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PLoS One. 2013 Sep 16;8(9):e74795. doi: 10.1371/journal.pone.0074795. eCollection 2013.

Application of quantitative MRI for brain tissue segmentation at 1.5 T and 3.0 T field strengths.

Author information

1
Center for Medical Image Science and Visualization, Linköping University, Linköping, Sweden ; Radiation Physics, Department of Medicine and Health, Linköping University, UHL County Council of Östergötland, Linköping, Sweden.

Abstract

BACKGROUND:

Brain tissue segmentation of white matter (WM), grey matter (GM), and cerebrospinal fluid (CSF) are important in neuroradiological applications. Quantitative Mri (qMRI) allows segmentation based on physical tissue properties, and the dependencies on MR scanner settings are removed. Brain tissue groups into clusters in the three dimensional space formed by the qMRI parameters R1, R2 and PD, and partial volume voxels are intermediate in this space. The qMRI parameters, however, depend on the main magnetic field strength. Therefore, longitudinal studies can be seriously limited by system upgrades. The aim of this work was to apply one recently described brain tissue segmentation method, based on qMRI, at both 1.5 T and 3.0 T field strengths, and to investigate similarities and differences.

METHODS:

In vivo qMRI measurements were performed on 10 healthy subjects using both 1.5 T and 3.0 T MR scanners. The brain tissue segmentation method was applied for both 1.5 T and 3.0 T and volumes of WM, GM, CSF and brain parenchymal fraction (BPF) were calculated on both field strengths. Repeatability was calculated for each scanner and a General Linear Model was used to examine the effect of field strength. Voxel-wise t-tests were also performed to evaluate regional differences.

RESULTS:

Statistically significant differences were found between 1.5 T and 3.0 T for WM, GM, CSF and BPF (p<0.001). Analyses of main effects showed that WM was underestimated, while GM and CSF were overestimated on 1.5 T compared to 3.0 T. The mean differences between 1.5 T and 3.0 T were -66 mL WM, 40 mL GM, 29 mL CSF and -1.99% BPF. Voxel-wise t-tests revealed regional differences of WM and GM in deep brain structures, cerebellum and brain stem.

CONCLUSIONS:

Most of the brain was identically classified at the two field strengths, although some regional differences were observed.

PMID:
24066153
PMCID:
PMC3774721
DOI:
10.1371/journal.pone.0074795
[Indexed for MEDLINE]
Free PMC Article

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