Phase-contrast MRI uses bipolar gradients to encode tissue or fluid motion into the MRI signal phase. If measured in 2D with 1-directional encoding this is termed 2D Phase-Contrast MRI. Extended to a time-resolved heart-or pulse rate triggered 3D sequence with 3-directional velocity encoding, this is termed 4D flow MRI. Error sources will be described throughout the course as well as data analysis and quantification approaches. Further extensions such as dual- and multi-venc, and 5D flow MRI will be described. Finally applications in the thorax, head, and abdomen will be introduced.