Intra-voxel and inter-voxel coherence in patients with multiple sclerosis assessed using diffusion tensor MRI
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Updated: Sep 30, 2026
Magnetic Resonance Imaging of Multiple Sclerosis at 7.0 Tesla
Published on: February 19, 2021
M Cercignani1, M Bozzali, G Iannucci
1Neuroimaging Research Unit, Dept. of Neuroscience, Scientific Institute and University, Ospedale San Raffaele, via Olgettina 60, 20132 Milan, Italy.
Abstract:
Previous diffusion tensor magnetic resonance imaging (DT-MRI) studies reported mean diffusivity () and fractional anisotropy (FA) changes in lesions and normal-appearing white matter (NAWM) of patients with multiple sclerosis (MS), but neglected the additional information which can be obtained by the analysis of the inter-voxel coherence (C). The present study is based on a large sample of patients with MS and it is aimed at assessing the potential role of C in the quantification of MS-related tissue damage of T2-visible lesions and NAWM. We obtained dual-echo, T1-weighted and DT-MRI scans from 78 patients with relapsing-remitting (RR), secondary progressive (SP), or primary progressive (PP) MS and from 26 healthy volunteers. We calculated, FA and C of T2-hyperintense lesions, T1-isointense lesions, T1-hypointense lesions and several areas of the NAWM. and FA of the majority of NAWM regions studied from MS patients were different from the corresponding quantities of the white matter from controls. NAWM C from patients was lower than white matter C from controls only for the parietal pericallosal areas. SPMS patients had higher corpus callosum and lower corpus callosum FA and C than patients with either RRMS or PPMS. Average lesion was higher, and average FA and C lower than the corresponding quantities measured in the NAWM. Average T1-hypointense lesion was higher and average FA lower than the corresponding quantities of T1-isointense lesions, whereas average C of these two lesion populations were not different. SPMS had higher average lesion than both PPMS and RRMS patients. NAWM and C of the corpus callosum were moderately correlated with disability. This study confirms the role of DT-MRI metrics to identify MS lesions with different amounts of tissue damage and to detect diffuse changes in the NAWM. It also shows that measuring C enables us to obtain additional information about tissue damage, which is complementary to that given by the analysis of and FA.
Insights
Inter-voxel coherence (C) analysis in diffusion tensor imaging (DT-MRI) reveals additional information on multiple sclerosis (MS) tissue damage. This DT-MRI metric complements mean diffusivity and fractional anisotropy in quantifying MS-related changes.
Area of Science:
- Neuroimaging
- Biomedical Engineering
- Radiology
Background:
- Previous diffusion tensor magnetic resonance imaging (DT-MRI) studies in multiple sclerosis (MS) primarily focused on mean diffusivity (MD) and fractional anisotropy (FA).
- These studies often overlooked the potential diagnostic value of inter-voxel coherence (C) in assessing MS-related tissue damage.
- Understanding diffuse changes in normal-appearing white matter (NAWM) and characterizing lesion heterogeneity remain critical challenges in MS research.
Purpose of the Study:
- To evaluate the role of inter-voxel coherence (C) in quantifying tissue damage in T2-visible lesions and normal-appearing white matter (NAWM) in patients with MS.
- To compare DT-MRI metrics (MD, FA, and C) across different MS subtypes (relapsing-remitting, secondary progressive, primary progressive) and healthy controls.
- To investigate the correlation between DT-MRI metrics, particularly C, and clinical disability in MS patients.
Main Methods:
- Acquisition of dual-echo, T1-weighted, and DT-MRI scans from 78 MS patients and 26 healthy volunteers.
- Calculation of mean diffusivity (MD), fractional anisotropy (FA), and inter-voxel coherence (C) for various lesion types (T2-hyperintense, T1-isointense, T1-hypointense) and NAWM regions.
- Statistical comparison of DT-MRI metrics between MS patient groups, lesion types, and controls, and correlation analysis with disability scores.
Main Results:
- Significant differences in MD and FA were observed in most NAWM regions between MS patients and controls.
- Lower NAWM C was found in MS patients compared to controls only in parietal pericallosal areas.
- Secondary progressive MS (SPMS) patients exhibited distinct corpus callosum MD, FA, and C compared to RRMS and PPMS patients; SPMS also showed higher average lesion load.
Conclusions:
- DT-MRI metrics, including MD and FA, effectively identify MS lesions and detect diffuse changes in NAWM.
- Inter-voxel coherence (C) provides complementary information to MD and FA, enhancing the quantification of MS-related tissue damage.
- C analysis holds potential for improved characterization of MS pathology and its correlation with clinical disability.
