Fig. 1

4D Flow CMR visualisation and quantification of valvular flow by retrospective valve tracking. Step 1. Identification of valve plane from cines acquired in 2 orthogonal planes. Step 2. Valve plane is tracked in all phases in the first view and cross-checked with the second view. Arrow allows confirmation of flow in the correct direction. Step 3. Visualisation of flow enables accurate quantification of flow in phase-contrast images