Contrast‐enhanced MR angiography using time resolved interleaved projection sampling with three‐dimensional cartesian phase and slice encoding (TRIPPS)

Undersampled projection reconstruction (PR) techniques provide contrast enhanced MR angiography (CE‐MRA) with high temporal resolution, but sensitivity to eddy current, gradient error and off‐resonance effects. It is desirable to combine the time efficiency of undersampled PR acquisition with the robustness of Cartesian imaging. In this work we present a technique designed to do this termed time resolved projection sampling with three‐dimensional (3D) Cartesian phase and slice encoding (TRIPPS), where 3D Cartesian k‐space is partitioned into multiple half projections in the ky‐kz plane. The phase and slice encoding are performed along predefined center‐out radial trajectories. The whole set of half projections is interleaved into multiple groups of half projections, with each group sparsely but uniformly covering the ky‐kz space. A view sharing sliding window reconstruction algorithm is adapted to reconstruct the dynamic images. The feasibility of the TRIPPS technique for CE‐MRA was demonstrated on the renal, pulmonary, and intracranial vasculatures of healthy volunteers with a high temporal resolution of 2 s/frame. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.