Forty years of obstetric ultrasound 1957-1997: from A-scope to three dimensions

Point-of-Care Ultrasound Training in Pediatric Residency: A National Needs Assessment

BACKGROUND AND OBJECTIVES

As point-of-care ultrasound (POCUS) evolves into a standard tool for the care of children, pediatric residency programs need to develop POCUS training programs. Few POCUS training resources exist for pediatric residents, and little is known about POCUS training in pediatric residencies. We aim to describe pediatric residency leadership perspectives regarding the value of POCUS and to elucidate the current state of POCUS training in pediatric residency programs.

METHODS

A group of pediatric educators and POCUS experts developed a novel survey followed by cognitive interviews to establish response-process validity. The survey was administered electronically to pediatric residency associate program directors between December 2019 and April 2020. Program characteristics, including region, setting, and size, were used to perform poststratification for analyses. We performed comparative analyses using program and respondent characteristics.

RESULTS

We achieved a 30% (58 of 196) survey response rate. Although only a minority of respondents (26%) used POCUS in clinical practice, a majority (56%) indicated that all pediatric residents should be trained in POCUS. A majority of respondents also considered 8 of 10 POCUS applications important for pediatric residents. Only 37% of programs reported any POCUS training for residents, primarily informal bedside education. Most respondents (94%) cited a lack of qualified instructors as a barrier to POCUS training.

CONCLUSIONS

Most pediatric residency programs do not provide residents with POCUS training despite its perceived value and importance. Numerous POCUS applications are considered important for pediatric residents to learn. Future curricular and faculty development efforts should address the lack of qualified POCUS instructors.

Machine learning algorithms to predict early pregnancy loss after in vitro fertilization-embryo transfer with fetal heart rate as a strong predictor

BACKGROUND AND OBJECTIVE

According to previous studies, after in vitro fertilization-embryo transfer (IVF-ET) there exist a high early pregnancy loss (EPL) rate. The objectives of this study were to construct a prediction model of embryonic development by using machine learning algorithms based on historical case data, in this way doctors can make more accurate suggestions on the number of patient follow-ups, and provide decision support for doctors who are relatively inexperienced in clinical practice.

METHODS

We analyzed the significance of the same type of features between ongoing pregnancy samples and EPL samples. At the same time, by analyzing the correlation between days after embryo transfer (ETD) and fetal heart rate (FHR) of those normal embryo samples, a regression model between the two was established to obtain FHR model of normal development, and the residual analysis was used to further clarify the importance of FHR in predicting pregnancy outcome. Finally we applied six representative machine learning algorithms including Logistic Regression (LR), Support Vector Machine (SVM), Decision Tree (DT), Back Propagation Neural Network (BNN), XGBoost and Random Forest (RF) to build prediction models. Sensitivity was selected to evaluate prediction results, and accuracy of what each algorithm above predicted under both the conditions with and without FHR was compared as well.

RESULTS

There were statically significant differences in the same type of features between ongoing pregnancy samples and EPL samples, which could serve as predictors. FHR, of which the normal development showed a strong correlation with ETD, had great predictive value for embryonic development. Among the six predictive models the one predicted with the highest accuracy was Random Forest, of which recall ratio and F1 could reach 97%, and AUC could reach 0.97, FHR taken into account as a feature. In addition, Random Forest had a higher prediction accuracy rate for samples with longer ETD-its accuracy rate could reach 99% when predicting those at 10 weeks after embryo transfer.

CONCLUSION

In this study, we established and compared six classification models to accurately predict EPL after the appearance of embryonic cardiac activity undergoing IVF-ET. Finally, Random Forest model outperformed the others. The implementation of Random Forest model in clinical environment can assist doctors to make clinical decisions.

From first concepts to Diasonograph: The role of product design in the first medical obstetric ultrasound machines in 1960s Glasgow

In the late 1950s and early-to-mid-1960s, Glasgow led the world in the development of diagnostic obstetric ultrasound technology, the result of fortuitous collaboration between key individuals advancing the application of an industrial technology. Originally used to detect flaws in metal pressure vessels, the obstetrician Ian Donald, during his military service, reflected on how ultrasound could benefit his own field. Donald involved the engineer Tom Brown to tackle the technical challenges. Brown, in turn, employed a young graduating industrial designer, Dugald Cameron, to address the design, aesthetic and ergonomic aspects of these early engineering prototypes. While previous accounts of these developments have rightly celebrated the medical, technical engineering and imaging achievements of this innovative technology, the discussion of the role of the creative design expertise which addressed serious ergonomic, aesthetic and production manufacturing shortcomings of the first prototypes has been less coherent. This article relates, through key drawings, extracts from witness statements and discussions with Cameron himself, the key design decisions and features resulting in the Sundén and Diasonograph machines, the latter being the world's first commercial production-series obstetric ultrasound machine, deployed in Glasgow hospitals and beyond.

