Obstetric ultrasound: where are we and where are we going?
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ABSTRACT:
SUBMITTER: Abramowicz JS
PROVIDER: S-EPMC7758093 | biostudies-literature | 2021 Jan
REPOSITORIES: biostudies-literature
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Obstetric ultrasound: where are we and where are we going?
Ultrasonography (Seoul, Korea) 20200825 1
Diagnostic ultrasound (DUS) is, arguably, the most common technique used in obstetrical practice. From A mode, first described by Ian Donald for gynecology in the late 1950s, to B mode in the 1970s, real-time and gray-scale in the early 1980s, Doppler a little later, sophisticated color Doppler in the 1990s and three dimensional/four-dimensional ultrasound in the 2000s, DUS has not ceased to be closely associated with the practice of obstetrics. The latest innovation is the use of artificial int ...[more]
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Project description:PurposeIn obstetric ultrasound (US) scanning, the learner's ability to mentally build a three-dimensional (3D) map of the fetus from a two-dimensional (2D) US image represents a major challenge in skill acquisition. We aim to build a US plane localisation system for 3D visualisation, training, and guidance without integrating additional sensors.MethodsWe propose a regression convolutional neural network (CNN) using image features to estimate the six-dimensional pose of arbitrarily oriented US planes relative to the fetal brain centre. The network was trained on synthetic images acquired from phantom 3D US volumes and fine-tuned on real scans. Training data was generated by slicing US volumes into imaging planes in Unity at random coordinates and more densely around the standard transventricular (TV) plane.ResultsWith phantom data, the median errors are 0.90 mm/1.17[Formula: see text] and 0.44 mm/1.21[Formula: see text] for random planes and planes close to the TV one, respectively. With real data, using a different fetus with the same gestational age (GA), these errors are 11.84 mm/25.17[Formula: see text]. The average inference time is 2.97 ms per plane.ConclusionThe proposed network reliably localises US planes within the fetal brain in phantom data and successfully generalises pose regression for an unseen fetal brain from a similar GA as in training. Future development will expand the prediction to volumes of the whole fetus and assess its potential for vision-based, freehand US-assisted navigation when acquiring standard fetal planes.
| S-EPMC9110476 | biostudies-literature
Project description:Objective This study aims to evaluate pregnancy outcomes in patients with spontaneous and iatrogenic chorioamniotic separation diagnosed by ultrasound after 17 weeks. Methods This is a retrospective cohort study of women with a singleton pregnancy who were diagnosed with chorioamniotic separation (n = 106) after 17 weeks' gestation from January 2000 to January 2013. Patients with chorioamniotic separation were compared with a group of patients who had obstetric ultrasounds without a diagnosis of chorioamniotic separation. Those without chorioamniotic separation were matched (1:1) on gestational age on the date of the ultrasound ( ± 2 weeks) (n = 106). The primary outcome was preterm delivery (< 37 weeks). Secondary outcomes included intrauterine growth restriction, stillbirth, and neonatal morbidity. Results The rate of preterm delivery was significantly higher for those with chorioamniotic separation than for those without (57.5 vs. 17.1%, p < 0.0001). There were no significant differences in the rate of aneuploidy, intrauterine growth restriction, stillbirth, or neonatal demise. The rate of stillbirth was significantly higher among those with chorioamniotic separation diagnosed before 24 weeks as compared with those diagnosed after 24 weeks (9.7 vs. 0%, p = 0.03). Conclusions Chorioamniotic separation is associated with preterm delivery. If diagnosed before 24 weeks, the rate of stillbirth is significantly higher.
