Real-Time Color overlay Cardiac Phase Contrast Spiral imaging at 3 Tesla

Introduction: The ability of MRI to quantify blood flow with high spatial and temporal resolution has made it a method of choice for accurate blood flow mapping in-vivo. The challenges comprise the development of techniques to accurately assess blood flow through heart valves by incorporating appropriate respiratory and cardiac motion compensation schemes as well as very fast measurement techniques to assess transient changes of blood flow such as ischemia-mediated flow responses. Nayak et al. have performed the real-time color flow MRI [1] in 1.5T systems. In this work we develop a fast spiral phase contrast pulse sequence and real-time reconstruction to compute both velocity and density maps in 3T systems. The spiral was chosen because of its insensitivity to motion and flow, and time efficiency. No breath holding or gating is required. We design two spiral acquisitions including uniform (uds) and variable (vds) density trajectories with different spatial resolutions. Image quality and performance were compared qualitatively by independent observers.