TraCer allows health workers to perform accurate pregnancy dating with minimal training and without expensive equipment.
The fully portable system uses a low-cost probe to capture fetal ultrasound videos. These are transferred to a tablet and processed automatically with machine-learning algorithms that measure two fetal structures and provide the corresponding gestational age.
The current TraCer system is integrated with a wireless ultrasound probe (Konted) and the application runs on a standard Android tablet.
Obtaining a gestational age estimation using TraCer requires automation of several processes using algorithms designed by the TraCer research team* including issues with videos of a lower quality.
- Standard plane detection and quality control:
- Check: The appropriate imaging plane for measurement is seen in the video;
- Check: The quality of the images is adequate for accurate biometry **;
- Optimise: Select the optimum frame within the video for measurement.
- Identify the target structure within the measurement frame.
- Estimate the measurement in pixels, convert to mm.
- Calculate GA using established formulae.
*Toward point-of-care ultrasound estimation of fetal gestational age from the trans-cerebellar diameter using CNN-based ultrasound image analysis, Journal of Medical Imaging 2020, Mohammad A. Maraci, Mohammad Yaqub, Rachel Craik, Sridevi Beriwal, Alice Self, Peter von Dadelszen, Aris Papageorghiou and J. Alison Noble
**Label efficient localization of fetal brain biometry planes in ultrasound through metric learning, International Workshop on Advances in Simplifying Medical Ultrasound 2020, Yuan Gao, Sridevi Beriwal, Rachel Craik, Aris T. Papageorghiou and J. Alison Noble
Why is TraCer necessary?
Accurate knowledge of gestational age (GA) is a cornerstone of modern maternity care, reducing unnecessary interventions while reducing stillbirths and other obstetric complications. In most low-income or middle-income countries, many women never receive antenatal care or, if they do, present at 20 weeks’ gestation or later. Pregnancy dating using either maternal recall of her last menstrual period or symphysis-fundal height is inaccurate. Although ultrasound is the most accurate approach, lack of expensive equipment and trained staff means accurate GA dating is often unavailable in less-developed countries despite its obvious need.
Pregnancy Care in low-resource settings
Few trained sonographers
Expensive ultrasound systems
How does TraCer estimate gestational age?
The TraCer software automatically detects and measures the trans-cerebellar diameter (TCD) and head circumference (HC) and translates this into GA. TCD and HC correlate with GA and, in the absence of fetal anomalies, are relatively protected from the influence of fetal growth restriction and remains reliable throughout pregnancy from 14 weeks until term (37+0 weeks).
TraCer and PRECISE
As part of the PRECISE (PREgnancy Care Integrating translational Science, Everywhere) study, the current TraCer system is being used by healthcare workers in the field in Kenya and The Gambia.
This phase includes usability- and beta-testing of the device and iterative feedback to refine the algorithm, if needed.
Qualitative data is being obtained through focus groups and in-depth interviews with health care providers and policy makers to identify current patterns of practice; barriers and facilitators for task-sharing of GA determination using the TraCer app; and what level of heath care worker would be best placed to use it.