Improving image quality of mid-trimester fetal sonography in obese women: role of ultrasound propagation velocity

Panniculus Retractor Use for Visualization of Fetal Anatomy: A Randomized Controlled Trial

OBJECTIVE

To evaluate whether use of a panniculus retractor device for pregnant patients with body mass index (BMI) 40 or higher and a panniculus improves the completion rate of the fetal anatomic examination.

METHODS

This was a randomized trial in which eligible patients with BMI 40 or higher and a panniculus were randomized to undergo their detailed fetal anatomic examination with a panniculus retractor device in place compared with usual care. The primary outcome was the completion rate of 16 prespecified views from the anatomic examination. Secondary outcomes included completion rate of all 64 views from our institution's detailed anatomic examination, duration of examination, major fetal anomaly detection rate, depth from the skin to amniotic cavity before and after retractor placement, patient and ultrasonographer satisfaction, and prespecified adverse events. We assumed a baseline completion rate of 23% for the primary outcome and targeted a twofold improvement with 80% power and two-sided α of 0.05, which resulted in a sample size of 132 participants. The goal enrollment was increased to 150 participants to account for potential dropout. Statistical tests included the Student's t test, χ 2 , and relative risks (RRs) as appropriate.

RESULTS

From March to July of 2023, 150 participants completed the study: 74 in the retractor group and 76 in the usual care group. Baseline characteristics were similar between groups except for panniculus grade. The completion rate of 16 prespecified views was 25.7% (19/74) in the retractor group and 31.6% (24/76) in the control group (RR 0.81, 95% CI, 0.49-1.35). There were no significant differences between groups for any of the secondary outcomes. Patient satisfaction and ultrasonographer satisfaction were similar between groups.

CONCLUSION

Use of a panniculus retractor device during the fetal anatomic examination for patients with BMI 40 or higher and a panniculus was well tolerated by patients and ultrasonographers but did not improve the completion rate of 16 prespecified fetal anatomic views.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov , NCT05764408.

Protocol for the e-POWUS Project: multicentre blinded-randomised controlled trial of ultrasound speed choice to improve sonography quality in pregnant women with obesity

INTRODUCTION

During pregnancy, maternal obesity increases the risk of fetal abnormalities. Despite advances in ultrasound imaging, the assessment of fetal anatomy is less thorough among these women. Currently, the construction of ultrasound images uses a conventional ultrasound propagation velocity (1540 m/s), which does not correspond to the slower speed of propagation in fat tissue.The main objective of this randomised study is to compare the completeness of fetal ultrasonography according to whether the operator could choose the ultrasound velocity (1420, 1480 or 1540 m/s) or was required to apply the 1540 m/s velocity.

METHODS AND ANALYSIS

This randomised trial is an impact study to compare a diagnostic innovation with the reference technique. The trial inclusion criteria require that a pregnant woman with obesity be undergoing a fetal morphology examination by ultrasound from 20⁺⁰ to 25⁺⁰ gestational weeks.Randomisation will allocate women into two groups. The first will be the 'modulable speed' group, in which operators can choose the speed of ultrasound propagation to be considered for the morphological analysis: 1420, 1480 or 1540 m/s. In the second 'conventional speed' group, operators will perform the morphological examination with the ultrasound speed fixed at 1540 m/s. The adjudication committee, two independent experts, will validate the completeness of each examination and the quality of the images.

ETHICS AND DISSEMINATION

This research protocol does not change the standard management. The only possible impact is an improvement of the ultrasound examination by improving the quality of the image and the completeness of morphological examination. The Agence du Médicament et produits de santé approved this study (2018-A03478-47). The anonymised data will be available on request from the principal investigator. Results will be reported in peer-reviewed journals and at scientific meetings.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov (http://www.clinicaltrials.gov) Registry (NCT04212234).

Antenatal diagnosis of absence of septum pellucidum

The absence of septum pellucidum (ASP) is a rare disease, which affects the structure of the brain. It is either isolated or associated with various congenital brain malformations. The diagnosis of ASP can be performed by second-trimester ultrasound. When the ASP is isolated, prenatal counseling is optimistic regarding neurological outcome, but there is a 20% risk of septo-optic dysplasia in the neonate.