What Is the Rate of Incomplete Fetal Anatomic Surveys During a Second-Trimester Scan? Retrospective Observational Study of 4000 Nonobese Pregnant Women

Development and validation of an artificial intelligence assisted prenatal ultrasonography screening system for trainees

OBJECTIVE

Fetal anomaly screening via ultrasonography, which involves capturing and interpreting standard views, is highly challenging for inexperienced operators. We aimed to develop and validate a prenatal-screening artificial intelligence system (PSAIS) for real-time evaluation of the quality of anatomical images, indicating existing and missing structures.

METHODS

Still ultrasonographic images obtained from fetuses of 18-32 weeks of gestation between 2017 and 2018 were used to develop PSAIS based on YOLOv3 with global (anatomic site) and local (structures) feature extraction that could evaluate the image quality and indicate existing and missing structures in the fetal anatomical images. The performance of the PSAIS in recognizing 19 standard views was evaluated using retrospective real-world fetal scan video validation datasets from four hospitals. We stratified sampled frames (standard, similar-to-standard, and background views at approximately 1:1:1) for experts to blindly verify the results.

RESULTS

The PSAIS was trained using 134 696 images and validated using 836 videos with 12 697 images. For internal and external validations, the multiclass macro-average areas under the receiver operating characteristic curve were 0.943 (95% confidence interval [CI], 0.815-1.000) and 0.958 (0.864-1.000); the micro-average areas were 0.974 (0.970-0.979) and 0.973 (0.965-0.981), respectively. For similar-to-standard views, the PSAIS accurately labeled 90.9% (90.0%-91.4%) with key structures and indicated missing structures.

CONCLUSIONS

An artificial intelligence system developed to assist trainees in fetal anomaly screening demonstrated high agreement with experts in standard view identification.

First trimester anatomy ultrasound for patients with obesity: a randomized controlled trial

BACKGROUND

Second-trimester ultrasound is the standard technique for fetal anatomy evaluation in the United States despite international guidelines and literature that suggest that first-trimester timing may be superior in patients with obesity. First-trimester imaging performs well in cohorts of participants with obesity.

OBJECTIVE

Our aim was to compare the completion rate of a first-trimester fetal anatomy ultrasound scan with that of a second-trimester fetal anatomy ultrasound scan among pregnant people with a body mass index ≥35 kg/m2.

STUDY DESIGN

This randomized controlled trial enrolled participants with a body mass index ≥35 kg/m2 with a singleton gestation and who presented before 14+0/7 weeks of gestation. Participants were randomized to receive an ultrasound assessment of anatomy at either 12+0/7 to 13+6/7 weeks or at 18+0/7 to 22+6/7 weeks. The primary outcome was completion rate (percentage of scans that optimally imaged all the required fetal structures). Secondary outcomes included the necessity of a transvaginal approach, completion rates for each individual view, number of anomalies identified and missed in each group, scan duration, and patient perspectives. A 1-year pilot sample was analyzed using Bayesian methods for the primary outcome with a neutral prior and frequentist analyses for the remaining outcomes.

RESULTS

A total of 128 participants were enrolled, and 1 withdrew consent; 62 subjects underwent a first-trimester ultrasound scan and 62 underwent a second-trimester ultrasound scan. A total of 2 participants did not attend the research visits, and 1 sought termination of pregnancy. In the first-trimester group, 66% (41/62) of ultrasound scans were completed in comparison with 53% (33/62) in the second-trimester ultrasound group (Bayesian relative risk, 1.20; 95% credible interval, 0.91-1.73). When compared with a second-trimester scan plus a follow-up ultrasound, a first-trimester ultrasound plus a second-trimester ultrasound was equally successful in completing the anatomy views (76%). First-trimester anatomy ultrasound scans required a transvaginal approach in 63% (39/62) of cases and had a longer duration than a second-trimester ultrasound scan. No anomalies were missed in either group. First-trimester ultrasound participants who responded to a survey described that they were very satisfied with the technique.

