Abstract：
Our objectives were: (1) to assess the visualization rate of the choroid bar in a consecutive series of 306 first-trimester scans; (2) to verify, in this cohort of fetuses, the normality of the posterior fossa later in pregnancy; and (3) to confirm the non-visualization of the choroid bar in a retrospective series of fetuses with posterior fossa malformations.
This study included a prospective and a retrospective series. The former comprised 306 fetuses undergoing routine obstetric ultrasound at our unit in both the first and second trimesters over a 6-month period, while the latter comprised 12 cases of posterior fossa malformations. In the prospective study, the presence of the choroid bar, which is defined as a visually continuous, homogeneously hyperechogenic, thick structure bridging the cisterna magna from side to side, was evaluated at the end of the first-trimester nuchal translucency scan. In the retrospective study, previously acquired three-dimensional volume datasets were processed in order to assess whether the choroid bar could be visualized in cases of open spinal dysraphisms and vermian cystic anomalies. In the prospective study, confirmation of a normal posterior fossa was based on the sonographic features of this anatomical region at the time of the second-trimester anomaly scan at 19-21 weeks\' gestation, while, in the retrospective study, it was based on autopsy results, when available, or further direct imaging of the defect later in pregnancy.
In the prospective study, the choroid bar could be visualized in all 306 fetuses, on transabdominal ultrasound in 287 (93.8%) cases and on transvaginal ultrasound in 19 (6.2%) cases. The choroid bar was displayed with a ventral/dorsal approach in 67 (21.9%) cases, with a lateral approach in 56 (18.3%) cases and with both in 183 (59.8%) cases. All 306 cases were confirmed to have a sonographically normal posterior fossa at 19-21 weeks. On the other hand, in the retrospective study, it was not possible to visualize the choroid bar in any of the fetuses with posterior fossa malformations.
We have described a new sign, the choroid bar, consistent with a normal posterior fossa at 12-14 weeks\' gestation. The choroid bar provides the option of screening for major abnormalities of the posterior fossa, since its absence raises suspicion of both open spinal dysraphisms and posterior fossa cystic malformations. At the same time, it is easy to visualize, as it can be seen with all lines of insonation. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.
This study included a prospective and a retrospective series. The former comprised 306 fetuses undergoing routine obstetric ultrasound at our unit in both the first and second trimesters over a 6-month period, while the latter comprised 12 cases of posterior fossa malformations. In the prospective study, the presence of the choroid bar, which is defined as a visually continuous, homogeneously hyperechogenic, thick structure bridging the cisterna magna from side to side, was evaluated at the end of the first-trimester nuchal translucency scan. In the retrospective study, previously acquired three-dimensional volume datasets were processed in order to assess whether the choroid bar could be visualized in cases of open spinal dysraphisms and vermian cystic anomalies. In the prospective study, confirmation of a normal posterior fossa was based on the sonographic features of this anatomical region at the time of the second-trimester anomaly scan at 19-21 weeks\' gestation, while, in the retrospective study, it was based on autopsy results, when available, or further direct imaging of the defect later in pregnancy.
In the prospective study, the choroid bar could be visualized in all 306 fetuses, on transabdominal ultrasound in 287 (93.8%) cases and on transvaginal ultrasound in 19 (6.2%) cases. The choroid bar was displayed with a ventral/dorsal approach in 67 (21.9%) cases, with a lateral approach in 56 (18.3%) cases and with both in 183 (59.8%) cases. All 306 cases were confirmed to have a sonographically normal posterior fossa at 19-21 weeks. On the other hand, in the retrospective study, it was not possible to visualize the choroid bar in any of the fetuses with posterior fossa malformations.
We have described a new sign, the choroid bar, consistent with a normal posterior fossa at 12-14 weeks\' gestation. The choroid bar provides the option of screening for major abnormalities of the posterior fossa, since its absence raises suspicion of both open spinal dysraphisms and posterior fossa cystic malformations. At the same time, it is easy to visualize, as it can be seen with all lines of insonation. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.
摘要：
目的：我们的目标是：（1）在连续的306个妊娠早期扫描中评估脉络膜棒的可视化率；（2）在该胎儿队列中验证妊娠后期后颅窝的正常状态；（3）在一系列具有后颅窝畸形的回顾性胎儿中确认脉络膜棒的非可视化。
方法：本研究包括前瞻性和回顾性系列。前者包括在过去6个月内在我们单位接受常规产科超声检查的306例胎儿，后者包括后颅窝畸形12例。在前瞻性研究中,脉络膜棒-定义为视觉上连续的，在妊娠早期颈部半透明扫描结束时，寻找从一侧到另一侧桥接大水箱的均匀高回声厚结构。在回顾性研究中,对先前获得的三维体积数据集进行了处理,以评估在开放性脊柱发育不良和Vermian囊性异常的情况下脉络膜棒是否可以可视化.在前瞻性研究患者中，正常后颅窝的确认是基于19-21孕周孕中期异常扫描时该解剖区域的超声检查。而在回顾性研究中，它是基于尸检结果，当可用时,或在怀孕后期进一步直接成像缺陷。
结果：在前瞻性研究中，脉络膜棒可以在所有306例胎儿中可视化：在287例（93.8％）的经腹超声检查中，经阴道19例（6.2%）。67例（21.9%）采用腹侧/背侧入路显示脉络膜棒，侧方入路56例(18.3%)，两路入路183例(59.8%)。所有306例均在19-21孕周被证实具有超声检查正常的后颅窝。相反,在回顾性研究中，不可能重现脉络膜棒.
结论：我们已经描述了一个新的体征-脉络膜棒-与12-14孕周的正常后颅窝一致。脉络膜条代表了一种筛查后颅窝主要异常的选项，因为它允许怀疑开放性脊柱发育不良和后颅窝囊性畸形同时非常容易可视化，因为它可以显示所有的声音。本文受版权保护。保留所有权利。
方法：本研究包括前瞻性和回顾性系列。前者包括在过去6个月内在我们单位接受常规产科超声检查的306例胎儿，后者包括后颅窝畸形12例。在前瞻性研究中,脉络膜棒-定义为视觉上连续的，在妊娠早期颈部半透明扫描结束时，寻找从一侧到另一侧桥接大水箱的均匀高回声厚结构。在回顾性研究中,对先前获得的三维体积数据集进行了处理,以评估在开放性脊柱发育不良和Vermian囊性异常的情况下脉络膜棒是否可以可视化.在前瞻性研究患者中，正常后颅窝的确认是基于19-21孕周孕中期异常扫描时该解剖区域的超声检查。而在回顾性研究中，它是基于尸检结果，当可用时,或在怀孕后期进一步直接成像缺陷。
结果：在前瞻性研究中，脉络膜棒可以在所有306例胎儿中可视化：在287例（93.8％）的经腹超声检查中，经阴道19例（6.2%）。67例（21.9%）采用腹侧/背侧入路显示脉络膜棒，侧方入路56例(18.3%)，两路入路183例(59.8%)。所有306例均在19-21孕周被证实具有超声检查正常的后颅窝。相反,在回顾性研究中，不可能重现脉络膜棒.
结论：我们已经描述了一个新的体征-脉络膜棒-与12-14孕周的正常后颅窝一致。脉络膜条代表了一种筛查后颅窝主要异常的选项，因为它允许怀疑开放性脊柱发育不良和后颅窝囊性畸形同时非常容易可视化，因为它可以显示所有的声音。本文受版权保护。保留所有权利。