A much valued tool that also brings ethical dilemmas - a qualitative study of Norwegian midwives' experiences and views on the role of obstetric ultrasound

Background

Midwives are the main providers of routine antenatal care services including the routine ultrasound examination in Norway. The ultrasound examination can be perceived by expectant parents not only as a medical examination but also as a social event facilitating attachment to their fetus. This study explores Norwegian midwives’ experiences and views on the role of ultrasound in clinical management of pregnancy.

Methods

A qualitative study design was applied. Twenty-four midwives who all performed obstetric ultrasound examinations were recruited for focus group discussions and individual interviews. Data collection took place in 2015 in five hospitals in two different regions of Norway. Data were analyzed using qualitative content analysis.

Results

Midwives described obstetric ultrasound examinations as very valuable although doing ultrasounds placed high demands on their operational and counselling skills. Increasing requests for ultrasound from pregnant women were mentioned. Advancements in ultrasound diagnosis were considered to have put the fetus in the position of a patient, and that pregnant women declining ultrasound could be viewed as irresponsible by some health professionals. Ethical concerns were raised regarding the possibility of pregnancy termination when fetal anomalies were detected. Fears were also expressed that prenatal diagnoses including those following ultrasound, might create a society where only ‘perfect’ children are valued. However, participants stressed that their intention in performing ultrasound was to optimize pregnancy outcome and thereby assist expectant couples and their unborn children.

Conclusions

Midwives in Norwegian maternity care services describe obstetric ultrasound as very valuable, playing a central role in pregnancy management by optimizing pregnancy outcomes. Although high demands are placed on operators’ technical skills and counseling, midwives described performing obstetric ultrasound as very satisfying work. However, midwives believed that expectant parents’ approach to the ultrasound examination, both its medical value and the precious images obtained of the fetus, could put extra strain on the midwives performing ultrasounds. The potential of ultrasound to detect fetal anomalies and the possibility that this may lead to termination of pregnancy, seemed to create some ambivalent feelings in midwives towards its use.

Electronic supplementary material

The online version of this article (10.1186/s12884-019-2178-x) contains supplementary material, which is available to authorized users.

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.

Two sides of the same coin--an interview study of Swedish obstetricians' experiences using ultrasound in pregnancy management

BACKGROUND

The extended use of ultrasound that is seen in maternity care in most Western countries has not only affected obstetric care but also impacted on the conception of the fetus in relation to the pregnant woman. This situation has also raised concerns regarding the pregnant woman's reproductive freedom. The purpose of this study was to explore Swedish obstetricians' experiences and views on the role of obstetric ultrasound particularly in relation to clinical management of complicated pregnancy, and in relation to situations where the interests of maternal and fetal health conflict.

METHODS

A qualitative study design was applied, and data were collected in 2013 through interviews with 11 obstetricians recruited from five different obstetric clinics in Sweden. Data were analysed using qualitative content analysis.

RESULTS

The theme that emerged in the analysis 'Two sides of the same coin' depicts the view of obstetric ultrasound as a very important tool in obstetric care while it also was experienced as having given rise to new and challenging issues in the management of pregnancy. This theme was built on three categories: I. Ultrasound is essential and also demanding; II. A woman's health interest is prioritised in theory, but not always in practice; and III. Ultrasound is rewarding but may also cause unwarranted anxiety.

CONCLUSIONS

The widespread use of ultrasound in obstetric care has entailed new challenges for clinicians due to enhanced possibilities to diagnose and treat fetal conditions, which in turn might conflict with the health interests of the pregnant woman. There is a need for further ethical discussions regarding the obstetrician's position in management of situations where maternal and fetal health interests conflict. The continuing advances in the potential of ultrasound to impact on pregnancy management will also increase the need for adequate and appropriate information and counselling. Together with other health care professionals, obstetricians therefore need to develop improved ways of enabling pregnant women and their partners to make informed decisions regarding pregnancy management.

Ultrasound's 'window on the womb' brings ethical challenges for balancing maternal and fetal health interests: obstetricians' experiences in Australia

Background

Obstetric ultrasound has become a significant tool in obstetric practice, however, it has been argued that its increasing use may have adverse implications for women’s reproductive freedom. This study aimed to explore Australian obstetricians’ experiences and views of the use of obstetric ultrasound both in relation to clinical management of complicated pregnancy, and in situations where maternal and fetal health interests conflict.

