产前超声诊断胎儿主动脉弓下左无名静脉的临床意义

Clinical significance of prenatal ultrasonography in diagnosis of fetal retroaortic left innominate vein

目的探讨胎儿主动脉弓下左无名静脉的产前超声诊断价值。方法30例主动脉弓下左无名静脉胎儿，包括单纯主动脉弓下左无名静脉17例，合并胎儿心脏畸形13例，其中法洛四联症6例（3例合并右位主动脉弓）、永存动脉干2例、右位主动脉弓＋迷走左锁骨下动脉5例（1例合并完全性房室管畸形和心下型肺静脉异位引流）。着重观察胎儿三血管气管切面上肺动脉的左侧有无异常的血管存在。随后将探头向胎儿头侧稍稍侧动，观察有无一条横向走行的静脉（左无名静脉）存在。如果在主动脉弓上方未测及左无名静脉，则上下侧动探头确定左无名静脉是否存在，再旋转探头至胎儿长轴切面，观察左无名静脉与主动脉弓的上下关系，并追踪观察左颈内静脉和左锁骨上静脉回流途径及血流方向。结果左无名静脉不从主动脉弓上方穿行汇人右上腔静脉，而是在主动脉弓下方穿行注入右上腔静脉，即为主动脉弓下左无名静脉。发现主动脉弓下左无名静脉最重要的切面是三血管气管切面，表现为肺动脉左侧出现异常静脉，将探头向足侧偏转可显示左无名静脉在三血管气管切面的下方注入右上腔静脉，旋转探头至胎儿长轴切面可直接显示左无名静脉于主动脉弓下方注入右上腔静脉。结论胎儿主动脉弓下左无名静脉在产前可以显示全程引流途径，它不仅是三血管气管切面肺动脉左侧出现异常静脉的原因之一，对心脏畸形手术决策和未来潜在心脏介入手术也具有一定的指导意义。

Objective To evaluate the clinical significance of prenatal ultrasonography in diagnosis of retroaortic left innominate vein （LINV）. Methods Thirty fetus with retroaortic LINV were involved, including 17 cases of isolated retroaortic LINV and 13 cases of complicated retroaortic LINV. Three-vessel and trachea （3VT） view was focused in the routine second trimester ultrasound screening to observe whether LINV existing or not. And then the transducer was rotated to the fetal sagittal view to assess the relationship between LINV and aortic arch and the convergence of left subclavian vein and left internal jugular vein into the LINV. Results The characteristic feature of retroaortic LINV was the LINV converge into right superior vena cava （SVC） under the aortic arch, not above the aortic arch. The most important plane to detect the retroaortic LINV was the 3VT view, which revealed the abnormal vein lying to the left of pulmonary artery. The abnormal vein then could be traced and revealed its connection with the right SVC beneath the aortic arch on the transverse plane inferior to the 3VT view and on the fetal sagittal plane. Conclusions The whole course of retroaortic LINV can be revealed by ultrasound prenatally, which can not only account for the abnormal vein to the left of pulmonary artery on 3VT view, but also play an important role in surgery decision and future cardiac intervention treatment.