3D Brachial Plexus Neurography With Variable‐Rate Selective Excitation RF Pulses

BACKGROUND: Slab-selective radiofrequency (RF) pulses are commonly required in three-dimensional (3D) turbo spin echo (TSE) in brachial plexus magnetic resonance neurography (MRN). However, their long selective RF pulses lead to violation of Carr-Purcell-Meiboom-Gill conditions, which might increase imaging artifacts. HYPOTHESIS: That VERSE STIR-TSE would yield comparable motion artifact to conventional STIR-TSE with superior nerve conspicuity and greater subjective appeal. STUDY TYPE: Prospective, cross-sectional study. POPULATION: Twenty-four subjects (16 females; mean age: 43.7 years; range: 19-76 years) evaluated for clinical suspicion of brachial plexopathy, undergoing brachial plexus MRI (10 left, 9 right, 5 bilateral, 29 total scans analyzed). Agar phantoms mimicking nerve and muscle were also evaluated. FIELD STRENGTH/SEQUENCE: 3-Tesla, 3D STIR-TSE with and without VERSE. ASSESSMENT: Three radiologists, blinded to the sequence type and clinical data, qualitatively evaluated nerve conspicuity, motion, and preferred sequence on a 5-point scale. STATISTICAL TESTS: Wilcoxon signed-rank tests compared nerve conspicuity (0-4 scale), motion artifact (0-4 scale), and preferred series between the non-VERSE and VERSE pulse sequences. Gwet's AC2 assessed inter-rater agreement. A p-value < 0.05 was considered statistically significant. RESULTS: The VERSE STIR-TSE sequence was significantly preferred by all raters. Motion artifact was not significantly different between the sequences (p = 0.11). Conspicuity of the suprascapular nerve was significantly greater with VERSE for both its proximal segments (median: 3, interquartile range: (2, 4), vs. 3 (1, 4)) and distal segments (4 (2, 4) vs. 3 (2, 4)), but conspicuity of the axillary nerve was not significantly different between the sequences (p = 0.27-0.61). Phantom scans confirmed a 74% and 49% increase in signal with VERSE in the muscle and nerve-mimicking phantoms, respectively. DATA CONCLUSION: STIR-TSE with VERSE provided overall superior image quality for brachial plexus MRN as compared to conventional STIR-TSE. EVIDENCE LEVEL: 2. TECHNICAL LEVEL: 1.