Golden-step phase encoding for flexible realtime Cardiac MRI

Introduction Realtime MRI involves an inevitable trade-off between spatial resolution, temporal resolution, field-of-view (FOV), and signal-to-noise (SNR) ratio. In conventional Cartesian imaging all these parameters are fixed prior to scanning, and images can typically only be reconstructed for the prescribed parameters. Previously, Winkelmann [1] demonstrated the Golden Angle radial technique, advancing the projection angle in 111° steps (the Golden Ratio of 180°), providing almost uniformly distributed projections after any arbitrary number of acquisitions. Here we propose and demonstrate the use of Golden Step phase encoding for Cartesian type acquisitions permitting the temporal resolution, FOV and SNR to be selected retrospectively and multiple reconstructions with varied parameters from the same data. Applications include interventional imaging where images are required to serve multiple purposes simultaneously (e.g. instrument guidance and subject monitoring).