Methods

A qualitative study was undertaken as part of the CROss-Country Ultrasound Study (CROCUS). Interviews were held in November 2012 with 14 obstetricians working in obstetric care in Victoria, Australia. Data were analysed using qualitative content analysis.

Results

One overall theme emerged from the analyses: The ethical challenge of balancing maternal and fetal health interests, built on four categories: First, Encountering maternal altruism’ described how pregnant women’s often ‘altruistic’ position in relation to the health and wellbeing of the fetus could create ethical challenges in obstetric management, particularly with an increasing imbalance between fetal benefits and maternal harms. Second, ‘Facing shifting attitudes due to visualisation and medico-technical advances’ illuminated views that ultrasound and other advances in care have contributed to a shift in what weight to give maternal versus fetal welfare, with increasing attention directed to the fetus. Third, ‘Guiding expectant parents in decision-making’ described the difficult task of facilitating informed decision-making in situations where maternal and fetal health interests were not aligned, or in situations characterised by uncertainty. Fourth, ‘Separating private from professional views’ illuminated divergent views on when the fetus can be regarded as a person. The narratives indicated that the fetus acquired more consideration in decision-making the further the gestation progressed. However, there was universal agreement that obstetricians could never act on fetal grounds without the pregnant woman’s consent.

Conclusions

This study suggests that medico-technical advances such as ultrasound have set the scene for increasing ethical dilemmas in obstetric practice. The obstetricians interviewed had experienced a shift in previously accepted views about what weight to give maternal versus fetal welfare. As fetal diagnostics and treatment continue to advance, how best to protect pregnant women’s right to autonomy requires careful consideration and further investigation.

The clinical practice patterns of fetal ultrasonography in the first-trimester: A questionnaire survey of members of the Korean Society of Ultrasound in Obstetrics and Gynecology

Objective

This study aimed to survey the current clinical practice of first-trimester ultrasonography among members of the Korean Society of Ultrasound in Obstetrics and Gynecology (KSUOG) and to provide basic data for making practical recommendations about first-trimester ultrasonography scan in Korea.

Methods

This survey was conducted using a self-administered anonymous questionnaire. The first-trimester in this survey was divided into two parts: early and late first-trimester. The survey was focused on safety issue, nuchal translucency (NT) cutoff, the anatomic structures they check, and the need for practical recommendations or educational courses during the first-trimester.

Results

During the study period, 194 KSUOG members participated into this survey. The survey on early first-trimester scan reveal that 173 (89.2%) of respondents had used pulsed-wave Doppler or color Doppler imaging to monitor fetal heart beat. For the late first-trimester scan, 145 (74.7%) of respondents was found to check for fetal anatomical assessments during their NT screening performance; however, the clinical practice patterns were considerably varied among participants. More than half of the respondents used the criterion of NT ≥3.0 mm to define increased NT. Approximately 80% of respondents stated that the screening ultrasonography of fetal structures in the first-trimester was necessary. Furthermore, 187 (96.4%) of respondents were in favor of a recommendation for first-trimester ultrasonography in Korea.

Conclusion

This is the first survey of the current clinical practice of first-trimester ultrasonography in Korea. Our survey findings highlight the need for the practical recommendation or educational course for first-trimester ultrasonography.

Ethics of prenatal ultrasound

Prenatal ultrasound has opened new opportunities to examine, diagnose and treat the fetus, but these advances bring with them ethical dilemmas. In this chapter, I address the ethical principles that need to be considered when treating both mother and fetus as patients, and how these can be applied in practice. In particular, ultrasound practitioners have an ethical duty to maintain their theoretical knowledge and practical skills to ensure they advise parents correctly. I also discuss the ethical issues in carrying out intrauterine therapy, ultrasound-related research, and termination of pregnancy for fetal abnormality.

Biophysical studies of the effect of high power ultrasound on the DNA solution

Stability and molecular size of the DNA double helical structure were studied on an aqueous solution of DNA after exposure to high power doses of continuous wave ultrasound at frequency of 20 kHz. Thermal transition spectrophotometry (UV-melting), constant-field gel electrophoresis (CFGE), differential scanning calorimetry (DSC) and dielectric properties measurements were used to evaluate the ultrasound-induced changes in the DNA double helical structure. The thermal transition spectrophotometry (UV-melting) and differential scanning calorimetry (DSC) results showed that ultrasound power caused loss of DNA double helical structure and the DNA double strands melting temperature decreased as the ultrasound power increased, indicating a decrease in the stability of the double helical structure of DNA. The constant-field gel electrophoresis (CFGE) results showed that the molecular size of the DNA fragments decreased as the ultrasound power increased. The dielectric data in the frequency range from 20 Hz to 100 kHz for the native DNA showed that dispersion at frequency of about 500 Hz resulted from polarization induced by counterions. The decrease in the dielectric increment indicated a decrease in length of DNA molecule after exposure to ultrasound power.

