产前影像学检查诊断胎儿尿道下裂准确性分析

Diagnostic accuracy of prenatal imaging for fetal hypospadias

目的探究产前影像学检查(产前超声和胎儿MRI)诊断胎儿尿道下裂的准确性。方法本研究为回顾性研究。以2012年3月至2021年3月浙江省产前诊断中心经产前多学科会诊存在胎儿尿道下裂的31名孕妇为研究对象,收集31名孕妇年龄、孕周、产前超声检查结果,以及胎儿MRI影像学特征。结果31名孕妇产前超声诊断均存在胎儿尿道下裂,孕妇年龄(29.8±4.4)岁,孕周(30.1±3.2)周。孕中期诊断4例,孕晚期诊断27例。31例产前疑似尿道下裂胎儿中,出生后确诊尿道下裂22例,诊断准确率为71.0%。胎儿尿道下裂的产前超声影像学特征如下:①外生殖器"郁金香"征19例(19/31,61.3%);②外生殖器短小4例(4/31,12.9%);③外生殖器形态模糊8例(8/31,25.8%)。外生殖器"郁金香"征诊断胎儿尿道下裂的准确率为84.2%(16/19),灵敏度72.7%,特异度66.7%。15名孕妇进一步行胎儿MRI,影像学特征如下:①外生殖器短小10例;②外生殖器"郁金香"征6例;③阴囊分裂4例;④阴茎头部圆钝3例;⑤阴茎腹侧弯曲2例;⑥阴茎阴囊转位1例;⑦性别可辨(女性)1例。胎儿MRI诊断尿道下裂准确率为85.7%(12/14)。1例羊水穿刺提示46,XY,雄激素不敏感综合征,引产后确诊为重度尿道下裂。结论产前超声是诊断胎儿尿道下裂的常用方法,外生殖器"郁金香"征是常用且准确性较高的超声诊断标准。对于产前超声提示胎儿尿道下裂者,进一步行胎儿MRI可增加产前诊断的准确性。

Objective To explore the diagnostic accuracy of prenatal imaging(prenatal ultrasound&fetal magnetic resonance imaging)for fetal hypospadias.Methods Retrospective review was conducted for 31 pregnant women with prenatally diagnosed hypospadias through multidisciplinary consultations at Zhejiang Prenatal Diagnosis Center from March 2012 to March 2021,including age,gestational week,ultrasound and fetal MRI images.Results Thirty-one pregnant women were diagnosed with fetal hypospadias by prenatal ultrasound with an average age of(29.8±4.4)years and an average gestational week of(30.1±3.2)weeks,including 4 cases in the second trimester and 27 cases in the third trimester.Among them,22 cases of hypospadias were confirmed postnatally with a diagnostic accuracy of 71.0%.The major ultrasonographic features included‘tulip sign’of external genitalia(n=19,61.3%),short external genitalia(n=4,12.9%)and ambiguous external genitalia(n=8,25.8%).The diagnostic accuracy of‘tulip sign’for fetal hypospadias was 84.2%(16/19)with a sensitivity of 72.7%and a specificity of 66.7%.Fetal MRI was performed in 15 cases.Major MRI features included short external genitalia(n=10),‘tulip sign’of external genitalia(n=6),bifid scrotum(n=4),blunt penile tip(n=3),penile curvature(n=2),penoscrotal transposition(n=1)and gender identification(female,n=1).The accuracy of fetal MRI in prenatal diagnosis of hypospadias was 85.7%(12/14).Result of amniocentesis hinted at 46,XY and androgen insensitivity syndrome.It was confirmed as severe hypospadias after induced labor.Conclusion Ultrasonography is the most common diagnostic procedure for fetal hypospadias.And‘tulip sign’is commonly present with a high accuracy.Fetal MRI may boost the accuracy of prenatal diagnosis when prenatal hypospadias is suspected by ultrasonography.