CONCLUSION

In pregnant subjects with a body mass index ≥35 kg/m2, a single first-trimester anatomy ultrasound scan was more likely to obtain all the recommended anatomic views than a single second-trimester ultrasound scan. An evaluation of anatomy at 12+0/7 to 13+6/7 weeks' gestation plus an evaluation at 18+0/7 to 22+6/7 led to complete anatomic evaluation 4 weeks earlier than 2 second trimester scans. Assessment of ultrasound duration in a clinical setting is needed to ensure feasibility outside of a research setting.

Effects of Asherman Syndrome on Maternal and Neonatal Morbidity with Evaluation by Conception Method

STUDY OBJECTIVE

Create a comprehensive summary of maternal and neonatal morbidities from patients previously treated for Asherman syndrome and evaluate for differences in perinatal outcomes based on conception method.

DESIGN

Retrospective cohort.

SETTING

Community teaching hospital affiliated with a large academic medical center.

PATIENTS

Total of 43 singleton births identified from 40 patients previously treated at our institution for Asherman syndrome.

INTERVENTIONS

Review of fertility and obstetric data to summarize the maternal and neonatal outcomes in singleton births from patients with Asherman syndrome who had been treated with hysteroscopic adhesiolysis.

MEASUREMENTS AND MAIN RESULTS

Primary outcomes of maternal morbidity (i.e., hypertensive disease, gestational diabetes, ruptured membranes, postpartum hemorrhage, morbidly adherent placenta [MAP]) and secondary outcomes of neonatal morbidity (i.e., gestational age at birth, method of delivery, weight, length, 1- and 5-minute Apgar score oxygen requirement, anatomic malformations, length of neonatal admission) were evaluated. We identified 40 patients who completed successful treatment of Asherman syndrome and went on to carry a singleton gestation within our institution: 20 (50%) with mild disease, 18 (45%) with moderate disease, and 2 (5%) with severe disease under the March classification system. In total, 43 singleton births were examined, with 27 of 43 (62.8%) conceived without in vitro fertilization (IVF) (group A: non-IVF conception) and 16 of 43 (37.2%) conceived through IVF (group B: IVF conception). The overall rate of preterm birth in Asherman pregnancies was 11.6%, with no difference between the 2 conception groups. We documented 9.3% cases with intrauterine growth restriction, with no difference based on conception groups. The rate of MAP in patients with Asherman syndrome was 14.0%, and the rate of postpartum hemorrhage was 32.6%, with no differences between the conception groups. Newborn anatomic malformations of any cause were documented in 18.6% of all singleton births, with no difference between the conception groups.

CONCLUSION

Our series indicates a higher incidence of intrauterine growth restriction, MAP, postpartum hemorrhage, and newborn anatomic malformations in Asherman syndrome pregnancies than that reported in pregnancies within the general population. However, we found no significant differences in the maternal and neonatal outcomes of patients with Asherman syndrome who conceived with or without IVF after being treated with hysteroscopic adhesiolysis.

Measurement error of mean sac diameter and crown-rump length among pregnant women at Mulago hospital, Uganda

Background

Ultrasonography is essential in the prenatal diagnosis and care for the pregnant mothers. However, the measurements obtained often contain a small percentage of unavoidable error that may have serious clinical implications if substantial. We therefore evaluated the level of intra and inter-observer error in measuring mean sac diameter (MSD) and crown-rump length (CRL) in women between 6 and 10 weeks’ gestation at Mulago hospital.

Methods

This was a cross-sectional study conducted from January to March 2016. We enrolled 56 women with an intrauterine single viable embryo. The women were scanned using a transvaginal (TVS) technique by two observers who were blinded of each other’s measurements. Each observer measured the CRL twice and the MSD once for each woman. Intra-class correlation coefficients (ICCs), 95% limits of agreement (LOA) and technical error of measurement (TEM) were used for analysis.

