Reproducibility of myelin water fraction analysis: a comparison of region of interest and voxel-based analysis methods.
This study compared region of interest (ROI) and voxel-based analysis (VBA) methods to determine the optimal method of myelin water fraction (MWF) analysis. Twenty healthy controls were scanned twice using a multi-echo T(2) relaxation sequence and ROIs were drawn in white and grey matter. MWF was defined as the fractional signal from 15 to 40 ms in the T(2) distribution. For ROI analysis, the mean intensity of voxels within an ROI was fit using non-negative least squares. For VBA, MWF was obtained for each voxel and the mean and median values within an ROI were calculated. There was a slightly higher correlation between Scan 1 and 2 for the VBA method (R(2)=0.98) relative to the ROI method (R(2)=0.95), and the VBA mean square difference between scans was 300% lower, indicating VBA was the most consistent between scans. For the VBA method, mean MWF was found to be more reproducible than median MWF. As the VBA method is more reproducible and gives more options for visualization and analysis of MWF, it is recommended over the ROI method of MWF analysis.
Department of Physics, University of Alberta, Edmonton, Canada.
Sandra M
SM
Meyers
Cornelia
C
Laule
Irene M
IM
Vavasour
Shannon H
SH
Kolind
Burkhard
B
Mädler
Roger
R
Tam
Anthony L
AL
Traboulsee
Jimmy
J
Lee
David K B
DK
Li
Alex L
AL
MacKay
D000328:Adult; D001834:Body Water / Q000737:chemistry; D001923:Brain Chemistry; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009413:Nerve Fibers, Myelinated / Q000737:chemistry* / Q000648:ultrastructure; D012372:ROC Curve; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014867:Water / Q000032:analysis*; D055815:Young Adult
D014867:Water