Evaluation and comparison of ECG-gated techniques at 1.5 T for contrast enhanced MR angiography of the thoracic aorta

Background 3D T1-weighted contrast-enhanced MRA (CE-MRA) is routinely used for non-invasive evaluation of the thoracic aorta. However, competing demands of high spatial resolution and fast (breath-hold) acquisition often preclude ECG-gating, leading to motion artifact at the aortic root. Standard Cartesian-sampled ECG-gated CE-MRA acquires 1 partition per heartbeat resulting in long scan times, often exceeding breath-hold capabilities. We evaluated image quality and diagnostic capabilities of a novel ECG-gated CE-MRA utilizing alternative Cartesian k-space sampling whereby adjacent ky and kz points are acquired in a zigzag pattern (Z-MRA) to improve scanning efficiency and co-ordinate contrast timing with optimal cardiac phase acquisition.