Abstract：
OBJECTIVE: Increased fetal lung heterogeneity has been associated with term fetal lungs in singleton gestations. The objective of this study was to determine if fetal lung heterogeneity index (HI) differs between twin and singleton fetuses in the late second and third trimesters.
METHODS: Prospective cohort study of women with singleton and twin gestations with medically-indicated ultrasound examinations at 24 weeks of gestation onward. Grayscale transverse fetal lung images were obtained at the level of the four-chamber heart. A region of interest was selected in each fetal lung image. Fetal lung HI was determined with MATLAB software using a dithering technique with ultrasound image pixels transformed into a binary map form from which a dynamic range value was determined. HI averages and standard deviations were generated for twin and singleton fetuses from 24 weeks gestation onward. Two sample t-tests were used to compare the mean HI at each gestational week between singleton and twin fetuses.
RESULTS: In total, 388 singleton and 478 twin images were analyzed. From 35 through 38 weeks of gestation a statistically significant divergence in mean HI was observed with higher means in singleton compared to twin fetuses. At 24 weeks of gestation there was a significantly higher HI in twin fetuses compared to singletons. No differences in fetal lung HI were observed between 25 and 34 weeks gestational age.
CONCLUSIONS: Differences in fetal lung HI were observed when comparing twin and singleton fetuses. Further investigation is required to determine the potential clinical significance of these findings.
METHODS: Prospective cohort study of women with singleton and twin gestations with medically-indicated ultrasound examinations at 24 weeks of gestation onward. Grayscale transverse fetal lung images were obtained at the level of the four-chamber heart. A region of interest was selected in each fetal lung image. Fetal lung HI was determined with MATLAB software using a dithering technique with ultrasound image pixels transformed into a binary map form from which a dynamic range value was determined. HI averages and standard deviations were generated for twin and singleton fetuses from 24 weeks gestation onward. Two sample t-tests were used to compare the mean HI at each gestational week between singleton and twin fetuses.
RESULTS: In total, 388 singleton and 478 twin images were analyzed. From 35 through 38 weeks of gestation a statistically significant divergence in mean HI was observed with higher means in singleton compared to twin fetuses. At 24 weeks of gestation there was a significantly higher HI in twin fetuses compared to singletons. No differences in fetal lung HI were observed between 25 and 34 weeks gestational age.
CONCLUSIONS: Differences in fetal lung HI were observed when comparing twin and singleton fetuses. Further investigation is required to determine the potential clinical significance of these findings.
摘要：
目的：在单胎妊娠中，胎儿肺异质性增加与足月胎儿肺相关。这项研究的目的是确定胎儿肺异质性指数（HI）是否在妊娠第二和妊娠晚期的双胞胎和单胎胎儿之间存在差异。
方法：对单胎和双胎妊娠妇女进行前瞻性队列研究，并在妊娠24周时进行医学指示的超声检查。在四腔心脏水平上获得灰度横向胎儿肺图像。在每个胎儿肺图像中选择感兴趣区域。利用MATLAB软件使用抖动技术确定胎肺HI,其中超声图像像素被变换为二值图形式,从该二值图形式确定动态范围值。从妊娠24周开始，对双胞胎和单胎胎儿产生HI平均值和标准偏差。使用两个样本t检验来比较单胎和双胎胎儿在每个妊娠周的平均HI。
结果：总计，分析了388张单例和478张双胞胎图像。从妊娠的35到38周，观察到平均HI的统计学显着差异，与双胞胎胎儿相比，单胎的平均值更高。妊娠24周时，双胎的HI明显高于单胎。在25至34周胎龄之间未观察到胎儿肺HI的差异。
结论：比较双胎和单胎胎儿时，观察到胎儿肺HI的差异。需要进一步研究以确定这些发现的潜在临床意义。
方法：对单胎和双胎妊娠妇女进行前瞻性队列研究，并在妊娠24周时进行医学指示的超声检查。在四腔心脏水平上获得灰度横向胎儿肺图像。在每个胎儿肺图像中选择感兴趣区域。利用MATLAB软件使用抖动技术确定胎肺HI,其中超声图像像素被变换为二值图形式,从该二值图形式确定动态范围值。从妊娠24周开始，对双胞胎和单胎胎儿产生HI平均值和标准偏差。使用两个样本t检验来比较单胎和双胎胎儿在每个妊娠周的平均HI。
结果：总计，分析了388张单例和478张双胞胎图像。从妊娠的35到38周，观察到平均HI的统计学显着差异，与双胞胎胎儿相比，单胎的平均值更高。妊娠24周时，双胎的HI明显高于单胎。在25至34周胎龄之间未观察到胎儿肺HI的差异。
结论：比较双胎和单胎胎儿时，观察到胎儿肺HI的差异。需要进一步研究以确定这些发现的潜在临床意义。
