Contributions
Abstract: P1038
Type: Poster
Abstract Category: Pathology and pathogenesis of MS - 21 Imaging
Background: Diffusion tensor imaging (DTI) of the white matter (WM) tracts within the thalamus has yielded insight into disease processes associated with multiple sclerosis (MS). Recent studies have also demonstrated that quantitative susceptibility mapping (QSM) provides a novel means to investigate thalamic pathology in MS. Considered as a single region, decreased thalamic susceptibility has been reported in MS. However, it is not known to what degree QSM provides additional information regarding intra-thalamic WM beyond that already captured by DTI parameters.
Objective: To investigate the potential role of QSM in quantifying intra-thalamic MS-related pathology.
Methods: This was a cross-sectional 3 Tesla MRI study of 26 relapsing MS and 19 progressive MS patients. Seventeen (17) age- and sex-matched healthy individuals (HIs) were also scanned. Tract-based spatial-statistics (TBSS), restricted to the bilateral thalami, was used to evaluate DTI-derived metrics of mean diffusivity (MD) and fractional anisotropy (FA). QSM maps were also generated and projected onto the TBSS skeleton. Univariate general linear models (GLM) were used to assess group differences in terms of FA, MD, and QSM. Next, multivariate, non-parametric combination (NPC) GLMs were used to perform joint inference on the skeletonised FA, MD and QSM images. Significant clusters were identified using threshold-free cluster enhancement. Permutation-based family-wise correction was employed, and results were considered significant at a corrected p value
of ≤ .05.
Results: As a proportion of the total skeleton volume, univariate models revealed increased MD in 39.2% (peak p=.009), decreased FA in 27.5% (peak p=.005), and decreased susceptibility in 17.6% (peak p=.002) of the voxels in MS patients. With respect to MD alone, the joint inference including FA yielded only a marginally greater proportion of voxels (45.3%, peak p=.003). For the MD and QSM model, however, the joint inference identified 63.0% (peak p=.001) of the thalamic skeleton as being affected in MS patients. The model including FA in addition to MD and QSM yielded similar results as MD and QSM only (60.5%, peak p=.001).
Conclusions: QSM of the intra-thalamic WM provides additional discriminatory power between HIs and MS patients. The biological meaning of decreased WM susceptibility in MS patients remains to be elucidated.
Disclosure:
N Bergsland has nothing to disclose.
F Schweser has nothing to disclose.
MG Dwyer has received consultant fees from Claret Medical and EMD Serono and research grant support from Novartis.
B Weinstock-Guttman received honoraria as a speaker and as a consultant for Biogen Idec, Teva Pharmaceuticals, EMD Serono, Genzyme, Sanofi, Novartis and Acorda. Dr Weinstock-Guttman received research funds from Biogen Idec, Teva Pharmaceuticals, EMD Serono,Genzyme, Sanofi, Novartis, Acorda.
R Zivadinov received personal compensation from EMD Serono, Genzyme-Sanofi, Novartis, Claret-Medical, Celgene for speaking and consultant fees. He received financial support for research activities from Claret Medical, Genzyme-Sanofi, QuintilesIMS Health, Novartis and Intekrin-Coherus.
Abstract: P1038
Type: Poster
Abstract Category: Pathology and pathogenesis of MS - 21 Imaging
Background: Diffusion tensor imaging (DTI) of the white matter (WM) tracts within the thalamus has yielded insight into disease processes associated with multiple sclerosis (MS). Recent studies have also demonstrated that quantitative susceptibility mapping (QSM) provides a novel means to investigate thalamic pathology in MS. Considered as a single region, decreased thalamic susceptibility has been reported in MS. However, it is not known to what degree QSM provides additional information regarding intra-thalamic WM beyond that already captured by DTI parameters.
Objective: To investigate the potential role of QSM in quantifying intra-thalamic MS-related pathology.
Methods: This was a cross-sectional 3 Tesla MRI study of 26 relapsing MS and 19 progressive MS patients. Seventeen (17) age- and sex-matched healthy individuals (HIs) were also scanned. Tract-based spatial-statistics (TBSS), restricted to the bilateral thalami, was used to evaluate DTI-derived metrics of mean diffusivity (MD) and fractional anisotropy (FA). QSM maps were also generated and projected onto the TBSS skeleton. Univariate general linear models (GLM) were used to assess group differences in terms of FA, MD, and QSM. Next, multivariate, non-parametric combination (NPC) GLMs were used to perform joint inference on the skeletonised FA, MD and QSM images. Significant clusters were identified using threshold-free cluster enhancement. Permutation-based family-wise correction was employed, and results were considered significant at a corrected p value
of ≤ .05.
Results: As a proportion of the total skeleton volume, univariate models revealed increased MD in 39.2% (peak p=.009), decreased FA in 27.5% (peak p=.005), and decreased susceptibility in 17.6% (peak p=.002) of the voxels in MS patients. With respect to MD alone, the joint inference including FA yielded only a marginally greater proportion of voxels (45.3%, peak p=.003). For the MD and QSM model, however, the joint inference identified 63.0% (peak p=.001) of the thalamic skeleton as being affected in MS patients. The model including FA in addition to MD and QSM yielded similar results as MD and QSM only (60.5%, peak p=.001).
Conclusions: QSM of the intra-thalamic WM provides additional discriminatory power between HIs and MS patients. The biological meaning of decreased WM susceptibility in MS patients remains to be elucidated.
Disclosure:
N Bergsland has nothing to disclose.
F Schweser has nothing to disclose.
MG Dwyer has received consultant fees from Claret Medical and EMD Serono and research grant support from Novartis.
B Weinstock-Guttman received honoraria as a speaker and as a consultant for Biogen Idec, Teva Pharmaceuticals, EMD Serono, Genzyme, Sanofi, Novartis and Acorda. Dr Weinstock-Guttman received research funds from Biogen Idec, Teva Pharmaceuticals, EMD Serono,Genzyme, Sanofi, Novartis, Acorda.
R Zivadinov received personal compensation from EMD Serono, Genzyme-Sanofi, Novartis, Claret-Medical, Celgene for speaking and consultant fees. He received financial support for research activities from Claret Medical, Genzyme-Sanofi, QuintilesIMS Health, Novartis and Intekrin-Coherus.