T2-weighted IDEAL fast spin echo imaging of the brachial plexus: comparison with STIR

Abstract

Background: Short TI inversion-recovery (STIR) imaging is widely used, but its signal-to-noise-ratio (SNR) is relatively low. Iterative decomposition of water and fat with echo asymmetric and least-squares estimation (IDEAL) imaging has demonstrated promising results in several areas.

Purpose: To compare T2-weighted fast spin-echo IDEAL (T2W IDEAL-FSE) with STIR to determine which sequence is superior to image the brachial plexus.

Material and methods: The brachial plexus was imaged in 18 patients and six volunteers. The patients' diseases comprised of: suspected chronic inflammatory demyelinating polyneuropathy (CIDP), brachial plexus palsy of unknown origin, and suspected amyotrophic lateral sclerosis. Frontal partial MIP images were acquired. Image quality was qualitatively and independently scored by two radiologists on a three-point grading scale for noise, visibility of the nerve roots, and overall image quality. Inter-observer agreement of the rating by two readers was assessed. The SNR and contrast-to-noise-ratio (CNR) were quantitatively calculated, and differences between T2W IDEAL-FSE and STIR were compared.

Results: Qualitatively, each score for T2W IDEAL-FSE was significantly higher (P < 0.01) than that for STIR. Quantitatively, both SNR and CNR for T2W IDEAL-FSE (45.3 ± 12.6 and 27.1 ± 12.1, respectively) were significantly higher (P < 0.001) than those for STIR (17.4 ± 6.1 and 8.2 ± 4.7, respectively).

Conclusion: T2W IDEAL-FSE could be used to replace STIR for visualization of the brachial plexus.

Keywords: Brachial plexus; IDEAL; STIR; magnetic resonance imaging (MRI).