Differential diagnosis of the etiologies of fetal megacystis by prenatal ultrasonography / 中华超声影像学杂志

ABSTRACT

Objective To explore the clinical value of prenatal ultrasonography in the differentiation among the etiologies of fetal megacystis.Methods Twenty seven fetuses,diagnosed as fetal megacystis by prenatal ultrasonography,were retrospectively analyzed.The etiologies of fetal megacystis were presumed by such characteristics as keyhole sign,thickness of the bladder wall,amniotic fluid index,fetal sex and other combined signs.All fetuses were followed up until to the induction of labor or birth.Results Twenty seven singleton fetuses (19 males and 8 females) were diagnosed as megacystis.According to the characteristics and other combined signs,8 cases of posterior urethral valves (PUV),1 of prune belly syndrome(PBS),1 of megacystis-microcolon intestinal hypoperistalsis syndrome(MMIHS),1 of urethral atresia and 5 of chromosomal abnormality were presumed by prenatal ultrasound.Multiple malformations were found in 5 fetuses and there were also 6 fetuses with unknown reason originally.Among the 27 fetuses,21 were induced labor and 6 continued pregnancy to birth.Except for the 6 cases of unknown reason,etiologies of 17 fetuses with megacystis were confirmed by autopsy,genetic tests,surgery or further examination after birth.The accuracy rate of prenatal ultrasonography in the differentiation among the etiologies of fetal megacystis was 80.95％ (17/21).Conclusions On the basis of detailed prenatal ultrasonography and typical characteristics,it is reliable to differentiate the etiologies of fetal megacystis.Sometimes fetal megacystis may be one part of multiple malformations or complex syndrome,such as VACTERL syndrome.However,it is difficult for ultrasonography to diagnose vesicoureteral reflux(VUR)prenatally.