Graphicflow ultrasound in fetal echocardiography: principles, hemodynamics, clinical applications, and future perspectives

Abstract Background Graphicflow is a commercially available ultrasound technology that uses trajectory-based blood speckle tracking to display intracardiac blood-cell movement in real time during fetal echocardiography. Unlike conventional Doppler ultrasound, which mainly measures blood-flow velocity and direction, this technique offers an additional perspective by revealing how blood moves, circulates, and organizes within the fetal heart. Although interest in this approach has grown over recent years, the current evidence remains limited and is largely based on early feasibility studies and small observational reports. Content This illustrated Opinion Paper brings together the available evidence on trajectory-based fetal hemodynamic imaging by reviewing published fetal, neonatal, and pediatric blood speckle-tracking studies alongside international fetal echocardiography guidelines, technical reports, and established principles of cardiovascular fluid dynamics. We discuss the underlying physics of blood speckle tracking, the physiological significance of intracardiac flow patterns, potential clinical applications, existing technical challenges, and key considerations for responsible clinical adoption. We also include original fetal imaging examples and conceptual illustrations to summarize current knowledge while highlighting important gaps that require further investigation. Given the limited clinical validation currently available, this review should be viewed as an evidence-informed synthesis and a framework for generating future research hypotheses rather than evidence supporting routine clinical use. Summary Current evidence suggests that trajectory-based blood-flow imaging may complement conventional fetal echocardiography by providing qualitative visualization of intracardiac flow organization beyond velocity mapping alone. However, standardized acquisition protocols, quantitative hemodynamic metrics, reproducibility, gestational age-specific normative datasets, and prospective multicenter validation remain necessary before routine clinical implementation can be recommended. Outlook Future research should prioritize methodological standardization, rigorous clinical validation, and demonstration of incremental clinical value beyond conventional fetal echocardiography to support the responsible integration of trajectory-based fetal hemodynamic imaging into clinical practice.