Rapid time‐resolved magnetic resonance angiography via a multiecho radial trajectory and GraDeS reconstruction

Contrast‐enhanced magnetic resonance angiography is challenging due to the need for both high spatial and temporal resolution. A multishot trajectory composed of pseudo‐random rotations of a single multiecho radial readout was developed. The trajectory is designed to give incoherent aliasing artifacts and a relatively uniform distribution of projections over all time scales. A field map (computed from the same data set) is used to avoid signal dropout in regions of substantial field inhomogeneity. A compressed sensing reconstruction using the GraDeS algorithm was used. Whole brain angiograms were reconstructed at 1‐mm isotropic resolution and a 1.1‐s frame rate (corresponding to an acceleration factor > 100). The only parameter which must be chosen is the number of iterations of the GraDeS algorithm. A larger number of iterations improves the temporal behavior at cost of decreased image signal‐to‐noise ratio. The resulting images provide a good depiction of the cerebral vasculature and have excellent arterial/venous separation. Magn Reson Med, 2013. © 2012 Wiley Periodicals, Inc.