Optimization of Fat Suppression Technique and Imaging Parameters for MR Neurography Using 3D Turbo Spin Echo with Variable Refocusing Flip Angle at 3.0 T: Visualization of Brachial Plexus

Abstract

Magnetic resonance neurography (MRN) has been used to evaluate abnormal conditions of entire nerves and nerve bundles. A fat-suppressed 3D turbo spin echo (TSE) sequence is one of the imaging techniques for MRN, which has been widely adopted at 1.5 T. However, MRN of the brachial plexus using a 3D TSE sequence with short-term inversion recovery (STIR) reduces the effect of fat suppression at 3.0 T. Moreover, the use of spectral pre-saturation with inversion recovery (SPIR) does not result in uniform fat suppression due to the inhomogeneity of the static magnetic field. On the other hand, it is well known that the visibility of the brachial plexus using a 3D TSE sequence greatly changes with the equivalent echo time (TEequiv). Therefore, we optimized the fat suppression technique and TEequiv so that the 3D TSE sequence, using a combination of STIR with SPIR and an optimal TEequiv (from 73 to 110 ms), achieved better visualization of the brachial plexus without residual fat.