| S-EPMC5039039 | biostudies-literature
Project description:BackgroundNinety-four percent of all maternal deaths occur in low- and middle-income countries, and the majority are preventable. Access to quality Obstetric ultrasound can identify some complications leading to maternal and neonatal/perinatal mortality or morbidity and may allow timely referral to higher-resource centers. However, there are significant global inequalities in access to imaging and many challenges to deploying ultrasound to rural areas. In this study, we tested a novel, innovative Obstetric telediagnostic ultrasound system in which the imaging acquisitions are obtained by an operator without prior ultrasound experience using simple scan protocols based only on external body landmarks and uploaded using low-bandwidth internet for asynchronous remote interpretation by an off-site specialist.MethodsThis is a single-center pilot study. A nurse and care technician underwent 8 h of training on the telediagnostic system. Subsequently, 126 patients (68 second trimester and 58 third trimester) were recruited at a health center in Lima, Peru and scanned by these ultrasound-naïve operators. The imaging acquisitions were uploaded by the telemedicine platform and interpreted remotely in the United States. Comparison of telediagnostic imaging was made to a concurrently performed standard of care ultrasound obtained and interpreted by an experienced attending radiologist. Cohen's Kappa was used to test agreement between categorical variables. Intraclass correlation and Bland-Altman plots were used to test agreement between continuous variables.ResultsObstetric ultrasound telediagnosis showed excellent agreement with standard of care ultrasound allowing the identification of number of fetuses (100% agreement), fetal presentation (95.8% agreement, κ =0.78 (p < 0.0001)), placental location (85.6% agreement, κ =0.74 (p < 0.0001)), and assessment of normal/abnormal amniotic fluid volume (99.2% agreement) with sensitivity and specificity > 95% for all variables. Intraclass correlation was good or excellent for all fetal biometric measurements (0.81-0.95). The majority (88.5%) of second trimester ultrasound exam biometry measurements produced dating within 14 days of standard of care ultrasound.ConclusionThis Obstetric ultrasound telediagnostic system is a promising means to increase access to diagnostic Obstetric ultrasound in low-resource settings. The telediagnostic system demonstrated excellent agreement with standard of care ultrasound. Fetal biometric measurements were acceptable for use in the detection of gross discrepancies in fetal size requiring further follow up.
| S-EPMC8074497 | biostudies-literature
Project description:Eye trackers can provide visual guidance to sonographers during ultrasound (US) scanning. Such guidance is potentially valuable for less experienced operators to improve their scanning skills on how to manipulate the probe to achieve the desired plane. In this paper, a multimodal guidance approach (Multimodal-GuideNet) is proposed to capture the stepwise dependency between a real-world US video signal, synchronized gaze, and probe motion within a unified framework. To understand the causal relationship between gaze movement and probe motion, our model exploits multitask learning to jointly learn two related tasks: predicting gaze movements and probe signals that an experienced sonographer would perform in routine obstetric scanning. The two tasks are associated by a modality-aware spatial graph to detect the co-occurrence among the multi-modality inputs and share useful cross-modal information. Instead of a deterministic scanning path, Multimodal-GuideNet allows for scanning diversity by estimating the probability distribution of real scans. Experiments performed with three typical obstetric scanning examinations show that the new approach outperforms single-task learning for both probe motion guidance and gaze movement prediction. Multimodal-GuideNet also provides a visual guidance signal with an error rate of less than 10 pixels for a 224 × 288 US image.
| S-EPMC7614062 | biostudies-literature
Project description:IntroductionDue to the introduction of cell-free DNA genetic testing options, the number of clinical ultrasound procedures has greatly diminished in recent years. With fewer real-life ultrasound-guided procedures being performed, it is difficult for OB/GYN and maternal-fetal medicine (MFM) trainees to achieve competency in doing them. Simulation can be utilized to address this issue and supplement a learner's real-life training.MethodsWe developed a simulation workshop incorporating previously described ultrasound guidance task trainers and simulators of amniocentesis and chorionic villus sampling. The workshop had three parts: needle guidance basics, targeting task performance, and procedure-specific simulation. A form of this workshop has been held at the annual meeting of the Society for Maternal-Fetal Medicine since 2015 and as a regional course for MFM fellows since 2017. During the 2019 and 2020 courses, participants completed Likert-scale surveys evaluating the course.ResultsSince the workshops began in 2015, approximately 300 people have participated. In 2019-2020, 41 MFM attending physicians, 136 MFM fellows, and three OB/GYN residents took our course and completed a postcourse survey. Participants rated the course highly and thought it was highly effective.DiscussionWe created an introductory simulation workshop for obstetric ultrasound-guided invasive procedures that participants rated highly and thought was very effective. Objective clinical assessment of skill improvement after completion of this course is needed to verify its true impact. Repeated exposure to this introductory simulation and creation of more challenging workshops are needed to achieve a sustained high level of procedural skill.