[A look into the past: improves in obstetrical and neonatal outcome in maternity since the 19th century]

OBJECTIVE

Evaluate changes in obstetrical and neonatal outcome of women who delivered in maternity hospital since the 19(th) century.

MATERIALS AND METHODS

Data from a historic cohort of 1022 women who delivered between 1871 and 1874 in the hôtel Dieu hospital of Marseille were compared to those from 1159 women who delivered from 2005 to 2006 in the level 3 maternity of Nord hospital of Marseille (contemporary cohort). Deliveries that had occured before 22 weeks and/or with a foetal birth weight of less than 500 g were excluded.

RESULTS

A total of 2131 pregnancies were included: 1011 and 1120 in historic and contemporary cohort, respectively. Despite comparable mean term of delivery, mean birth weight of neonates from historic cohort were significantly lower: 2971 g (550-4900 g) vs 3250 g (500-5375 g), respectively (p<0.001). Stillbirths were reported in 72 (7.1%) cases in historic cohort compared to nine (0.8%) in contemporary cohort (p<0.001). Neonatal mortality was 3.7% in historic cohort and 1.9% in contemporary cohort (p=0.012). A total of 99 (9.8%) maternal deaths were reported in historic cohort, while none in contemporary cohort (p<0.001). A wide majority of maternal deaths were caused by maternal infection (72.9%); 5.2% were caused by postpartum haemorrhage.

CONCLUSION

Our results illustrate the tremendous impact on maternal and neonatal outcome of advances in obstetrical management. The significant increase in the median foetal birth weight is likely to be related to wide changes in environmental conditions and behaviour.

Measurements, phantoms, and standardization

The last 25 years has seen a number of significant developments in the establishment of a measurement infrastructure supporting medical applications of ultrasound. This has allowed manufacturers and users of medical ultrasonic equipment to undertake and compare measurements of key parameters describing the magnitude or strength of the applied ultrasonic field in a meaningful and traceable way: for equipment development, standards compliance, and quality assurance purposes. This paper describes the current state of the art for measurement techniques used to determine the key properties of an ultrasonic field, principally acoustic pressure and acoustic power. Measurement tools and methodologies are described in detail, alongside considerations of how these are likely to develop, shaped by user need. The way that these measurement methods underpin a range of international and national specification standards enabling equipment manufacturers to demonstrate that their equipment is safe and fit for purpose is covered.

Let's All Jump on the Ultrasound Bandwagon: Further Debate on the Use of Ultrasound

No imaging technique is more popular or more in demand than ultrasound. But should it be considered a specialist technique to be employed only by highly trained professionals or as a readily available tool to be used by many? This paper will discuss some of the implications of having ultrasound performed by a range of individuals and will emphasize the importance of training and regulation.

Metrology for ultrasonic applications

This paper provides a review of current metrological capability applied to the characterisation of the acoustic output of equipment used within medical ultrasonic applications. Key measurement devices, developed to underpin metrology in this area, are the radiation force balance, used to determine total output power, and the piezo-electric hydrophone, used to resolve the spatial and temporal distribution of acoustic pressure. The measurement infrastructure in place within the United Kingdom ensuring users are able to carry out traceable measurements of these quantities in a meaningful way, is described. This includes the relevant primary standards, the way international equivalence of national standards is demonstrated and the routes by which the standards are disseminated to the user community. Emerging measurement techniques that may in future lead to improved measurement capability, are also briefly discussed.

Three-dimensional (3D) ultrasound--a useful imaging technique in the assessment of neonatal brain

Clinical application of ultrasound began about fifty years ago. From one-dimensional A-mode, through two-dimensional real time and Doppler examinations, a new era in clinical ultrasonography then began in the late eighties. Development of computer technology enabled introduction of 3D ultrasonography into clinical practice. In obstetrics ultrasound revolutionized fetal follow-up, but it was as important for the detection of intracranial pathology during the neonatal period and infancy. Two-dimensional real time ultrasonography was [table: see text] an exciting method that changed our understanding of the prevalence and pathophysiology of brain pathology in premature and term infants. Will application of 3D ultrasonography bring any substantial improvement to neuroimaging diagnostics in the newborn period? This article attempts to find the answer to this question, despite the limitations set by the short period of application of 3D neurosonography in neonates. The advantages of 3D brain ultrasonography application in neonates are: quicker and observer independent data acquisition, the possibility of off-line data analysis, projection of 3D data on a 2D plane with volumetric, color and power Doppler studies. Unavailability of equipment is the main reason why 3D ultrasonography was performed in only half of the newborns in whom it was indicated. Cost of equipment prevents introduction of 3D as a standard diagnostic procedure in neonates, although its diagnostic value is indisputable.

