Investig Magn Reson Imaging.  2016 Jun;20(2):81-87. 10.13104/imri.2016.20.2.81.

Detecting Peripheral Nerves in the Elbow using Three-Dimensional Diffusion-Weighted PSIF Sequences: a Feasibility Pilot Study

• Na D
• Ryu J
• Hong SJ
• Hong SH
• Yoon MA
• Ahn KS
• Kang CH
• Kim BH

• KMID: 2327419
• DOI: http://doi.org/10.13104/imri.2016.20.2.81

Abstract

PURPOSE
To analyze the feasibility of three-dimensional (3D) diffusion-weighted (DW) PSIF (reversed FISP [fast imaging with steady-state free precession]) sequence in order to evaluate peripheral nerves in the elbow.
MATERIALS AND METHODS
Ten normal, asymptomatic volunteers were enrolled (6 men, 4 women, mean age 27.9 years). The following sequences of magnetic resonance images (MRI) of the elbow were obtained using a 3.0-T machine: 3D DW PSIF, 3D T2 SPACE (sampling perfection with application optimized contrasts using different flip angle evolution) with SPAIR (spectral adiabatic inversion recovery) and 2D T2 TSE (turbo spin echo) with modified Dixon (m-Dixon) sequence. Two observers used a 5-point grading system to analyze the image quality of the ulnar, median, and radial nerves. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of each nerve were measured. We compared 3D DW PSIF images with other sequences using the Wilcoxon-signed rank test and Friedman test. Inter-observer agreement was measured using intraclass correlation coefficient (ICC) analysis.
RESULTS
The mean 5-point scores of radial, median, and ulnar nerves in 3D DW PSIF (3.9/4.2/4.5, respectively) were higher than those in 3D T2 SPACE SPAIR (1.9/2.8/2.8) and 2D T2 TSE m-Dixon (1.7/2.8/2.9) sequences (P < 0.05). The mean SNR in 3D DW PSIF was lower than 3D T2 SPACE SPAIR, but there was no difference between 3D DW PSIF and 2D T2 TSE m-Dixon in all of the three nerves. The mean CNR in 3D DW PSIF was lower than 3D T2 SPACE SPAIR and 2D T2 TSE m-Dixon in the median and ulnar nerves, but no difference among the three sequences in the radial nerve.
CONCLUSION
The three-dimensional DW PSIF sequence may be feasible to evaluate the peripheral nerves around the elbow in MR imaging. However, further optimization of the image quality (SNR, CNR) is required.

Keyword

3T MR neurography; 3D DW PSIF; Elbow joint; Peripheral nerve

MeSH Terms

Elbow Joint
Elbow*
Female
Humans
Magnetic Resonance Imaging
Male
Peripheral Nerves*
Pilot Projects*
Radial Nerve
Signal-To-Noise Ratio
Ulnar Nerve
Volunteers

Figure

• 

  Fig. 1 Qualitative analysis score of each nerve.

• 

  Fig. 2 MR neurography images. (a) Fat-suppressed 3D DW PSIF image, (b) Fat-suppressed 3D T2 SPAIR image, (c) Fatsuppressed 2D T2 m-Dixon image. In the fat-suppressed 3D DWI PSIF images, the median (thick arrows), radial (arrows) and ulnar nerves (curved arrows) are easily defined with suppressed adjacent vessel signals. However, in other sequences, it is difficult to differentiate the nerves from the adjacent vessel signals, even though the SNR and CNR of the nerves are better than are the fat-suppressed 3D DW PSIF images.

• 

  Fig. 3 Quantitative analysis score of each nerve (SNR).

• 

  Fig. 4 Quantitative analysis score of each nerve (CNR).

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