51, P =0.01）. The areas under the ROC curve were 0.80±0.07 for AvgDC and 0. 60±0. 09 for FA. With cut-off value of 1.33× 10-3 mm2/s for the AvgDC, DTI reached the sensitivity of 75.00% （18/24） and specificity of 77.27% （17/22） for the diagnosis of BA. Conclusion The AvgDC value measured by DTI may be helpful for the diagnosis of BA, vchile the sensi- tivity and specificity of DTI should be improved.