Blood Pool Agent Contrast-Enhanced MRA: Level-Set Based Artery-Vein Separation

Blood pool agents (BPAs) for contrast-enhanced magnetic resonance angiography (CE-MRA) allow prolonged imaging times for higher contrast and resolution by imaging during the steady state when the contrast agent is distributed through the complete vascular system. However, simultaneous arterial and venous enhancement hampers interpretation. It is shown that venous and arterial segmentation in this equilibrium phase can be achieved if the central arterial axis (CAA) and central venous axis (CVA) are known. Since the CAA cannot straightforwardly be obtained from the steady-state data, images acquired during the first pass of the contrast agent can be utilized to determine the CAA with minimal user initialization. Utilizing the CAA to provide a rough arterial segmentation, the CVA can subsequently be determined from the steady-state dataset. The final segmentations of the arteries and veins are achieved by simultaneously evolving two level-sets in the steady-state dataset starting from the CAA and CVA.