| S-EPMC9061933 | biostudies-literature
Project description:Ultrasound is the primary modality for obstetric imaging and is highly sonographer dependent. Long training period, insufficient recruitment and poor retention of sonographers are among the global challenges in the expansion of ultrasound use. For the past several decades, technical advancements in clinical obstetric ultrasound scanning have largely concerned improving image quality and processing speed. By contrast, sonographers have been acquiring ultrasound images in a similar fashion for several decades. The PULSE (Perception Ultrasound by Learning Sonographer Experience) project is an interdisciplinary multi-modal imaging study aiming to offer clinical sonography insights and transform the process of obstetric ultrasound acquisition and image analysis by applying deep learning to large-scale multi-modal clinical data. A key novelty of the study is that we record full-length ultrasound video with concurrent tracking of the sonographer's eyes, voice and the transducer while performing routine obstetric scans on pregnant women. We provide a detailed description of the novel acquisition system and illustrate how our data can be used to describe clinical ultrasound. Being able to measure different sonographer actions or model tasks will lead to a better understanding of several topics including how to effectively train new sonographers, monitor the learning progress, and enhance the scanning workflow of experts.
| S-EPMC8266837 | biostudies-literature
Project description:OBJECTIVE:The purpose of this article was to review the published literature on 3-dimensional ultrasound (3DUS) and 4-dimensional ultrasound (4DUS) in obstetrics and determine whether 3DUS adds diagnostic information to what is currently provided by 2-dimensional ultrasound (2DUS) and, if so, in what areas. METHODS:A PubMed search was conducted for articles reporting on the use of 3DUS or 4DUS in obstetrics. Seven-hundred six articles were identified, and among those, 525 were actually related to the subject of this review. Articles describing technical developments, clinical studies, reviews, editorials, and studies on fetal behavior or maternal-fetal bonding were reviewed. RESULTS:Three-dimensional ultrasound provides additional diagnostic information for the diagnosis of facial anomalies, especially facial clefts. There is also evidence that 3DUS provides additional diagnostic information in neural tube defects and skeletal malformations. Large studies comparing 2DUS and 3DUS for the diagnosis of congenital anomalies have not provided conclusive results. Preliminary evidence suggests that sonographic tomography may decrease the examination time of the obstetric ultrasound examination, with minimal impact on the visualization rates of anatomic structures. CONCLUSIONS:Three-dimensional ultrasound provides additional diagnostic information for the diagnosis of facial anomalies, evaluation of neural tube defects, and skeletal malformations. Additional research is needed to determine the clinical role of 3DUS and 4DUS for the diagnosis of congenital heart disease and central nervous system anomalies. Future studies should determine whether the information contained in the volume data set, by itself, is sufficient to evaluate fetal biometric measurements and diagnose congenital anomalies.
