Non-Contrast-Enhanced MR Portography With Time-Spatial Labeling Inversion Pulses: Comparison of Imaging With Three-Dimensional Half-Fourier Fast Spin-Echo and True Steady-State Free-Precession Sequences

Abstract

Purpose: To compare and evaluate images acquired with two different MR angiography (MRA) sequences, three-di- mensional (3D) half-Fourier fast spin-echo (FSE) and 3D true steady-state free-precession (SSFP) combined with two time-spatial labeling inversion pulses (T-SLIPs), for selective and non-contrast-enhanced (non-CE) visualiza- tion of the portal vein. Materials and Methods: Twenty healthy volunteers were examined using half-Fourier FSE and true SSFP sequences on a 1.5T MRI system with two T-SLIPs, one placed on the liver and thorax, and the other on the lower abdomen. For quantitative analysis, vessel-to-liver contrast (Cv-l) ratios of the main portal vein (MPV), right portal vein (RPV), and left portal vein (LPV) were measured. The quality of visualiza- tion was also evaluated. Results: In both pulse sequences, selective visualization of the portal vein was successfully conducted in all 20 volun- teers. Quantitative evaluation showed significantly better Cv-l at the RPVs and LPVs in half-Fourier FSE (P 0.0001). At the MPV, Cv-l was better in true SSFP, but was not statistically different. Visualization scores were signifi- cantly better only at branches of segments four and eight for half-Fourier FSE (P 0.001 and 0.03, respectively). Conclusion: Both 3D half-Fourier FSE and true SSFP scans with T-SLIPs enabled selective non-CE visualization of the portal vein. Half-Fourier FSE was considered appropriate for intrahepatic portal vein visualization, and true SSFP may be preferable when visualization of the MPV is required. © 2009.