Published online Sep 28, 2015. doi: 10.4329/wjr.v7.i9.279
Peer-review started: February 11, 2015
First decision: March 6, 2015
Revised: June 24, 2015
Accepted: July 29, 2015
Article in press: August 3, 2015
Published online: September 28, 2015
Processing time: 244 Days and 12.3 Hours
AIM: To assess inter- and intra-rater reliability (agreement) between two region of interest (ROI) methods in pediatric spinal cord diffusion tensor imaging (DTI).
METHODS: Inner-Field-of-View DTI data previously acquired from ten pediatric healthy subjects (mean age = 12.10 years) was used to assess for reliability. ROIs were drawn by two neuroradiologists on each subject data twice within a 3-mo interval. ROIs were placed on axial B0 maps along the cervical spine using free-hand and fixed-size ROIs. Agreement analyses for fractional anisotropy (FA), axial diffusivity, radial diffusivity and mean diffusivity were performed using intra-class-correlation (ICC) and Cronbach’s alpha statistical methods.
RESULTS: Inter- and intra-rater agreement between the two ROI methods showed moderate (ICC = 0.5) to strong (ICC = 0.84). There were significant differences between raters in the number of pixels selected using free-hand ROIs (P < 0.05). However, no significant differences were observed in DTI parameter values. FA showed highest variability in ICC values (0.10-0.87). Cronbach’s alpha showed moderate-high values for raters and ROI methods.
CONCLUSION: The study showed that high reproducibility in spinal cord DTI can be achieved, and demonstrated the importance of setting detailed methodology for post-processing DTI data, specifically the placement of ROIs.
Core tip: We tested the reliability of spinal cord diffusion tensor imaging (DTI) by assessing inter- and intra-rater agreement between two region of interest (ROI) selection methods. Results showed moderate to strong agreement between repeated measurements. There was a variation in DTI parameters at lower and upper spinal cord levels and significant differences between raters in the number of pixels they chose to outline ROIs. There were no significant differences in DTI parameter values derived from these ROIs. The study showed that strong reproducibility in spinal cord DTI can be achieved, and highlighted the importance of setting detailed methodology to standardize ROI drawing techniques.