| S-EPMC7062383 | biostudies-literature
Project description:Mirror artifacts are produced by the reflection of ultrasound waves after they propagate through a structure and encounter a strong and smooth interface capable of acting as a mirror. Ultrasound waves bounce back and forth between the mirroring interface and the reflective object and then eventually return to the transducer. The typical display of the mirror artifact consists of two similar structures separated and at similar distances from the reflective interface. We report a mirror artifact in a patient with a singleton gestation at 18 weeks. The image was interpreted as consistent with a twin gestation using transabdominal and transvaginal ultrasound. The differential diagnosis consisted of an abdominal heterotopic pregnancy. The presence of synchronized but opposite movements of both fetuses, and the blurred image of the second fetus, suggested a mirror artifact. The reflective surface was created by the interface located between a distended rectosigmoid filled with gas and the posterior uterine wall. Mirror artifacts can lead to diagnostic errors. This case illustrates how a distended rectosigmoid colon can generate an image that simulates either a twin gestation or an abdominal heterotopic pregnancy.
| S-EPMC3973438 | biostudies-literature
Project description:Automated ultrasound (US)-probe movement guidance is desirable to assist inexperienced human operators during obstetric US scanning. In this paper, we present a new visual-assisted probe movement technique using automated landmark retrieval for assistive obstetric US scanning. In a first step, a set of landmarks is constructed uniformly around a virtual 3D fetal model. Then, during obstetric scanning, a deep neural network (DNN) model locates the nearest landmark through descriptor search between the current observation and landmarks. The global position cues are visualised in real-time on a monitor to assist the human operator in probe movement. A Transformer-VLAD network is proposed to learn a global descriptor to represent each US image. This method abandons the need for deep parameter regression to enhance the generalization ability of the network. To avoid prohibitively expensive human annotation, anchor-positive-negative US image-pairs are automatically constructed through a KD-tree search of 3D probe positions. This leads to an end-to-end network trained in a self-supervised way through contrastive learning.
| S-EPMC7612564 | biostudies-literature
Project description:BackgroundEthiopia is a low-income country located in the horn of Africa's sub-Saharan region, with very high incidences of maternal and neonatal mortality. Quality antenatal care improves perinatal health outcomes. The USAID funded Transform: Primary Health Care Activity in collaboration with the Ministry of Health and GE Healthcare introduced Vscan limited obstetric ultrasound services in 120 health centers in Ethiopia. So far, the experiences and opinions of midwives on their use have not been explored and described within the local context. This study therefore aims to explore and describe the experiences and opinions of midwives on Vscan limited obstetric ultrasound services at health centers within Ethiopia.MethodsAn exploratory and descriptive qualitative study was conducted in Amhara, Oromia, and Southern Nations, Nationalities and Peoples' (SNNP) regions of Ethiopia. Twenty-four participants were selected through a purposeful sampling technique. In-depth individual interviews with trained midwives with practical hands-on limited obstetric ultrasound service provision experience were conducted. The thematic analysis was conducted manually.ResultsThe qualitative data analysis on the experiences and opinions of midwives revealed three themes, namely: individual perception of self-efficacy, facilitators, and barriers of limited obstetric ultrasound services. The basic ultrasound training, which was unique in its organization and arrangement, prepared and built the self-efficacy of trainees in executing their expected competencies. Support of health systems and health managers in dedicating space, availing essential supplies, and assigning human resources emerged as facilitators of the initiated limited obstetric ultrasound services, whereas high workload on one or two ultrasound trained midwives, interruption of essential supplies like paper towels, gel, and alternative power sources were identified as barriers for limited ultrasound services.ConclusionThis study explored the experiences and opinions of midwives who were trained on the provision of limited obstetric ultrasound services and served the community in health centers in rural parts of Ethiopia. The results of this study revealed the positive impacts of the intervention on the perceived self-efficacy, facilitation, and breaking-down of barriers to obstetric ultrasound services. Before scaling-up limited obstetric ultrasound interventions, health managers should ensure and commit to availing essential supplies (e.g., paper towels, ultrasound gel, and large memory hard discs), arranging private rooms, and training other mid-level health professionals. In addition, improving pregnant women's literacy on the national schedule for ultrasound scanning services is recommended.
| S-EPMC8915526 | biostudies-literature