经腹部三维超声成像对正常胎儿颅后窝结构的定量评价

Quantitative evaluation of normal fetal posterior fossa anatomy using transabdominal three-dimensional ultrasound

目的分析经腹部三维超声成像定量评价正常胎儿颅后窝结构的一致性和重复性,探讨其临床应用价值。方法选取2020年5月至2021年5月于首都医科大学附属北京妇产医院建档的正常单胎胎儿127例(22~34周),采用三维超声容积成像技术获得胎儿的颅脑正中矢状切面,由2名观察者分别测量三维超声定量指标,其中1名观察者测量上述指标2次,测量过程对数据实行双盲,评价上述指标的组内差异与组间差异,并分析其与孕周的相关性。结果三维超声定量小脑蚓部大小的指标,包括蚓部面积、周长、上下径和前后径与孕周呈正相关(r=0.934、0.936、0.920、0.879,均P<0.001),组内与组间一致性很好,组内相关系数均>0.80(均P<0.001);脑干-蚓部夹角(BV角)与脑干-小脑幕夹角(BT角)分别与孕周呈负相关和正相关(r=-0.317、0.366,均P<0.001),二者组内与组间重复性中等或差。结论三维超声定量小脑蚓部大小的指标测量具有高度的一致性与重复性,具有临床实用性及推广性。而BV角和BT角一致性和重复性欠佳,不适用于初级医师应用。

Objective To analyze the consistency and repeatability for quantitative evaluation of normal fetal posterior fossa anatomy using transabdominal three-dimensional ultrasound,and assess the clinical value.Methods The midsagittal planes of fetal brain from 127 normal singleton fetuses with 22-34 weeks of gestation were obtained using transabdominal three-dimensional ultrasound between May,2020 and May,2021.The quantitative three-dimensional indicators were measured by two observers,then were measured twice by one of the two observers.The double blind was performed in course of measuring procedures.The intraobserver and interobserver agreements were evaluated.The relationships between three-dimensional indicators and gestational age were analyzed.Results The quantitative three-dimensional indicators expressing the size of vermis,including area,perimeter,suprainferior diameter and anteroposterior diameter,had positive correlations with advanced gestational age(r=0.934,0.936,0.920,0.879;all P<0.001).The intra-and interobserver reproducibilities of measurements were very good with all intraclass correlation coefficients>0.80(all P<0.001).Brainstem-vermis(BV)angle and Brainstem-tentorium(BT)angle had negative and positive correlations with advanced gestational age respectively(r=-0.317,0.366;both P<0.001).The intra-and interobserver reproducibilities of measurements were moderate or poor.Conclusions The quantitative three-dimensional indicators describing the size of vermis are worthy of clinical application for evaluation of fetal posterior fossa owing to the excellent reproducibility and simple and feasible method of measurement.BV angle and BT angle are not applicable for junior physicians due to the poor reproducibility of measurement.