Results

Intra-observer ICCs for CRL measurements were 0.995 and 0.993 while inter-observer ICCs were 0.988 for CRL and 0.955 for MSD measurements. Intra-observer 95% LOA for CRL were ± 2.04 mm and ± 1.66 mm. Inter-observer LOA were ± 2.35 mm for CRL and ± 4.87 mm for MSD. The intra-observer relative TEM for CRL were 4.62% and 3.70% whereas inter-observer relative TEM were 5.88% and 5.93% for CRL and MSD respectively.

Conclusions

Intra- and inter-observer error of CRL and MSD measurements among pregnant women at Mulago hospital were acceptable. This implies that at Mulago hospital, the error in pregnancy dating is within acceptable margins of ±3 days in first trimester, and the CRL and MSD cut offs of ≥7 mm and ≥ 25 mm respectively are fit for diagnosis of miscarriage on TVS. These findings should be extrapolated to the whole country with caution. Sonographers can achieve acceptable and comparable diagnostic accuracy levels of MSD and CLR measurements with proper training and adherence to practice guidelines.

Cost Analysis of Following Up Incomplete Low-Risk Fetal Anatomy Ultrasounds

OBJECTIVES

To examine the clinical utility and cost of follow-up ultrasounds performed as a result of suboptimal views at the time of initial second-trimester ultrasound in a cohort of low-risk pregnant women.

METHODS

We conducted a retrospective cohort study of women at low risk for fetal structural anomalies who had second-trimester ultrasounds at 16 to less than 24 weeks of gestation from 2011 to 2013. We determined the probability of women having follow-up ultrasounds as a result of suboptimal views at the time of the initial second-trimester ultrasound, and calculated the probability of detecting an anomaly on follow-up ultrasound. These probabilities were used to estimate the national cost of our current ultrasound practice, and the cost to identify one fetal anomaly on follow-up ultrasound.

RESULTS

During the study period, 1,752 women met inclusion criteria. Four fetuses (0.23% [95% CI 0.06-0.58]) were found to have anomalies at the initial ultrasound. Because of suboptimal views, 205 women (11.7%) returned for a follow-up ultrasound, and one (0.49% [95% CI 0.01-2.7]) anomaly was detected. Two women (0.11%) still had suboptimal views and returned for an additional follow-up ultrasound, with no anomalies detected. When the incidence of incomplete ultrasounds was applied to a similar low-risk national cohort, the annual cost of these follow-up scans was estimated at $85,457,160. In our cohort, the cost to detect an anomaly on follow-up ultrasound was approximately $55,000.

CONCLUSIONS

The clinical yield of performing follow-up ultrasounds because of suboptimal views on low-risk second-trimester ultrasounds is low. Since so few fetal abnormalities were identified on follow-up scans, this added cost and patient burden may not be warranted.

Frequency and Importance of Incomplete Screening Fetal Anatomic Sonography in Pregnancy

OBJECTIVES

To determine (1) how often routine screening fetal anatomic sonography fails to completely visualize fetal anatomy; (2) the proportion of women with incomplete ultrasound examinations who are recommended for repeat screening and then undergo repeat sonography; and (3) how often abnormal fetal anatomy is detected on repeat sonography.

METHODS

We conducted a retrospective cohort study at a high-volume academic obstetric ultrasound center. Participants were 16,300 women at 17 through 21 weeks' gestation with a singleton pregnancy presenting for screening anatomic sonography between January 2009 and December 2013. Main outcome measures were (1) incomplete visualization of anatomy at initial screening sonography; (2) among women with incomplete but otherwise normal initial screening ultrasound examinations, recommendation for and performance of repeat sonography; and (3) among women undergoing repeat sonography, discovery of abnormal fetal anatomy within anatomic components that were previously incompletely visualized.

RESULTS

The mean maternal age ± SD was 30.8 ± 6.3 years, and the mean gestational age was 18.8 ± 1.0 weeks. Among 16,300 initial screening ultrasound examinations, 2157 (13.2%) had incomplete visualization of fetal anatomy. Of those women eligible for follow-up, 91.5% were recommended for repeat screening, of whom 92.8% had a subsequent examination. Of 1560 repeat screening ultrasound examinations, 8 (0.5%) showed an abnormality in the components of anatomy that were previously visualized incompletely.

