Extended Reality in Congenital Heart Disease: 4D Flow Visualization: A Case Series in Fontan Patients

Background: Extended reality (XR), a stereoscopic three-dimensional visualization technique (3DVT), enables 3D and four-dimensional (4D) cardiac visualization and can improve spatial understanding of anatomy and hemodynamics in congenital heart disease. Cases Summary: Four-dimensional flow magnetic resonance imaging data from 2 Fontan patients was visualized using the HoloLens, an immersive and interactive 3DVT that allowed users to explore the 4D model and select various flow effects. Complex flow patterns—such as tornado-like coiling and helical flows—provided insights into abnormal hemodynamics. Discussion: Monoscopic 3DVT may hinder accurate interpretation of 4D data, especially in users with lower visual-spatial abilities (VSA). XR supports these users by making 4D data more intuitive to interpret, enabling performance comparable to those with higher VSA and thereby enhancing clinical data interpretation and decision-making. Take-Home Message: With interactive 3D/4D models, XR can facilitate a more intuitive and accurate interpretation of clinical data, allowing users with lower VSA to achieve performance levels comparable to those with higher VSA.