Search

Objective: To analyze the anatomical relationship between the pubic symphysis and the ischial spines to determine reliable landmarks for the assessment of fetal head descent by intrapartum translabial ultrasound (ITU)., Methods: All computed tomography (CT) scans performed for breech presentation and for twin delivery between 2006 and 2014 in a tertiary university hospital were obtained for measurement and analysis by two operators. The symphysis-left ischial spine angle (SIA) and the symphysis-left ischial spine distance (SID) were measured on three-dimensional reconstructions from the CT volume dataset. We calculated intra- and interobserver agreements for SIA and SID with 95% prediction intervals, created Bland-Altman plots with 95% limits of agreement and estimated the intraclass correlation coefficient (ICC). A sagittal plane projection from the SIA enabled calculation of a sagittal angle, corresponding to the angle of progression (AoP) on ITU., Results: SIA and SID were obtained from CT images from 458 women. Reproducibility was good for both SIA (intraobserver ICC, 0.94 (95% CI, 0.88-0.97) and interobserver ICC, 0.81 (95% CI, 0.66-0.92)) and SID (intraobserver ICC, 0.92 (95% CI, 0.82-0.97) and interobserver ICC, 0.83 (95% CI, 0.73-0.92)). The median SIA was 106° (interquartile range (IQR), 105-109°) and median SID was 26.1 (IQR, 23.4-29.5) mm. SIA and SID were not correlated with pelvic diameter or height. The 50 th percentile of AoP was 110°., Conclusion: Knowledge of the anatomical relationship between the pubic symphysis and ischial spines makes it possible to establish a sonographic method for assesssing fetal head descent by taking into account the level of the ischial spines. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd., (Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.)

Objective: In the first trimester of pregnancy, a biparietal diameter (BPD) below the 5(th) percentile is a simple marker that enables the prenatal detection of half of all cases of open spina bifida. We hypothesized that relating the BPD measurement to the transverse abdominal diameter (TAD) might be another simple and effective screening method. In this study we assessed the performance of using the BPD/TAD ratio during the first trimester of pregnancy in screening for open spina bifida., Methods: A total of 20,551 first-trimester ultrasound scans (11-13 weeks' gestation), performed between 2000 and 2013, were analyzed retrospectively; there were 26 cases of open spina bifida and 17,665 unaffected pregnancies with a crown-rump length of 45-84 mm and a record of both BPD and TAD measurements., Results: The mean (± SD) BPD/TAD ratio was 1.00 ± 0.06 for fetuses with spina bifida and 1.13 ± 0.06 for those without (P < 0.0001). A BPD ≤ 5(th) percentile enabled the prenatal detection of 46.2% of spina bifida cases, while a BPD/TAD ratio of ≤ 1.00 detected 69.2%. If we considered cases in which either BPD was ≤ 5(th) percentile or BPD/TAD ratio was ≤ 1, we identified 76.9% of cases. In the latter case, the false-positive rate was 5.1%, while that for using a combination of both BPD ≤ 5th percentile and BPD/TAD ratio ≤ 1 was 0.6%, with a sensitivity of 38.5%. The positive predictive value of using a combination of BPD ≤ 5th percentile and BPD/TAD ratio ≤ 1 for detecting spina bifida was 8.5%., Conclusions: Between 11 and 13 weeks' gestation, relating BPD to TAD improves considerably the diagnostic performance of using BPD measurement alone in screening for open spina bifida. Screening using this marker is simple and applicable to a large population., (Copyright © 2014 ISUOG. Published by John Wiley & Sons Ltd.)

In cases of placenta previa, the distance from the placental edge to the internal os is determinant in deciding on the mode of delivery that will minimize the risk of hemorrhage. The reproducibility and interobserver reliability of this measure are unknown. The internal os is not a point, as two-dimensional (2D) ultrasonography might suggest, but an oval patch that has a measurable width, which may be as wide as the distance separating it from the placenta. It is therefore difficult to determine the exact location of the os using a 2D sectional plane. We report the case of a nulliparous woman admitted for vaginal bleeding at 37 weeks' gestation in whom transvaginal ultrasound examination showed placenta previa, but for which two sonographers reported different measurements for the distance between the placental edge and the internal os. We describe a technique to measure this distance using multiplanar three-dimensional (3D) ultrasound imaging, which allows the smallest distance between the middle of the os and the edge of the placenta, which appears as a line, to be determined. In this case, measurement using 3D ultrasound showed a shorter distance than was suggested by 2D examination. This led us to schedule a Cesarean section delivery, during which there was minimal bleeding. Standardization of 3D measurements should make it possible to define more relevant cut-offs for determining the management of cases of placenta previa., (Copyright © 2012 ISUOG. Published by John Wiley & Sons, Ltd.)