Flow, like any movement in MRI, is at the origin of spatial encoding perturbations and artifacts. This MRI sensitivity has been harnessed to develop vascular imaging using the physical modifications linked to flow (non-contrast MRA): time-of-flight, phase contrast, fresh blood imaging (FBI). Contrast-enhanced MR Angiography exploits the relaxivity properties of contrast agents to visualize vascular structures.
Whatever the principle employed, these sequences implement a strategy to suppress the background signal represented by the stationary tissue. All these techniques can be adapted to 3D, and later post-processed (reconstruction by maximum intensity projection MIP). They can all benefit from the progress brought by parallel imaging, in terms of speed and enhanced image quality.