Quality assessment of the detailed anomaly ultrasound scan

Comparison of Prenatal and Postmortem Diagnoses from 251 Fetal Autopsies: High Rate of Placenta Pathologies, Low Rate of Discrepancies

Background: In cases of intrauterine fetal death (IUFD), autopsy and placenta pathology can provide additional information to sonographic findings. We assessed the frequency of prenatally missed relevant diagnoses. Materials and methods: A retrospective evaluation of fetal autopsies from 2006 to 2021 was performed and were classified as: i) agreement, ii) cases where autopsy revealed additional findings, or iii) postmortem findings which changed the diagnosis. Results: A total of 199/251 spontaneous IUFD and 52/251 induced abortions were included. In spontaneous IUFD, placenta pathologies were the leading cause of death (89%). Full agreement was found in most cases (91% and 87% in spontaneous IUFD and induced abortion, respectively), while additional findings (7% and 12%) and major discrepancies (each 2%) were detected less frequently. Conclusion: In some cases where major findings were missed, autopsy could establish a diagnosis.

Clinical workflow of sonographers performing fetal anomaly ultrasound scans: deep-learning-based analysis

OBJECTIVE

Despite decades of obstetric scanning, the field of sonographer workflow remains largely unexplored. In the second trimester, sonographers use scan guidelines to guide their acquisition of standard planes and structures; however, the scan-acquisition order is not prescribed. Using deep-learning-based video analysis, the aim of this study was to develop a deeper understanding of the clinical workflow undertaken by sonographers during second-trimester anomaly scans.

METHODS

We collected prospectively full-length video recordings of routine second-trimester anomaly scans. Important scan events in the videos were identified by detecting automatically image freeze and image/clip save. The video immediately preceding and following the important event was extracted and labeled as one of 11 commonly acquired anatomical structures. We developed and used a purposely trained and tested deep-learning annotation model to label automatically the large number of scan events. Thus, anomaly scans were partitioned as a sequence of anatomical planes or fetal structures obtained over time.

RESULTS

A total of 496 anomaly scans performed by 14 sonographers were available for analysis. UK guidelines specify that an image or videoclip of five different anatomical regions must be stored and these were detected in the majority of scans: head/brain was detected in 97.2% of scans, coronal face view (nose/lips) in 86.1%, abdomen in 93.1%, spine in 95.0% and femur in 92.3%. Analyzing the clinical workflow, we observed that sonographers were most likely to begin their scan by capturing the head/brain (in 24.4% of scans), spine (in 23.2%) or thorax/heart (in 22.8%). The most commonly identified two-structure transitions were: placenta/amniotic fluid to maternal anatomy, occurring in 44.5% of scans; head/brain to coronal face (nose/lips) in 42.7%; abdomen to thorax/heart in 26.1%; and three-dimensional/four-dimensional face to sagittal face (profile) in 23.7%. Transitions between three or more consecutive structures in sequence were uncommon (up to 13% of scans). None of the captured anomaly scans shared an entirely identical sequence.

CONCLUSIONS

We present a novel evaluation of the anomaly scan acquisition process using a deep-learning-based analysis of ultrasound video. We note wide variation in the number and sequence of structures obtained during routine second-trimester anomaly scans. Overall, each anomaly scan was found to be unique in its scanning sequence, suggesting that sonographers take advantage of the fetal position and acquire the standard planes according to their visibility rather than following a strict acquisition order. © 2022 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Delay of Fetal Anatomy Ultrasound Assessment Based on Maternal Body Mass Index Does Not Reduce the Rate of Inadequate Visualization

OBJECTIVES

To determine whether delay of initial anatomy ultrasound based on the maternal body mass index (BMI) reduces the rate of inadequate visualization compared to standard timing at 18^0/7 to 19^6/7 weeks.

METHODS

A retrospective study of singleton anatomy assessments was conducted at a tertiary care center in the 2-year period before (A, 2012-2014) and after (B, 2014-2016) protocol initiation. Assessments in period B were scheduled on the basis of the BMI in the first trimester: lower than 25 kg/m² , 18^0/7 to 19^6/7 weeks; 25 to 29.9 kg/m² , 19^0/7 to 20^6/7 weeks; 30 to 34.9 kg/m² , 20^0/7 to 21^6/7 weeks; 35 to 39.9 kg/m² , 21^0/7 to 22^6/7 weeks; and 40 kg/m² or higher, 22^0/7 to 23^6/7 weeks. In period A, assessments were scheduled between 18^0/7 and 19^6/7 weeks. The rate of inadequate visualization and repeated assessments in periods A and B were compared. Multivariable logistic regression, per-protocol, and BMI subgroup analyses were completed.

RESULTS

In total, 3491 pregnancies in period A and 3672 in period B were included. In period B, 74% were scheduled per protocol; however, this rate decreased for higher-BMI categories (52% for BMI ≥40 kg/m² ). The inadequate visualization rate was slightly higher in period B versus A (16.9% versus 15.0%; P = .03) and exceeded 35% for a BMI of 40 kg/m² or higher, with or without delay. After adjusting for maternal age and fetal presentation, period B had small increased odds of inadequate visualization versus period A (adjusted odds ratio, 1.2; 95% confidence interval, 1.02-1.38). Repeated assessment rates were similar in periods B and A (14.0% versus 13.1%; P = .25).

CONCLUSIONS

In pregnancies with obesity, a protocol delaying the initial assessment beyond 19^6/7 weeks based on the maternal BMI does not reduce the rate of inadequate visualization.

Detection of fetal cardiac anomalies: cost-effectiveness of increased number of cardiac views

OBJECTIVE

To compare the recommended three-view fetal heart screening method to detect major congenital heart disease (CHD) with more elaborate screening strategies to determine the cost-effective strategy in unselected (low-risk) pregnancies.

METHODS

A decision-analytic model was designed to compare four screening strategies to identify fetuses with major CHD in a theoretical cohort of 4 000 000 births in the USA. The four strategies were: (1) three views: four-chamber view (4CV) and views of the left (LVOT) and right (RVOT) ventricular outflow tracts; (2) five views: 4CV, LVOT, RVOT and longitudinal views of the ductal arch and aortic arch; (3) five axial views: 4CV, LVOT, RVOT, three-vessel (3V) view and three-vessels-and-trachea view; and (4) six views: 4CV, LVOT, RVOT and 3V views and longitudinal views of the ductal arch and aortic arch. Outcomes related to neonatal mortality and neurodevelopmental disability were evaluated. The analysis was performed from a healthcare-system perspective, with a cost-effectiveness willingness-to-pay threshold set at $100 000 per quality-adjusted life year (QALY). Baseline analysis, one-way sensitivity analysis and Monte-Carlo simulation were performed.

RESULTS

In our baseline model, screening with five axial views was the optimal strategy, detecting 3520 more CHDs, and resulting in 259 fewer children with neurodevelopmental disability, 40 fewer neonatal deaths and only slightly higher costs, compared with screening with the currently recommended three views. Screening with six views was more effective, but also cost considerably more, compared with screening with five axial views, and had an incremental cost of $490 023/QALY, which was over the willingness-to-pay threshold. The five-view strategy was dominated by the other three strategies, i.e. it was more costly and less effective in comparison. The data were robust when tested with Monte-Carlo and one-way sensitivity analysis.

CONCLUSION

Although current guidelines recommend a minimum of three views for detecting CHD during the mid-trimester anatomy scan, screening with five axial views is a cost-effective strategy that may lead to improved outcome compared with three-view screening. Copyright © 2020 ISUOG. Published by John Wiley & Sons Ltd.