CONCLUSIONS

In this large single-center study, incomplete visualization was common in screening fetal anatomic ultrasound examinations. Recommendations for repeat imaging were nearly universal, but abnormal fetal anatomy was infrequently discovered on repeat screening.

Completed Sonographic Anatomic Surveys: The Exception Rather Than the Rule

OBJECTIVES

To determine how often fetal organ systems are imaged completely and whether this rate varies by hospital.

METHODS

All initial sonographic anatomic examinations between 16 and 24 weeks from 3 hospitals (perinatal designation levels I-III) from January 2012 through December 2013 were identified in their obstetric and gynecologic anatomic survey report databases, focusing on 36 anatomic fields. Structures were grouped into regions: brain, face, spine, heart, abdomen, and extremities. Rates of complete visualization of each structure, structure grouping, and the total were calculated and compared by χ² testing.

RESULTS

From 7211 examinations (2578 from level I, 986 from level II, and 3647 from level III), the completion rate was 16.8% (I, 20.6%; II, 20.0%; and III, 13.2%; P < .00001). Brain and extremity imaging was complete 85% of the time or more but spine only 62.4% (sacrum consistently lowest). Completeness rates varied significantly (P< .00001) for the face (28.1%-64.4%, due to low rates of clearing lips at level III, and level I not clearing profiles), heart (37.3%-56.1%, level I < II < III), and abdomen (65.2%-85.7%, due to lower rates of clearing kidneys at level I). Completion of both the heart and spine was 32.0% (I, 23.0%; II, 25.4%; and III, 40.2%; P < .00001).

CONCLUSIONS

With a comprehensive reporting system, completion rates for full anatomic sonograms are low. Facial, cardiac, and spinal structures are least complete, and follow-up examinations often remain incomplete. Completion benchmarks would be helpful because "incomplete" studies lead to repeated examinations that increase health care costs.

Helping expectant mothers understand inadequate ultrasound images

BACKGROUND

Obstetric ultrasound scans may fail to provide all the information that is needed because of poor visualisation. Two main causes of poor visualisation are addressed. These are poor foetal position and poor quality imaging due to beam distortion by overlying fatty tissue.

METHOD

To improve communication with patients attending obstetric scans, a poster and leaflet were designed to explain these causes of inadequate scans. A questionnaire was used to assess the value of the poster.

RESULTS

57/66 (86%) questionnaires were completed. 52 (91%) found the information on the poster was helpful and well explained. For 8 (14%) the information changed their thoughts about the scan.

CONCLUSION

Clear communication aids the expectant mothers understanding of why scans may be suboptimal. The way this is recorded in the scan results is discussed.

Ultrasonographic evaluation of placental cord insertion at different gestational ages in low-risk singleton pregnancies: a predictive algorithm

OBJECTIVE

To evaluate the accuracy of ultrasound in visualizing placental cord insertion (PCI) at different gestational ages in order to recommend the most feasible period during pregnancy to identify it. Secondary aim was to propose a predictive algorithm for PCI visualization.

METHODS

We performed a single-center, prospective cohort study. We enrolled patients with singleton low-risk pregnancies who underwent fetal ultrasound scan at different gestational ages. We excluded patients with body mass index of 30 Kg/m2 or more, uterine fibroids larger than 5 cm, high-risk pregnancies, fetal weight lower than < 10° percentile or higher than > 90° percentile, increased ("deep pocket" > 80 mm) or decreased ("deep pocket" < 20 mm) amniotic fluid.

RESULTS

Among the 468 recruited patients, the visualization of PCI was not possible in 5.77% of the cases. Furthermore, we showed that PCI visualization was lower as the gestational age increased (p = 0.049) and more difficult in case of posterior placenta (p = 0.001).

CONCLUSIONS

PCI should be evaluated in the first trimester or as early as possible during the second trimester. Moreover, we propose a feasible model to predict the possibility of PCI visualization according to gestational age and uterine site of implantation.