Intensity non-uniformity correction using N3 on 3-T scanners with multichannel phased array coils

Boyes, Richard G., Gunter, Jeff L., Frost, Chris, Janke, Andrew L., Yeatman, Thomas, Hill, Derek L.G., Bernstein, Matt A., Thompson, Paul M., Weiner, Michael W., Schuff, Norbert, Alexander, Gene E., Killiany, Ronald J., DeCarli, Charles, Jack, Clifford R. and Fox, Nick C. (2008) Intensity non-uniformity correction using N3 on 3-T scanners with multichannel phased array coils. NeuroImage, 39 4: 1752-1762. doi:10.1016/j.neuroimage.2007.10.026

Author Boyes, Richard G.
Gunter, Jeff L.
Frost, Chris
Janke, Andrew L.
Yeatman, Thomas
Hill, Derek L.G.
Bernstein, Matt A.
Thompson, Paul M.
Weiner, Michael W.
Schuff, Norbert
Alexander, Gene E.
Killiany, Ronald J.
DeCarli, Charles
Jack, Clifford R.
Fox, Nick C.
Title Intensity non-uniformity correction using N3 on 3-T scanners with multichannel phased array coils
Journal name NeuroImage   Check publisher's open access policy
ISSN 1053-8119
Publication date 2008-02-15
Year available 2007
Sub-type Article (original research)
DOI 10.1016/j.neuroimage.2007.10.026
Volume 39
Issue 4
Start page 1752
End page 1762
Total pages 11
Place of publication Maryland Heights, MO, United States
Publisher Academic Press
Language eng
Formatted abstract
Measures of structural brain change based on longitudinal MR imaging are increasingly important but can be degraded by intensity non-uniformity. This non-uniformity can be more pronounced at higher field strengths, or when using multichannel receiver coils. We assessed the ability of the non-parametric non-uniform intensity normalization (N3) technique to correct non-uniformity in 72 volumetric brain MR scans from the preparatory phase of the Alzheimer's Disease Neuroimaging Initiative (ADNI). Normal elderly subjects (n = 18) were scanned on different 3-T scanners with a multichannel phased array receiver coil at baseline, using magnetization prepared rapid gradient echo (MP-RAGE) and spoiled gradient echo (SPGR) pulse sequences, and again 2 weeks later.

When applying N3, we used five brain masks of varying accuracy and four spline smoothing distances (d = 50, 100, 150 and 200 mm) to ascertain which combination of parameters optimally reduces the non-uniformity. We used the normalized white matter intensity variance (standard deviation/mean) to ascertain quantitatively the correction for a single scan; we used the variance of the normalized difference image to assess quantitatively the consistency of the correction over time from registered scan pairs.

Our results showed statistically significant (p < 0.01) improvement in uniformity for individual scans and reduction in the normalized difference image variance when using masks that identified distinct brain tissue classes, and when using smaller spline smoothing distances (e.g., 50–100 mm) for both MP-RAGE and SPGR pulse sequences. These optimized settings may assist future large-scale studies where 3-T scanners and phased array receiver coils are used, such as ADNI, so that intensity non-uniformity does not influence the power of MR imaging to detect disease progression and the factors that influence it.
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ
Additional Notes Available online 30 October 2007

Document type: Journal Article
Sub-type: Article (original research)
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Centre for Advanced Imaging Publications
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Created: Tue, 24 Jan 2012, 11:14:50 EST by Sandrine Ducrot on behalf of Centre for Advanced Imaging