Diffusion tensor imaging focusing on lower cervical spinal cord using 2D reduced FOV interleaved multislice single-shot diffusion-weighted echo-planar imaging: comparison with conventional single-shot diffusion-weighted echo-planar imaging

Abstract

PURPOSE: To evaluate the performance of diffusion tensor imaging (DTI) of the cervical spinal cord by comparing 2-dimensional standard single-shot interleaved multisection inner volume diffusion-weighted echo-planar imaging (2D ss-IMIV-DWEPI) and conventional 2D ss-DWEPI in a clinical population, focusing on the lower cervical spinal cord.

MATERIALS AND METHODS: From July to September 2013, a total of 23 patients who underwent cervical spinal MR imaging with DTI were retrospectively enrolled in this study (M:F=7:16, mean age 45years, age range 24-76 years). Exclusion criteria were: previous prosthesis insertion (n=5), syringomyelia on T2-weighted imaging (n=4), and spinal cord tumor (n=0). All MRI examinations were performed using 3.0T imaging with a phased-array spine coil including two different 2D reduced FOV DTI sequences: 2D ss-IMIV-DWEPI (iDTI) and 2D ss-DWEPI without interleaving (cDTI). For quantitative analysis, two musculoskeletal radiologists who were blinded to the sequence measured fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values throughout the whole cervical spinal cord (C1-T1). For qualitative analysis, the readers rated each image based on spinal cord distortion, dural margin delineation, and depiction of intervertebral disc. Quantitative and qualitative evaluations were analyzed separately for upper and lower segments. The t-test was used for quantitative analysis and two-way analysis of variance (ANOVA) and t-tests were performed for qualitative analysis.

RESULTS: FA was significantly higher and ADC was significantly lower on iDTI compared with cDTI (0.679 versus 0.563, respectively, for FA; 631 versus 1026, respectively, for ADC; p<0.001), and this was consistently observed in the lower segment of the spinal cord. The reviewers rated iDTI as superior in terms of all assessed characteristics. For qualitative analysis, the mean iDTI score was significantly higher than the cDTI score for both the lower and upper segments (p<0.001).

CONCLUSION: 2D rFOV ss-IMIV-DWEPI demonstrated higher performance than conventional 2D rFOV ss-DWEPI in terms of improving image quality, even in the lower segment of the cervical spinal cord.