Compatible Dual-Echo Arteriovenography (CODEA) using an Echo-Specific K-Space Reordering Scheme

Abstract

An improved dual-echo sequence magentic resonance (MR) imaging technique was developed to simultaneously acquire a time-of-flight MR angiogram (MRA) and a blood oxygenation level-dependent MR venogram (MRV) in a single MR acquisition at 3 T. MRA and MRV require conflicting scan conditions (e.g., excitation RF profile, flip angle, and spatial presaturation pulse) for their optimal image quality. This conflict was not well counterbalanced or reconciled in previous methods reported for simultaneous acquisition of MRA and MRV. In our dual-echo sequence method, an echo-specific K-space reordering scheme was used to uncouple the scan parameter requirements for MRA and MRV. The MRA and MRV vascular contrast was enhanced by maximally separating the K-space center regions acquired for the MRA and MRV, and by adjusting and applying scan parameters compatible between the MRA and MRV. As a preliminary result, we were able to acquire a simultaneous dual-echo MRA and MRV with image quality comparable to that of the conventional single-echo MRA and MRV that were acquired separately at two different sessions. Furthermore, integrated with tilted optimized nonsaturating excitation and multiple overlapping thin-slab acquisition techniques, our dual-echo MRA and MRV provided seamless vascular continuity over a large coverage volume of the brain anatomy. Magn Reson Med 61:767-774, 2009. (C) 2009 Wiley-Liss, Inc.