Shipp T D, Bromley B, Lieberman E, Benacerraf B R
Department of Obstetrics and Gynecology, Massachusetts General Hospital, Boston, USA.
Obstet Gynecol. 1997 Mar;89(3):446-50. doi: 10.1016/S0029-7844(97)00508-5.
To determine whether measurements of the iliac wing angle on sonograms of the second-trimester fetus can be used to detect fetuses at increased risk for Down syndrome.
All second-trimester Down syndrome fetuses karyotyped by amniocentesis over 5 years for whom adequate views of the iliac bones were available were reviewed retrospectively. The control group consisted of consecutive, normal second-trimester fetuses undergoing karyotyping during the same period. The angles between the iliac bones of the fetal pelves were measured on transverse sonograms, and the two groups were compared. A separate prospective evaluation of the ideal level for measurement of the iliac angle was made in two fetuses, one with and one without Down syndrome.
We evaluated 38 Down syndrome and 46 control fetuses. The mean iliac-angle measurements differed significantly for the Down syndrome fetuses as compared with normal control fetuses: 78.8 degrees +/- standard deviation (SD) 18.5 and 66.9 degrees +/- SD 13.9, respectively. An iliac angle of at least 90 degrees was measured in 14 (36.8%) Down syndrome fetuses and in two (4.3%) control fetuses, also a significant difference. In a prospective pilot evaluation of two fetuses, we measured the largest iliac angle at the most cephalad level of the iliac bones, and the smallest angle was measured at the most caudad level. The iliac angle measurements for the fetus with Down syndrome ranged from 55 degrees to 100 degrees; for the normal fetus, the range was 52 degrees to 80 degrees.
Although there is considerable overlap, the average iliac angle for fetuses with Down syndrome is significantly larger than that of normal fetuses. The angle measurement varies widely in any given fetus and is dependent on the level of the image. A prospective study is needed to evaluate the best level of angle measurement for the detection of fetuses with Down syndrome.
确定孕中期胎儿超声图像上髂骨翼角度的测量是否可用于检测唐氏综合征风险增加的胎儿。
回顾性分析5年间所有通过羊膜腔穿刺术进行核型分析且有足够髂骨图像的孕中期唐氏综合征胎儿。对照组由同期连续接受核型分析的正常孕中期胎儿组成。在横向超声图像上测量胎儿骨盆髂骨之间的角度，并对两组进行比较。对两名胎儿（一名患有唐氏综合征，一名未患）进行了髂骨角度测量理想水平的单独前瞻性评估。
我们评估了38例唐氏综合征胎儿和46例对照胎儿。唐氏综合征胎儿的平均髂骨角度测量值与正常对照胎儿相比有显著差异：分别为78.8度±标准差（SD）18.5和66.9度±SD 13.9。14例（36.8%）唐氏综合征胎儿和2例（4.3%）对照胎儿的髂骨角度至少为90度，这也是一个显著差异。在对两名胎儿的前瞻性初步评估中，我们在髂骨最头侧水平测量到最大的髂骨角度，在最尾侧水平测量到最小角度。患有唐氏综合征的胎儿的髂骨角度测量范围为55度至100度；正常胎儿的范围为52度至80度。
尽管存在相当大的重叠，但唐氏综合征胎儿的平均髂骨角度明显大于正常胎儿。在任何给定胎儿中，角度测量变化很大，并且取决于图像水平。需要进行前瞻性研究以评估检测唐氏综合征胎儿的最佳角度测量水平。
