胎儿右位主动脉弓产前超声诊断、妊娠结局及漏误诊分析

目的探讨并总结胎儿右位主动脉弓（RAA）超声图像特征、鉴别诊断方法，分析其漏误诊原因，提高胎儿RAA产前超声诊断准确率。 方法选取2014年1月至2017年12月黑龙江省哈尔滨市红十字中心医院31例经产后小儿超声心动图检查、手术或引产后尸体解剖病理证实的胎儿RAA病例，总结胎儿RAA及其合并圆锥动脉干畸形产前超声图像特征、鉴别诊断方法，分析其漏误诊原因并随访其妊娠结局。应用胎儿心脏标准超声切面的灰阶和彩色多普勒血流成像，进行胎儿心脏系统超声检查。当三血管气管切面（3VT）发现主动脉弓位于气管右侧时，再获取气管及其分支冠状切面进一步明确主动脉弓、动脉导管弓与气管的位置关系。 结果产前超声诊断41例胎儿RAA，活产20例，引产15例，失访6例；产后证实31例，产前超声正确诊断25例（25/31，80.65%），漏误诊6例（6/31，19.35%）。2例左位主动脉弓产前超声均未获取胎儿气管及其分支冠状切面，在3VT切面将支气管横断面误认为气管横断面而误诊为RAA，2例RAA伴左锁骨下动脉迷走（ALSA）左位动脉导管（LDA），将左颈总动脉误认为发育不良的左弓而误诊为双主动脉弓（DAA），2例RAA合并心脏圆锥动脉干畸形产前超声漏诊RAA。31例胎儿RAA在3VT切面显示主动脉弓位于气管右侧，不同类型的胎儿RAA在3VT切面形成血管环或无血管环。胎儿RAA合并圆锥动脉干畸形在3VT切面和气管及其分支冠状切面有不同超声表现。20例活产胎儿中13例孤立性RAA、2例合并永存左上腔、1例合并2~3腰椎椎体融合、2例合并室间隔缺损手术治疗、最大年龄随访至3岁半，无呼吸道消化道压迫症状，小儿状态良好。1例IDD型矫正型大动脉转位并RAA，未经手术治疗，目前小儿11个月，状态良好。1例合并食道闭锁产后14 d新生儿死亡。6例行胎儿染色体核型检查，5例染色体核型正常，1例合并心内外严重多发畸形胎儿染色体核型检查为18-三体。 结论3VT切面是诊断胎儿RAA的主要切面，联合应用气管及其分支冠状切面可提高产前超声诊断准确率。单纯性RAA多数预后好、RAA合并严重心内外畸形预后与其合并畸形严重程度有关。

Prenatal ultrasound diagnosis,pregnancy outcome,and reasons for misdiagnosis and missed diagnosis of fetal right aortic arch

ObjectiveTo investigate the ultrasonic imaging features of and differential diagnosis methods for the right aortic arch, to analyze the causes of missed diagnosis and misdiagnosis, and to further improve the accuracy of prenatal ultrasound diagnosis. MethodsCardiac screening examination of the fetus was carried out with views of gray-scale and color Doppler or power Doppler imaging (PDI). When the three-vessel tracheal (3VT) view found that the aortic arch was located in the right of the trachea, the coronary views of the trachea and its branches were obtained to further clarify the relationship among the aortic arch, arterial ductus, and trachea. The sonographic features of 31 cases of fetal right aortic arch were summarized, and the reasons for misdiagnosis were analyzed. ResultsOf the 31 cases of fetal right aortic arch diagnosed by prenatal ultrasound, 20 were alive, 15 were induced, and 6 were lost. As for the results of echocardiography for postpartum children, operation or autopsy were obtained in 31 cases, of which 6 had misdiagnosis or missed diagnosis by prenatal ultrasonography. The coronal views of the trachea and its branches were not obtained in two cases of fetal left aortic arch, and they were misdiagnosed as right aortic arch because the transversely sectioned bronchus were mistaken as the transversely sectioned trachea in the 3VT view. In two cases of right aortic arch with aberrant left subclavian artery, the left common carotid artery was misdiagnosed as a stunted left arch, which resulted in a misdiagnosis as a double aortic arch of the advantage type. In two cases of right aortic arch combined with cardiac defects, right aortic arch was missed in prenatal ultrasound diagnosis. Of 20 children who were followed, 13 were diagnosed with isolated right aortic arch, 2 with combined persistent left superior cavity, 1 with combined 2-3 lumbar vertebral body fusion, and 2 with combined right aortic arch inner or outer non-complex structure abnormality. Follow-up was conducted to the maximum age up to 3 years and 6 months, and 18 of these cases were in good condition and showed no symptoms of respiratory tract compression. One case suffered from complicated intracardiac malformation combined with IDD type congenitally corrected transposition of the great arteries. The child is currently in good condition 11 months after the delivery. One case suffered from combined esophageal atresia and died 14 days after delivery. Chromosome karyotype determination was performed in 6 cases, of whom 5 were normal and 1 was confirmed to have 18-trisomy with severe intracardiac multiple malformation. ConclusionsThe 3VT view is the most important view for diagnosis of right aortic arch of fetus. The accuracy of prenatal ultrasound diagnosis can be improved through the combination of the 3VT view and the coronal view of the trachea and its branches. Simple right aortic arch offers a good prognosis, and the prognosis of right aortic arch with severe ectopic and extracardial malformations depends on the severity of the combined malformation.