Simultaneous Variable-Slab Dual-Echo TOF MR Angiography and Susceptibility-Weighted Imaging

In this paper, we propose a new 3-D dual-echo method for simultaneous multislab time-of-flight MR angiography (TOF MRA) and single-slab susceptibility-weighted imaging (SWI). The previous echo-specific k-space reordering scheme for compatible dual-echo arteriovenography (CODEA) was advanced to applying excitation RF pulses for multiple thin slabs and a single thick slab to the first (TOF MRA) and second (SWI) echoes, respectively. Single-slab CODEA and multislab CODEA (fixed-slab CODEAs) were additionally acquired as comparison reference to the proposed variable-slab CODEA. Parallel imaging was also tested for feasibility of accelerating the proposed method. TOF MRA and SWI from the proposed variable-slab CODEA were visually and quantitatively comparable to multislab TOF MRA and single-slab SWI, respectively, separately acquired from the fixed-slab CODEAs. The parallel imaging reduced the scan time from 10.3 to 5.6 min. Furthermore, the proposed variable-slab approach improved the vessel continuities at slab boundaries of TOF MRA for CODEA as well as for the conventional single echo method. The proposed variable-slab CODEA provided multislab TOF MRA and single-slab SWI simultaneously in a clinically reasonable scan time of ~5 min with minimal impact on image qualities, while suppressing slab boundary artifacts in TOF MRA.