胎儿主动脉弓离断的产前超声诊断

Prenatal ultrasound in diagnosis of fetal aortic arch interruption

目的探讨胎儿主动脉弓离断的超声诊断特点。方法回顾性分析产前超声诊断为胎儿主动脉弓离断的35胎胎儿资料,同时纳入180胎正常胎儿。二维超声判断胎儿内脏及心脏位置,获取四腔心切面、左右心室流出道切面、三血管切面及三血管-气管切面等横断面,并扫查腔静脉长轴切面、主动脉弓切面及动脉导管弓切面等矢状切面。测量主动脉弓离断胎儿左右心室内径比值及主动脉与肺动脉内径比值,并与相应孕周的正常胎儿进行比较。结果产前二维超声诊断A型、B型及C型主动脉弓离断分别为16、18及1胎,均伴室间隔缺损,共27胎经尸体检查或产后检查证实产前诊断,3胎诊断错误,余5例新生儿失访。四腔心切面及三血管切面发现主动脉弓离断胎儿左右心室内径比值和主动脉与肺动脉内径比值显著小于相应孕周正常胎儿,差异有统计学意义(P均<0.01)。矢状切面对主动脉追踪连续扫查可确定主动脉的分支及走行,可明确诊断及分型。A型、B型及C型离断升主动脉走行及分支分别呈现典型的"W型"、"Y型"及"I型"。矢状面扫查及横断面扫查对胎儿主动脉弓离断的诊断率分别为90.00%(27/30)及56.67%(17/30),差异有统计学意义(P<0.01)。结论产前二维超声可诊断胎儿主动脉弓离断,横断面扫查可发现某些线索,矢状面连续扫查对诊断胎儿主动脉弓离断具有重要意义。

Objective To analyze the ultrasonic characteristics in the diagnosis of fetal aortic arch interruption （IAA）. Methods Thirty-five fetuses of IAA diagnosed prenatally were retrospectively reviewed, and 180 normal fetuses were also included. The visceral and cardiac positions were determined at first. A serial transverse views, including four chamber view, the left and right outflow tract views, the three-vessel view and the three-vessel-trachea view, were obtained by fetal 2D sonography. In addition, several sagittal views, including long axis view of vena cava, aortic arch view, and ductal arch view, were obtained. The ratio of left ventricle to right ventricle, and the ratio of aorta to pulmonary artery calculated in both IAA and normal fetuses, and then compared. Results A total of 16 fetuses, 18 fetuses, and 1 fetus of type A, type B, and type C IAA were prenatally diagnosed, respectively, and all with ventricular septal defect. Twenty-seven fetuses were confirmed by autopsy or postnatal echocardiography, 3 fetuses were misdiagnosed, and the other 5 cases were lost following up. Cross sectional scans found that the ratio of left ventricle to right ventricle and the ratio of aorta to pulmonary artery reduced, compared with normal fetuses with similar gestational ages （all P〈0.01）. Continuous sagittal scans played an important role in the determine of the branching of ascending aorta. Typical branches of ascending aorta presented as ＂W＂ type, ＂Y＂ type, and ＂I＂ type. The diagnostic rates of fetal IAA by the sagittal scans and the transverse scans were 90.00% （27/30） and 56.67% （17/30）, respectively, and the difference was significant （P〈0.01）. Conclusion Fetal 2D sonography can diagnose IAA with the sagittal scans and play the most important role. Abnormal signs presented in the cross sectional planes may suggest the possibility of IAA.