Retrospective Cohort Study
Copyright ©The Author(s) 2015. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Radiol. Sep 28, 2015; 7(9): 279-285
Published online Sep 28, 2015. doi: 10.4329/wjr.v7.i9.279
Inter- and intra-rater reliability of diffusion tensor imaging parameters in the normal pediatric spinal cord
Nadia Barakat, Pallav Shah, Scott H Faro, John P Gaughan, Devon Middleton, MJ Mulcahey, Feroze B Mohamed
Nadia Barakat, Pallav Shah, Scott H Faro, Devon Middleton, Feroze B Mohamed, Department of Radiology, Temple University, Philadelphia, PA 19140, United States
Nadia Barakat, John P Gaughan, Biostatistics Consulting Center, Temple University School of Medicine, Philadelphia, PA 19140, United States
MJ Mulcahey, Thomas Jefferson University School of Health Professions, Philadelphia, PA 19107, United States
Author contributions: All the authors solely contributed to this paper.
Supported by The Shriners Hospitals for Children, No. #8956.
Institutional review board statement: Subjects and their parents provided written informed assent and consent of the IRB-approved protocol.
Informed consent statement: Subjects and their parents provided written informed assent and consent of the IRB-approved protocol.
Conflict-of-interest statement: All the authors participated in this work do not have any conflict of interest.
Data sharing statement: All the authors participated in this work do not have any data sharing.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Nadia Barakat, PhD, Department of Radiology, Temple University, 3401 N. Broad St., Philadelphia, PA 19140, United States. nadia.barakat@temple.edu
Telephone: +1-215-7079047
Received: February 11, 2015
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
Abstract

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.

Keywords: Diffusion tensor imaging; Reproducibility; Reliability; Spinal cord; Inter-rater; Intra-rater

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.