SHINKEI--a novel 3D isotropic MR neurography technique: technical advantages over 3DIRTSE-based imaging

Technical assessment of SHINKEI pulse sequence and conventional 3DIRTSE for LS plexus MR neurography.

Twenty-one MR neurography examinations of the LS plexus were performed at 3 T, using 1.5-mm isotropic 3DIRTSE and SHINKEI sequences. Images were evaluated for motion and pulsation artefacts, nerve signal-to-noise ratio, contrast-to-noise ratio, nerve-to-fat ratio, muscle-to-fat ratio, fat suppression homogeneity and depiction of LS plexus branches. Paired Student t test was used to assess differences in nerve conspicuity (p < 0.05 was considered statistically significant). ICC correlation was obtained for intraobserver performance.

Four examinations were excluded due to prior spine surgery. Bowel motion artefacts, pulsation artefacts, heterogeneous fat saturation and patient motion were seen in 16/17, 0/17, 17/17, 2/17 on 3DIRTSE and 0/17, 0/17, 0/17, 1/17 on SHINKEI. SHINKEI performed better (p < 0.01) for nerve signal-to-noise, contrast-to-noise, nerve-to-fat and muscle-to-fat ratios. 3DIRTSE and SHINKEI showed all LS plexus nerve roots, sciatic and femoral nerves. Smaller branches including obturator, lateral femoral cutaneous and iliohypogastric nerves were seen in 10/17, 5/17, 1/17 on 3DIRTSE and 17/17, 16/17, 7/17 on SHINKEI. Intraobserver reliability was excellent.

SHINKEI MRN demonstrates homogeneous and superior fat suppression with increased nerve signal- and contrast-to-noise ratios resulting in better conspicuity of smaller LS plexus branches.

• SHINKEI provides homogeneous and superior fat suppression, shown by higher nerve and muscle-to-fat ratios. • SHINKEI shows better nerve signal-to-noise and contrast-to-noise ratios than 3DIRTSE. • SHINKEI enables nerve-selective images with increased conspicuity of smaller LS plexus branches. • SHINKEI should be considered in routine MR neurography of the LS plexus.