3D Brachial Plexus Neurography With Variable-Rate Selective Excitation RF Pulses
Emma J McKinney1, Xiaoying Cai2, Darryl B Sneag1
1Department of Radiology and Imaging, Hospital for Special Surgery, New York, New York, USA.
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.
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