Velocity guided segmentation of phase contrast magnetic resonance angiography

Atherosclerosis, the precursor to acute events such as myocardial infarction and stroke, is a focal inflammatory disease that is influenced by local hemodynamic forces such as wall shear stress (WSS). Phase contrast (PC) MRI is an established method that encodes blood velocity into the phase of an image. A requisite step for the calculation of WSS from PC-MRI data is delineation of the vasculature. Previous automatic segmentation algorithms have primarily relied on the image magnitude. Phase based segmentation algorithms have reduced the phase data to image features prior to segmentation. We outline a novel method that directly incorporates phase data as an additional external force in an active model. We demonstrate improved segmentation results over current methods on both synthetic and real data.