Comparison between two- and three-dimensional ultrasound measurements of nuchal translucency

OBJECTIVE

Fetal nuchal translucency measurement has been introduced as a screening test for the calculation of risk of chromosomal abnormalities. The purpose of this study was to investigate: (1) the feasibility of obtaining nuchal translucency measurements using three-dimensional ultrasound; (2) whether three-dimensional ultrasound could improve and facilitate the required repeated measurements of nuchal translucency; (3) the correlation between two- and three-dimensional nuchal translucency measurement values.

SUBJECTS AND METHODS

Between September 1999 and May 2000, in a prospective cohort study, 229 unselected pregnant women with a mean age of 34.6 (range, 20-46) years were examined. The mean fetal crown-rump length was 64.3 (range, 45-84) mm. Nuchal translucency thickness was measured first by two- and then by three-dimensional ultrasound in two planes (three-dimensional mid-sagittal and three-dimensional transverse). An attempt was made to repeat each nuchal translucency measurement three times (totalling nine measurements per patient) and the means of the two- and three-dimensional measurements were compared. The majority (95%) of the measurements were made transabdominally and 5% were made transvaginally. The time limit for each examination was 20 min.

RESULTS

With the two-dimensional method, nuchal translucency could be measured in 96.8% of cases. Of these, three measurements could be obtained in 51.7%, two in 23.2% and only one in 25.1%. The three-dimensional examination was successful in 98.6% of cases. Of these, three measurements could be obtained in 60%, two in 22.8% and one in 17.2%. Transvaginally, all examinations were successful. The main reason for the failure of two-dimensional ultrasound was the fetal position, which in some cases precluded the distinction between fetal skin and amnion or the uterine wall. Using two-dimensional ultrasound, 6.3% of the cases of measurement failure were due to an inability to differentiate clearly between fetal skin and amnion, whilst the equivalent value for the three-dimensional method was only 3.3%. For the three-dimensional technique, fetal movement was the main reason for failure. The mean time for both methods was similar (9 min and 10 min for two- and three-dimensional ultrasound, respectively) and the correlation between the measurements obtained by the two- and three-dimensional techniques was very high (r = 0.97).

CONCLUSION

The number of fetuses in which nuchal translucency could be measured tended to be higher with three-dimensional ultrasound, although the difference was not statistically significant. The possibility of rotating a stored volume and inspecting it in three orthogonal planes makes three-dimensional ultrasound a useful tool for nuchal translucency measurements, especially in doubtful cases.

Three-dimensional ultrasonography in early pregnancy

Three-dimensional ultrasound was introduced into clinical use over a decade ago. Early attempts on three-dimensional ultrasound were primitive and limited to experimental use only. Recently, it was used as a powerful tool to display three-dimensional fetal appearance and assess normal and pathological conditions. Because of the improvement in image resolution and reconstruction speed, three-dimensional ultrasound is now more and more popular in many centers, and used commonly as an adjunct in prenatal diagnosis. Indeed, a skillful sonographer may usually make the correct diagnosis of fetal anomaly with simply two-dimensional ultrasound. Nonetheless, the situation is gradually changing, because some anomalies have been diagnosed only based on the findings of three-dimensional ultrasound. In spite of that, the application of three-dimensional ultrasound is still less discussed in early pregnancy. In this article, the authors clarify the capability of three-dimensional ultrasound in different anatomic areas, and catalog its clinical merits in the early pregnancy to date. We also present the safety guidelines for its use in the first trimester.

The impact of piezoelectric PVDF on medical ultrasound exposure measurements, standards, and regulations

This paper describes the development of PVDF hydrophones for characterizing medical ultrasound fields. The polymer hydrophone approaches that have resulted from this work are discussed, with emphasis given to the spot-poled membrane design that has become the de facto reference device for these measurements. The various national and international standards and regulations that have followed from the successful use of PVDF hydrophones also are summarized. The works discussed encompass polymer-based hydrophones designed primarily for diagnostic and lithotripsy exposure measurements, both in water and in vivo. The advent of these hydrophones has made possible accurate and reliable measurements of exposure levels encountered in medical ultrasound and, thus, has allowed questions of ultrasound bioeffects and device safety to be addressed in a consistent and scientifically sound manner.