Sebire N J, Noble P L, Thorpe-Beeston J G, Snijders R J, Nicolaides K H
Harris Birthright Research Centre for Fetal Medicine, King's College Hospital Medical School, London, UK.
Ultrasound Obstet Gynecol. 1997 Dec;10(6):403-5. doi: 10.1046/j.1469-0705.1997.10060403.x.
In three cases of lumbosacral spina bifida diagnosed at 12, 13 and 14 weeks of gestation there was an associated lemon sign, or scalloping of the frontal bones, and in one case the fetal nuchal translucency was increased. In a multicenter ultrasound screening study at 10-14 weeks there were 61,972 singleton pregnancies including 29 cases of spina bifida, none of which was diagnosed at the routine first-trimester scan, but 28 of the 29 cases were detected by ultrasonography at 16-22 weeks; in one case the diagnosis was missed at the 20-week scan and the defect was identified at 32 weeks during a scan for localization of the placenta. The fetal nuchal translucency was above the 95th centile in only one of the cases (3.4%). It is possible that the majority of fetuses with spina bifida have a lemon sign in the first trimester, but the sensitivity of the 10-14-week scan in the diagnosis of spina bifida and the prevalence of the lemon sign at this gestation will only be established by further studies incorporating early systematic examination of the head and spine.
在妊娠12、13和14周时诊断出的3例腰骶部脊柱裂病例中，均伴有柠檬征或额骨扇贝样改变，其中1例胎儿颈部透明带增厚。在一项针对10至14周的多中心超声筛查研究中，共有61972例单胎妊娠，其中包括29例脊柱裂病例，在常规孕早期扫描中均未诊断出，但29例中有28例在16至22周时通过超声检查发现；1例在20周扫描时漏诊，在32周扫描胎盘定位时发现了该缺陷。胎儿颈部透明带仅在其中1例（3.4%）高于第95百分位数。大多数脊柱裂胎儿在孕早期可能有柠檬征，但10至14周扫描对脊柱裂诊断的敏感性以及该孕周柠檬征的患病率，只有通过进一步纳入早期头部和脊柱系统检查的研究才能确定。
